ViewFlow是一个Android UI部件提供水平滚的viewGroup从一个适配器填充的项,
在布局中的用法如下:
<org.taptwo.android.widget.ViewFlow android:id="@+id/viewflow" app:sidebuffer="5" />
在Acitivity中的用法如下:
ViewFlow viewFlow = (ViewFlow) findViewById(R.id.viewflow); viewFlow.setAdapter(myAdapter);
viewFlow.setAdapter(myAdapter, 8);
设置屏幕上改变的监听事件
viewFlow.setOnViewSwitchListener(new ViewSwitchListener() { public void onSwitched(View v, int position) { // Your code here } });
viewFlow.setOnViewLazyInitializeListener(new ViewLazyInitializeListener() { public void onViewLazyInitialize(View view, int position) { // Your code here e.g. ((MyAdapter)((AbsListView)view).getAdapter()).initializeData(); } });
Circle Flow Indicator
的一般布局如下:<org.taptwo.android.widget.CircleFlowIndicator android:padding="10dip" android:layout_height="wrap_content" android:layout_width="wrap_content" android:id="@+id/viewflowindic" android:background="#00000000"/>
ViewFlow
连接的
FlowIndicator
CircleFlowIndicator indic = (CircleFlowIndicator) findViewById(R.id.viewflowindic); viewFlow.setFlowIndicator(indic);然后呢,看一个小Demo
首先是布局:
viewflowdemo.xml
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res/com.nyist.activity" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" > <FrameLayout android:id="@+id/framelayout" android:layout_width="fill_parent" android:layout_height="150dip" android:background="#ffffff" > <com.nyist.viewflowtest.ViewFlow android:id="@+id/viewflow" android:layout_width="fill_parent" android:layout_height="fill_parent" > </com.nyist.viewflowtest.ViewFlow> <LinearLayout android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_gravity="bottom" android:background="#88252525" android:gravity="center" android:padding="3dip" > <com.nyist.viewflowtest.CircleFlowIndicator android:id="@+id/viewflowindic" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_horizontal|bottom" android:padding="2dip" app:activeColor="#ff0000" app:activeType="fill" app:circleSeparation="20dip" app:inactiveColor="#ffffff" app:inactiveType="fill" app:radius="4dip" /> </LinearLayout> </FrameLayout> <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="@string/hello" /> </LinearLayout>
image_item.xml
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" > <ImageView android:id="@+id/imgView" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_gravity="center_vertical|center_horizontal" android:contentDescription="@string/app_name" android:scaleType="fitXY" android:src="@drawable/t1" > </ImageView> </LinearLayout>
attrs.xml
<?xml version="1.0" encoding="utf-8"?> <resources> <declare-styleable name="ViewFlow"> <attr name="sidebuffer" format="integer" /> </declare-styleable> <declare-styleable name="CircleFlowIndicator"> <attr name="activeColor" format="color" /> <attr name="inactiveColor" format="color" /> <attr name="radius" format="dimension" /> <attr name="centered" format="boolean" /> <attr name="fadeOut" format="integer" /> <attr name="inactiveType"> <flag name="stroke" value="0" /> <flag name="fill" value="1" /> </attr> <attr name="activeType"> <flag name="stroke" value="0" /> <flag name="fill" value="1" /> </attr> <attr name="circleSeparation" format="dimension" /> <attr name="activeRadius" format="dimension" /> </declare-styleable> </resources>然后是实现的活动,和一些类
ViewFlow
