退出时如何保存 Activity 的状态?安卓

I have a basic app with text inputs, a spinner input, and a second spinner input whose array depends on a setting changed in the Options menu.

Currently, when I press Home or press Return while in my app, I either return to the desktop or cycle back through old inputs i put in recently.

How can I prevent my app from opening multiple instances of itself so that there is only one instance running at any given time, and then how can I save the data entered into inputs, and the settings chosen in my option menu?

I'm a bit new to Java, so I apologize if this is a simple problem.

解决方案

In your acticity override onSaveInstanceState and onRestoreInstanceState. These methods will allow you to save data into a Bundle You can also save data to Preferences. In all of my applications I override both onSaveInstanceState and onRestoreInstanceState to save and load values to a Bundle. I also save data to preferences in onPause and load preferences in onResume. Also in onCreate(Bundle savedInstanceState) I do a check like this

    if(savedInstanceState != null)
    {
        m_mainView.restoreInstanceState(savedInstanceState);
    }
    else
    {
        m_mainView.loadGameFromDatabase(getPreferences(MODE_PRIVATE));
    }

These practices have always worked for me.