Combination of canvas and layout (Android)

Question

My question is about Android UI. When we work with an XML layout, we write (for example)

setContentView(R.layout.main);

And when we work with 2d graphics, we write

Draw2D d = new Draw2D(this);
setContentView(d);

So what if I want to use both? I need to use layout-xml and part of the screen is fir painting (Canvas). I read about surfaceView, but what about the simple use of Canvas?

Answer 1

In fact, you can inflate your layout from an XML file, and then get any view to draw it. SurfaceView is especially handy for drawing.

The following is an example:

main.xml:

 <?xml version="1.0" encoding="utf-8"?> <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" > <SurfaceView android:id="@+id/surface" android:layout_width="match_parent" android:layout_height="match_parent" /> </FrameLayout> 

TestActivity.java:

 public class TestActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); SurfaceView surface = (SurfaceView) findViewById(R.id.surface); surface.getHolder().addCallback(new Callback() { @Override public void surfaceCreated(SurfaceHolder holder) { // Do some drawing when surface is ready Canvas canvas = holder.lockCanvas(); canvas.drawColor(Color.RED); holder.unlockCanvasAndPost(canvas); } @Override public void surfaceDestroyed(SurfaceHolder holder) { } @Override public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) { } }); } }