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> Activity A跳到横屏Activity B，B进行横竖屏切换，导致A重新执行OnCreate()生命周期，如何让A不重建？

在Activity A中注册文件描述中加入 android:configChanges="orientation|screenSize|keyboardHidden"  

Caution: Beginning with Android 3.2 (API level 13), the "screen size" also changes when the device switches between portrait and landscape orientation. Thus, if you want to prevent runtime restarts due to orientation change when developing for API level 13 or higher (as declared by the minSdkVersion and targetSdkVersion attributes), you must include the "screenSize" value in addition to the "orientation" value. That is, you must decalare android:configChanges="orientation|screenSize". However, if your application targets API level 12 or lower, then your activity always handles this configuration change itself (this configuration change does not restart your activity, even when running on an Android 3.2 or higher device).

竖屏Activity跳到横屏Activity引发的混乱，Activity横竖屏切换- http://blog.csdn.net/a1030260075/article/details/50560222

> 横竖屏切换代码：

setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);

@TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR1)

    public void onConfigurationChanged(Configuration newConfig) {         super.onConfigurationChanged(newConfig);         int mCurrentOrientation = getResources().getConfiguration().orientation;         if (mCurrentOrientation == Configuration.ORIENTATION_PORTRAIT) {             LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT, ViewGroup.LayoutParams.FILL_PARENT);             params.height = CommonUtils.getScreenWidth(PlayerActivity.this) * 9 / 16;             rl_content.setLayoutParams(params);         } else if (mCurrentOrientation == Configuration.ORIENTATION_LANDSCAPE) {             LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT, ViewGroup.LayoutParams.FILL_PARENT);             rl_content.setLayoutParams(params);         }         DisplayMetrics dm = getResources().getDisplayMetrics();         Point point = new Point();         getWindowManager().getDefaultDisplay().getRealSize(point);         VideoView.setScreenSize(point.x / dm.xdpi * 0.0254f, point.y / dm.ydpi * 0.0254f);     }

Android横竖屏切换及其对应布局加载问题- http://www.cnblogs.com/Joanna-Yan/p/4824525.html