当我完成结果活动时调用 OnCreate 和 onActivityResult

Question

I have Activity A. it displays some data retrieved from the server by calling void loadData() in onCreate.

User click a button which open a new Activity B for result. Once it finishes it back to Activty A. onActivtyresult should call loadData() to reload the data.

When Activty B finishes both onCreate and onActivityResult called as A was destroyed. Which is not Ok for me.

The question is:

• Dose activity A always will be destroyed and onCreate will be called? Is this documented as I could not find any thing about this. If this is the case then I will call loadData only in onCreate.

  If not I have to call loadData from onActivityResult also, which again leaded to call loadData 2 time in some cases, which I dont want.

  Class A:

   public void onCreate(@Nullable Bundle bundle) { .... creation code loadData(); // will be called first time activity created as well when back from the activity B } public void createNew() { Intent createService = new Intent(this,CreateService.class); startActivityForResult(createService, 1001); overridePendingTransition(R.anim.out_top,R.anim.fp); } public void onActivityResult(int i, int i2, Intent intent) { super.onActivityResult(i, i2, intent); if (i2 != -1) { loadData(); ///will be called when back from Activty B } }

  Class B:

   public void on taskFinish() { setResult(1); finish(); overridePendingTransition(R.anim.s_right, R.anim.s_in_right); }

Answer 1

I have come with a work around like this

     boolean loaded = false;
     void onCreate() {
        loadData();
        loaded=true;
     }

    public void createNew() {
        loaded = false;  /// Set before start the new Activity
        Intent createService =  new Intent(this,CreateService.class);
        startActivityForResult(createService, 1001);
        overridePendingTransition(R.anim.out_top,R.anim.fp);
     } 

     public void onActivityResult(int i, int i2, Intent intent) {
        super.onActivityResult(i, i2, intent);
        if (i2 != -1) {
           if (!loaded) {
             loadData();
             loaded = true;
          }
       }
     }

I have 2 scansion

1- Activity created form scrach- loadData will be called once in OnCrate()

2- Start new Activity for result - set loaded = false

a- after back for result if activity destroyed then loaded == true in onCreate and loadData will be called once. then onActivityResult will be called but loadData will not be called.

b- after back for result if Activity not destroyed then loaded = false and loadData will be called

Answer 2

No, there is no guarantee that Activity A will be destroyed. You'd need to find some way of tracking whether the data needs to be reloaded - perhaps you could pass back a timestamp or something similar in the result from Activity B that you could use to check if the data you have in Activity A is up-to-date.