Adding text on top of an image using a Canvas - Android

Question

I want to add some text on top of an image. I read the image from the sd card and set it to a Bitmap variable.

Bitmap myBitmap = BitmapFactory.decodeFile(imgFile.getAbsolutePath());

Then I added it to a canvas. The code I used is given below,

Canvas c = new Canvas(myBitmap);

But when I added this line, the app crashed at that point. Why is it and how can i solve this ??

Note : Above mention code lines are inside onActivityResult method.

Answer 1

You app crash because your

BitmapFactory.decodeFile

return a immutable bitmap and public Canvas (Bitmap bitmap) only accept a mutable bitmap.

To solve your problem you must convert your immutable Bitmap into mutable see here the method

If you target only >= API 11 , you can use

final BitmapFactory.Options options = new BitmapFactory.Options();
options.inMutable = true;
Bitmap myBitmap = BitmapFactory.decodeFile(imgFile.getAbsolutePath(), options);