setResult() does not work after activitiy is restarted

问题

I have three activities A, B and C.

A starts B with startActivityForResult(getIntent(), ACTIVITY_B); and B starts C with startActivityForResult(getIntent(), ACTIVITY_C);. ACTIVITY_B and ACTIVITY_C are constants with same value across activities.

When C returns with RESULT_OK, then B is restarted with the code:

if (resultCode == Activity.RESULT_OK){
    finish();
    startActivityForResult(getIntent(), ACTIVITY_B);
}

This works fine.

When B has to return (on clicking a menu item), it sets the activity result.

public boolean onMenuItemSelected(int featureId, MenuItem item) {
    switch(item.getItemId()) {
        case MENU_CONFIRM:
            System.out.println("Setting Result to RESULT_OK");
            setResult(Activity.RESULT_OK);
            finish();
            return true;
    }
    return super.onMenuItemSelected(featureId, item);
}

However I can see that the setResult(Activity.RESULT_OK); is ignored because it is always received as RESULT_CANCEL in the Activity A (onActivityResult). I'm using 2.3.

Any clues?

回答1:

Don't finish B and start a new one, A will not get notified because it's not the B it opened. Instead, if C needs to return something to B when it ends, create an Intent, put your result values on it, and check this result in B:

Intent data = new Intent();
// Store values you want to return on the intent
setResult(RESULT_OK, data);
finish();

B: in onActivityResult

if (resultCode == Activity.RESULT_OK) {
  // get values from the intent and change B accordingly
}

回答2:

I am curious how you are handling your Intents and Activity lifecycle.

From what I have read in both of your posts:

A starts B with startActivityForResult().
B starts C with startActivityForResult().
C completes its task, calls setResult() and finish().

Now unless there is something I am missing, Activity B uses this code:

if (resultCode == Activity.RESULT_OK){
    finish();
    startActivityForResult(getIntent(), ACTIVITY_B);
}

to start itself? Could you clarify this?

Addition

I believe you are starting B from B so when you call setResult() and finish() in your second instance of B you are returning to the first B Activity.

If you are not using any special Intent flags the lifecycle will be:

A starts B
- B starts C
  - C finishes
- B resumes automatically, B finishes
A resumes automatically.

From what I understand you have altered that cycle to:

A starts B
- B starts C
  - C finishes
- B resumes automatically, onActivityResult() starts 2nd B
  - 2nd B finishes, (You expect to see A next, however...)
- B resumes automatically (If you call finish() again you should see A at this point).
...
A is waiting in the stack to be resumed.

来源：https://stackoverflow.com/questions/11043239/setresult-does-not-work-after-activitiy-is-restarted

标签

android

android-activity

restart