Question

I have an Android widget that has a configure activity. I also have an ImageView “button” set up on the widget to launch the configure activity, in case the user wants to change his/her preferences after initializing them.

So, basic lifecycle:

1. User adds the widget
2. Configure activity pops up, user fills in fields and clicks “Submit”
3. Widget is added on screen
4. User taps the ImageView to launch the configure activity
5. Configure activity pops up, user edits fields
6. After either hitting “Submit” or backing out, the widget is updated
7. User can continue to go through steps 5 and 6 as needed.

My problem is at step 5. The very first and only the first time that the user taps the ImageView, it looks like two configure activities are launched. That is, when I back out of the first one, there’s still another one “behind” it. On all subsequent launches of the configure activity, however, only one is launched and everything works great.

What could be the problem? I’ll post relevant code below.

AndroidManifest.xml

    <activity
        android:name=".ConfigActivity"
        android:label="@string/app_name" >
        <intent-filter>
            <action android:name="android.appwidget.action.APPWIDGET_CONFIGURE" />
        </intent-filter>
    </activity>
    <receiver
        android:name=".Widget"
        android:label="Widget" >
        <intent-filter>
            <action
                android:name="android.appwidget.action.APPWIDGET_UPDATE" />
        </intent-filter>
        <intent-filter>
            <action
                android:name="android.appwidget.action.APPWIDGET_UPDATE" />
                <data android:scheme="sample_widget" />
        </intent-filter>
        <intent-filter>
            <action
                android:name="com.this.that.WIDGET_CONTROL" />
            <data
                android:scheme="sample_widget" />
        </intent-filter>
        <meta-data
            android:name="android.appwidget.provider"
            android:resource="@xml/widget" />
    </receiver>

AppWidget-Provider widget.xml

<?xml version="1.0" encoding="utf-8"?>
<appwidget-provider
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:updatePeriodMillis="5000"
    android:minWidth="294dp"
    android:minHeight="220dp"
    android:initialLayout="@layout/widgetlayout"
    android:configure="com.this.that.ConfigActivity" >
</appwidget-provider>

ConfigActivity.java

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

    // Get the data we were launched with
    Intent launchIntent = getIntent();
    Bundle extras = launchIntent.getExtras();
    if (extras != null) {
        appWidgetId = extras.getInt(AppWidgetManager.EXTRA_APPWIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID);

        Intent cancelResultValue = new Intent();
        cancelResultValue.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);
        setResult(RESULT_CANCELED, cancelResultValue);
    } else {
        // Only launch if it's for configuration
        finish();
    }

    setContentView(R.layout.myconfig);

    // Create Buttons/EditTexts
    SubmitBTN = (Button) findViewById(R.id.BTNSubmit);
    SampleET= (EditText) findViewById(R.id.ETSample);
    SubmitBTN.setOnClickListener(submitListener);

    loadPreferences(ConfigActivity.this, appWidgetId);
}

private OnClickListener submitListener = new OnClickListener() {
    public void onClick(View v) {
        final Context context = PriorityViewConfig.this;

        // Save strings in our prefs
        String sample = SampleET.getText().toString();
        SharedPreferences.Editor prefs = context.getSharedPreferences(PREFS_NAME, 0).edit();
        prefs.putString(PREF_PREFIX_KEY + appWidgetId + "sample", sample);
        prefs.commit();

        if (appWidgetId != AppWidgetManager.INVALID_APPWIDGET_ID) {
            // Tell the AppWidgetManager that we're now configured
            Intent resultValue = new Intent();
            //resultValue.setAction(AppWidgetManager.ACTION_APPWIDGET_UPDATE);
            resultValue.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);
            setResult(RESULT_OK, resultValue);

            // Get an instance of the AppWidgetManager
            AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(context);

            // Update the App Widget with the layout
            RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.widgetlayout);
            Widget.updateDisplayState(context, appWidgetId);
        }

        // Activity is now done
        finish();
    }
};

private void loadPreferences(Context context, int appWidgetId) {
    SharedPreferences prefs = context.getSharedPreferences(PREFS_NAME, 0);
    String sample = prefs.getString(PREF_PREFIX_KEY + appWidgetId + "sample", null);

    if (sample != null) {
        SampleET.setText(sample);
    } else {
        // Nothing stored, don't need to do anything
    }
}

Widget.java

@Override
public void onReceive(Context context, Intent intent) {
    final String action = intent.getAction();
    Log.d(LOG_TAG, "OnReceive:Action: " + action);

    if (ACTION_WIDGET_CONTROL.equals(action)) {
        // Pass this on to the action handler where we'll figure out what to do and update the widget
        final int appWidgetId = intent.getIntExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID);
        if (appWidgetId != AppWidgetManager.INVALID_APPWIDGET_ID) {
            this.onHandleAction(context, appWidgetId, intent.getData());
        }           
    }
    super.onReceive(context, intent);
}

public static void updateDisplayState(Context context, int appWidgetId) {
    Intent configIntent = new Intent(context, ConfigActivity.class);
    configIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);
    // Make this unique for this appWidgetId
    configIntent.setData(Uri.withAppendedPath(Uri.parse(Widget.URI_SCHEME + "://widget/id/"), String.valueOf(appWidgetId)));
    PendingIntent pendingIntent = PendingIntent.getActivity(context, 0, configIntent, PendingIntent.FLAG_UPDATE_CURRENT);
    views.setOnClickPendingIntent(R.id.IVConfig, pendingIntent);

    AppWidgetManager.getInstance(context).updateAppWidget(appWidgetId, views);
}

private void onHandleAction(Context context, int appWidgetId, Uri data) {
    String controlType = data.getFragment();        
    // Nothing here yet
    updateDisplayState(context, appWidgetId);
}

I think these are the most relevant sections. The places I’m going to be looking further into are in ConfigActivity.java in the submitListener and in the updateDisplayState method in Widget.java

Any help would be awesome! Thanks!

Answer 1

When calling an explicit intent, you should consider using one of the intent flags like FLAG_ACTIVITY_CLEAR_TOP to keep the stack organized. For example:

configIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);

You can spot the lack of this flag in some apps like the IMDB app where each click of the Home button adds another instance of the home activity on the stack, so you need to click the Back button as many times to pop through the stack and back out of the app. 🙂