自定义ViewGroup的探究
先说现象吧，如下是一个比较简单的没有任何功能的一个ViewGroup，写此demo的意图就是了解自定义ViewGroup情况下，内部代码走向
public class HViewGroup extends ViewGroup {
int xFirst;int yFirst;
int mLastX;
int mLastY;
int RawX;
int RawY;
int x;
int y;
boolean intercepted=false;
publicHViewGroup(Context context) {
super(context);
Log.i("zhm","1");
}
publicHViewGroup(Context context, AttributeSet attrs) {
super(context, attrs);Log.i("zhm","2");
}
publicHViewGroup(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);Log.i("zhm","3");
}
@RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
publicHViewGroup(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
super(context, attrs, defStyleAttr, defStyleRes);Log.i("zhm","4");
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
}
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN:
Log.i("zhm","onIntercept中down");
xFirst= (int) ev.getX();
yFirst= (int) ev.getY();
Log.i("zhm","down中xFirst=="+xFirst+"==yFirst=="+yFirst);
intercepted=false;
break;
case MotionEvent.ACTION_MOVE:
Log.i("zhm","onIntercept中move");
x= (int) ev.getX();
y= (int) ev.getY();
mLastX=x;
mLastY=y;
Log.i("zhm","move中mLastX=="+mLastX+"==mLastY=="+mLastY);
if (parentMove(ev)) {
intercepted = true;
} else {
intercepted=false;
}
break;
case MotionEvent.ACTION_UP:
Log.i("zhm","onIntercept中up");
x= (int) ev.getX();
y= (int) ev.getY();
RawX=(int)ev.getRawX();
RawY=(int)ev.getRawY();
mLastX=x;
mLastY=y;
Log.i("zhm","up中mLastX=="+mLastX+"==mLastY=="+mLastY);
intercepted=false;
break;
}
// mLastX=x;
// mLastY=y;
return intercepted;
}
@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
Log.i("zhm","dispatchTouchEvent");
return super.dispatchTouchEvent(ev);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
Log.i("zhm","onTouch中down");
Log.i("zhm","Touchdown中xFirst=="+event.getX()+"==yFirst=="+event.getY());
break;
case MotionEvent.ACTION_UP:
Log.i("zhm","onTouch中up");
break;
case MotionEvent.ACTION_MOVE:
Log.i("zhm","onTouch中move");
x= (int) event.getX();
y= (int) event.getY();
mLastX=x;
mLastY=y;
Log.i("zhm","touch move中mLastX=="+mLastX+"==mLastY=="+mLastY);
if (parentMove(event)) {
intercepted = true;
} else {
intercepted=false;
}
break;
}
// if (onInterceptTouchEvent(event)) {
// Log.i("zhm","onTouchevent true====");
// } else {
// Log.i("zhm","onTouchevent false====");
// }
return true;
}
//父容器是否move
private boolean parentMove(MotionEvent event) {
int X= (int) Math.abs(event.getX()-xFirst);
int Y= (int) Math.abs(event.getY()-yFirst);
Log.i("zhm","parentMove中xFirst=="+xFirst+"==yFirst=="+yFirst);
Log.i("zhm","parentMove中X=="+X+"==Y=="+Y);
if (X > Y) {
return true;
} else {
return false;
}
}
}
接下来看Logcat：
11-30 09:57:53.112 21881-21881/com.example.user.myapplication I/zhm: dispatchTouchEvent
11-30 09:57:53.112 21881-21881/com.example.user.myapplication I/zhm: onIntercept中down
11-30 09:57:53.112 21881-21881/com.example.user.myapplication I/zhm: down中xFirst==144==yFirst==539
11-30 09:57:53.112 21881-21881/com.example.user.myapplication I/zhm: onTouch中down
11-30 09:57:53.112 21881-21881/com.example.user.myapplication I/zhm: Touchdown中xFirst==144.82146==yFirst==539.5908
11-30 09:57:53.418 21881-21881/com.example.user.myapplication I/zhm: dispatchTouchEvent
11-30 09:57:53.418 21881-21881/com.example.user.myapplication I/zhm: onTouch中move
