CODEWITHSUNDEEP
androidimagecanvas
Karthik
Karthik

Reputation: 5033

How to display the Canvas part of a view in android?

I am working on a code where we use canvas to detect the touch on the screen.As of now the canvas is been directly drawn.How to add it as part of a view which comprises of other elements in xml.Here is the code 

public class Tutorial2D extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(new Panel(this));
    }
}

Here is the other part of it 

public class Panel extends SurfaceView implements SurfaceHolder.Callback {

private ViewThread mThread;
private ArrayList<Element> mElements = new ArrayList<Element>();

public Panel(Context context) {
    super(context);
    getHolder().addCallback(this);
    mThread = new ViewThread(this);
}

public void doDraw(Canvas canvas) {
    canvas.drawColor(Color.TRANSPARENT);
    synchronized (mElements) {
        for (Element element : mElements) {
            element.doDraw(canvas);
        }
    }
}

@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
    // TODO Auto-generated method stub
}

@Override
public void surfaceCreated(SurfaceHolder holder) {
    if (!mThread.isAlive()) {
        mThread = new ViewThread(this);
        mThread.setRunning(true);
        mThread.start();
    }
}

@Override
public void surfaceDestroyed(SurfaceHolder holder) {
    if (mThread.isAlive()) {
        mThread.setRunning(false);
    }
}

@Override
public boolean onTouchEvent(MotionEvent event) {
    synchronized (mElements) {
        mElements.add(new Element(getResources(), (int) event.getX(), (int) event.getY()));
    }
    return super.onTouchEvent(event);
}

}

How to add this canvas to the main xml and been displayed over an image,any snippet on this or how should I change working on this code,anything will be greatful.Thanks

Upvotes: 0

Views: 456

Answers (2)

eyespyus
eyespyus

Reputation: 1576

Try this constructor for the Panel class:

public Panel(Context context, AttributeSet attrs) {
    super(context, attrs);
    getHolder().addCallback(this);
    mThread = new ViewThread(this);
}

Upvotes: 1

chiuki
chiuki

Reputation: 14700

You can use the custom view in xml layout with its package name. For example, in main.xml:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:orientation="vertical">
  <TextView
    android:layout_width="match_parent"
    android:layout_height="wrap_content" 
    android:text="Hello" />
  <your.package.name.Panel
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />
</LinearLayout>

Then, in onCreate of your activity:

setContentView(R.layout.main);

Upvotes: 1

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