自定义控件（阴影，渐变）

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ShaderView.java:

public class ShaderView extends View {
    private Paint paint;
    public ShaderView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public ShaderView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }
    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        paint = new Paint(Paint.ANTI_ALIAS_FLAG);
        paint.setStrokeWidth(5);
        paint.setTextSize(100);
        this.setLayerType(View.LAYER_TYPE_SOFTWARE,paint);//设置为SOFTWARE才会实现阴影
        paint.setShadowLayer(10,1,1, Color.BLUE);//偏移度很小时则变成发光字体
        canvas.drawText("Android开发",100,100,paint);
        canvas.restore();
        paint.setShadowLayer(10,5,5,Color.GREEN);//如果想要取消阴影，则将Radius设为0即可
        canvas.drawText("Android,你好",100,400,paint);
    }
}

渐变效果代码：

public class RadialGradientView extends View {
    private int color[]={Color.GREEN,Color.BLUE,Color.RED};
    //private float position[]={0,0.5f,1};
    public RadialGradientView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public RadialGradientView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        Rect rect=new Rect(100,100,600,600);
        //1.径向渐变
        RadialGradient r=new RadialGradient(350,350,250, Color.BLUE,Color.YELLOW, Shader.TileMode.MIRROR);
        //2.线性渐变
      //  LinearGradient r=new LinearGradient(100,100,600,600,Color.RED,Color.GREEN, Shader.TileMode.CLAMP);
        //3.扫描渐变
       // SweepGradient r=new SweepGradient(350,350,Color.RED,Color.GREEN);
        //SweepGradient r=new SweepGradient(350,350,color,null);
        //4.位图渐变
//        Bitmap bitmap= BitmapFactory.decodeResource(getResources(),R.drawable.boy);
//        BitmapShader r=new BitmapShader(bitmap, Shader.TileMode.REPEAT, Shader.TileMode.MIRROR);
        //5.混合渐变
//        LinearGradient lg=new LinearGradient(100,100,600,600,Color.RED,Color.GREEN, Shader.TileMode.CLAMP);
//        Bitmap bitmap= BitmapFactory.decodeResource(getResources(),R.drawable.boy);
//        BitmapShader bs=new BitmapShader(bitmap, Shader.TileMode.REPEAT, Shader.TileMode.MIRROR);
//        ComposeShader r=new ComposeShader(bs,lg, PorterDuff.Mode.SRC_ATOP);
        //公用部分
        Paint paint=new Paint(Paint.ANTI_ALIAS_FLAG);
        paint.setShader(r);
        canvas.drawRect(rect,paint);
        canvas.translate(0,500);
        canvas.drawOval(new RectF(rect),paint);
    }
}

我们做一个旋转的圆， 圆内使用 SweepGradient 渐变填充，看起来像一张光盘。首先， 我们创建了一个 Matrix 对象 mMatrix， mMatrix 定义了以圆点为中心渐变的旋转效
果， 注意不是旋转 Canvas 而是旋转 SweepGradient。 onDraw()方法中不断调用 invalidate()重绘自己， 每重绘一次就旋转 2 度，于是就形成了一个旋转的动画。

SweepMatrixView.java:

public class SweepMatrixView extends View {
    private Paint mpaint=new Paint(Paint.ANTI_ALIAS_FLAG);
    private float mRotate;
    private Matrix matrix=new Matrix();
    private Shader mshader;
    private int[] color={ Color.GREEN,Color.RED,Color.BLUE};
    public SweepMatrixView(Context context, AttributeSet attrs) {
        super(context, attrs);
        setFocusable(true);
        setFocusableInTouchMode(true);

        float x=100;
        float y=100;
        mshader=new SweepGradient(x,y,color,null);
        mpaint.setShader(mshader);
    }

    public SweepMatrixView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        Paint paint =mpaint;
        float x=100;
        float y=100;
        canvas.translate(100,100);
        canvas.drawColor(Color.WHITE);
        matrix.setRotate(mRotate,x,y);
        mshader.setLocalMatrix(matrix);
        mRotate+=2;
        if(mRotate>=360){
            mRotate=0;
        }
        invalidate();
        canvas.drawCircle(x,y,100,paint);
    }
}

自定义控件（阴影，渐变）

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原文地址：http://blog.csdn.net/fuzhongbin/article/details/51321469