package com.nyist.viewflowtest; import java.util.ArrayList; import java.util.LinkedList; import com.nyist.activity.R; import android.content.Context; import android.content.res.Configuration; import android.content.res.TypedArray; import android.database.DataSetObserver; import android.os.Handler; import android.os.Message; import android.util.AttributeSet; import android.view.MotionEvent; import android.view.VelocityTracker; import android.view.View; import android.view.ViewConfiguration; import android.view.ViewGroup; import android.view.ViewTreeObserver.OnGlobalLayoutListener; import android.widget.AbsListView; import android.widget.Adapter; import android.widget.AdapterView; import android.widget.Scroller; public class ViewFlow extends AdapterView<Adapter> { private static final int SNAP_VELOCITY = 1000; private static final int INVALID_SCREEN = -1; private final static int TOUCH_STATE_REST = 0; private final static int TOUCH_STATE_SCROLLING = 1; private LinkedList<View> mLoadedViews; private int mCurrentBufferIndex; private int mCurrentAdapterIndex; private int mSideBuffer = 2; private Scroller mScroller; private VelocityTracker mVelocityTracker; private int mTouchState = TOUCH_STATE_REST; private float mLastMotionX; private int mTouchSlop; private int mMaximumVelocity; private int mCurrentScreen; private int mNextScreen = INVALID_SCREEN; private boolean mFirstLayout = true; private ViewSwitchListener mViewSwitchListener; private Adapter mAdapter; private int mLastScrollDirection; private AdapterDataSetObserver mDataSetObserver; private FlowIndicator mIndicator; private int mLastOrientation = -1; private long timeSpan = 3000; private Handler handler; private OnGlobalLayoutListener orientationChangeListener = new OnGlobalLayoutListener() { @Override public void onGlobalLayout() { getViewTreeObserver().removeGlobalOnLayoutListener( orientationChangeListener); setSelection(mCurrentAdapterIndex); } }; /** * 当一个新的接收调用支持{ @link视图 */ public static interface ViewSwitchListener { /** * * * @param view * the {@link View} currently in focus. * @param position * The position in the adapter of the {@link View} currently in focus. */ void onSwitched(View view, int position); } public ViewFlow(Context context) { super(context); mSideBuffer = 3; init(); } public ViewFlow(Context context, int sideBuffer) { super(context); mSideBuffer = sideBuffer; init(); } public ViewFlow(Context context, AttributeSet attrs) { super(context, attrs); TypedArray styledAttrs = context.obtainStyledAttributes(attrs, R.styleable.ViewFlow); mSideBuffer = styledAttrs.getInt(R.styleable.ViewFlow_sidebuffer, 3); init(); } private void init() { mLoadedViews = new LinkedList<View>(); mScroller = new Scroller(getContext()); final ViewConfiguration configuration = ViewConfiguration .get(getContext()); mTouchSlop = configuration.getScaledTouchSlop(); mMaximumVelocity = configuration.getScaledMaximumFlingVelocity(); } public void startAutoFlowTimer(){ handler = new Handler(){ @Override public void handleMessage(Message msg) { snapToScreen((mCurrentScreen+1)%getChildCount()); Message message = handler.obtainMessage(0); sendMessageDelayed(message, timeSpan); } }; Message message = handler.obtainMessage(0); handler.sendMessageDelayed(message, timeSpan); } public void stopAutoFlowTimer(){ if(handler!=null) handler.removeMessages(0); handler = null; } public void onConfigurationChanged(Configuration newConfig) { if (newConfig.orientation != mLastOrientation) { mLastOrientation = newConfig.orientation; getViewTreeObserver().addOnGlobalLayoutListener(orientationChangeListener); } } public int getViewsCount() { return mSideBuffer; } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); final int width = MeasureSpec.getSize(widthMeasureSpec); final int widthMode = MeasureSpec.getMode(widthMeasureSpec); if (widthMode != MeasureSpec.EXACTLY && !isInEditMode()) { throw new IllegalStateException( "ViewFlow can only be used in EXACTLY mode."); } final int heightMode = MeasureSpec.getMode(heightMeasureSpec); if (heightMode != MeasureSpec.EXACTLY && !isInEditMode()) { throw new IllegalStateException( "ViewFlow can only be used in EXACTLY mode."); } // The children are given the same width