startActivityForResult(Intent intent, int requestC

问题:

According to the Android documentation public void startActivityForResult (Intent intent, int requestCode, Bundle options).

I can not figure it out how to retrieve the extra bundle options that I am passing on the intent.

I want to pass an ArrayList with data as an extra bundle option when I am calling the startActivityForResult method.

Sample of code:

ArrayList<String> list = new ArrayList<>();
        list.add("test1");
        list.add("test2");

        Bundle bundleOptions = new Bundle();
        bundleOptions.putStringArrayList("key", list);

startActivityForResult(intent, 10, bundleOptions);

Upon retrieving the data:

@Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data)

Bundle extras = data.getExtras();

Bundle extras does not contain the extra bundle that I am trying to pass. What I am missing and I can not retrieve the extra Bundle data that I am passing to the method?

I also tried with intent.putExtra("key", bundleOptions);, also with intent.putExtra("key", list); but with no success either and calling the method startActivityForResult(intent, 10); but again with no success.

I am sure that I am missing something does anybody know how to achieve this?

回答1:

Bundle extras does not contain the extra bundle that I am trying to pass.

Correct.

What I am missing

If you wish to retrieve a value using getExtras(), use putExtras() or individual putExtra() methods.

I can not retrieve the extra Bundle data that I am passing to the method?

That third parameter to startActivity()/startActivityForResult() are to pass options to Android itself, not to pass data to another activity.

I also tried with... intent.putExtra("key", list); but with no success either

In general, that works. For example, this sample app has worked since Android 1.0. The launcher activity uses putExtra() to add a string extra; the other activity uses getStringExtra() to get the value.

If you have continued problems using putExtra(), post a separate Stack Overflow question, where you supply your code for setting and retrieving the extra, along with a detailed description of your symptoms.

回答2:

I am sure that I am missing something

I suspect you misunderstand how the result thing works.

Let's suppose you have a HomeActivity and a SettingsActivity. HomeActivity starts a SettingsActivity with some parameters and wants to know some result. Here's how it works:

HomeActivity

This is how you open the SettingsActivity:

public void openSettings() {
    Intent i = new Intent(this, SettingsActivity.class);
    i.putExtra("myParam", 1);
    startActivityForResult(i, 10);
}

This is the call you receive when SettingsActivity is closed:

public void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == 10) {
        if (resultCode == RESULT_OK) {
            // Get result from the result intent.
            String result = data.getStringExtra("myResult");

            // Do something with result...
        }
    }
}

SettingsActivity

This is just the necessary bit. Reads the input, builds the output and closes itself. I hope it's enough for a demonstration.

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    // Retrieve the parameter.
    int param = getIntent().getIntExtra("myParam");

    // Get a result somewhere.
    String resultValue = "RESULT=" + param;

    // Build a result intent and post it back.
    Intent resultIntent = new Intent();
    resultIntent.putExtra("myResult", resultValue);
    setResult(RESULT_OK, resultIntent);
    finish();
}

See this http://developer.android.com/training/basics/intents/result.html.