自定义view的流程分为measure、 layout、draw三个主要步骤，今天我们通过源码来分下下measure的过程
我们从*view开始，*view即DecorView， view的事件都是先经过这个DecorView, 接下来我们来看看这个DecorView的MeasureSpec的创建过程：
ViewRoot 对应 ViewRootImpl类， 是连接WindowManager 和 DecorView的纽带， 进入ViewRootImpl中，查看measureHierarchy方法，有如下代码：
final DisplayMetrics packageMetrics = res.getDisplayMetrics();
res.getValue(com.android.internal.R.dimen.config_prefDialogWidth, mTmpValue, true);
int baseSize = 0;
if (mTmpValue.type == TypedValue.TYPE_DIMENSION) {
baseSize = (int)mTmpValue.getDimension(packageMetrics);
}
if (DEBUG_DIALOG) Log.v(mTag, "Window " + mView + ": baseSize=" + baseSize
+ ", desiredWindowWidth=" + desiredWindowWidth);
if (baseSize != 0 && desiredWindowWidth > baseSize) {
childWidthMeasureSpec = getRootMeasureSpec(baseSize, lp.width);
childHeightMeasureSpec = getRootMeasureSpec(desiredWindowHeight, lp.height);
performMeasure(childWidthMeasureSpec, childHeightMeasureSpec);
这里只是截选一部分的源码， 我们看到这个baseSize， 其实就是屏幕的尺寸大小， 获取宽的MeasureSpc的方法：
childWidthMeasureSpec = getRootMeasureSpec(baseSize, lp.width);
这里传入的参数是屏幕尺寸以及DecorView自身的大小， 接着我们来看 getRootMeasureSpec方法：
private static int getRootMeasureSpec(int windowSize, int rootDimension) {
int measureSpec;
switch (rootDimension) {
case ViewGroup.LayoutParams.MATCH_PARENT:
// Window can't resize. Force root view to be windowSize.
measureSpec = MeasureSpec.makeMeasureSpec(windowSize, MeasureSpec.EXACTLY);
break;
case ViewGroup.LayoutParams.WRAP_CONTENT:
// Window can resize. Set max size for root view.
measureSpec = MeasureSpec.makeMeasureSpec(windowSize, MeasureSpec.AT_MOST);
break;
default:
// Window wants to be an exact size. Force root view to be that size.
measureSpec = MeasureSpec.makeMeasureSpec(rootDimension, MeasureSpec.EXACTLY);
break;
}
return measureSpec;
}
就是这个方法确定了DecorView的MeasureSpec， 这里分了三种情况，
1.如果传入的view大小为math_parent，那么这个view的mode为EXACTLY， 大小为屏幕的尺寸.
2.如果传入的view大小为wrap_content，那么这个view的mode为AT_MOST,大小为屏幕的尺寸.
3.如果传入的view大小为一个具体的值，那么这个view的mode为EXACTLY，大小为view本身大小。
以上就是DecorView的MeaureSpec的整个创建的过程了。
看了*view之后我们来看普通的view， 普通的view的measure过程是由viewgroup传递过来的，接着我们来看看viewgroup的measureChildWithMargins方法：
protected void measureChildWithMargins(View child,
int parentWidthMeasureSpec, int widthUsed,
int parentHeightMeasureSpec, int heightUsed) {
final MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();
final int childWidthMeasureSpec = getChildMeasureSpec(parentWidthMeasureSpec,
mPaddingLeft + mPaddingRight + lp.leftMargin + lp.rightMargin
+ widthUsed, lp.width);
final int childHeightMeasureSpec = getChildMeasureSpec(parentHeightMeasureSpec,
mPaddingTop + mPaddingBottom + lp.topMargin + lp.bottomMargin
+ heightUsed, lp.height);
child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
}
这个方法获得了子view的MeasureSpec，并且将其传入子view的measure方法中， 这里重点来看下viewgroup是如何创建子view的MeasuerSpec的。来看getChildMeasureSpec方法内部的实现：
public static int getChildMeasureSpec(int spec, int padding, int childDimension) {
int specMode = MeasureSpec.getMode(spec);
int specSize = MeasureSpec.getSize(spec);
int size = Math.max(0, specSize - padding);
int resultSize = 0;
int resultMode = 0;
switch (specMode) {
// Parent has imposed an exact size on us
case MeasureSpec.EXACTLY:
if (childDimension >= 0) {
resultSize = childDimension;
resultMode = MeasureSpec.EXACTLY;
} else if (childDimension == LayoutParams.MATCH_PARENT) {
// Child wants to be our size. So be it.
resultSize = size;
resultMode = MeasureSpec.EXACTLY;
} else if (childDimension == LayoutParams.WRAP_CONTENT) {
// Child wants to determine its own size. It can't be
// bigger than us.
resultSize = size;
resultMode = MeasureSpec.AT_MOST;
}
break;
// Parent has imposed a maximum size on us
case MeasureSpec.AT_MOST:
if (childDimension >= 0) {
// Child wants a specific size... so be it
resultSize = childDimension;
resultMode = MeasureSpec.EXACTLY;
} else if (childDimension == LayoutParams.MATCH_PARENT) {
// Child wants to be our size, but our size is not fixed.
// Constrain child to not be bigger than us.
resultSize = size;
resultMode = MeasureSpec.AT_MOST;
} else if (childDimension == LayoutParams.WRAP_CONTENT) {
// Child wants to determine its own size. It can't be
// bigger than us.
resultSize = size;
resultMode = MeasureSpec.AT_MOST;
}
break;
// Parent asked to see how big we want to be
case MeasureSpec.UNSPECIFIED:
if (childDimension >= 0) {
// Child wants a specific size... let him have it
resultSize = childDimension;
resultMode = MeasureSpec.EXACTLY;
} else if (childDimension == LayoutParams.MATCH_PARENT) {
// Child wants to be our size... find out how big it should
// be
resultSize = View.sUseZeroUnspecifiedMeasureSpec ? 0 : size;
resultMode = MeasureSpec.UNSPECIFIED;
} else if (childDimension == LayoutParams.WRAP_CONTENT) {
// Child wants to determine its own size.... find out how
// big it should be
resultSize = View.sUseZeroUnspecifiedMeasureSpec ? 0 : size;
resultMode = MeasureSpec.UNSPECIFIED;
}
break;
}
//noinspection ResourceType
return MeasureSpec.makeMeasureSpec(resultSize, resultMode);
}
这个方法很长，但是我们只需要注意到AT_MOST跟EXACTLY这两种情况就行，稍微分析下这个过程：
首先要理解这个方法的三个参数， 第一个是父view的MeasureSpec, 第二个是父view已占用的大小，第三个是view的LayoutParams的大小，如果不理解可以看看ViewGroup的MeasureChildWithMargins方法中的调用：
final int childWidthMeasureSpec = getChildMeasureSpec(parentWidthMeasureSpec,
mPaddingLeft + mPaddingRight + lp.leftMargin + lp.rightMargin
+ widthUsed, lp.width);
第二个参数很长 ， mPaddingLeft + mPaddingRight + lp.leftMargin + lp.rightMargin + withUsed ，这些所有的值都有一个共同特点，就是这些位置是不能摆放任何view的，即父view已经占用的地盘，现在是不是对参数更加理解了呢。
接着我们回到getChildMeasureSpec方法中继续看看viewGroup到底是怎么创建view的MeasureSpec的。
第一步： 根据参数一，即传入的父view的MeasureSpec获得父view的Mode和Size。这里的第三行代码：
int size = Math.max(0, specSize - padding);
这个size表示取0与父容器中可占用的位置的最大值，可以直接理解为父view的大小。
第二步：根据父view的Mode分情况处理， 到这一步我们应该就清楚为什么说view的大小是由父view的MeasureSpec与本身LayoutParmas大小共同决定的吧。
这里我们依然只看AT_MOST跟EXACTLY两种情况，
switch (specMode) {
// Parent has imposed an exact size on us
case MeasureSpec.EXACTLY:
if (childDimension >= 0) {
resultSize = childDimension;
resultMode = MeasureSpec.EXACTLY;
} else if (childDimension == LayoutParams.MATCH_PARENT) {
// Child wants to be our size. So be it.
