Android AppCompat 21海拔

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最佳答案

ViewCompat.setElevation(View, int) currently creates no shims.

The only way to simulate elevation right now is to apply a shadow pre-v21. Define your style/layout/drawable in values and override it in values-v21. For buttons I use style overrides. For layouts, I usually go for reference override (use @null to get rid of a drawable).

Hopefully in the future an update to the support library will add shims.

This reddit thread keeps track of said update.

Edit

The new support design library actually does create shims for the floating action button.

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This is an example how to add a shadow below the Toolbar on pre-lollipop devices:

enter image description here

The layout should be this:

<RelativeLayout
android:id="@+id/toolbar_container"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentTop="true" >


<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:animateLayoutChanges="true"
android:background="?attr/colorPrimary"
android:minHeight="?attr/actionBarSize"
app:theme="@style/ThemeOverlay.AppCompat.ActionBar" />


<View
android:id="@+id/toolbar_shadow"
android:layout_width="match_parent"
android:layout_height="@dimen/toolbar_shadow"
android:layout_below="@id/toolbar"
android:background="@drawable/toolbar_dropshadow" />
</RelativeLayout>

And the shadow is:

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle" >


<gradient
android:angle="90"
android:endColor="#88444444"
android:startColor="@android:color/transparent" />


</shape>

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I achieve same effect using,

  android:background="@android:drawable/dialog_holo_light_frame"

My tested output:

enter image description here

reference - https://stackoverflow.com/a/25683148/3879847

Update : If you want change color of this drawable try @Irfan answer

https://stackoverflow.com/a/40815944/3879847

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You can now use the schema xmlns:app="http://schemas.android.com/apk/res-auto" and app:elevation

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools">
...


<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom|end"
app:elevation="5dp">