and height as the workspace final int count = getChildCount(); for (int i = 0; i < count; i++) { getChildAt(i).measure(widthMeasureSpec, heightMeasureSpec); } if (mFirstLayout) { mScroller.startScroll(0, 0, mCurrentScreen * width, 0, 0); mFirstLayout = false; } } @Override protected void onLayout(boolean changed, int l, int t, int r, int b) { int childLeft = 0; final int count = getChildCount(); for (int i = 0; i < count; i++) { final View child = getChildAt(i); if (child.getVisibility() != View.GONE) { final int childWidth = child.getMeasuredWidth(); child.layout(childLeft, 0, childLeft + childWidth, child.getMeasuredHeight()); childLeft += childWidth; } } } @Override public boolean onInterceptTouchEvent(MotionEvent ev) { if (getChildCount() == 0) return false; if (mVelocityTracker == null) { mVelocityTracker = VelocityTracker.obtain(); } mVelocityTracker.addMovement(ev); final int action = ev.getAction(); final float x = ev.getX(); switch (action) { case MotionEvent.ACTION_DOWN: /* * If being flinged and user touches, stop the fling. isFinished * will be false if being flinged. */ if (!mScroller.isFinished()) { mScroller.abortAnimation(); } // Remember where the motion event started mLastMotionX = x; mTouchState = mScroller.isFinished() ? TOUCH_STATE_REST : TOUCH_STATE_SCROLLING; if(handler!=null) handler.removeMessages(0); break; case MotionEvent.ACTION_MOVE: final int xDiff = (int) Math.abs(x - mLastMotionX); boolean xMoved = xDiff > mTouchSlop; if (xMoved) { // Scroll if the user moved far enough along the X axis mTouchState = TOUCH_STATE_SCROLLING; } if (mTouchState == TOUCH_STATE_SCROLLING) { // Scroll to follow the motion event final int deltaX = (int) (mLastMotionX - x); mLastMotionX = x; final int scrollX = getScrollX(); if (deltaX < 0) { if (scrollX > 0) { scrollBy(Math.max(-scrollX, deltaX), 0); } } else if (deltaX > 0) { final int availableToScroll = getChildAt( getChildCount() - 1).getRight() - scrollX - getWidth(); if (availableToScroll > 0) { scrollBy(Math.min(availableToScroll, deltaX), 0); } } return true; } break; case MotionEvent.ACTION_UP: if (mTouchState == TOUCH_STATE_SCROLLING) { final VelocityTracker velocityTracker = mVelocityTracker; velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity); int velocityX = (int) velocityTracker.getXVelocity(); if (velocityX > SNAP_VELOCITY && mCurrentScreen > 0) { // Fling hard enough to move left snapToScreen(mCurrentScreen - 1); } else if (velocityX < -SNAP_VELOCITY && mCurrentScreen < getChildCount() - 1) { // Fling hard enough to move right snapToScreen(mCurrentScreen + 1); } else { snapToDestination(); } if (mVelocityTracker != null) { mVelocityTracker.recycle(); mVelocityTracker = null; } } mTouchState = TOUCH_STATE_REST; if(handler!=null){ Message message = handler.obtainMessage(0); handler.sendMessageDelayed(message, timeSpan); } break; case MotionEvent.ACTION_CANCEL: mTouchState = TOUCH_STATE_REST; } return false; } @Override public boolean onTouchEvent(MotionEvent ev) { if (getChildCount() == 0) return false; if (mVelocityTracker == null) { mVelocityTracker = VelocityTracker.obtain(); } mVelocityTracker.addMovement(ev); final int action = ev.getAction(); final float x = ev.getX(); switch (action) { case MotionEvent.ACTION_DOWN: /* * If being flinged and user touches, stop the fling. isFinished * will be false if being flinged. */ if (!mScroller.isFinished()) { mScroller.abortAnimation(); } // Remember where the motion event started mLastMotionX = x; mTouchState = mScroller.isFinished() ? TOUCH_STATE_REST : TOUCH_STATE_SCROLLING; if(handler!