resultSize = size;
resultMode = MeasureSpec.EXACTLY;
} else if (childDimension == LayoutParams.WRAP_CONTENT) {
// Child wants to determine its own size. It can't be
// bigger than us.
resultSize = size;
resultMode = MeasureSpec.AT_MOST;
}
break;
// Parent has imposed a maximum size on us
case MeasureSpec.AT_MOST:
if (childDimension >= 0) {
// Child wants a specific size... so be it
resultSize = childDimension;
resultMode = MeasureSpec.EXACTLY;
} else if (childDimension == LayoutParams.MATCH_PARENT) {
// Child wants to be our size, but our size is not fixed.
// Constrain child to not be bigger than us.
resultSize = size;
resultMode = MeasureSpec.AT_MOST;
} else if (childDimension == LayoutParams.WRAP_CONTENT) {
// Child wants to determine its own size. It can't be
// bigger than us.
resultSize = size;
resultMode = MeasureSpec.AT_MOST;
}
break;
这里有个比较难以理解的值就是childDimension > 0 ， 这个其实就表示view的大小是一个具体的值比如100dp , 因为view的match_parent和 wrap_content在系统内部定义的都是负数，一个是-1. 一个是-2 ，所以判断childDimension > 0即，view的大小为一个具体的值。
接着就比较好理解了， 我们来稍微总结下：
无论父view是match_parent还是 wrap_content ，只要view是一个具体的值，view的Mode永远都是EXACTLY, 大小均是view本身定义的大小。
父view模式如果是EXACTLY, ---> 子view如果是mathch_parent ，那么子view的大小是父view的大小，模式也跟父view一样为EXACTLY. 子view如果是wrap_content， 大小还是父view的大小， 模式为AT_MOST
父view模式如果是AT_MOST , --- > 子view如果是math_parent， 那么子view大小为父view大小， 模式与父view一样都是AT_MOST, 子view如果是wrap_content， 子view大小为父view大小， 模式为AT_MOST
上面说的有点绕，但其实我们只需要记住一点， 无论上面那种情况，子view在wrap_content下，大小都是父view的大小， 到这里我们是不是就能理解为什么在自定义view的过程中如果不重写onMeasure， wrap_content是和match_parent是一个效果了吧。
以上过程是viewGroup中创建子view的MeasureSpec的过程， 有了这个MeasureSpec，测量子view大小就很简单了，我们可以看到在ViewGroup获取到子view的MeasureSpec之后，传入到子view的measure方法中：
child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
进入到view的measure方法,
不知不觉我们已经从viewgroup进入到了view的测量过程，
这里是不是突然意识到，ViewGroup根本没有测绘自己本身啊， 只是获取到子view的MeasureSpec然后传入子view的measure方法里去，这是因为ViewGroup是个抽象类，本身并没有定义测量的过程， ViewGroup的onMeasure需要各个子类去实现，比如LinearLayout 、 RelativeLayout等等，并且每个子类的测量过程都不一样，这个我们后面会讲， 现在我们还是接着看view的Measure过程。
上面说到viewgroup将创建的子view的MeasureSpec传入到了view的Measure方法中， 那么我们就来看看View的Measure方法：
public final void measure(int widthMeasureSpec, int heightMeasureSpec) {
boolean optical = isLayoutModeOptical(this);
if (optical != isLayoutModeOptical(mParent)) {
Insets insets = getOpticalInsets();
int oWidth = insets.left + insets.right;
int oHeight = insets.top + insets.bottom;
widthMeasureSpec = MeasureSpec.adjust(widthMeasureSpec, optical ? -oWidth : oWidth);
heightMeasureSpec = MeasureSpec.adjust(heightMeasureSpec, optical ? -oHeight : oHeight);
}
// Suppress sign extension for the low bytes
long key = (long) widthMeasureSpec << 32 | (long) heightMeasureSpec & 0xffffffffL;
if (mMeasureCache == null) mMeasureCache = new LongSparseLongArray(2);
final boolean forceLayout = (mPrivateFlags & PFLAG_FORCE_LAYOUT) == PFLAG_FORCE_LAYOUT;
// Optimize layout by avoiding an extra EXACTLY pass when the view is
// already measured as the correct size. In API 23 and below, this
// extra pass is required to make LinearLayout re-distribute weight.
final boolean specChanged = widthMeasureSpec != mOldWidthMeasureSpec
|| heightMeasureSpec != mOldHeightMeasureSpec;
final boolean isSpecExactly = MeasureSpec.getMode(widthMeasureSpec) == MeasureSpec.EXACTLY && MeasureSpec.getMode(heightMeasureSpec) == MeasureSpec.EXACTLY;
final boolean matchesSpecSize = getMeasuredWidth() == MeasureSpec.getSize(widthMeasureSpec)
&& getMeasuredHeight() == MeasureSpec.getSize(heightMeasureSpec);
final boolean needsLayout = specChanged
&& (sAlwaysRemeasureExactly || !isSpecExactly || !matchesSpecSize);
if (forceLayout || needsLayout) {
// first clears the measured dimension flag
mPrivateFlags &= ~PFLAG_MEASURED_DIMENSION_SET;
resolveRtlPropertiesIfNeeded();
int cacheIndex = forceLayout ? -1 : mMeasureCache.indexOfKey(key);
if (cacheIndex < 0 || sIgnoreMeasureCache) {
// measure ourselves, this should set the measured dimension flag back
onMeasure(widthMeasureSpec, heightMeasureSpec);
mPrivateFlags3 &= ~PFLAG3_MEASURE_NEEDED_BEFORE_LAYOUT;
} else {
long value = mMeasureCache.valueAt(cacheIndex);
// Casting a long to int drops the high 32 bits, no mask needed
setMeasuredDimensionRaw((int) (value >> 32), (int) value);
mPrivateFlags3 |= PFLAG3_MEASURE_NEEDED_BEFORE_LAYOUT;
}
// flag not set, setMeasuredDimension() was not invoked, we raise
// an exception to warn the developer
if ((mPrivateFlags & PFLAG_MEASURED_DIMENSION_SET) != PFLAG_MEASURED_DIMENSION_SET) {
throw new IllegalStateException("View with id " + getId() + ": "
+ getClass().getName() + "#onMeasure() did not set the"
+ " measured dimension by calling"
+ " setMeasuredDimension()");
}
mPrivateFlags |= PFLAG_LAYOUT_REQUIRED;
}
mOldWidthMeasureSpec = widthMeasureSpec;
mOldHeightMeasureSpec = heightMeasureSpec;
mMeasureCache.put(key, ((long) mMeasuredWidth) << 32 |
(long) mMeasuredHeight & 0xffffffffL); // suppress sign extension
}
这个方法真是又臭又长。。。讲道理的话其实我也看不懂， 但是我们只需要注意到一点， 就是这个方法调用了OnMeasure方法！
也就是说measure --> OnMeasure
OnMeasure就简单了 ：
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
setMeasuredDimension(getDefaultSize(getSuggestedMinimumWidth(), widthMeasureSpec),
getDefaultSize(getSuggestedMinimumHeight(), heightMeasureSpec));
}
很简洁对不，但是简洁并不代表简单， 这里套了好几层。。。 不要被迷惑 ， 我们看最外层其实就是setMeasureDimension().
