Linking nested SurfaceView class inside xml

Question

I have a class inside a class that extends SurfaceView like this:

MainActivity.java

public class MainActivity extends Activity implements OnTouchListener {

    SurfaceTest mySurface;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.surface);
        mySurface = (SurfaceTest) findViewById(R.layout.surface);
        mySurface.setOnTouchListener(this);
    }
    @Override
    public boolean onTouch(View arg0, MotionEvent arg1) {
        // TODO Auto-generated method stub
        // ... some code ...
        return true;
    }
    public class SurfaceTest extends SurfaceView implements Runnable {

        SurfaceHolder myHolder;

        public SurfaceTest(Context context) {
            super(context);
            // TODO Auto-generated constructor stub
            myHolder = getHolder();
        }

        public SurfaceTest(Context context, AttributeSet attrs) {
            super(context, attrs);
            // TODO Auto-generated constructor stub
            myHolder = getHolder();
        }

        public SurfaceTest(Context context, AttributeSet attrs, int defStyle) {
            super(context, attrs, defStyle);
            // TODO Auto-generated constructor stub
            myHolder = getHolder();
        }

        @Override
        public void run() {
            // TODO Auto-generated method stub
            while (true) {
                if (!myHolder.getSurface().isValid()) {
                    continue;
                }
                Canvas canvas = myHolder.lockCanvas();
                //...some code...
                myHolder.unlockCanvasAndPost(canvas);
            }
        }
    }
}

surface.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
    <com.example.testsurfaceview.MainActivity.SurfaceTest
        android:id="@+id/surfaceView"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" />

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Button" />

</FrameLayout>

I have an error in Graphical Layout of this xml file saying

"The following classes could not be instantiated:
- com.example.testsurfaceview.MainActivity.SurfaceTest"

One possible solution that worked for me was to create new class for SurfaceTest class and then using com.example.testsurfaceview.SurfaceTest in xml file.

But the problem again is I use a lot of information from onTouch event which is used to draw on canvas in run() method. This is the reason I implemented SurfaceTest class inside MainActivity

So I have two choices right now:

1) make xml work for nested SurfaceTest class 2) create new SurfaceTest class and pass all the info obtained in onTouch using an Intent.

What do you suggest?

score 1 · Answer 1 · edited May 28 '13 at 07:08

1

Create a different class file named as SurfaceTest in your package and then add it into your xml file. It will surely work. Add the onDraw(Canvas canvas) and onTouchEvent(MotionEvent event) into your Surface View class.

edited May 28 '13 at 07:08

Storm

684
9
20

answered May 28 '13 at 06:45

Karan Maru

991
6
17

so, I put all 'variables' and 'onTouch' event in different 'SurfaceTest' class... okay..lets see.. I'll be right back to let you know the result. :) Thanks for the suggestion @Karan – Ravi Ojha May 28 '13 at 07:12
I'm stuck at one more poblem while implementing the above setup, As you said I created a new different class `SurfaceTest`, and in `MainActivity` I declared `SurfaceTest mySurface;` and in onCreate() `mySurface = new SurfaceTest(this);` but what about `mySurface.setOnTouchListener(this);` where to put this now? Sorry I'm not very much familiar with Android Programming. – Ravi Ojha May 28 '13 at 07:23
add the SurfaceTest class into your MainActivty xml file(for which region u need surface object movement) & remove all declaration of SurfaceTest from MainActivity class. – Karan Maru May 29 '13 at 05:20
go through this. It might be useful for your problem :::http://stackoverflow.com/questions/4938822/how-can-i-use-the-animation-framework-inside-the-canvas/4946893#4946893 – Karan Maru May 29 '13 at 05:51
I found a way using SurfaceHolder.Callback.. It worked till now, though I have not finished my project...thank you for your help..@Karan – Ravi Ojha May 30 '13 at 14:22

Linking nested SurfaceView class inside xml

1 Answers1