CODEWITHSUNDEEP
androidbuttoncanvasbitmapdraw
Sang Nguyen
Sang Nguyen

Reputation: 11

Create Buttons on Canvas in Android

I have a problem, I don't know how to create buttons on my canvas. This code below I wrote to draw a line on a picture. Then I want to add some buttons on that picture. Hope you guys can help me.

public class DrawShape extends Activity implements View.OnTouchListener {
ImageView imagTest;
Bitmap bitmap;
Canvas canvas;
Paint paint;
Button abc;
float downX, downY, moveX, moveY, upX, upY = 0;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.drawshape);

    imagTest = (ImageView) findViewById(R.id.imgTest);//Add image 

    Display display = getWindowManager().getDefaultDisplay();
    int dw = display.getWidth();
    int dh = display.getHeight();

    Bitmap loadedBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.image1);//load image onto bitmap
    Bitmap scaledloadedBitmap = Bitmap.createScaledBitmap(loadedBitmap, dw, dh, false);
    Bitmap drawableBitmap = scaledloadedBitmap.copy(Bitmap.Config.ARGB_8888, true);
    Matrix matrix = new Matrix();
    imagTest.setScaleType(ImageView.ScaleType.MATRIX);
    matrix.postRotate(90);

    canvas = new Canvas(drawableBitmap);
    paint = new Paint();
    paint.setColor(Color.GREEN);
    paint.setShadowLayer(5, 2, 2, Color.BLUE);
    paint.setStrokeWidth(10);
    imagTest.setImageBitmap(drawableBitmap);
    imagTest.setOnTouchListener(this);


}
@Override
public boolean onTouch(View v, MotionEvent event) {
    switch (event.getAction()) {
        case MotionEvent.ACTION_DOWN:
            downX = event.getX();
            downY = event.getY();
            break;
        case MotionEvent.ACTION_MOVE:
            moveX = event.getX();
            moveY = event.getY();

            break;
        case MotionEvent.ACTION_UP:
            upX = event.getX();
            upY = event.getY();
            canvas.drawLine(downX, downY, upX, upY, paint);//Handle when touch up
            imagTest.invalidate();
            break;
    }
    return true;
}
}

Upvotes: 1

Views: 3511

Answers (2)

GHosT
GHosT

Reputation: 276

You need to create a Custom View Class which extends the View class Button and override its onDraw() method, like this:

public class MyButtonClass extends Button {
    public MyButtonClass(Context context) {
        super(context);

        // Here you can set a default parameters for this View, e.g.:
        this.setText("My Green Button...");
    }

    @Override
    protected void onDraw(Canvas canvas) {
        // Here you need to declare what paint you canvas, e.g.:
        canvas.drawColor(Color.GREEN); // Set color
        canvas.drawBitmap(BitmapFactory.decodeResource(getResources(), 
            R.drawable.my_button), 0f, 0f, null); // Set drawable
        // .......... set others

        super.onDraw(canvas);
    }
}

In the onCreate() method, you need to write next:

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    LinearLayout groupview = 
        (LinearLayout) findViewById(R.id.groupview); // Find container for button
    MyButtonClass myBtn = new MyButtonClass(this); // Create custom button
    groupview.addView(myBtn); // Add your button to layout
}

Upvotes: 0

Yakovlev Ilya
Yakovlev Ilya

Reputation: 11

You can not put a button on the canvas. You can put canvas into new layer, then add your buttons into related layer under layer with canvas.

Upvotes: 1

Related Questions