android中的自定义布局：看不到按钮

Question

So guys,

I made custom layout which extends ViewGroup.Earlier, I made custom view, but later I discovered that it can't contain children like buttons. I did extending viewgroup because I want to add buttons, like in linear layout, just with property of glowing on touch. Anything else will like in linear layout.

WrapLayout class :

public class WrapLayout extends ViewGroup { 
boolean drawGlow = false;
float glowX = 0;
float glowY = 0;
float radius = 20;
Paint paint = new Paint();
{
    paint.setAntiAlias(true);
    paint.setColor(3515877);
    paint.setAlpha(50);
};
public WrapLayout(Context context, AttributeSet attrs) {

    super( context, attrs );
    setWillNotDraw(false);
}
public WrapLayout(Context context, AttributeSet attrs, int defStyle) {

    super( context, attrs, defStyle );
    setWillNotDraw(false);
}
public WrapLayout(Context context) {
    super(context);
    setWillNotDraw(false);
}
public void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    if(drawGlow)
        canvas.drawCircle(glowX, glowY, radius, paint);
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
    // TODO Auto-generated method stub
}
@Override
public boolean onTouchEvent(MotionEvent event){
    if(event.getAction() == MotionEvent.ACTION_DOWN){
        drawGlow = true;
    }else if(event.getAction() == MotionEvent.ACTION_UP)
        drawGlow = false;
    glowX = event.getX();
    glowY = event.getY();
    this.invalidate();
    return true;
}

}

Then I initialized my activity_main.xml file like this:

<com.example.secondcustomlayout.WrapLayout
.....
>
<Button
android:id="@+id/button1"
...
</Button>
</com.example.secondcustomlayout.WrapLayout>

MainActivity :

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    }

RESULT : Nothing but blank screen.

SOLUTION : What can I do?

With regards

Answer 1

you override onLayout but you not assign the position to the children, that's why you do not see nothing. If you don not want to override onLayout , you should use ( extends ) one of the concrete implementation of ViewGroup , provided by the framework