关于给Dialog设置setCanceledOnTouchOutside(true)后如何监听Dialog消失

我们设置点击Dialog以外的区域时Dialog消失的设置如下：

dialog.setCanceledOnTouchOutside(true);

首先看Dialog的 setCanceledOnTouchOutside(true)的方法里究竟是什么代码，点击进入Dialog的源码可以看到方法

public void setCanceledOnTouchOutside(boolean cancel) {
if (cancel && !mCancelable) {
mCancelable = true;
}
mWindow.setCloseOnTouchOutside(cancel);
}

以上代码中的mCancelable变量就是我们Dialog另外一个设置是否可消失的方法中设置的.

dialog.setCancelable(true);

接着我们继续看关键代码mWindow.setCloseOnTouchOutside(cancel)

/** @hide */
public void setCloseOnTouchOutside(boolean close) {
mCloseOnTouchOutside = close;
mSetCloseOnTouchOutside = true;
}

既然是点击事件，肯定离不开onTouchEvent()

public boolean onTouchEvent(MotionEvent event) {
if (mCancelable && mShowing && mWindow.shouldCloseOnTouch(mContext, event)) {
cancel();
return true;
}

return false;
}

上面的mCancelable是dialog.setCancelable设置的，关键我们来看mWindow.shouldCloseOnTouch(mContext, event)方法

/** @hide */
public boolean shouldCloseOnTouch(Context context, MotionEvent event) {
if (mCloseOnTouchOutside && event.getAction() == MotionEvent.ACTION_DOWN
&& isOutOfBounds(context, event) && peekDecorView() != null) {
return true;
}
return false;
}

根据名字我们都看出我们的关键方法是isOutOfBounds(context, event)

private boolean isOutOfBounds(Context context, MotionEvent event) {
final int x = (int) event.getX();
final int y = (int) event.getY();
final int slop = ViewConfiguration.get(context).getScaledWindowTouchSlop();
final View decorView = getDecorView();
return (x < -slop) || (y < -slop)
|| (x > (decorView.getWidth()+slop))
|| (y > (decorView.getHeight()+slop));
}

所以可以看出setCanceledOnTouchOutside(true)的监听其实是通过isOutOfBounds(context, event) 的，所以我们要监听点击其他区域关闭dialog的方法就要重写dialog的onTouchEvent方法，然后将isOutOfBounds中的代码加上，代码如下：

class myDialog extends Dialog{

//其他代码略·······

//触摸对话框其他区域的监听
private void onTouchOutside(){}

@Override
public boolean onTouchEvent(MotionEvent event) {
//触摸外部弹窗
if (isOutOfBounds(getContext(), event)) {
onTouchOutside();
}
return super.onTouchEvent(event);
}

private boolean isOutOfBounds(Context context, MotionEvent event) {
final int x = (int) event.getX();
final int y = (int) event.getY();
final int slop = ViewConfiguration.get(context).getScaledWindowTouchSlop();
final View decorView = getWindow().getDecorView();
return (x < -slop) || (y < -slop) || (x > (decorView.getWidth() + slop))
|| (y > (decorView.getHeight() + slop));
}
}