Android-DIY-ShimmerTextView

Android自定义控件：闪烁文字效果

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源码传送门

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效果展示

讲解

使用线性渲染LinearGradient设置画笔的着色器Shader，Matrix用于对图像的图形处理，然后不停绘制文本。

@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();
			// 设置线性渲染
			mLinearGradient = new LinearGradient(-mViewWidth, 0, 0, 0, new int[] { 0x59ffffff, 0xffffffff, 0x59ffffff }, new float[] { 0, 0.5f, 1 }, Shader.TileMode.CLAMP);
			// 设置Paint着色器
			mPaint.setShader(mLinearGradient);
			mGradientMatrix = new Matrix();
		}
	}
}

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