android横竖屏切换后不重建不销毁Activity

最新推荐文章于 2021-05-31 08:20:37 发布

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本文介绍如何在Android应用中通过配置实现横竖屏切换时不重启Activity，避免数据丢失。主要涉及AndroidManifest.xml中activity节点的configChanges属性设置，及Activity类中onConfigurationChanged方法的重写。

在AndroidManifest.xml文件的activity节点设置属性 android:configChanges="keyboardHidden|orientation"后可以使应用横竖屏切换时,不会重启对应的 Activity重新加载。可以在对应的Activity java类中重写onConfigurationChanged(Configuration newConfig)方法来处理纵横屏各自的布局，但要记得最后调用super.onConfigurationChanged(newConfig)，如果不重写此方法，系统默认使用同一布局。

从3.2版本开始，横竖屏切换时屏幕分辨率可能发生改变，configChanges加入了screenSize属性，例：android:configChanges="orientation|screenSize"

如果仍希望切换后不重建Activity，设定android:targetSdkVersion小于13即可

http://developer.android.com/guide/topics/resources/runtime-changes.html

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Caution: Beginning with Android 3.2 (API level 13), the"screen size" also changes when the device switches between portrait and landscapeorientation. Thus, if you want to prevent runtime restarts due to orientation change when developingfor API level 13 or higher (as declared by theminSdkVersion and targetSdkVersionattributes), you must include the "screenSize" value in addition to the "orientation" value. That is, you must decalareandroid:configChanges="orientation|screenSize". However, if your application targets API level12 or lower, then your activity always handles this configuration change itself (this configurationchange does not restart your activity, even when running on an Android 3.2 or higher device).