如何快到的时候回跑活动code [英] How to run code when coming back to activity

问题描述

在我的应用程序有3项活动。第一个-The主要从我做起活动＃2。从＃2我开始＃3，并在同一时间，我完成＃2。当我完成＃3我会自动回到＃1。问：我怎样才能快到的时候回3至1添加/运行code？

in my application I have 3 activities. First one -the main from which I start activity #2. From #2 I start #3 and at the same time I finish #2. When I finish #3 I automatically come back to #1. Question: How can I add/run code when coming back from 3 to 1?

不知道，如果它是有道理的。但我想要做的是，当结束＃3和回来＃1我想检查文件是否存在XYZ，并在此基础上，以改变用户界面的活动＃1。

not sure if it makes sense. But what I want to do is, when ending #3 and coming back to #1 I want to check if file xyz exists and based on it to change UI in activity #1.

OnResume在＃1不跑了，从来没有。 （可能是系统不运行的onPause这第一个活动）

OnResume in #1 is not ran, never. (Probably system doesn't run onpause for this first activity)

如果有唯一的活动＃1和2，我可以用startActivityForResult。但两项活动没有做什么，我需要......

If there was only activity #1 and 2 I could use startActivityForResult. But two activities don't do what I need...

推荐答案

参见下面的例子。

你的活动＃1 code是这样

your activity#1 code is like this

public class MainActivity extends Activity {

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

}

@Override
protected void onRestart() {
// TODO Auto-generated method stub
super.onRestart();

          //Do your code here
}
}

您的活动＃3 code是这样

Your activity#3 code is like this

public class Activity3 extends Activity{



@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity3); 
}
@Override
public void onBackPressed() {
    // TODO Auto-generated method stub
    super.onBackPressed();
    finish();
}


}

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