=null) handler.removeMessages(0); break; case MotionEvent.ACTION_MOVE: final int xDiff = (int) Math.abs(x - mLastMotionX); boolean xMoved = xDiff > mTouchSlop; if (xMoved) { // Scroll if the user moved far enough along the X axis mTouchState = TOUCH_STATE_SCROLLING; } if (mTouchState == TOUCH_STATE_SCROLLING) { // Scroll to follow the motion event final int deltaX = (int) (mLastMotionX - x); mLastMotionX = x; final int scrollX = getScrollX(); if (deltaX < 0) { if (scrollX > 0) { scrollBy(Math.max(-scrollX, deltaX), 0); } } else if (deltaX > 0) { final int availableToScroll = getChildAt( getChildCount() - 1).getRight() - scrollX - getWidth(); if (availableToScroll > 0) { scrollBy(Math.min(availableToScroll, deltaX), 0); } } return true; } break; case MotionEvent.ACTION_UP: if (mTouchState == TOUCH_STATE_SCROLLING) { final VelocityTracker velocityTracker = mVelocityTracker; velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity); int velocityX = (int) velocityTracker.getXVelocity(); if (velocityX > SNAP_VELOCITY && mCurrentScreen > 0) { // Fling hard enough to move left snapToScreen(mCurrentScreen - 1); } else if (velocityX < -SNAP_VELOCITY && mCurrentScreen < getChildCount() - 1) { // Fling hard enough to move right snapToScreen(mCurrentScreen + 1); } // else if (velocityX < -SNAP_VELOCITY // && mCurrentScreen == getChildCount() - 1) { // snapToScreen(0); // } // else if (velocityX > SNAP_VELOCITY // && mCurrentScreen == 0) { // snapToScreen(getChildCount() - 1); // } else { snapToDestination(); } if (mVelocityTracker != null) { mVelocityTracker.recycle(); mVelocityTracker = null; } } mTouchState = TOUCH_STATE_REST; if(handler!=null){ Message message = handler.obtainMessage(0); handler.sendMessageDelayed(message, timeSpan); } break; case MotionEvent.ACTION_CANCEL: snapToDestination(); mTouchState = TOUCH_STATE_REST; } return true; } @Override protected void onScrollChanged(int h, int v, int oldh, int oldv) { super.onScrollChanged(h, v, oldh, oldv); if (mIndicator != null) { /* * The actual horizontal scroll origin does typically not match the * perceived one. Therefore, we need to calculate the perceived * horizontal scroll origin here, since we use a view buffer. */ int hPerceived = h + (mCurrentAdapterIndex - mCurrentBufferIndex) * getWidth(); mIndicator.onScrolled(hPerceived, v, oldh, oldv); } } private void snapToDestination() { final int screenWidth = getWidth(); final int whichScreen = (getScrollX() + (screenWidth / 2)) / screenWidth; snapToScreen(whichScreen); } private void snapToScreen(int whichScreen) { mLastScrollDirection = whichScreen - mCurrentScreen; if (!mScroller.isFinished()) return; whichScreen = Math.max(0, Math.min(whichScreen, getChildCount() - 1)); mNextScreen = whichScreen; final int newX = whichScreen * getWidth(); final int delta = newX - getScrollX(); mScroller.startScroll(getScrollX(), 0, delta, 0, Math.abs(delta) * 2); invalidate(); } @Override public void computeScroll() { if (mScroller.computeScrollOffset()) { scrollTo(mScroller.getCurrX(), mScroller.getCurrY()); postInvalidate(); } else if (mNextScreen != INVALID_SCREEN) { mCurrentScreen = Math.max(0, Math.min(mNextScreen, getChildCount() - 1)); mNextScreen = INVALID_SCREEN; postViewSwitched(mLastScrollDirection); } } /** * Scroll to the {@link View} in the view buffer specified by the index. * * @param indexInBuffer * Index of the view in the view buffer. */ private void setVisibleView(int indexInBuffer, boolean uiThread) { mCurrentScreen = Math.max(0, Math.min(indexInBuffer, getChildCount() - 1)); int dx = (mCurrentScreen * getWidth()) - mScroller.getCurrX(); mScroller.startScroll(mScroller.getCurrX(), mScroller.getCurrY(), dx, 0, 0); if(dx == 0) onScrollChanged(mScroller.getCurrX() + dx, mScroller.getCurrY(), mScroller.getCurrX() + dx, mScroller.getCurrY()); if (uiThread) invalidate(); else postInvalidate(); } /** * Set