设置宽和高， 这个宽和高是在 getDefaultSize方法里返回的， 所以我们来看看getDefaultSize的具体代码：
public static int getDefaultSize(int size, int measureSpec) {
int result = size;
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);
switch (specMode) {
case MeasureSpec.UNSPECIFIED:
result = size;
break;
case MeasureSpec.AT_MOST:
case MeasureSpec.EXACTLY:
result = specSize;
break;
}
return result;
}
如果我们忽略掉UNSPECIFIED情况的话， 我们会发现第一个参数size根本用不到。。。
也就是说view的大小其实就是父view给他创建的MeasureSpec中的size大小。
这也进一步说明，view在wrap_content情况下 ，大小还是会跟父view大小一样， 所以我们需要在自定义view的时候重写OnMeasure。
//为了支持wrap_content， 一般的实现方法如下：
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec , heightMeasureSpec);
int widthSpecMode = MeasureSpec.getMode(widthMeasureSpec);
int widthSpceSize = MeasureSpec.getSize(widthMeasureSpec);
int heightSpecMode=MeasureSpec.getMode(heightMeasureSpec);
int heightSpceSize=MeasureSpec.getSize(heightMeasureSpec);
if(widthSpecMode==MeasureSpec.AT_MOST && heightSpecMode==MeasureSpec.AT_MOST){
setMeasuredDimension(mWidth, mHeight);
}else if(widthSpecMode == MeasureSpec.AT_MOST){
setMeasuredDimension(mWidth, heightSpceSize);
}else if(heightSpecMode == MeasureSpec.AT_MOST){
setMeasuredDimension(widthSpceSize, mHeight);
}
}
Layout:
直接看view的layout源码：
public void layout(int l, int t, int r, int b) {
if ((mPrivateFlags3 & PFLAG3_MEASURE_NEEDED_BEFORE_LAYOUT) != 0) {
onMeasure(mOldWidthMeasureSpec, mOldHeightMeasureSpec);
mPrivateFlags3 &= ~PFLAG3_MEASURE_NEEDED_BEFORE_LAYOUT;
}
int oldL = mLeft;
int oldT = mTop;
int oldB = mBottom;
int oldR = mRight;
boolean changed = isLayoutModeOptical(mParent) ?
setOpticalFrame(l, t, r, b) : setFrame(l, t, r, b);
if (changed || (mPrivateFlags & PFLAG_LAYOUT_REQUIRED) == PFLAG_LAYOUT_REQUIRED) {
onLayout(changed, l, t, r, b);
mPrivateFlags &= ~PFLAG_LAYOUT_REQUIRED;
ListenerInfo li = mListenerInfo;
if (li != null && li.mOnLayoutChangeListeners != null) {
ArrayList<OnLayoutChangeListener> listenersCopy =
(ArrayList<OnLayoutChangeListener>)li.mOnLayoutChangeListeners.clone();
int numListeners = listenersCopy.size();
for (int i = 0; i < numListeners; ++i) {
listenersCopy.get(i).onLayoutChange(this, l, t, r, b, oldL, oldT, oldR, oldB);
}
}
}
mPrivateFlags &= ~PFLAG_FORCE_LAYOUT;
mPrivateFlags3 |= PFLAG3_IS_LAID_OUT;
}
这里挑重点来看
boolean changed = isLayoutModeOptical(mParent) ?
setOpticalFrame(l, t, r, b) : setFrame(l, t, r, b);
private boolean setOpticalFrame(int left, int top, int right, int bottom) {
Insets parentInsets = mParent instanceof View ?
((View) mParent).getOpticalInsets() : Insets.NONE;
Insets childInsets = getOpticalInsets();
return setFrame(
left + parentInsets.left - childInsets.left,
top + parentInsets.top - childInsets.top,
right + parentInsets.left + childInsets.right,
bottom + parentInsets.top + childInsets.bottom);
}
点进setOpticalFrame我们发现最终也是调用的setFrame方法， 所以我们直接来看这个方法：
protected boolean setFrame(int left, int top, int right, int bottom) {
boolean changed = false;
if (DBG) {
Log.d("View", this + " View.setFrame(" + left + "," + top + ","
+ right + "," + bottom + ")");
}
if (mLeft != left || mRight != right || mTop != top || mBottom != bottom) {
changed = true;
// Remember our drawn bit
int drawn = mPrivateFlags & PFLAG_DRAWN;
int oldWidth = mRight - mLeft;
int oldHeight = mBottom - mTop;
int newWidth = right - left;
int newHeight = bottom - top;
boolean sizeChanged = (newWidth != oldWidth) || (newHeight != oldHeight);
// Invalidate our old position
invalidate(sizeChanged);
mLeft = left;
mTop = top;
mRight = right;
mBottom = bottom;
mRenderNode.setLeftTopRightBottom(mLeft, mTop, mRight, mBottom);
mPrivateFlags |= PFLAG_HAS_BOUNDS;
if (sizeChanged) {
sizeChange(newWidth, newHeight, oldWidth, oldHeight);
}
if ((mViewFlags & VISIBILITY_MASK) == VISIBLE || mGhostView != null) {
// If we are visible, force the DRAWN bit to on so that
// this invalidate will go through (at least to our parent).
