Android：在布局后面模糊列表视图

Question

我有一个列表视图和一个位于列表视图前面的布局。我希望该布局以他背后的列表视图的模糊为背景。就像图片中一样。模糊根据列表视图滚动而变化。我该怎么做呢？

Answer 1

这个库就是你需要的https://github.com/Dimezis/BlurView

<eightbitlab.com.blurview.BlurView
    android:id="@+id/blurView"
    android:layout_width="match_parent"
    android:layout_height="66dp"
    android:layout_alignParentBottom="true"
    >
    <!--anything below this view will be blured-->
</eightbitlab.com.blurview.BlurView>

在 app.gradle 默认配置中

    renderscriptTargetApi 23
    renderscriptSupportModeEnabled true

在活动中

    blurView = (BlurView) findViewById(R.id.blurView);

    final View decorView = getWindow().getDecorView();
    final View rootView = decorView.findViewById(android.R.id.content);
    final Drawable windowBackground = decorView.getBackground();

    blurView.setupWith(rootView)
            .windowBackground(windowBackground)
            .blurAlgorithm(new RenderScriptBlur(this, true)) //Preferable algorithm, needs RenderScript support mode enabled
            .blurRadius(10);

Answer 2

参考本博客post

private void blur(Bitmap bkg, View view, float radius) {
        Bitmap overlay = Bitmap.createBitmap(
                view.getMeasuredWidth(),
                view.getMeasuredHeight(),
                Bitmap.Config.ARGB_8888);

        Canvas canvas = new Canvas(overlay);

        canvas.drawBitmap(bkg, -view.getLeft(),
                -view.getTop(), null);

        RenderScript rs = RenderScript.create(this);

        Allocation overlayAlloc = Allocation.createFromBitmap(
                rs, overlay);

        ScriptIntrinsicBlur blur = ScriptIntrinsicBlur.create(
                rs, overlayAlloc.getElement());

        blur.setInput(overlayAlloc);

        blur.setRadius(radius);

        blur.forEach(overlayAlloc);

        overlayAlloc.copyTo(overlay);

        view.setBackground(new BitmapDrawable(
                getResources(), overlay));

        rs.destroy();
    }