Android RelativeLayout不显示视图

Question

I've been trying to set a View inside a RelativeLayout but something strange is happeing. When i set the LayoutParams to MATCH_PARENT the view is not showing. However when I set the size of the LayoutParams manually the View is showing correcly. Here is my code:

protected void onCreate(Bundle savedInstanceState) {
...
    RelativeLayout layout = new RelativeLayout(this);
    RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(
        LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
    layout.setLayoutParams(params);

    rectangle = new Rectangle (this);   
    RelativeLayout.LayoutParams rectParams = new RelativeLayout.LayoutParams(LayoutParams.MATCH_PARENT,
           LayoutParams.MATCH_PARENT);
    rectangle.setLayoutParams(rectParams); 
    //rectangle.setLayoutParams(new LayoutParams(2000, 1280)); If I do this the Rectangle shows correctly

    rectangle.setX(valueX);
    rectangle.setX(valueY);
    layout.addView(rectangle);
}
class Rectangle extends View {
    Paint paint = new Paint();
    Paint paint2 = new Paint();
    RectF rect = new RectF();
    public Rectangle(Context context) {
        super(context);   
    }

    @Override
    public void onDraw(Canvas canvas) {      
        paint.setColor(Color.rgb(255,20,147));
        rect.set(10, 10, 250, 90);
        paint.setStyle(Paint.Style.FILL);
        canvas.drawRoundRect(rect, 3, 3, paint);

        paint2.setColor(Color.WHITE);
        rect.set(10, 10, 250, 90);
        paint2.setStrokeWidth(5);
        paint2.setStyle(Paint.Style.STROKE);
        canvas.drawRoundRect(rect, 5, 5, paint2);
        canvas.drawLine(210, 39, 230,54, paint2);
        canvas.drawLine(210, 63, 230,52, paint2);
        super.onDraw(canvas);           
    }
}

The layout object is inside a scroll . I've been trying to change the LayoutParameters but no success. Nothing is seen. Any ideas?

Answer 1

Maybe the problem is that you set the layout height of the container (the RelativeLayout) as WRAP_CONTENT, and the height of the content (the Rectangle) as MATCH_PARENT. Try to change

RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);

with

RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);

Furthermore, you call two times setX (I suppose the second time you want to call setY):

rectangle.setY(valueY);