// This is because someone may have invalidated this view
// before this call to setFrame came in, thereby clearing
// the DRAWN bit.
mPrivateFlags |= PFLAG_DRAWN;
invalidate(sizeChanged);
// parent display list may need to be recreated based on a change in the bounds
// of any child
invalidateParentCaches();
}
// Reset drawn bit to original value (invalidate turns it off)
mPrivateFlags |= drawn;
mBackgroundSizeChanged = true;
if (mForegroundInfo != null) {
mForegroundInfo.mBoundsChanged = true;
}
notifySubtreeAccessibilityStateChangedIfNeeded();
}
return changed;
}
看到这句：
if (mLeft != left || mRight != right || mTop != top || mBottom != bottom) {
changed = true;
在该方法中把l，t， r， b分别与之前的mLeft，mTop，mRight，mBottom一一作比较，假若其中任意一个值发生了变化，那么就判定该View的位置发生了变化
if (changed || (mPrivateFlags & PFLAG_LAYOUT_REQUIRED) == PFLAG_LAYOUT_REQUIRED) {
onLayout(changed, l, t, r, b);
若发生变化则会调用onLayout方法。
接着我们来看View的onLayout方法：
/** * Called from layout when this view should * assign a size and position to each of its children. * * Derived classes with children should override * this method and call layout on each of * their children. * @param changed This is a new size or position for this view * @param left Left position, relative to parent * @param top Top position, relative to parent * @param right Right position, relative to parent * @param bottom Bottom position, relative to parent */protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
}
居然是空的！
查看注释我们发现View的onLayout是确定子view的位置的，所以我们直接来看viewGroup的onLayout方法：
@Override
protected abstract void onLayout(boolean changed,
int l, int t, int r, int b);
居然是个抽象方法！
到这里我们发现view和viewGroup都没有真正实现onLayout方法。
既然ViewGroup中的方法是抽象方法，那么子类就一定会重写这个方法， 我们来看LinearLayout：
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
if (mOrientation == VERTICAL) {
layoutVertical(l, t, r, b);
} else {
layoutHorizontal(l, t, r, b);
}
}
果然重写了，并且分为水平跟垂直的两种情况
随便挑一个来看看
void layoutVertical(int left, int top, int right, int bottom) {
final int paddingLeft = mPaddingLeft;
int childTop;
int childLeft;
// Where right end of child should go
final int width = right - left;
int childRight = width - mPaddingRight;
// Space available for child
int childSpace = width - paddingLeft - mPaddingRight;
final int count = getVirtualChildCount();
final int majorGravity = mGravity & Gravity.VERTICAL_GRAVITY_MASK;
final int minorGravity = mGravity & Gravity.RELATIVE_HORIZONTAL_GRAVITY_MASK;
switch (majorGravity) {
case Gravity.BOTTOM:
// mTotalLength contains the padding already
childTop = mPaddingTop + bottom - top - mTotalLength;
break;
// mTotalLength contains the padding already
case Gravity.CENTER_VERTICAL:
childTop = mPaddingTop + (bottom - top - mTotalLength) / 2;
break;
case Gravity.TOP:
default:
childTop = mPaddingTop;
break;
}
for (int i = 0; i < count; i++) {
final View child = getVirtualChildAt(i);
if (child == null) {
childTop += measureNullChild(i);
} else if (child.getVisibility() != GONE) {
final int childWidth = child.getMeasuredWidth();
final int childHeight = child.getMeasuredHeight();
final LinearLayout.LayoutParams lp =
(LinearLayout.LayoutParams) child.getLayoutParams();
int gravity = lp.gravity;
if (gravity < 0) {
gravity = minorGravity;
}
final int layoutDirection = getLayoutDirection();
final int absoluteGravity = Gravity.getAbsoluteGravity(gravity, layoutDirection);
switch (absoluteGravity & Gravity.HORIZONTAL_GRAVITY_MASK) {
case Gravity.CENTER_HORIZONTAL:
childLeft = paddingLeft + ((childSpace - childWidth) / 2)
+ lp.leftMargin - lp.rightMargin;
break;
case Gravity.RIGHT:
childLeft = childRight - childWidth - lp.rightMargin;
break;
case Gravity.LEFT:
default:
childLeft = paddingLeft + lp.leftMargin;
break;
}
if (hasDividerBeforeChildAt(i)) {
childTop += mDividerHeight;
}
childTop += lp.topMargin;
setChildFrame(child, childLeft, childTop + getLocationOffset(child),
childWidth, childHeight);
childTop += childHeight + lp.bottomMargin + getNextLocationOffset(child);
i += getChildrenSkipCount(child, i);
}
}
}
这里简单的分析下layoutVertical的逻辑， 首先遍历所有子元素并调用setChildFrame方法为子元素指定对应的位置，其中childTop在不断的增大，这就意味着越后面的子元素位置就越靠下，刚好符合垂直linearLayout的特性。
Draw:
平时用的最多的就是canvas里的各种绘图api, 以及一些关于画布的操作
canvas.save和canvas.restore
网上有一种说法叫： save跟restore一般都是成对出现，但是restore不能比save多，否则会抛异常。 但是我在测试的时候发现restore即使比save多也没有出现异常。
rotate(float degrees)
画布旋转， 值为正顺时针， 负逆时针。
Canvas的图层概念：
for(int=0;<5;++){
canvas.drawCircle(50,50,50,);
canvas.translate(100,100);}
如图画布的坐标原点每次分别在x轴、y轴上移动100 ， 那么假如我们要重新回到（0 ，0）点处绘制新的图形呢， 不会要translate( -100 ,-100) 慢慢的平移过去吧，
我们在平移之前可以将当前的canvas状态进行保存， canvas为我们提供了图层的支持， 而这些图层是按栈结构来进行管理的， 当我们调用save()方法，会保存当前Canvas的状态后最为一个Layer(图层) ， 添加到Canvas栈中， 另外这个Layer不是一个具体的类， 就是一个概念性的东西而已， 而当我们调用restore（）方法的时候， 会恢复之前canvas的状态，而此时Canvas的图层栈会弹出栈顶那个layer
PorterDuffXfermode
public Bitmap getRoundCornerBitmap(Bitmap bitmap, float pixels) {
//生成Canvas ， 给canvas设置的Bitmap的大小是和原图的大小一致
int width=bitmap.getWidth();
int height=bitmap.getHeight();
Bitmap roundCornerBitmap = Bitmap.createBitmap(width,height,Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(roundCornerBitmap);
//绘制圆角矩形
Paint paint = new Paint();
paint.setColor(Color.BLACK);
paint.setAntiAlias(true);
Rect rect = new Rect(0, 0, width, height);
RectF rectF = new RectF(rect);
canvas.drawRoundRect(rectF, pixels, pixels, paint);
//为paint设置PorterDuffXfermode
PorterDuffXfermode xfermode=new PorterDuffXfermode(PorterDuff.Mode.SRC_IN);
paint.setXfermode(xfermode);
//绘制原图
canvas.drawBitmap(bitmap, rect, rect, paint);
return roundCornerBitmap;
}
Bitmap和Matrix
除了刚才提到的给图片设置圆角之外，在开发中还常有其他涉及到图片的操作，比如图片的旋转，缩放，平移等等，这些操作可以结合Matrix来实现。
在此举个例子，看看利用matrix实现图片的平移和缩放。
private void drawBitmapWithMatrix(Canvas canvas){
//画出原图
Paint paint = new Paint();
paint.setAntiAlias(true);
Bitmap bitmap = BitmapFactory.decodeResource(getResources(),R.drawable.mm); i
nt width=bitmap.getWidth();
int height=bitmap.getHeight();
Matrix matrix = new Matrix();
canvas.drawBitmap(bitmap, matrix, paint);
//平移原图
matrix.setTranslate(width/2, height);
canvas.drawBitmap(bitmap, matrix, paint);
//缩放原图
matrix.postScale(0.5f, 0.5f);
canvas.drawBitmap(bitmap, matrix, paint); }
利用Matrix对图形操作是跟坐标系无关的 ，操作的是每个像素点，比如平移缩放每个像素点
matrix.postScale(0.5f, 0.5f);
如上代码，表示对每个像素点缩放到原来的一半大小
在使用Matrix时经常用到一系列的set，pre，post方法
• pre表示在队头插入一个方法
• post表示在队尾插入一个方法
• set表示清空队列
队列中只保留该set方法，其余的方法都会清除。
下面请看几个小示例：
1.
