Shader as a drawable (Android)

问题:

How do I use obtain a drawable from a Shader (such as LinearGradient) so that I can use it as a background in my UI?

回答1:

Since the background will probably need to resize, we will use a ShaderFactory to produce the Shader:

ShapeDrawable.ShaderFactory sf=new ShapeDrawable.ShaderFactory() {     @Override     public Shader resize(int width, int height) {         return new LinearGradient(0, 0, width, height,             new int[]{Color.WHITE, Color.GRAY, Color.BLACK},             new float[]{0,0.5f,1}, Shader.TileMode.MIRROR);     } }; 

We use this to create a PaintDrawable which we can use as a background:

PaintDrawable p=new PaintDrawable(); p.setShape(new RectShape()); p.setShaderFactory(sf); getWindow().setBackgroundDrawable(p); 

This is just an example and in this case it would actually be better to just declare this using XML. Look at the example here.

文章来源: Shader as a drawable (Android)