Java (Android): How to scale a drawable without Bitmap?

问题

I need to scale the background image of a button but can't turn it into a Bitmap. Here is the code right now:

int height = 50;
int width = 80;

Button b = new Button (this);
b. setBackgroundResource(R.drawable.btn);

Now I need to scale "R.drawable.btn" according to the "height" and "width". The setBackgroundResource won't accept a Bitmap. How do I do that?

Thank you.

回答1:

You can allow the layout parameters to control the scale or you can scale the image yourself.

Allow the layout to scale the image:

b.setBackground(getResources().getDrawable(R.drawable.btn));

Scale the image manually:

Bitmap original = BitmapFactory.decodeResource(context.getResources(), R.drawable.btn);
Bitmap b = Bitmap.createScaledBitmap(original, width, height, false);
Drawable d = new BitmapDrawable(context.getResources(), b);
button.setBackground(d);

Warning: The image may not appear onscreen scaled exactly as you expect. This is because depending on the layout parameters of your Button, Android may additionally scale the image based on the hardware screen density of your device.

回答2:

this will turn a bitmap into a drawable

image = new BitmapDrawable(getResources(),MenuScreen.image1);

image is the drawable and image1 is the bitmap

来源：https://stackoverflow.com/questions/15627712/java-android-how-to-scale-a-drawable-without-bitmap