Matrix m = new Matrix();
m.setRotate(45);
m.setTranslate(80, 80);
只有m.setTranslate(80, 80)有效，因为m.setRotate(45)被清除.
2.
Matrix m = new Matrix();
m.setTranslate(80, 80);
m.postRotate(45);
先执行m.setTranslate(80, 80)后执行m.postRotate(45)
3.
Matrix m = new Matrix();
m.setTranslate(80, 80);
m.preRotate(45);
先执行m.preRotate(45)后执行m.setTranslate(80, 80)
4.
Matrix m = new Matrix();
m.preScale(2f,2f);
m.preTranslate(50f, 20f);
m.postScale(0.2f, 0.5f);
m.postTranslate(20f, 20f);
执行顺序：
m.preTranslate(50f, 20f)–>m.preScale(2f,2f)–>m.postScale(0.2f, 0.5f)–>m.postTranslate(20f, 20f)
5.
Matrix m = new Matrix();
m.postTranslate(20, 20);
m.preScale(0.2f, 0.5f);
m.setScale(0.8f, 0.8f);
m.postScale(3f, 3f);
m.preTranslate(0.5f, 0.5f);
执行顺序：
m.preTranslate(0.5f, 0.5f)–>m.setScale(0.8f, 0.8f)–>m.postScale(3f, 3f)
Demo1:
/**
* Created by Administrator on 2016/12/17.
*
* 仿支付宝芝麻信用圆形仪表盘
*/
public class ERoundIndicatorView extends View {
private Paint paint;
private Paint paint_2;
private Paint paint_3;
private Paint paint_4;
private Context context;
private int maxNum;
private int startAngle;
private int sweepAngle;
private int radius;
private int mWidth;
private int mHeight;
private int sweepInWidth;//内圆的宽度
private int sweepOutWidth;//外圆的宽度
private int currentNum=0;//需设置setter、getter 供属性动画使用
private String[] text ={"较差","中等","良好","优秀","极好"};
private int[] indicatorColor = {0xffffffff,0x00ffffff,0x99ffffff,0xffffffff};
public int getCurrentNum() {
return currentNum;
}
public void setCurrentNum(int currentNum) {
this.currentNum = currentNum;
invalidate();
}
public ERoundIndicatorView(Context context) {
this(context,null);
}
public ERoundIndicatorView(Context context, AttributeSet attrs) {
this(context, attrs,0);
}
public ERoundIndicatorView(final Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
this.context = context;
setBackgroundColor(0xFFFF6347);
initAttr(attrs);
initPaint();
}
public void setCurrentNumAnim(int num) {
float duration = (float)Math.abs(num-currentNum)/maxNum *1500+500; //根据进度差计算动画时间
ObjectAnimator anim = ObjectAnimator.ofInt(this,"currentNum",num);
anim.setDuration((long) Math.min(duration,2000));
anim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
int value = (int) animation.getAnimatedValue();
int color = calculateColor(value);
setBackgroundColor(color);
}
});
anim.start();
}
private int calculateColor(int value){
ArgbEvaluator evealuator = new ArgbEvaluator();
float fraction = 0;
int color = 0;
if(value <= maxNum/2){
fraction = (float)value/(maxNum/2);
color = (int) evealuator.evaluate(fraction,0xFFFF6347,0xFFFF8C00); //由红到橙
}else {
fraction = ( (float)value-maxNum/2 ) / (maxNum/2);
color = (int) evealuator.evaluate(fraction,0xFFFF8C00,0xFF00CED1); //由橙到蓝
}
return color;
}
private void initPaint() {
paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setDither(true);
paint.setStyle(Paint.Style.STROKE);
paint.setColor(0xffffffff);
paint_2 = new Paint(Paint.ANTI_ALIAS_FLAG);
paint_3 = new Paint(Paint.ANTI_ALIAS_FLAG);
paint_4 = new Paint(Paint.ANTI_ALIAS_FLAG);
}
private void initAttr(AttributeSet attrs) {
TypedArray array = context.obtainStyledAttributes(attrs,R.styleable.RoundIndicatorView);
maxNum = array.getInt(R.styleable.RoundIndicatorView_maxNum,500);
startAngle = array.getInt(R.styleable.RoundIndicatorView_startAngle,160);
sweepAngle = array.getInt(R.styleable.RoundIndicatorView_sweepAngle,220);
//内外圆的宽度
sweepInWidth = dp2px(8);
sweepOutWidth = dp2px(3);
array.recycle();
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
int wSize = MeasureSpec.getSize(widthMeasureSpec);
int wMode = MeasureSpec.getMode(widthMeasureSpec);
int hSize = MeasureSpec.getSize(heightMeasureSpec);
int hMode = MeasureSpec.getMode(heightMeasureSpec);
if (wMode == MeasureSpec.EXACTLY ){
mWidth = wSize;
}else {
mWidth =dp2px(300);
}
if (hMode == MeasureSpec.EXACTLY ){
mHeight= hSize;
}else {
mHeight =dp2px(400);
}
setMeasuredDimension(mWidth,mHeight);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
radius = getMeasuredWidth()/4; //不要在构造方法里初始化，那时还没测量宽高
canvas.save();
canvas.translate(mWidth/2,(mWidth)/2);
drawRound(canvas); //画内外圆
drawScale(canvas);//画刻度
drawIndicator(canvas); //画当前进度值
drawCenterText(canvas);//画中间的文字
canvas.restore();
}
private void drawCenterText(Canvas canvas) {
canvas.save();
paint_4.setStyle(Paint.Style.FILL);
paint_4.setTextSize(radius/2);
paint_4.setColor(0xffffffff);
canvas.drawText(currentNum+"",-paint_4.measureText(currentNum+"")/2,0,paint_4);
paint_4.setTextSize(radius/4);
String content = "信用";
if(currentNum < maxNum*1/5){
content += text[0];
}else if(currentNum >= maxNum*1/5 && currentNum < maxNum*2/5){
content += text[1];
}else if(currentNum >= maxNum*2/5 && currentNum < maxNum*3/5){
content += text[2];
}else if(currentNum >= maxNum*3/5 && currentNum < maxNum*4/5){
content += text[3];
}else if(currentNum >= maxNum*4/5){
content += text[4];
}
Rect r = new Rect();
paint_4.getTextBounds(content,0,content.length(),r);
canvas.drawText(content,-r.width()/2,r.height()+20,paint_4);
canvas.restore();
}
private void drawIndicator(Canvas canvas) {
canvas.save();
paint_2.setStyle(Paint.Style.STROKE);
int sweep = 0;
if(currentNum<=maxNum){
sweep = (int)((float)currentNum/(float)maxNum*sweepAngle);
}else {
sweep = sweepAngle;
}
paint_2.setStrokeWidth(sweepOutWidth);
Shader shader =new SweepGradient(0,0,indicatorColor,null);
paint_2.setShader(shader);
int w = dp2px(10);
RectF rectf = new RectF(-radius-w , -radius-w , radius+w , radius+w);
