ScrollView是带有滚动事件的控件，与listView和GridView以及Viewpager嵌套使用时经常会出现很多问题。例如listView和GridView只能在ScrollView显示一行等。所以Google是不推荐我们去做ScrollView内嵌操作的，但是有的时候，需求需要~我们不得不这么使用。所以接下来我给大家讲一些基础的解决冲突的办法。
1.ScrollView嵌套ListView,有2种方法解决
1.1自定义View
public class ScrollListView extends ListView {
public ScrollListView(Context context, AttributeSet attrs) {
super(context, attrs);
// TODO Auto-generated constructor stub
}
public ScrollListView(Context context) {
super(context);
// TODO Auto-generated constructor stub
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
// TODO Auto-generated method stub
int expandSpec = MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE >> 2,
MeasureSpec.AT_MOST);
super.onMeasure(widthMeasureSpec, expandSpec);
}
}
1.2动态测量Listview的高度
/**
* 动态控制listView的高度
*/
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);
}
2.ScrollView嵌套GridView,有2种方法解决---与ListView类似
2.1自定义View
public class ScrollGridView extends GridView {
public ScrollGridView(Context context, AttributeSet attrs) {
super(context, attrs);
// TODO Auto-generated constructor stub
}
public ScrollGridView(Context context) {
super(context);
// TODO Auto-generated constructor stub
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
// TODO Auto-generated method stub
int expandSpec = MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE >> 2,
MeasureSpec.AT_MOST);
super.onMeasure(widthMeasureSpec, expandSpec);
}
}
2.2动态测量Gridview的高度
/**
* 动态控制gridview的高度
*/
public static void setGridViewHeightBasedOnChildren(GridView gridView, int number) {
//获取listview的适配器
ListAdapter listAdapter = gridView.getAdapter();
int numCollumn = number;
//item的高度
if (listAdapter == null) {
return;
}
int totalHeight = 0;
for (int i = 0; i < listAdapter.getCount(); i++) {
if (i % numCollumn == 0) {
View listItem = listAdapter.getView(i, null, gridView);
listItem.measure(0, 0);
totalHeight += listItem.getMeasuredHeight();
}
}
ViewGroup.LayoutParams params = gridView.getLayoutParams();
params.height = totalHeight;
gridView.setLayoutParams(params);
}
3.ScrollView嵌套ViewPager,有2种方法解决
3.1自定义ScrollView
/**
* 能够兼容ViewPager的ScrollView
*
* @Description: 解决了ViewPager在ScrollView中的滑动反弹问题
*/
public class ScrollViewExtend extends ScrollView {
// 滑动距离及坐标
private float xDistance, yDistance, xLast, yLast;
public ScrollViewExtend(Context context, AttributeSet attrs) {
super(context, attrs);
}
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN:
xDistance = yDistance = 0f;
xLast = ev.getX();
yLast = ev.getY();
break;
case MotionEvent.ACTION_MOVE:
final float curX = ev.getX();
final float curY = ev.getY();
xDistance += Math.abs(curX - xLast);
yDistance += Math.abs(curY - yLast);
xLast = curX;
yLast = curY;
if (xDistance > yDistance) {
return false;
}
}
return super.onInterceptTouchEvent(ev);
}
}
3.2自定义viewPager
public class MyViewPager extends ViewPager {
/**
* 触摸时按下的点
**/
PointF downP = new PointF();
/**
* 触摸时当前的点
**/
PointF curP = new PointF();
OnSingleTouchListener onSingleTouchListener;
public MyViewPager(Context context) {
super(context);
}
public MyViewPager(Context context, AttributeSet attrs) {
super(context, attrs);
}
@Override
public boolean onTouchEvent(MotionEvent arg0) {
// 每次进行onTouch事件都记录当前的按下的坐标
curP.x = arg0.getX();
curP.y = arg0.getY();
if (arg0.getAction() == MotionEvent.ACTION_DOWN) {
// 记录按下时候的坐标
// 切记不可用 downP = curP ，这样在改变curP的时候，downP也会改变
downP.x = arg0.getX();
downP.y = arg0.getY();
// 此句代码是为了通知他的父ViewPager现在进行的是本控件的操作，不要对我的操作进行干扰
getParent().requestDisallowInterceptTouchEvent(true);
}
if (arg0.getAction() == MotionEvent.ACTION_MOVE) {
// 此句代码是为了通知他的父ViewPager现在进行的是本控件的操作，不要对我的操作进行干扰
getParent().requestDisallowInterceptTouchEvent(true);
}
if (arg0.getAction() == MotionEvent.ACTION_UP) {
// 在up时判断是否按下和松手的坐标为一个点
// 如果是一个点，将执行点击事件，这是我自己写的点击事件，而不是onclick
if (downP.x == curP.x && downP.y == curP.y) {
onSingleTouch();
return true;
}
}
return super.onTouchEvent(arg0);
}
/**
* 单击
*/
public void onSingleTouch() {
if (onSingleTouchListener != null) {
onSingleTouchListener.onSingleTouch();
}
}
/**
* 创建点击事件接口
*/
public interface OnSingleTouchListener {
public void onSingleTouch();
}
public void setOnSingleTouchListener(
OnSingleTouchListener onSingleTouchListener) {
this.onSingleTouchListener = onSingleTouchListener;
}
}
4.若嵌套的ListView和GridView的高度超出了ScrollView，那么ScrollView会自动滑到底部。
那么我们只需要使用一个顶部控件主动获取焦点便能解决这个问题。解决代码如下。
view.setFocusable(true);
view.setFocusableInTouchMode(true);
view.requestFocus();
备注：自定义ListView的详细介绍 传送门
