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();//獲得當前繪制的Paint對象 
    mLinearGradient = new LinearGradient( 
      0,//漸變起始點x坐標 
      0,//漸變起始點y坐標 
      mViewWidth,//漸變結束點x點坐標 
      0,//漸變結束點y坐標 
      new int[]{ 
        Color.BLUE, 0xffffffff, 
        Color.BLUE,Color.RED,Color.YELLOW},//顏色的int數組 
      null,//相對位置的顏色數組,可為null, 若為null,可為null,顏色沿漸變線均勻分布 
      Shader.TileMode.MIRROR);//平鋪模式 
    mPaint.setShader(mLinearGradient);//給這個paint設置linearFradient屬性 
    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);//通過矩陣的方式不斷平移產生漸變效果 
   postInvalidateDelayed(100); 
 
  } 
 
 } 
}