I would like to create a background with two colors at a 45 degree angle, but without transition. I did it this way:
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle" >
<gradient
android:type="linear"
android:startColor="#000"
android:endColor="#FFF"
android:angle="45"/>
</shape>
The problem is that you get a transition, like this:
I'dlikesomethingwithoutthis"transition": 
In XML I do not know if it's possible. In Java, a possible way is to create a Shape and build a ShapeDrawable with it.
TwoTrianglesDrawable.java
public class DoisTriangulosDrawable extends ShapeDrawable {
public DoisTriangulosDrawable(){
super();
setShape(new DoisTriangulosShape());
}
private class DoisTriangulosShape extends Shape {
@Override
public void draw(Canvas canvas, Paint paint) {
Path path = new Path();
path.setFillType(Path.FillType.INVERSE_EVEN_ODD);
Path path1 = new Path();
path1.setFillType(Path.FillType.INVERSE_EVEN_ODD);
paint.setStrokeWidth(0);
paint.setStyle(Paint.Style.FILL);
paint.setAntiAlias(true);
paint.setColor(Color.BLACK);
Point a = new Point(0, 0);
Point b = new Point(0, (int) getHeight());
Point c = new Point((int)getWidth(), (int)getHeight());
path.moveTo(a.x, a.y);
path.lineTo(b.x, b.y);
path.lineTo(c.x, c.y);
path.close();
canvas.drawPath(path, paint);
paint.setColor(Color.RED);
Point a1 = new Point(0, 0);
Point b1 = new Point((int)getWidth(),0);
Point c1 = new Point((int)getWidth(), (int)getHeight());
path1.moveTo(a1.x, a1.y);
path1.lineTo(b1.x, b1.y);
path1.lineTo(c1.x, c1.y);
path1.close();
canvas.drawPath(path1, paint);
}
}
}
To use, for example, background of a RelativeLayout :
RelativeLayout layout = (RelativeLayout) findViewById(R.id.layout);
ShapeDrawable background = new DoisTriangulosDrawable();
layout.setBackground(background);//Requer API16 ou superior