CODEWITHSUNDEEP
android
user2471612
user2471612

Reputation: 53

Drawing on Button Click

I want to draw a rectangle on a button click. All the research I've done says to me that this should work, but it doesn't. I simply can't understand why.

In my MainActivity class I have:

Bitmap b = Bitmap.createBitmap(100, 100, Bitmap.Config.ARGB_8888);
public Canvas canvas = new Canvas(b);

In my constructor I have:

 button.setOnClickListener(new View.OnClickListener()
    {
        public void onClick(View v)
        {
            Paint paint = new Paint();
            paint.setColor(Color.GREEN);
            //paint.setStrokeWidth(5);
            canvas.drawRect(0, 0, 50, 50, paint);
            Log.e("Blah Blah Blah", "Blah Blah, Blah");
        }
    });

It does go into the function, which I see because when I click it the "Blah Blah Blah" is logged, but it doesn't draw the rectangle.

Any ideas?

Upvotes: 0

Views: 1162

Answers (1)

Waza_Be
Waza_Be

Reputation: 39577

You need to set your canvas to an ImageView

//Create a new image bitmap and attach a brand new canvas to it
Bitmap tempBitmap = Bitmap.createBitmap(myBitmap.getWidth(), myBitmap.getHeight(), Bitmap.Config.RGB_565);
Canvas tempCanvas = new Canvas(tempBitmap);

//Draw the image bitmap into the cavas
tempCanvas.drawBitmap(myBitmap, 0, 0, null);

 Paint paint = new Paint();
 paint.setColor(Color.GREEN);
 //paint.setStrokeWidth(5);
tempCanvas.drawRoundRect(new RectF(x1,y1,x2,y2), 2, 2, paint);

//Attach the canvas to the ImageView
myImageView.setImageDrawable(new BitmapDrawable(getResources(), tempBitmap));

Upvotes: 1

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