android画图----ShapeDrawable和shader

在这个例程中主要讲述了ShapeDrawable，以及各种Gradient
首先初始化了 mDrawables = new ShapeDrawable[7];默认的是矩形，
当然还有其他形状：
mDrawables[0] = new ShapeDrawable(new RectShape());
mDrawables[1] = new ShapeDrawable(new OvalShape());
mDrawables[4] = new ShapeDrawable(new RoundRectShape(outerR, inset,
innerR));
mDrawables[5] = new ShapeDrawable(new PathShape(path, 100, 100));
float[] outerR = new float[] { 12, 12, 12, 12, 0, 0, 0, 0 };
RectF inset = new RectF(20, 20, 20, 20);
float[] innerR = new float[] { 12, 12, 0, 0, 12, 12, 0, 0 };

Path path = new Path();
path.moveTo(50, 0);
path.lineTo(0, 50);
path.lineTo(50, 100);
path.lineTo(100, 50);
path.close();

实例化ShapeDrawable后就可以对他们进行设置：
设置渐变
mDrawables[0].getPaint().setShader(makeTiling());
设置颜色
mDrawables[1].getPaint().setColor(0xFF00FF00);
设置影响 影响呢有很多 可以设置单个 也可以用组合
PathEffect pe = new DiscretePathEffect(10, 2);
PathEffect pe2 = new CornerPathEffect(8);
mDrawables[3].getPaint().setPathEffect(
new SumPathEffect(pe2, pe));
其中渐变又包括：
private static Shader makeSweep() {
return new SweepGradient(150, 25, new int[] { 0xFFFF0000, 0xFF00FF00, 0xFF0000FF, 0xFFFF0000 }, null);
//return new SweepGradient(150, 25, new int[] { 0xFFFF0000, 0xFF00FF00, 0xFF0000FF }, new float[]{0.9f,0.1f,0.9f});
}

private static Shader makeLinear() {
return new LinearGradient(0, 0, 50, 50,
new int[] { 0xFFFF0000, 0xFF00FF00, 0xFF0000FF },
null, Shader.TileMode.REPEAT);
}

private Shader makeTiling() {
int[] pixels = new int[] { 0xFFFF0000, 0xFF00FF00, 0xFF0000FF, 0};

Bitmap bm = Bitmap.createBitmap(pixels, 2, 2, Bitmap.Config.ARGB_8888);
// Bitmap bm = Bitmap.createBitmap(mBitmap, 60, 45, Bitmap.Config.ARGB_8888);

return new BitmapShader(bm, Shader.TileMode.REPEAT,
Shader.TileMode.REPEAT);
}

最后在这个实例中 可以自定义一个ShapeDrawable
private static class MyShapeDrawable extends ShapeDrawable {
private Paint mStrokePaint = new Paint(Paint.LINEAR_TEXT_FLAG);

public MyShapeDrawable(Shape s) {
super(s);
mStrokePaint.setStyle(Paint.Style.STROKE);
mStrokePaint.setColor(Color.GREEN);
}

public Paint getStrokePaint() {
return mStrokePaint;
}

@Override protected void onDraw(Shape s, Canvas c, Paint p) {
//第一个调用父类的p，第二个调用自己刚才设置的p，如果你不想使用默认的父类，默认的颜色为黑了
s.draw(c, p);
s.draw(c, mStrokePaint);
}

mDrawables[6] = new MyShapeDrawable(new ArcShape(45, 360));
MyShapeDrawable msd = (MyShapeDrawable)mDrawables[6];
msd.getStrokePaint().setStrokeWidth(1);
}