the listener that will receive notifications every time the {code * ViewFlow} scrolls. * * @param l * the scroll listener */ public void setOnViewSwitchListener(ViewSwitchListener l) { mViewSwitchListener = l; } @Override public Adapter getAdapter() { return mAdapter; } @Override public void setAdapter(Adapter adapter) { setAdapter(adapter, 0); } public void setAdapter(Adapter adapter, int initialPosition) { if (mAdapter != null) { mAdapter.unregisterDataSetObserver(mDataSetObserver); } mAdapter = adapter; if (mAdapter != null) { mDataSetObserver = new AdapterDataSetObserver(); mAdapter.registerDataSetObserver(mDataSetObserver); } if (mAdapter == null || mAdapter.getCount() == 0) return; setSelection(initialPosition); } @Override public View getSelectedView() { return (mCurrentBufferIndex < mLoadedViews.size() ? mLoadedViews .get(mCurrentBufferIndex) : null); } @Override public int getSelectedItemPosition() { return mCurrentAdapterIndex; } /** * Set the FlowIndicator * * @param flowIndicator */ public void setFlowIndicator(FlowIndicator flowIndicator) { mIndicator = flowIndicator; mIndicator.setViewFlow(this); } @Override public void setSelection(int position) { mNextScreen = INVALID_SCREEN; mScroller.forceFinished(true); if (mAdapter == null) return; position = Math.max(position, 0); position = Math.min(position, mAdapter.getCount()-1); ArrayList<View> recycleViews = new ArrayList<View>(); View recycleView; while (!mLoadedViews.isEmpty()) { recycleViews.add(recycleView = mLoadedViews.remove()); detachViewFromParent(recycleView); } View currentView = makeAndAddView(position, true, (recycleViews.isEmpty() ? null : recycleViews.remove(0))); mLoadedViews.addLast(currentView); for(int offset = 1; mSideBuffer - offset >= 0; offset++) { int leftIndex = position - offset; int rightIndex = position + offset; if(leftIndex >= 0) mLoadedViews.addFirst(makeAndAddView(leftIndex, false, (recycleViews.isEmpty() ? null : recycleViews.remove(0)))); if(rightIndex < mAdapter.getCount()) mLoadedViews.addLast(makeAndAddView(rightIndex, true, (recycleViews.isEmpty() ? null : recycleViews.remove(0)))); } mCurrentBufferIndex = mLoadedViews.indexOf(currentView); mCurrentAdapterIndex = position; for (View view : recycleViews) { removeDetachedView(view, false); } requestLayout(); setVisibleView(mCurrentBufferIndex, false); if (mIndicator != null) { mIndicator.onSwitched(mLoadedViews.get(mCurrentBufferIndex), mCurrentAdapterIndex); } if (mViewSwitchListener != null) { mViewSwitchListener .onSwitched(mLoadedViews.get(mCurrentBufferIndex), mCurrentAdapterIndex); } } private void resetFocus() { mLoadedViews.clear(); removeAllViewsInLayout(); for (int i = Math.max(0, mCurrentAdapterIndex - mSideBuffer); i < Math .min(mAdapter.getCount(), mCurrentAdapterIndex + mSideBuffer + 1); i++) { mLoadedViews.addLast(makeAndAddView(i, true, null)); if (i == mCurrentAdapterIndex) mCurrentBufferIndex = mLoadedViews.size() - 1; } requestLayout(); } private void postViewSwitched(int direction) { if (direction == 0) return; if (direction > 0) { // to the right mCurrentAdapterIndex++; mCurrentBufferIndex++; // if(direction > 1) { // mCurrentAdapterIndex += mAdapter.getCount() - 2; // mCurrentBufferIndex += mAdapter.getCount() - 2; // } View recycleView = null; // Remove view outside buffer range if (mCurrentAdapterIndex > mSideBuffer) { recycleView = mLoadedViews.removeFirst(); detachViewFromParent(recycleView); // removeView(recycleView); mCurrentBufferIndex--; } // Add new view to buffer int newBufferIndex = mCurrentAdapterIndex + mSideBuffer; if (newBufferIndex < mAdapter.getCount()) mLoadedViews.addLast(makeAndAddView(newBufferIndex, true, recycleView)); } else { // to the left