11-30 09:57:53.418 21881-21881/com.example.user.myapplication I/zhm: touch move中mLastX==155==mLastY==536
11-30 09:57:53.418 21881-21881/com.example.user.myapplication I/zhm: parentMove中xFirst==144==yFirst==539
11-30 09:57:53.418 21881-21881/com.example.user.myapplication I/zhm: parentMove中X==11==Y==2
11-30 09:57:53.435 21881-21881/com.example.user.myapplication I/zhm: dispatchTouchEvent
11-30 09:57:53.435 21881-21881/com.example.user.myapplication I/zhm: onTouch中move
11-30 09:57:53.435 21881-21881/com.example.user.myapplication I/zhm: touch move中mLastX==160==mLastY==535
11-30 09:57:53.435 21881-21881/com.example.user.myapplication I/zhm: parentMove中xFirst==144==yFirst==539
11-30 09:57:53.435 21881-21881/com.example.user.myapplication I/zhm: parentMove中X==16==Y==3
11-30 09:57:53.452 21881-21881/com.example.user.myapplication I/zhm: dispatchTouchEvent
11-30 09:57:53.452 21881-21881/com.example.user.myapplication I/zhm: onTouch中move
11-30 09:57:53.452 21881-21881/com.example.user.myapplication I/zhm: touch move中mLastX==164==mLastY==535
11-30 09:57:53.452 21881-21881/com.example.user.myapplication I/zhm: parentMove中xFirst==144==yFirst==539
11-30 09:57:53.452 21881-21881/com.example.user.myapplication I/zhm: parentMove中X==20==Y==3
11-30 09:57:53.468 21881-21881/com.example.user.myapplication I/zhm: dispatchTouchEvent
11-30 09:57:53.469 21881-21881/com.example.user.myapplication I/zhm: onTouch中move
11-30 09:57:53.469 21881-21881/com.example.user.myapplication I/zhm: touch move中mLastX==167==mLastY==535
11-30 09:57:53.469 21881-21881/com.example.user.myapplication I/zhm: parentMove中xFirst==144==yFirst==539
11-30 09:57:53.469 21881-21881/com.example.user.myapplication I/zhm: parentMove中X==23==Y==3
11-30 09:57:53.485 21881-21881/com.example.user.myapplication I/zhm: dispatchTouchEvent
11-30 09:57:53.485 21881-21881/com.example.user.myapplication I/zhm: onTouch中move
11-30 09:57:53.485 21881-21881/com.example.user.myapplication I/zhm: touch move中mLastX==170==mLastY==534
11-30 09:57:53.485 21881-21881/com.example.user.myapplication I/zhm: parentMove中xFirst==144==yFirst==539
11-30 09:57:53.486 21881-21881/com.example.user.myapplication I/zhm: parentMove中X==26==Y==4
11-30 09:57:53.502 21881-21881/com.example.user.myapplication I/zhm: dispatchTouchEvent
11-30 09:57:53.502 21881-21881/com.example.user.myapplication I/zhm: onTouch中move
11-30 09:57:53.502 21881-21881/com.example.user.myapplication I/zhm: touch move中mLastX==172==mLastY==534
11-30 09:57:53.502 21881-21881/com.example.user.myapplication I/zhm: parentMove中xFirst==144==yFirst==539
11-30 09:57:53.502 21881-21881/com.example.user.myapplication I/zhm: parentMove中X==28==Y==4
11-30 09:57:53.519 21881-21881/com.example.user.myapplication I/zhm: dispatchTouchEvent
11-30 09:57:53.519 21881-21881/com.example.user.myapplication I/zhm: onTouch中move
11-30 09:57:53.519 21881-21881/com.example.user.myapplication I/zhm: touch move中mLastX==174==mLastY==533
11-30 09:57:53.519 21881-21881/com.example.user.myapplication I/zhm: parentMove中xFirst==144==yFirst==539
11-30 09:57:53.519 21881-21881/com.example.user.myapplication I/zhm: parentMove中X==30==Y==5
11-30 09:57:53.536 21881-21881/com.example.user.myapplication I/zhm: dispatchTouchEvent
11-30 09:57:53.536 21881-21881/com.example.user.myapplication I/zhm: onTouch中move