canvas.drawArc(rectf,startAngle,sweep,false,paint_2);
float x = (float) ((radius+dp2px(10))*Math.cos(Math.toRadians(startAngle+sweep)));
float y = (float) ((radius+dp2px(10))*Math.sin(Math.toRadians(startAngle+sweep)));
Log.d("x ----> ", x + "");
Log.d("y ----> ", y + "");
paint_3.setStyle(Paint.Style.FILL);
paint_3.setColor(0xffffffff);
paint_3.setMaskFilter(new BlurMaskFilter(dp2px(3), BlurMaskFilter.Blur.SOLID)); //需关闭硬件加速
canvas.drawCircle(x,y,dp2px(3),paint_3);
canvas.restore();
}
private void drawScale(Canvas canvas)
canvas.save();
float angle = (float)sweepAngle/30;//刻度间隔
canvas.rotate(-270+startAngle); //将起始刻度点旋转到正上方（270) 画布旋转负角度表示逆时针
for (int i = 0; i <= 30; i++) {
if(i%6 == 0){ //画粗刻度和刻度值
paint.setStrokeWidth(dp2px(2));
paint.setAlpha(0x70);
canvas.drawLine(0, -radius-sweepInWidth/2,0, -radius+sweepInWidth/2+dp2px(1), paint);
drawText(canvas,i*maxNum/30+"",paint);
}else { //画细刻度
paint.setStrokeWidth(dp2px(1));
paint.setAlpha(0x50);
canvas.drawLine(0,-radius-sweepInWidth/2,0, -radius+sweepInWidth/2, paint);
}
if(i==3 || i==9 || i==15 || i==21 || i==27){ //画刻度区间文字
paint.setStrokeWidth(dp2px(2));
paint.setAlpha(0x50);
drawText(canvas,text[(i-3)/6], paint);
}
canvas.rotate(angle); //逆时针
}
canvas.restore();
}
private void drawText(Canvas canvas ,String text ,Paint paint)
paint.setStyle(Paint.Style.FILL);
paint.setTextSize(sp2px(8));
float width = paint.measureText(text); //相比getTextBounds来说，这个方法获得的类型是float，更精确些
// Rect rect = new Rect();
// paint.getTextBounds(text,0,text.length(),rect);
canvas.drawText(text,-width/2 , -radius + dp2px(15),paint);
paint.setStyle(Paint.Style.STROKE);
}
private void drawRound(Canvas canvas)
canvas.save();
//内圆
paint.setAlpha(0x40);
paint.setStrokeWidth(sweepInWidth);
RectF rectf = new RectF(-radius,-radius,radius,radius);
canvas.drawArc(rectf,startAngle,sweepAngle,false,paint);
//外圆
paint.setStrokeWidth(sweepOutWidth);
int w = dp2px(10);
RectF rectf2 = new RectF(-radius-w , -radius-w , radius+w , radius+w);
canvas.drawArc(rectf2,startAngle,sweepAngle,false,paint);
canvas.restore();
}
//一些工具方法
protected int dp2px(int dp){
return (int) TypedValue.applyDimension(
TypedValue.COMPLEX_UNIT_DIP,
dp,
getResources().getDisplayMetrics());
}
protected int sp2px(int sp){
return (int)TypedValue.applyDimension(
TypedValue.COMPLEX_UNIT_SP,
sp,
getResources().getDisplayMetrics());
}
public static DisplayMetrics getScreenMetrics(Context context) {
WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
DisplayMetrics dm = new DisplayMetrics();
wm.getDefaultDisplay().getMetrics(dm);
return dm;
}
}
/**
* Created by gao_feng on 2016/12/20 下午9:17.
*/
public class WaveView extends View {
private Path mPath;
private Paint mPaint;
private int vWidth , vHeight;//控件宽高
private float ctrx , ctry;//控制点的xy坐标
private float waveY;//整个Wave顶部两端的Y坐标
private boolean isInc; //判断控制点是右移还是左移
public WaveView(Context context) {
this(context , null);
}
public WaveView(Context context, AttributeSet attrs) {
this(context, attrs , 0);
}
public WaveView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
mPaint = new Paint(Paint.ANTI_ALIAS_FLAG | Paint.DITHER_FLAG);
mPaint.setColor(0xFFA2D6AE);
//实例化路径对象
mPath = new Path();
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
Log.d("a", "onMeasure");
}
@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
super.onLayout(changed, left, top, right, bottom);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
//获取控件宽、高
vWidth = w;
vHeight = h;
waveY = 1 / 8F * vHeight;
//计算端点Y坐标
ctry = -1 / 16F * vHeight;
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
mPath.moveTo(-1 / 4F * vWidth , waveY);//起始点
mPath.quadTo(ctrx , ctry , vWidth + 1/4F * vWidth , waveY);
mPath.lineTo(vWidth + 1/4F * vWidth, vHeight);
mPath.lineTo(-1 / 4f * vWidth, vHeight);
mPath.close();
canvas.drawPath(mPath, mPaint);
if (ctrx >= vWidth + 1/4F * vWidth) {
isInc = false;
} else if (ctrx <= -1 / 4F * vWidth) {
isInc = true;
}
ctrx = isInc ? ctrx + 20 : ctrx - 20;
if (ctry <= vHeight) {
ctry += 2;
waveY += 2;
}
mPath.reset();
invalidate();
}
}
继承系统自带的控件：
/** * @author admin * @date 2014-11-27 下午4:23:09 * @description 带删除的EditText */public class EditTextWithDelete extends EditText {
private Drawable imgEnable;
private Drawable imgEnableleft;
private Context context;
private boolean canDelete = true;
private Drawable moreEnable;
private IEditDeleteListener mListener;
private boolean isShowMore = false;
private int deleteSrc;
private int moreSrc;
public EditTextWithDelete(Context context) {
super(context);
this.context = context;
init(null);
}
public EditTextWithDelete(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
this.context = context;
init(attrs);
}
public EditTextWithDelete(Context context, AttributeSet attrs) {
super(context, attrs);
this.context = context;
init(attrs);
}
public void setListener(IEditDeleteListener listener) {
this.mListener = listener;
}
public void setShowMore(boolean isMore) {
isShowMore = isMore;
}
private void init(AttributeSet attrs) {
// 获取图片资源
TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.EditTextWithDelete);
deleteSrc = typedArray.getResourceId(R.styleable.EditTextWithDelete_deleteSrc,R.drawable.img_close_normal);
moreSrc = typedArray.getResourceId(R.styleable.EditTextWithDelete_moreSrc, R.drawable.img_login_userxl);
typedArray.recycle();
imgEnable = layoutToDrawable(deleteSrc);
moreEnable = layoutToDrawable(moreSrc);
addTextChangedListener(new TextWatcher() {
