颜色渐变滚动Textview

public class FlashTextView extends android.support.v7.widget.AppCompatTextView {  
    private Paint mPaint;  
    private int mViewWidth;  
    private LinearGradient mLinearGradient;  
    private Matrix mGradientMatrix;  
    private int mTransalte;  
  
    public FlashTextView(Context context, @Nullable AttributeSet attrs) {  
        super(context, attrs);  
    }  
  
    @Override  
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {  
        super.onSizeChanged(w, h, oldw, oldh);  
        if (mViewWidth == 0) {  
            mViewWidth = getMeasuredWidth();  
            if (mViewWidth > 0) {  
                mPaint = getPaint();//获得当前绘制的Paint对象  
                mLinearGradient = new LinearGradient(  
                        0,//渐变起始点x坐标  
                        0,//渐变起始点y坐标  
                        mViewWidth,//渐变结束点x点坐标  
                        0,//渐变结束点y坐标  
                        new int[]{  
                                Color.BLUE, 0xffffffff,  
                                Color.BLUE,Color.RED,Color.YELLOW},//颜色的int数组  
                        null,//相对位置的颜色数组,可为null,  若为null,可为null,颜色沿渐变线均匀分布  
                        Shader.TileMode.MIRROR);//平铺模式  
                mPaint.setShader(mLinearGradient);//给这个paint设置linearFradient属性  
                mGradientMatrix = new Matrix();  
            }  
        }  
    }  
  
    @Override  
    protected void onDraw(Canvas canvas) {  
        super.onDraw(canvas);  
  
        if (mGradientMatrix != null) {  
            mTransalte += mViewWidth / 5;  
            if (mTransalte > 2 * mViewWidth) {  
                mTransalte -= mViewWidth;  
            }  
            mGradientMatrix.setTranslate(mTransalte, 0);  
            mLinearGradient.setLocalMatrix(mGradientMatrix);//通过矩阵的方式不断平移产生渐变效果  
            postInvalidateDelayed(100);  
  
        }  
  
    }  
}  

原文链接：http://blog.csdn.net/qq_29703975/article/details/66973941