在活动被销毁之前只调用了什么Android事件？

Question

我正在寻找一个答案（但我可能会问错问题）

问题 - 只有在活动被销毁之前只会调用一次任何事件？

我问是因为当我的用户旋转手机来横向创建andCreate并且onstart都被调用，导致重新加载各种类型。

我正在寻找一个我可以将行为放入那个只会运行1x（直到活动被杀死）

提前谢谢

Answer 1

If it is specific to the Activity just check your savedInstanceState parameter in the onCreate event. If it is null, run your code, if not, your code has already been run.

Example:

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    if(savedInstanceState == null) {
        // Run your code
    }        
}

savedInstanceState will always be null when onCreate is run for the first time, and it will be populated thereafter.

Answer 2

You don't really specify what you're trying to do with it, so I can't guarantee this is appropriate for your use, but Application.onCreate is only called once.

Answer 3

If you want to eliminate the recreation of your activity on an orientationchange you can listen for configchanges in the manifest.

    <activity
            android:name=".MyActivity"
            android:configChanges="orientation" >
    </activity>

And then you can override onConfigurationChanged like so:

@Override
public void onConfigurationChanged(Configuration newConfig) {
    super.onConfigurationChanged( newConfig );

    LinearLayout main = (LinearLayout) findViewById( R.id.mainLayout );
    main.requestLayout();
}

to recreate the layout so that it matches the new orientation, without recreating the entire activity.

Answer 4

Check http://developer.android.com/guide/topics/resources/runtime-changes.html to handle configuration changes and to maintain your huge data between them...if all you need to maintain between the configuration change is just the settings,you can use the onSavedInstanceState() and onRestoreInstanceState() callbacks and the given bundles.