NullpointerException at startActivityForResult

Question

I am currently trying to implement and work with the Google API for Java on Android. To test things, I have been following two examples (CalendarSample, TasksSample). The code for calling the AccountManager and other stuff is the same as in the two examples. However, the following code does not work for me and results in a NullPointerException:

startActivityForResult(credential.newChooseAccountIntent(),2); I am calling this from a normal Activity after a button click, onCreate has already been called. I have tried searching Google and other sources of information for a few hours, but nothing seems to work.

Manifest:

<activity
android:name=".ManageAccounts"
android:label="@string/title_activity_manage_accounts"
        android:launchMode="singleTop"
        android:parentActivityName=".SettingsActivity" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.GET_ACCOUNTS" />
<uses-permission android:name="android.permission.USE_CREDENTIALS" />
<uses-permission android:name="android.permission.MANAGE_ACCOUNTS" />

Here is the full activity:

public class ManageAccounts extends Activity implements GoogleLoginFragment.OnSignedIn{

DataHandler dataHandler;
//for testing of google add friend
private static final String PREF_ACCOUNT_NAME = "accountName";
Circles service;
final HttpTransport httpTransport = AndroidHttp.newCompatibleTransport();
final JsonFactory jsonFactory = GsonFactory.getDefaultInstance();
static final int REQUEST_GOOGLE_PLAY_SERVICES = 0;
static final int REQUEST_AUTHORIZATION = 1;
static final int REQUEST_ACCOUNT_PICKER = 2;
GoogleAccountCredential credential;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_manage_accounts);
    ActionBar actionBar = getActionBar();
    actionBar.setDisplayHomeAsUpEnabled(true);

    dataHandler = new DataHandler(this);

    //Add GoogleLoginFragment
    GoogleLoginFragment.attachToActivity(this);


    //testing of google add friend code
    GoogleAccountCredential credential =
            GoogleAccountCredential.usingOAuth2(this, Collections.singleton(CirclesScopes.CIRCLE_ADD +" "+ CirclesScopes.CIRCLES));
    SharedPreferences settings = this.getPreferences(Context.MODE_PRIVATE);
    credential.setSelectedAccountName(settings.getString(PREF_ACCOUNT_NAME, null));
    service =
            new Circles.Builder(httpTransport, jsonFactory, credential)
                    .setApplicationName("Social Contacts/1.0").build();
    Log.i("Activity","onCreateDone");
}


@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.manage_accounts, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    //Request Code for Twitter button: 140
    if (requestCode == 140) {
        loginButton.onActivityResult(requestCode, resultCode, data);
    }

    switch (requestCode) {
        case REQUEST_GOOGLE_PLAY_SERVICES:
            if (resultCode == Activity.RESULT_OK) {
                haveGooglePlayServices();
            } else {
                checkGooglePlayServicesAvailable();
            }
            break;
        case REQUEST_AUTHORIZATION:
            if (resultCode == Activity.RESULT_OK) {
//                    AsyncLoadTasks.run(this);

            } else {
                chooseAccount();
            }
            break;
        case REQUEST_ACCOUNT_PICKER:
            if (resultCode == Activity.RESULT_OK && data != null && data.getExtras() != null) {
                String accountName = data.getExtras().getString(AccountManager.KEY_ACCOUNT_NAME);
                if (accountName != null) {
                    credential.setSelectedAccountName(accountName);
                    SharedPreferences settings = getPreferences(Context.MODE_PRIVATE);
                    SharedPreferences.Editor editor = settings.edit();
                    editor.putString(PREF_ACCOUNT_NAME, accountName);
                    editor.commit();
//                        AsyncLoadTasks.run(this);
                }
            }
            break;
    }
}

public void onSignedIn(GoogleApiClient googleApiClient) {
    GoogleSocialActions gsa = new GoogleSocialActions(googleApiClient, dataHandler, this);
    gsa.saveAuthenticatedUser();
}