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
}
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
}
@Override
public void afterTextChanged(Editable s) {
// 如果获取焦点了
if (isFocusable()) {
setDrawable();
} else {
setCompoundDrawablesWithIntrinsicBounds(imgEnableleft, null, null, null);
}
}
});
// 这个是判断是否有左图标
Drawable[] compoundDrawables = getCompoundDrawables();
if (compoundDrawables.length > 0) {
imgEnableleft = compoundDrawables[0];
}
// setDrawable();
setOnFocusChangeListener(new OnFocusChangeListener() {
@Override
public void onFocusChange(View v, boolean hasFocus) {
if (hasFocus) {
String value = getText().toString().trim();
if (TextUtils.isEmpty(value)) {
if (isShowMore) {
setCompoundDrawablesWithIntrinsicBounds(imgEnableleft, null, moreEnable, null);
} else {
setCompoundDrawablesWithIntrinsicBounds(imgEnableleft, null, null, null);
}
} else {
setCompoundDrawablesWithIntrinsicBounds(imgEnableleft, null, imgEnable, null);
}
} else {
if (isShowMore) {
setCompoundDrawablesWithIntrinsicBounds(imgEnableleft, null, moreEnable, null);
} else {
setCompoundDrawablesWithIntrinsicBounds(imgEnableleft, null, null, null);
}
if (length() > 0) {
setCompoundDrawablesWithIntrinsicBounds(imgEnableleft, null, imgEnable, null);
}
}
}
});
}
/** * Layout转Drawable * * @param imgId * @return */ public Drawable layoutToDrawable(int imgId) {
View mView = LayoutInflater.from(context).inflate(R.layout.layout_editdelete_img, null);
ImageView mImg = (ImageView) mView.findViewById(R.id.editdelete_img);
mImg.setImageResource(imgId);
mView.measure(MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED),
MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
mView.layout(0, 0, mView.getMeasuredWidth(), mView.getMeasuredHeight());
mView.buildDrawingCache();
Bitmap bitmap = mView.getDrawingCache();
Drawable drawable = (Drawable) new BitmapDrawable(bitmap);
return drawable;
}
/** * 设置删除图片 */ private void setDrawable() {
if (length() == 0) {
if (isShowMore) {
setCompoundDrawablesWithIntrinsicBounds(imgEnableleft, null, moreEnable, null);
} else {
setCompoundDrawablesWithIntrinsicBounds(imgEnableleft, null, null, null);
}
} else {
if (isFocusable()) {
setCompoundDrawablesWithIntrinsicBounds(imgEnableleft, null, imgEnable, null);
} else {
if (isShowMore) {
setCompoundDrawablesWithIntrinsicBounds(imgEnableleft, null, moreEnable, null);
} else {
setCompoundDrawablesWithIntrinsicBounds(imgEnableleft, null, null, null);
}
}
}
}
/** * event.getX() 获取相对应自身左上角的X坐标 event.getY() 获取相对应自身左上角的Y坐标 getWidth() * 获取控件的宽度 getTotalPaddingRight() 获取删除图标左边缘到控件右边缘的距离 getPaddingRight() * 获取删除图标右边缘到控件右边缘的距离 getWidth() - getTotalPaddingRight() 计算删除图标左边缘到控件左边缘的距离 * getWidth() - getPaddingRight() 计算删除图标右边缘到控件左边缘的距离 */ @Override
public boolean onTouchEvent(MotionEvent event) {
if (length() == 0 && event.getAction() == MotionEvent.ACTION_UP) {
if (null != mListener) {
int x = (int) event.getX();
// 判断触摸点是否在水平范围内
boolean isInnerWidth = (x > (getWidth() - getTotalPaddingRight())) && (x < (getWidth() - getPaddingRight()));
// 获取删除图标的边界，返回一个Rect对象
Rect rect = moreEnable.getBounds();
// 获取删除图标的高度
int height = rect.height();
int y = (int) event.getY();
// 计算图标底部到控件底部的距离
int distance = (getHeight() - height) / 2;
// 判断触摸点是否在竖直范围内(可能会有点误差)
// 触摸点的纵坐标在distance到（distance+图标自身的高度）之内，则视为点中删除图标
boolean isInnerHeight = (y > distance) && (y < (distance + height));
if (isInnerHeight && isInnerWidth) {
mListener.shwoMore();
}
}
}
if (imgEnable != null && event.getAction() == MotionEvent.ACTION_UP) {
int x = (int) event.getX();
// 判断触摸点是否在水平范围内
boolean isInnerWidth = (x > (getWidth() - getTotalPaddingRight())) && (x < (getWidth() - getPaddingRight()));
// 获取删除图标的边界，返回一个Rect对象
Rect rect = imgEnable.getBounds();
// 获取删除图标的高度
int height = rect.height();
int y = (int) event.getY();
// 计算图标底部到控件底部的距离
int distance = (getHeight() - height) / 2;
// 判断触摸点是否在竖直范围内(可能会有点误差)
// 触摸点的纵坐标在distance到（distance+图标自身的高度）之内，则视为点中删除图标
boolean isInnerHeight = (y > distance) && (y < (distance + height));
if (isInnerWidth && isInnerHeight && canDelete) {
setText("");
}
}
return super.onTouchEvent(event);
}
public void setCanDelete(boolean isCanDelete) {
this.canDelete = isCanDelete;
}
@Override
protected void finalize() throws Throwable {
super.finalize();
}
public interface IEditDeleteListener {
public void shwoMore();
}
}
Demo2:
/** * @author 御轩 * @created on 2016-2-23 */public class FlowLayout extends ViewGroup {
//存储所有子View
private List<List<View>> mAllChildViews = new ArrayList<List<View>>();
//每一行的高度
private List<Integer> mLineHeight = new ArrayList<Integer>();
public FlowLayout(Context context) {
this(context, null);
// TODO Auto-generated constructor stub }
public FlowLayout(Context context, AttributeSet attrs) {
this(context, attrs, 0);
// TODO Auto-generated constructor stub }
public FlowLayout(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
// TODO Auto-generated constructor stub }
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
// TODO Auto-generated method stub
//父控件传进来的宽度和高度以及对应的测量模式
int sizeWidth = MeasureSpec.getSize(widthMeasureSpec);
int modeWidth = MeasureSpec.getMode(widthMeasureSpec);
int sizeHeight = MeasureSpec.getSize(heightMeasureSpec);
int modeHeight = MeasureSpec.getMode(heightMeasureSpec);
//如果当前ViewGroup的宽高为wrap_content的情况
int width = 0;//自己测量的 宽度
int height = 0;//自己测量的高度
//记录每一行的宽度和高度
int lineWidth = 0;
int lineHeight = 0;
//获取子view的个数
int childCount = getChildCount();
