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);    }   } }