Animating Layout Changes 动画布局的更改

xiaoxiao2021-03-01  6

A layout animation is a pre-loaded animation that the system runs each time you make a change to the layout configuration. All you need to do is set an attribute in the layout to tell the Android system to animate these layout changes, and system-default animations are carried out for you.

Tip: If you want to supply custom layout animations, create a LayoutTransition object and supply it to the layout with the setLayoutTransition() method.

Here's what a default layout animation looks like when adding items to a list:

If you want to jump ahead and see a full working example, download and run the sample app and select the Crossfade example. See the following files for the code implementation:

src/ layout/activity_layout_changes.xml menu/activity_layout_changes.xml

Create the Layout

In your activity's layout XML file, set the android:animateLayoutChanges attribute to true for the layout that you want to enable animations for. For instance:

<LinearLayout android:id="@+id/container" android:animateLayoutChanges="true" ... />

Add, Update, or Remove Items from the Layout

Now, all you need to do is add, remove, or update items in the layout and the items are animated automatically:

private ViewGroup mContainerView; ... private void addItem() { View newView; ... mContainerView.addView(newView, 0); }