将视图分配给RelativeLayout

Question

I want to draw a path that is confined to just a single RelativeLayout , not the entire layout. So I have my DrawPath Class like this:

public class DrawPath extends View {
Paint paint = new Paint();
Path path = new Path();
...

And then in my Main Activity I have this bit of code:

RelativeLayout gB_RL = (RelativeLayout)findViewById(R.id.rel_RL);

dp = new DrawPath(this);
dp.setBackgroundColor(Color.WHITE);
// setContentView(dp);

I've commented out setContentView(dp); because that would assign the DrawPath class to the entire layout. But what I can't figure out is how to assign DrawPath to just the gB_RL Relative Layout

Answer 1

All ViewGroup subclasses (such as RelativeLayout ) have a collection of addView() methods that you can use to add a new View to that ViewGroup.

In this case, your call can be as simple as gB_RL.addView(dp) .

Since you are using a RelativeLayout, you probably want to also create an instance of RelativeLayout.LayoutParams and set that on your dp View so that you can align the dp View correctly.