11-30 09:57:53.536 21881-21881/com.example.user.myapplication I/zhm: touch move中mLastX==177==mLastY==533
11-30 09:57:53.536 21881-21881/com.example.user.myapplication I/zhm: parentMove中xFirst==144==yFirst==539
11-30 09:57:53.536 21881-21881/com.example.user.myapplication I/zhm: parentMove中X==33==Y==5
11-30 09:57:53.552 21881-21881/com.example.user.myapplication I/zhm: dispatchTouchEvent
11-30 09:57:53.553 21881-21881/com.example.user.myapplication I/zhm: onTouch中move
11-30 09:57:53.553 21881-21881/com.example.user.myapplication I/zhm: touch move中mLastX==179==mLastY==533
11-30 09:57:53.553 21881-21881/com.example.user.myapplication I/zhm: parentMove中xFirst==144==yFirst==539
11-30 09:57:53.553 21881-21881/com.example.user.myapplication I/zhm: parentMove中X==35==Y==5
11-30 09:57:53.569 21881-21881/com.example.user.myapplication I/zhm: dispatchTouchEvent
11-30 09:57:53.569 21881-21881/com.example.user.myapplication I/zhm: onTouch中move
11-30 09:57:53.569 21881-21881/com.example.user.myapplication I/zhm: touch move中mLastX==181==mLastY==533
11-30 09:57:53.570 21881-21881/com.example.user.myapplication I/zhm: parentMove中xFirst==144==yFirst==539
11-30 09:57:53.570 21881-21881/com.example.user.myapplication I/zhm: parentMove中X==37==Y==5
11-30 09:57:53.586 21881-21881/com.example.user.myapplication I/zhm: dispatchTouchEvent
11-30 09:57:53.586 21881-21881/com.example.user.myapplication I/zhm: onTouch中move
11-30 09:57:53.586 21881-21881/com.example.user.myapplication I/zhm: touch move中mLastX==183==mLastY==532
11-30 09:57:53.586 21881-21881/com.example.user.myapplication I/zhm: parentMove中xFirst==144==yFirst==539
11-30 09:57:53.586 21881-21881/com.example.user.myapplication I/zhm: parentMove中X==39==Y==6
11-30 09:57:53.603 21881-21881/com.example.user.myapplication I/zhm: dispatchTouchEvent
11-30 09:57:53.603 21881-21881/com.example.user.myapplication I/zhm: onTouch中move
11-30 09:57:53.603 21881-21881/com.example.user.myapplication I/zhm: touch move中mLastX==184==mLastY==532
11-30 09:57:53.603 21881-21881/com.example.user.myapplication I/zhm: parentMove中xFirst==144==yFirst==539
11-30 09:57:53.603 21881-21881/com.example.user.myapplication I/zhm: parentMove中X==40==Y==6
11-30 09:57:53.700 21881-21881/com.example.user.myapplication I/zhm: dispatchTouchEvent
11-30 09:57:53.700 21881-21881/com.example.user.myapplication I/zhm: onTouch中move
11-30 09:57:53.700 21881-21881/com.example.user.myapplication I/zhm: touch move中mLastX==184==mLastY==532
11-30 09:57:53.700 21881-21881/com.example.user.myapplication I/zhm: parentMove中xFirst==144==yFirst==539
11-30 09:57:53.700 21881-21881/com.example.user.myapplication I/zhm: parentMove中X==40==Y==6
11-30 09:57:53.700 21881-21881/com.example.user.myapplication I/zhm: dispatchTouchEvent
11-30 09:57:53.700 21881-21881/com.example.user.myapplication I/zhm: onTouch中up
总结规律：代码运行起来，即走了2，所以必须publicHViewGroup(Context context, AttributeSet attrs) {
super(context, attrs);Log.i("zhm","2");
}
当手指触摸或者滑动都会开始触发dispatchTouchEvent方法，只走了一遍onInterceptTouchEvent方法中ACTION_DOWN的情况，--->onTouchEvent中ACTION_DOWN情况----->dispatchTouchEvent方法--->onToucheEvent中ACTION_MOVE------>dispatchTouchEvent方法------>onTouchEvent中ACTION_MOVE......----->dispatchTouchEvent方法------>onTouchEvent中 ACTION_UP
断点跟踪
此处进入ViewGroup，会后续走Activity、View、ViewRootImpl、InputEventReceiver、MotionEvent类