mCurrentAdapterIndex--; mCurrentBufferIndex--; // if(direction < -1) { // mCurrentAdapterIndex -= mAdapter.getCount() - 2; // mCurrentBufferIndex -= mAdapter.getCount() - 2; // } View recycleView = null; // Remove view outside buffer range if (mAdapter.getCount() - 1 - mCurrentAdapterIndex > mSideBuffer) { recycleView = mLoadedViews.removeLast(); detachViewFromParent(recycleView); } // Add new view to buffer int newBufferIndex = mCurrentAdapterIndex - mSideBuffer; if (newBufferIndex > -1) { mLoadedViews.addFirst(makeAndAddView(newBufferIndex, false, recycleView)); mCurrentBufferIndex++; } } requestLayout(); setVisibleView(mCurrentBufferIndex, true); if (mIndicator != null) { mIndicator.onSwitched(mLoadedViews.get(mCurrentBufferIndex), mCurrentAdapterIndex); } if (mViewSwitchListener != null) { mViewSwitchListener .onSwitched(mLoadedViews.get(mCurrentBufferIndex), mCurrentAdapterIndex); } } private View setupChild(View child, boolean addToEnd, boolean recycle) { ViewGroup.LayoutParams p = (ViewGroup.LayoutParams) child .getLayoutParams(); if (p == null) { p = new AbsListView.LayoutParams( ViewGroup.LayoutParams.FILL_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT, 0); } if (recycle) attachViewToParent(child, (addToEnd ? -1 : 0), p); else addViewInLayout(child, (addToEnd ? -1 : 0), p, true); return child; } private View makeAndAddView(int position, boolean addToEnd, View convertView) { View view = mAdapter.getView(position, convertView, this); return setupChild(view, addToEnd, convertView != null); } class AdapterDataSetObserver extends DataSetObserver { @Override public void onChanged() { View v = getChildAt(mCurrentBufferIndex); if (v != null) { for (int index = 0; index < mAdapter.getCount(); index++) { if (v.equals(mAdapter.getItem(index))) { mCurrentAdapterIndex = index; break; } } } resetFocus(); } @Override public void onInvalidated() { // Not yet implemented! } } public void setTimeSpan(long timeSpan) { this.timeSpan = timeSpan; } public void setmSideBuffer(int mSideBuffer) { this.mSideBuffer = mSideBuffer; } }
ImageAdapter
package com.nyist.viewflowtest; import com.nyist.activity.R; import android.content.Context; import android.content.Intent; import android.os.Bundle; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.view.View.OnClickListener; import android.widget.BaseAdapter; import android.widget.ImageView; import android.widget.Toast; public class ImageAdapter extends BaseAdapter { private Context mContext; private LayoutInflater mInflater; private static final int[] ids = {R.drawable.t1, R.drawable.t2, R.drawable.t3 }; public ImageAdapter(Context context) { mContext = context; mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); } @Override public int getCount() { //返回很大的值使得getView中的position不断增大来实现循环 return Integer.MAX_VALUE; } @Override public Object getItem(int position) { return position; } @Override public long getItemId(int position) { return position; } @Override public View getView(final int position, View convertView, ViewGroup parent) { if (convertView == null) { convertView = mInflater.inflate(R.layout.image_item, null); } ((ImageView) convertView.findViewById(R.id.imgView)).setImageResource(ids[position%ids.length]); convertView.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { //在这里可以设置跳转界面 // Intent intent = new Intent(mContext,DetailActivity.class); // Bundle bundle = new Bundle(); // bundle.putInt("image_id", ids[position%ids.length]); // intent.putExtras(bundle); // mContext.startActivity(intent); } }); return convertView; } }
FlowIndicator
