我正在构建一个简单的计时器应用程序，其中我使用 android 计时器来跟踪经过的时间。但是当我启动计时器并将方向更改为横向时，计时器会重置并再次显示 00:00。我希望它保持其价值。 布局为portrait and landscape是不同的

portrait--> Layout folder

landscape->layout_land folder

<Chronometer 
    android:layout_height="wrap_content" 
    android:layout_width="wrap_content"
    android:id="@+id/chronometer1"
    android:layout_above="@+id/button2"
    android:textStyle="bold"
    android:textColor="@color/Indigo"
    android:text="Chronometer"
    android:layout_toLeftOf="@+id/save_btn"
    android:typeface="serif"
    android:textSize="40dp"/>

这是医生所说的：

重新创建活动 http://developer.android.com/training/basics/activity-lifecycle/recreating.html

注意：每次用户旋转屏幕时，您的 Activity 都会被销毁并重新创建。当屏幕改变方向时，系统会销毁并重新创建前台 Activity，因为屏幕配置已更改，并且您的 Activity 可能需要加载替代资源（例如布局）。

如果你需要保存活动的状态 http://developer.android.com/training/basics/activity-lifecycle/recreating.html#SaveState在改变方向之前，你必须覆盖onSaveInstanceState()。此方法将帮助您保存方向更改后想要恢复的所有值。然后将它们恢复到onCreate() method.

这是一个例子：

String myVar;

/* 
     ...
*/
@Override
public void onSaveInstanceState(Bundle savedInstanceState) {
    // Save myVar's value in saveInstanceState bundle
    savedInstanceState.putString("myVar", myVar);
    super.onSaveInstanceState(savedInstanceState);
}

现在在创建活动时检索它：

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState); 
    // savedInstanceState is the bundle in which we stored myVar in onSaveInstanceState() method above
    // savedInstanceState == null means that activity is being created a first time
    if (savedInstanceState == null) {
        // some code here
        myVar = "first value";
    } else {  // savedInstance != null means that activity is being recreated and onSaveInstanceState() has already been called.
        myVar = savedInstanceState.getString("myVar");
    }
    /*
       ...
    */
}