for (int i = 0; i < childCount; i++) {
View child = getChildAt(i);
//测量子View的宽和高
measureChild(child, widthMeasureSpec, heightMeasureSpec);
//得到LayoutParams
MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();
//子View占据的宽度
int childWidth = child.getMeasuredWidth() + lp.leftMargin + lp.rightMargin;
//子View占据的高度
int childHeight = child.getMeasuredHeight() + lp.topMargin + lp.bottomMargin;
//换行时候
if (lineWidth + childWidth > sizeWidth) {
//对比得到最大的宽度
width = Math.max(width, lineWidth);
//重置lineWidth
lineWidth = childWidth;
//记录行高
height += lineHeight;
lineHeight = childHeight;
} else {//不换行情况
//叠加行宽
lineWidth += childWidth;
//得到最大行高
lineHeight = Math.max(lineHeight, childHeight);
}
//处理最后一个子View的情况
if (i == childCount - 1) {
width = Math.max(width, lineWidth);
height += lineHeight;
}
}
//wrap_content
setMeasuredDimension(modeWidth == MeasureSpec.EXACTLY ? sizeWidth : width,
modeHeight == MeasureSpec.EXACTLY ? sizeHeight : height);
// super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
@SuppressLint("DrawAllocation")
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
// TODO Auto-generated method stub mAllChildViews.clear();
mLineHeight.clear();
//获取当前ViewGroup的宽度
int width = getWidth();
int lineWidth = 0;
int lineHeight = 0;
//记录当前行的view
List<View> lineViews = new ArrayList<View>();
int childCount = getChildCount();
for (int i = 0; i < childCount; i++) {
View child = getChildAt(i);
MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();
int childWidth = child.getMeasuredWidth();
int childHeight = child.getMeasuredHeight();
//如果需要换行
if (childWidth + lineWidth + lp.leftMargin + lp.rightMargin > width) {
//记录LineHeight
mLineHeight.add(lineHeight);
//记录当前行的Views
mAllChildViews.add(lineViews);
//重置行的宽高
lineWidth = 0;
lineHeight = childHeight + lp.topMargin + lp.bottomMargin;
//重置view的集合
lineViews = new ArrayList();
}
lineWidth += childWidth + lp.leftMargin + lp.rightMargin;
lineHeight = Math.max(lineHeight, childHeight + lp.topMargin + lp.bottomMargin);
lineViews.add(child);
}
//处理最后一行
mLineHeight.add(lineHeight);
mAllChildViews.add(lineViews);
//设置子View的位置
int left = 0;
int top = 0;
//获取行数
int lineCount = mAllChildViews.size();
for (int i = 0; i < lineCount; i++) {
//当前行的views和高度
lineViews = mAllChildViews.get(i);
lineHeight = mLineHeight.get(i);
for (int j = 0; j < lineViews.size(); j++) {
View child = lineViews.get(j);
//判断是否显示
if (child.getVisibility() == View.GONE) {
continue;
}
MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();
int cLeft = left + lp.leftMargin;
int cTop = top + lp.topMargin;
int cRight = cLeft + child.getMeasuredWidth();
int cBottom = cTop + child.getMeasuredHeight();
//进行子View进行布局
child.layout(cLeft, cTop, cRight, cBottom);
left += child.getMeasuredWidth() + lp.leftMargin + lp.rightMargin;
}
left = 0;
top += lineHeight;
}
}
网络：
/** * Created by gaofeng on 2016/11/30. * 对网络请求的简单封装。 */
public class MyBaseFragment extends BaseFragment implements IResponseListener {
protected int responseCode = 0;// 标记第N个网络请求
protected LoadingView mLoadingView;
protected boolean isFirstRequest = true;
/** * 请求失败点击刷新按钮 */ private void OnReload() {
if (mLoadingView != null) {
mLoadingView.setOnRefreshListener(new LoadingView.OnReloadListener() {
@Override
public void onReload(View v) {
onReLoad();
}
});
}
}
/** * 发送网络请求的方法 * @param method 请求url * @param request 请求参数 * @param code 请求码，不能重复。 * @param isFirstRequest 是否是当前页面第一次请求 */ protected void sendRequest(String method, final BaseRequest request, int code , boolean isFirstRequest) {
this.isFirstRequest = isFirstRequest;
//页面第一次进来需要展示loadingView,此外都是展示progress.
if (!isFirstRequest) {
showProgressDialog();
} else {
if (mLoadingView != null) {
if (!NetUtils.isHttpConnected(mActivity)) { //没有网络请求
mLoadingView.setStatus(LoadingView.No_Network);
} else {
mLoadingView.setStatus(LoadingView.Loading);
}
}
}
this.responseCode = code;
Request<String> stringRequest ;
if (request != null) {
stringRequest = NoHttpUtils.getRequest(method, request.toMap());
} else {
stringRequest = NoHttpUtils.getRequest(method, new HashMap());
}
requestQueue.add(responseCode , stringRequest, mOnLoadListener);
}
/** * 请求回调 */ protected OnLoadListener<String> mOnLoadListener = new OnLoadListener<String>() {
@Override
public void onSuccess(int what, Response<String> response) {
dismissProgress();
try {
JSONObject object = new JSONObject(response.get());
String code = object.getString("code");
if (code.equals("0")) {
if (mLoadingView != null)
mLoadingView.setStatus(LoadingView.Success);
if (object.has("data")) {
onResponse(responseCode ,response.get());
}
} else if (code.equals("4")) {//token失效返回登陆页面
Common.getInstance().logOut(mActivity);
} else if (isFirstRequest && mLoadingView != null) {
mLoadingView.setStatus(LoadingView.Error);
mLoadingView.setErrorText(object.getString("msg"));
} else {
toast(object.getString("msg"));
}
} catch (JSONException e) {
e.printStackTrace();
}
}
@Override
public void onError(int what, Response<String> response) {
dismissProgress();
onResponseFail(responseCode ,response.get());
if (isFirstRequest && mLoadingView != null) {
mLoadingView.setStatus(LoadingView.Error);
}
}
};
/** * 成功回调 * @param what * @param response */ @Override
public void onResponse(int what ,String response) {
}
/** * 失败回调 * @param what * @param errorInfo */
@Override
public void onResponseFail(int what ,String errorInfo) {
}
/** * 点击重新加载的回调 */ @Override
public void onReLoad() {
}
}
