众所周知ListView与ScrollView都具有滚动能力，对于这样的View控件，当ScrollView与ListView相互嵌套会成为一种问题：
问题一:ScrollView与ListView嵌套导致ListView显示不全面
问题二:ScrollView不能正常滑动
解决方式一:
ScrollView+LinearLayout+ListView可以换成ScrollView+LinearLayout+LinearLayout，对于开发中，ScrollView所能滚动的样式形式各异，另外的话，ScrollView所显示的内容肯定不会太多，因此这种方案是合理而且可选的
解决方式二：
同样是替换：ListView具有HeaderView与FooterView2部分，因此，在非下拉刷新，上拉加载的需求中，完全可以使用ListView来代替ScrollView，因此是合理可选的方案
解决方式三：
主动计算和设置ListView的高度，这样的结果最终得出类似解决方案一效果，具体来说缺点是大材小用，但也是合理的解决办法。
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public class Utility {
public static void setListViewHeightBasedOnChildren(ListView listView) {
ListAdapter listAdapter = listView.getAdapter();
if (listAdapter == null) {
return;
}
int totalHeight = 0;
for (int i = 0; i < listAdapter.getCount(); i++) {
View listItem = listAdapter.getView(i, null, listView);
listItem.measure(0, 0);
totalHeight += listItem.getMeasuredHeight();
}
ViewGroup.LayoutParams params = listView.getLayoutParams();
params.height = totalHeight + (listView.getDividerHeight() * (listAdapter.getCount() - 1));
listView.setLayoutParams(params);
}
}
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解决方式四：
复写ScrollView，从事件方向进行处理，缺点是灵活性不够好
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public class ListScrollView extends ScrollView {
private List list = new ArrayList();
private int scrollPaddingTop; // scrollview的顶部内边距
private int scrollPaddingLeft;// scrollview的左侧内边距
private int[] scrollLoaction = new int[2]; // scrollview在窗口中的位置
private final static int UPGLIDE = 0;
private final static int DOWNGLIDE = 1;
private int glideState;
public ListScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
}
private int downY = 0;
private int moveY = 0;
@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN:
downY = (int) ev.getY();
//System.out.println("actiondown" + ev.getY());
break;
case MotionEvent.ACTION_MOVE:
moveY= (int) ev.getY();
//System.out.println("move" + moveY + "down" + downY);
if((moveY - downY) >= 0) {
//System.out.println("'''''''''DOWNGLIDE'''''''''''");
glideState = DOWNGLIDE;
} else {
//System.out.println("'''''''''UPGLIDE'''''''''''");
glideState = UPGLIDE;
}
break;
case MotionEvent.ACTION_UP:
default:
break;
}
return super.dispatchTouchEvent(ev);
}
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
// 该事件的xy是以scrollview的左上角为00点而不是以窗口为00点
int x = (int) ev.getX() + scrollLoaction[0];
int y = (int) ev.getY() + scrollLoaction[1];
for (int i = 0; i < list.size(); i++) {
ListView listView = list.get(i);
int[] location = new int[2];
listView.getLocationInWindow(location);
int width = listView.getWidth();
int height = listView.getHeight();
// 在listview的位置之内则可以滑动
if (x >= location[0] + scrollPaddingLeft
&& x <= location[0] + scrollPaddingLeft + width
&& y >= location[1] + scrollPaddingTop
&& y <= location[1] + scrollPaddingTop + height) {
//System.out.println(glideState);
if(( (listView.getLastVisiblePosition() == (listView.getCount()-1)) && (glideState == UPGLIDE) ) ) {
//System.out.println("up");
break;
}
if(( (listView.getFirstVisiblePosition() == 0) && (glideState == DOWNGLIDE))) {
//System.out.println("down");
break;
}
return false; //让子控件直接处理
}
}
return super.onInterceptTouchEvent(ev);
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
return super.onTouchEvent(ev);
}
private void findAllListView(View view) {
if (view instanceof ViewGroup) {
int count = ((ViewGroup) view).getChildCount();
for (int i = 0; i < count; i++) {
if (!(view instanceof ListView)) {
findAllListView(((ViewGroup) view).getChildAt(i));
}
}
if (view instanceof ListView) {
list.add((ListView) view);
}
}
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
scrollPaddingTop = getTop();
scrollPaddingLeft = getLeft();
getLocationInWindow(scrollLoaction);
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
super.onLayout(changed, l, t, r, b);
if (this.getChildCount() != 1) {
try {
throw new ScrollException();
} catch (ScrollException e) {
e.printStackTrace();
}
}
list.clear();
findAllListView(this.getChildAt(0));
}
} |