重写ImageView中的方法，如下所示:

Override methods in ImageView as written below:

private float FadeStrength = 1.0f;
private int FadeLength = 40px;

@Override
protected float getTopFadingEdgeStrength() {
    return FadeStrength;
}

@Override
protected float getBottomFadingEdgeStrength() {
    return FadeStrength;
}

@Override
protected float getLeftFadingEdgeStrength() {
    return FadeStrength;
}

@Override
protected float getRightFadingEdgeStrength() {
    return FadeStrength;
}

在初始化视图时添加行:

And on initialization of view add lines:

setFadingEdgeLength(FadeLength);
setVerticalFadingEdgeEnabled(true);
setHorizontalFadingEdgeEnabled(true);