像应用程序Etsy中的模糊效果？

这有几个部分:

1.创建模糊位图:

当抽屉首次打开时,我们从抽屉后面的内容视图创建一个缩小尺寸的位图(缩小使模糊变快).然后我们使用RenderScript将模糊应用于缩小尺寸的图像(更快).为此,您应该阅读已经提到的博客http://nicolaspomepuy.fr/?p=18并查看GlassActionBar项目以获取参考代码https://github.com/ManuelPeinado/GlassActionBar.

注意: RenderScript现在可以在支持库中使用 ...但是无法使用Gradle(现在)构建它.在某些设备上也存在ScriptIntrinsicBlur的问题,尤其是Nexus 10 - 请参阅Roman Nurik的解释

2.展示和动画模糊:

我们的导航抽屉布局包含一个位于内容之上的隐藏ImageView.

<FrameLayout
    android:id="@+id/nav_content_frame"
    android:layout_
    android:layout_ />

<!-- our blur image -->
<ImageView
    android:id="@+id/blur_image"
    android:layout_
    android:layout_
    android:scaleType="centerCrop"
    android:visibility="gone" />

在Activities onCreate()中,您需要获取对此ImageView的引用并设置自定义抽屉侦听器:

mBlurImage = (ImageView) findViewById(R.id.blur_image);
mDrawerLayout = (DrawerLayout) findViewById(R.id.nav_drawer_layout);

mDrawerToggle = new EtsyNavActionBarDrawerToggle(
            this, 
            mDrawerLayout,
            R.drawable.ic_drawer, 
            R.string.nav_drawer_open, 
            R.string.nav_drawer_closed);

mDrawerLayout.setDrawerListener(mDrawerToggle);

我们的抽屉有自定义的稀松布颜色(这是覆盖颜色)而不是默认的透明黑色.这也隐藏了模糊图像在缩小图像上的事实.

mDrawerLayout.setScrimColor(getResources().getColor(R.color.background_main_v2_glass));

抽屉听众设置,清除和动画模糊图像:

private class EtsyNavActionBarDrawerToggle extends ActionBarDrawerToggle {

    public EtsyNavActionBarDrawerToggle(Activity activity, DrawerLayout drawerLayout, 
            int drawerImageRes, int openDrawerContentDescRes, int closeDrawerContentDescRes) {
        super(activity, drawerLayout, drawerImageRes, openDrawerContentDescRes, closeDrawerContentDescRes);
    }

    @Override
    public void onDrawerSlide(final View drawerView, final float slideOffset) {
        super.onDrawerSlide(drawerView, slideOffset);
        if (slideOffset > 0.0f) {
            setBlurAlpha(slideOffset);
        }
        else {
            clearBlurImage();
        }
    }

    @Override
    public void onDrawerClosed(View view) {
        clearBlurImage();
    }

}

private void setBlurAlpha(float slideOffset) {
    if (mBlurImage.getVisibility() != View.VISIBLE) {
        setBlurImage();
    }
    ViewHelper.setAlpha(mBlurImage, slideOffset);
}

public void setBlurImage() {
    mBlurImage.setImageBitmap(null);
    mBlurImage.setVisibility(View.VISIBLE);
    Bitmap downScaled = ... // do the downscaling
    Bitmap blurred = ... // apply the blur
    mBlurImage.setImageBitmap(blurred);
}

public void clearBlurImage() {
    mBlurImage.setVisibility(View.GONE);
    mBlurImage.setImageBitmap(null);
}

最后,ViewHelper来自NineOldAndroids,因此我们可以设置alpha()预蜂窝.