自定义TextView 实现文字渐变效果

上代码

public class MyTextView extends TextView {

private LinearGradient mLinearGradient;
private Matrix mGradientMatrix;
private Paint mPaint;
private int mViewWidth = 0;
private int mTranslate = 0;

private boolean mAnimating = true;

public MyTextView(Context context, 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();
mLinearGradient = new LinearGradient(-mViewWidth, 0, 0, 0,
new int[] { 0x33ffffff, 0xffffffff, 0x33ffffff },
new float[] { 0, 0.5f, 1 }, Shader.TileMode.CLAMP);
mPaint.setShader(mLinearGradient);
mGradientMatrix = new Matrix();
}
}
}

@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (mAnimating && mGradientMatrix != null) {
mTranslate += mViewWidth / 10;
if (mTranslate > 2 * mViewWidth) {
mTranslate = -mViewWidth;
}
mGradientMatrix.setTranslate(mTranslate, 0);
mLinearGradient.setLocalMatrix(mGradientMatrix);
postInvalidateDelayed(50);
}
}
}