The Mystery of startActivityForResult with RESULT_OK: Unraveling the Enigma

Are you tired of banging your head against the wall, trying to figure out why startActivityForResult with RESULT_OK doesn’t seem to work as expected? Do you find yourself wondering why the resultCode from onBackPressed() is always null, leaving you stranded in a sea of confusion? Fear not, dear Android developer, for we’re about to embark on a journey to demystify this conundrum and bring clarity to your coding woes.

What is startActivityForResult, Anyway?

Before we dive into the nitty-gritty of the issue, let’s take a step back and revisit the basics. startActivityForResult is a method in Android that allows an activity to start another activity and receive a result from it. This result is returned as an integer, which can be one of the following:

• RESULT_OK: The activity has completed its task successfully.
• RESULT_CANCELED: The activity was canceled or didn’t complete its task.
• Any other value: A custom result code defined by the activity.

In a typical startActivityForResult scenario, the calling activity (let’s call it Activity A) starts another activity (Activity B) and expects a result from it. When Activity B finishes its task, it sets the result code using the setResult() method and calls finish() to close itself. The result code is then passed back to Activity A, which can be retrieved using the onActivityResult() method.

// In Activity A
Intent intent = new Intent(this, ActivityB.class);
startActivityForResult(intent, REQUEST_CODE);

// In Activity B
Intent resultIntent = new Intent();
resultIntent.putExtra("key", "value");
setResult(RESULT_OK, resultIntent);
finish();

// Back in Activity A
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == REQUEST_CODE && resultCode == RESULT_OK) {
        // Process the result
    }
}

The Problem: startActivityForResult with RESULT_OK Fails to Deliver

So, what’s going on? You’ve followed the guidelines, set the result code to RESULT_OK, and even added a dash of magic to your code (just kidding about that last part!). Yet, when you run your app, the resultCode in onActivityResult() is always RESULT_CANCELED or null. What sorcery is at play here?

Fear not, dear developer, for we’re about to unveil the secrets behind this mysterious behavior.

Reason 1: Overriding onBackPressed()

One common pitfall is overriding the onBackPressed() method in your Activity B without calling the superclass method. When you do this, the result code is never set, and the activity is simply finished without passing the result back to the caller.

@Override
public void onBackPressed() {
    // DO NOT DO THIS!
    finish();
}

Instead, make sure to call the superclass method:

@Override
public void onBackPressed() {
    super.onBackPressed();
    // Set the result code here, if needed
}

Reason 2: Not Setting the Result Code

Sometimes, it’s as simple as forgetting to set the result code in the activity that’s being started. Double-check that you’re setting the result code using setResult() before calling finish().

// In Activity B
Intent resultIntent = new Intent();
resultIntent.putExtra("key", "value");
setResult(RESULT_OK, resultIntent);
finish();

Reason 3: Request Code Mismatch

Another common mistake is using the wrong request code when starting the activity. Make sure the request code you pass to startActivityForResult() matches the one you check in onActivityResult().

// In Activity A
startActivityForResult(intent, REQUEST_CODE);

// In Activity A
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == REQUEST_CODE && resultCode == RESULT_OK) {
        // Process the result
    }
}

Reason 4: Activity Not Finishing Properly

In some cases, the activity might not be finishing properly, which prevents the result code from being passed back to the caller. This can happen if you’re using a fragment or a dialog that’s not properly dismissed.

Ensure that you’re calling finish() on the activity itself, rather than just dismissing a fragment or dialog.

// In Activity B
finish();

Reason 5: Android System Errors

In rare cases, the issue might be due to an Android system error, such as a memory leak or a permission issue. If you’ve checked all the above reasons and still aren’t getting the expected result, try debugging your app to see if there are any system-level errors occurring.

Conclusion: Unraveling the Mystery of startActivityForResult with RESULT_OK

There you have it, folks! With these common pitfalls identified and addressed, you should now be able to successfully use startActivityForResult with RESULT_OK in your Android app. Remember to:

• Call the superclass method in onBackPressed()
• Set the result code using setResult()
• Use the correct request code
• Ensure the activity finishes properly
• Debug for system-level errors

By following these guidelines, you’ll be well on your way to creating seamless activity interactions in your Android app. Happy coding!

Reason	Solution
Overriding onBackPressed()	Call the superclass method
Not Setting the Result Code	Set the result code using setResult()
Request Code Mismatch	Use the correct request code
Activity Not Finishing Properly	Call finish() on the activity itself
Android System Errors	Debug for system-level errors

Remember, when in doubt, debug it out!

1. Check the Android documentation for startActivityForResult and onActivityResult.
2. Inspect your code for any of the common pitfalls mentioned above.
3. Use the Android Studio debugger to step through your code and identify the issue.
4. Search for similar issues on Stack Overflow or other developer communities.

With persistence and patience, you’ll crack the code and make startActivityForResult with RESULT_OK work like a charm. Happy coding, and may the code be with you!

Frequently Asked Question

Are you stuck with the pesky startActivityForResult and RESULT_OK not working as expected? Well, worry no more! We’ve got you covered with the top 5 FAQs to get you out of this predicament.