/** Check that Google Play services APK is installed and up to date. */
private boolean checkGooglePlayServicesAvailable() {
    final int connectionStatusCode = GooglePlayServicesUtil.isGooglePlayServicesAvailable(this);
    if (GooglePlayServicesUtil.isUserRecoverableError(connectionStatusCode)) {
        showGooglePlayServicesAvailabilityErrorDialog(connectionStatusCode);
        return false;
    }
    return true;
}

void showGooglePlayServicesAvailabilityErrorDialog(final int connectionStatusCode) {
    runOnUiThread(new Runnable() {
        public void run() {
            Dialog dialog =
                    GooglePlayServicesUtil.getErrorDialog(connectionStatusCode, ManageAccounts.this,
                            REQUEST_GOOGLE_PLAY_SERVICES);
            dialog.show();
        }
    });
}

private void haveGooglePlayServices() {
// check if there is already an account selected
    if (credential.getSelectedAccountName() == null) {
// ask user to choose account
        chooseAccount();
    } else {
// load calendars
//            AsyncLoadTasks.run(this);
    }
}
private void chooseAccount() {
    startActivityForResult(credential.newChooseAccountIntent(), 2);
}

public void chooser(View view) {
    if (view.getId() == R.id.chooser) {
        startActivityForResult(credential.newChooseAccountIntent(), REQUEST_ACCOUNT_PICKER);
    }
}

}

Stacktrace is as following. The NullPointer at line 204 is the one line shown above.

java.lang.IllegalStateException: Could not execute method of the activity at android.view.View$1.onClick(View.java:3602) at android.view.View.performClick(View.java:4095) at android.view.View$PerformClick.run(View.java:17078) at android.os.Handler.handleCallback(Handler.java:615) at android.os.Handler.dispatchMessage(Handler.java:92) at android.os.Looper.loop(Looper.java:137) at android.app.ActivityThread.main(ActivityThread.java:4872) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:511) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:557) at dalvik.system.NativeStart.main(Native Method) Caused by: java.lang.reflect.InvocationTargetException at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:511) at android.view.View$1.onClick(View.java:3597) at android.view.View.performClick(View.java:4095) at android.view.View$PerformClick.run(View.java:17078) at android.os.Handler.handleCallback(Handler.java:615) at android.os.Handler.dispatchMessage(Handler.java:92) at android.os.Looper.loop(Looper.java:137) at android.app.ActivityThread.main(ActivityThread.java:4872) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:511) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:557) at dalvik.system.NativeStart.main(Native Method) Caused by: java.lang.NullPointerException at com.example.martin.contacts.ManageAccounts.chooser(ManageAccounts.java:204) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:511) at android.view.View$1.onClick(View.java:3597) at android.view.View.performClick(View.java:4095) at android.view.View$PerformClick.run(View.java:17078) at android.os.Handler.handleCallback(Handler.java:615) at android.os.Handler.dispatchMessage(Handler.java:92) at android.os.Looper.loop(Looper.java:137) at android.app.ActivityThread.main(ActivityThread.java:4872) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:511) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:557) at dalvik.system.NativeStart.main(Native Method)

Hi Martin, post the activity code also,from where you are starting the activity... — Vny Kumar, Mar 24 '15 at 05:48
possible duplicate of [What is a Null Pointer Exception, and how do I fix it?](http://stackoverflow.com/questions/218384/what-is-a-null-pointer-exception-and-how-do-i-fix-it) — Dan Oberlam, Mar 24 '15 at 05:51

Amit K. Saha · Accepted Answer · 2015-03-24T06:20:58.820

Are you getting any intent from credential.newChooseAccountIntent()?? your stack traces indicates that you are not getting any intent , thus it is failing to invoke startActivityForResult().

Updated answer

you have GoogleAccountCredential credential; as a instance member. But you have not initialized this member. in your onCreate , you have declared another local credential but your member credential is never initialized properly, here is your problematic line-

//testing of google add friend code
    GoogleAccountCredential credential =
            GoogleAccountCredential.usingOAuth2(this, Collections.singleton(CirclesScopes.CIRCLE_ADD +" "+ CirclesScopes.CIRCLES));

instead you should write only

    //testing of google add friend code
 credential =GoogleAccountCredential.usingOAuth2(this, Collections.singleton(CirclesScopes.CIRCLE_ADD +" "+ CirclesScopes.CIRCLES));

Currently looking into that but it seems that I am not getting any intent. Makes me wonder why... — Martin Wentzel, Mar 24 '15 at 06:11
That worked. Sometime you just don't notice and check the small things...Thanks! — Martin Wentzel, Mar 24 '15 at 06:39

NullpointerException at startActivityForResult

1 Answers1

Updated answer