结合支付宝和微信首页巩固android事件分发机制 (附项目源码)

结合支付宝和微信首页巩固android事件分发机制

文章出处大黑的博客--事件分发

源码地址 https://github.com/halibobo/TouchListenerConflict 欢迎star

android的事件分发和处理方式

demo布局

难点分析和讲解

解决问题

解决问题一

为了解决这一系列问题，我需要重写DragGridView继承GridView，第一步需要让DragGridView的每一项item占满整个视图，而gridview默认是限定高度的，解决办法是重写onMeasure，修改测量高度方法，如下

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int expandSpec = View.MeasureSpec.makeMeasureSpec(
Integer.MAX_VALUE >> 2, View.MeasureSpec.AT_MOST);//1.精确模式（MeasureSpec.EXACTLY） 2.最大模式（MeasureSpec.AT_MOST） 3.未指定模式（MeasureSpec.UNSPECIFIED）
super.onMeasure(widthMeasureSpec, expandSpec);
}

解决问题二

现在我们需要长按GridView某一项可以替换位置，思路是首先需要捕捉到长按事件，那么怎么算长按事件呢？手指快速的从item上划是不算的，手指按下然后很快离开这是点击事件也不能算长按。只有手指在item上按下并且停留在item上一定时间才能算长按。有了思路，下面看关键的几处代码：

private Handler mHandler = new Handler();
//用来处理是否为长按的Runnable
private Runnable mLongClickRunnable = new Runnable() {

@Override
public void run() {
//todo
}
};

@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
switch(ev.getAction()){
case MotionEvent.ACTION_DOWN:
//使用Handler延迟dragResponseMS执行mLongClickRunnable
mHandler.postDelayed(mLongClickRunnable, dragResponseMS);
break;
case MotionEvent.ACTION_MOVE:
//如果我们在按下的item上面移动，只要不超过item的边界我们就不移除mRunnable
if(!isTouchInItem(mStartDragItemView, moveX, moveY)){
mHandler.removeCallbacks(mLongClickRunnable);
mHandler.removeCallbacks(mScrollRunnable);
}

break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
mHandler.removeCallbacks(mLongClickRunnable);
break;
}
return super.dispatchTouchEvent(ev);
}

有了长按事件如何滑动某一条item呢？如何替换两个item位置呢？

这里的解决思路是，当其中的某项假设是item1接收到长按事件后，先隐藏item1，在item1的位置上新建一个和item1长相位置都一样view假设叫它litem，手指滑动时对litem跟随滑动，接着重点来了，当手指滑动到item2区域后发出一个替换事件。这样我们就成功将两个item替换了位置并且用户体验比较好，代码片段如下：

//用来处理是否为长按的Runnable
private Runnable mLongClickRunnable = new Runnable() {

@Override
public void run() {
if (onDragStartListener != null) {
onDragStartListener.onDragStart();
}
isDrag = true; //设置可以拖拽
mVibrator.vibrate(50); //震动一下
mStartDragItemView.setVisibility(View.INVISIBLE);//隐藏该item
//根据我们按下的点显示item镜像
createDragImage(mDragBitmap, mDownX, mDownY);

}
};
/**
* 设置替换回调接口
* @param onChangeListener
*/
public void setOnChangeListener(OnChangeListener onChangeListener){
this.onChangeListener = onChangeListener;
}
/**
* 创建拖动的镜像
* @param bitmap
* @param downX
*          按下的点相对父控件的X坐标
* @param downY
*          按下的点相对父控件的X坐标
*/
private void createDragImage(Bitmap bitmap, int downX , int downY){
mWindowLayoutParams = new WindowManager.LayoutParams();
mWindowLayoutParams.format = PixelFormat.TRANSLUCENT; //图片之外的其他地方透明
mWindowLayoutParams.gravity = Gravity.TOP | Gravity.LEFT;
mWindowLayoutParams.x = downX - mPoint2ItemLeft + mOffset2Left;
mWindowLayoutParams.y = downY - mPoint2ItemTop + mOffset2Top - mStatusHeight;
mWindowLayoutParams.alpha = 0.55f; //透明度
mWindowLayoutParams.width = WindowManager.LayoutParams.WRAP_CONTENT;
mWindowLayoutParams.height = WindowManager.LayoutParams.WRAP_CONTENT;
mWindowLayoutParams.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
| WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE ;

mDragImageView = new ImageView(getContext());
mDragImageView.setImageBitmap(bitmap);
mWindowManager.addView(mDragImageView, mWindowLayoutParams);
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
if(isDrag && mDragImageView != null){
switch(ev.getAction()){
case MotionEvent.ACTION_MOVE:
moveX = (int) ev.getX();
moveY = (int) ev.getY();
moveRawY = (int) ev.getRawY();
//拖动item
onDragItem(moveX, moveY);
break;
case MotionEvent.ACTION_UP:
onStopDrag();
isDrag = false;
break;
}
return true;
}
return super.onTouchEvent(ev);
}

解决问题三

为题三的解决比较简单，当gridview接收到长按事件后，处理ViewPager和ScrollView的方法一样

requestDisallowInterceptTouchEvent(false);

这个方法是让ViewGroup本身不拦截触摸事件。当gridView滑动结束在

requestDisallowInterceptTouchEvent(true);

解决问题四

直接上源码

public class ControlScrollView extends ScrollView {

private boolean isInControl = true;
private int moveSpeed = 5;
private final int msgWhat = 1;
private final int time = 20;
private ScrollState scrollState;

public ControlScrollView(Context context) {
super(context);
init();
}

public ControlScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}

@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
switch (ev.getAction()) {
case MotionEvent.ACTION_MOVE:/**/
if (!isInControl) {
if (ev.getY() < 0) {
if (!myHandler.hasMessages(msgWhat)) {
Message msg = new Message();
msg.arg1 = -1;
msg.what = msgWhat;
myHandler.sendMessageDelayed(msg, time);
}
return super.dispatchTouchEvent(ev);
} else if (ev.getY() > getHeight()) {
if (!myHandler.hasMessages(msgWhat)) {
Message msg = new Message();
msg.arg1 = 1;
msg.what = msgWhat;
myHandler.sendMessageDelayed(msg, time);
}
return super.dispatchTouchEvent(ev);
} else {
myHandler.removeMessages(msgWhat);
}
} else {
myHandler.removeMessages(msgWhat);
}
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
if (scrollState != null) {
scrollState.stopTouch();
}
myHandler.removeMessages(msgWhat);
requestDisallowInterceptTouchEvent(false);
break;
}
return super.dispatchTouchEvent(ev);
}

@Override
protected void onDetachedFromWindow() {
super.onDetachedFromWindow();
myHandler.removeMessages(msgWhat);
}

private void init() {
moveSpeed = ScreenUtils.dip2px(getContext(), moveSpeed);
}

public boolean isInControl() {
return isInControl;
}

public ScrollState getScrollState() {
return scrollState;
}

public void setScrollState(ScrollState scrollState) {
this.scrollState = scrollState;
}

public void setInControl(boolean inControl) {
isInControl = inControl;
}

private Handler myHandler = new Handler() {
@Override
public void dispatchMessage(Message msg) {
super.dispatchMessage(msg);
smoothScrollBy(0, moveSpeed * (msg.arg1 > 0 ? 1 : -1));
Message msg1 = new Message();
msg1.what = msg.what;
msg1.arg1 = msg.arg1;
myHandler.sendMessageDelayed(msg1, time);
}
};

public interface ScrollState {
void stopTouch();
}

}

结束

源码地址 https://github.com/halibobo/TouchListenerConflict 欢迎star