package com.nyist.viewflowtest; import com.nyist.viewflowtest.ViewFlow.ViewSwitchListener; //定义一个接口,FlowIndicator负责显示一个视觉指示器的总数量和当前视图可见视图。 public interface FlowIndicator extends ViewSwitchListener { /* * 设置当前ViewFlow。这个方法被调用的ViewFlow当FlowIndicator附属于它。 */ public void setViewFlow(ViewFlow view); /** * * 滚动位置已经被改变了。一个FlowIndicator可能实现这个方法,以反映当前的位置 */ public void onScrolled(int h, int v, int oldh, int oldv); }
CircleFlowIndicator
package com.nyist.viewflowtest; import com.nyist.activity.R; import android.content.Context; import android.content.res.TypedArray; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.Paint.Style; import android.os.AsyncTask; import android.util.AttributeSet; import android.view.View; import android.view.animation.Animation; import android.view.animation.AnimationUtils; import android.view.animation.Animation.AnimationListener; public class CircleFlowIndicator extends View implements FlowIndicator, AnimationListener { private static final int STYLE_STROKE = 0; private static final int STYLE_FILL = 1; private float radius = 4; private float circleSeparation = 2 * radius + radius; private float activeRadius = 0.5f; private int fadeOutTime = 0; private final Paint mPaintInactive = new Paint(Paint.ANTI_ALIAS_FLAG); private final Paint mPaintActive = new Paint(Paint.ANTI_ALIAS_FLAG); private ViewFlow viewFlow; private int currentScroll = 0; private int flowWidth = 0; private FadeTimer timer; public AnimationListener animationListener = this; private Animation animation; private boolean mCentered = false; public CircleFlowIndicator(Context context) { super(context); initColors(0xFFFFFFFF, 0xFFFFFFFF, STYLE_FILL, STYLE_STROKE); } public CircleFlowIndicator(Context context, AttributeSet attrs) { super(context, attrs); // 检索风格 TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.CircleFlowIndicator); // 变得不活跃的圆式,默认为“填补” int activeType = a.getInt(R.styleable.CircleFlowIndicator_activeType, STYLE_FILL); int activeDefaultColor = 0xFFFFFFFF; // 得到一个自定义颜色 int activeColor = a .getColor(R.styleable.CircleFlowIndicator_activeColor, activeDefaultColor); // 变得不活跃的圆式 int inactiveType = a.getInt( R.styleable.CircleFlowIndicator_inactiveType, STYLE_STROKE); int inactiveDefaultColor = 0x44FFFFFF; int inactiveColor = a.getColor( R.styleable.CircleFlowIndicator_inactiveColor, inactiveDefaultColor); //检索半径 radius = a.getDimension(R.styleable.CircleFlowIndicator_radius, 4.0f); circleSeparation = a.getDimension( R.styleable.CircleFlowIndicator_circleSeparation, 2 * radius + radius); activeRadius = a.getDimension( R.styleable.CircleFlowIndicator_activeRadius, 0.5f); // 检索淡出时间 fadeOutTime = a.getInt(R.styleable.CircleFlowIndicator_fadeOut, 0); mCentered = a.getBoolean(R.styleable.CircleFlowIndicator_centered, false); initColors(activeColor, inactiveColor, activeType, inactiveType); } private void initColors(int activeColor, int inactiveColor, int activeType, int inactiveType) { // 选择涂料类型给定类型attr switch (inactiveType) { case STYLE_FILL: mPaintInactive.setStyle(Style.FILL); break; default: mPaintInactive.setStyle(Style.STROKE); } mPaintInactive.setColor(inactiveColor); // switch (activeType) { case STYLE_STROKE: mPaintActive.setStyle(Style.STROKE); break; default: mPaintActive.setStyle(Style.FILL); } mPaintActive.setColor(activeColor); } protected void onDraw(Canvas canvas) { super.onDraw(canvas); int count = 3; if (viewFlow != null) { count = viewFlow.getViewsCount(); } // 第一圈数量应该抵消,使得整个事情集中 float centeringOffset = 0; int leftPadding = getPaddingLeft(); // 画圆 for (int iLoop = 0; iLoop < count; iLoop++) { canvas.drawCircle(leftPadding + radius + (iLoop * circleSeparation) + centeringOffset, getPaddingTop() + radius, radius, mPaintInactive); } float cx = 0; if (flowWidth != 0) { // 画的实心圆根据当前的滚动的值 cx = (currentScroll * circleSeparation) / flowWidth; } // 流宽度已经更新 canvas.drawCircle(leftPadding + radius + cx + centeringOffset, getPaddingTop() + radius, radius + activeRadius, mPaintActive); } @Override public void onSwitched(View view, int position) { } @Override public void setViewFlow(ViewFlow view) { resetTimer(); viewFlow = view; flowWidth = viewFlow.getWidth(); invalidate(); } @Override public void onScrolled(int h, int v, int oldh, int oldv) { setVisibility(View.VISIBLE); resetTimer(); flowWidth = viewFlow.getWidth(); if (viewFlow.getViewsCount() * flowWidth != 0) { currentScroll = h % (viewFlow.getViewsCount() * flowWidth); } else { currentScroll = h; } invalidate(); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { setMeasuredDimension(measureWidth(widthMeasureSpec), measureHeight(heightMeasureSpec)); } private int measureWidth(int measureSpec) { int result = 0; int specMode = MeasureSpec.getMode(measureSpec); int specSize = MeasureSpec.getSize(measureSpec); // 设置尺寸 if (specMode == MeasureSpec.EXACTLY) { result = specSize; } // 计算宽度根据视图计数 else { int count = 3; if (viewFlow != null) { count = viewFlow.getViewsCount(); } float temp = circleSeparation - 2 * radius; result = (int) (getPaddingLeft() + getPaddingRight() + (count * 2 * radius) + (count - 1) * temp + 1); // if (specMode == MeasureSpec.AT_MOST) { result = Math.min(result, specSize); } } return result; } /** * * 确定这一视图的高度 */ private int measureHeight(int measureSpec) { int result = 0; int specMode = MeasureSpec.getMode(measureSpec); int specSize = MeasureSpec.getSize(measureSpec); if (specMode == MeasureSpec.EXACTLY) { result = specSize; } // 确定这一视图的高度 else { result = (int) (2 * radius + getPaddingTop() + getPaddingBottom() + 1); if (specMode == MeasureSpec.AT_MOST) { result = Math.min(result, specSize); } } return result; } public void setFillColor(int color) { mPaintActive.setColor(color); invalidate(); } public void setStrokeColor(int color) { mPaintInactive.setColor(color); invalidate(); } /** * 重置为0的淡出计时器 */ private void resetTimer() { //只有设置定时器,如果我们有一个超时至少1毫秒 if (fadeOutTime > 0) { // 检查是否我们需要创建一个新的计时器 if (timer == null || timer._run == false) { timer = new FadeTimer(); timer.execute(); } else { timer.resetTimer(); } } } private class FadeTimer extends AsyncTask<Void, Void, Void> { private int timer = 0; private boolean _run = true; public void resetTimer() { timer = 0; } @Override protected Void doInBackground(Void... arg0) { while (_run) { try { // Wait for a millisecond Thread.sleep(1); timer++; if (timer == fadeOutTime) { _run = false; } } catch (InterruptedException e) { e.printStackTrace(); } } return null; } @Override protected void onPostExecute(Void result) { animation = AnimationUtils.loadAnimation(getContext(), android.R.anim.fade_out); animation.setAnimationListener(animationListener); startAnimation(animation); } } @Override public void onAnimationEnd(Animation animation) { setVisibility(View.GONE); } @Override public void onAnimationRepeat(Animation animation) { } @Override public void onAnimationStart(Animation animation) { } }
ViewFlowDemoActivity
package com.nyist.activity; import com.nyist.viewflowtest.CircleFlowIndicator; import com.nyist.viewflowtest.ImageAdapter; import com.nyist.viewflowtest.ViewFlow; import android.app.Activity; import android.os.Bundle; public class ViewFlowDemoActivity extends Activity { private ViewFlow viewFlow; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.viewflowdemo); circleimage(); } void circleimage() { viewFlow = (ViewFlow) findViewById(R.id.viewflow); viewFlow.setAdapter(new ImageAdapter(this)); viewFlow.setmSideBuffer(3); // 实际图片张数, 我的ImageAdapter实际图片张数为3 CircleFlowIndicator indic = (CircleFlowIndicator) findViewById(R.id.viewflowindic); viewFlow.setFlowIndicator(indic); viewFlow.setTimeSpan(4500); viewFlow.setSelection(3 * 1000); // 设置初始位置 viewFlow.startAutoFlowTimer(); // 启动自动播放 } }
最后,效果如图: