Android Textview实现颜色渐变滚动效果

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);    }   } }