Hosting widgets in an android launcher

Question

I am making a launcher for android, and I'm stuck at the widget part. I've been searching for about an hour and a half on the internet trying to figure out how can I host widgets in my application, but no luck.

I have went through some stock launchers and ADW launcher codes but both just have miles of code and this is the first time I'm making a launcher.

Could someone please guide me through how can I add widgets into my launcher? Or at least post any links/tutorials? Please explain it since this is my first time.

Answer 1

Try this:

final int APPWIDGET_HOST_ID = 2048;
final int REQUEST_PICK_APPWIDGET = 0;
final int REQUEST_CREATE_APPWIDGET = 5;

AppWidgetManager appWidgetManager;
AppWidgetHost appWidgetHost;

// Let user pick a widget from the list of intalled AppWidgets
public void selectWidget()
{
    int appWidgetId = this.appWidgetHost.allocateAppWidgetId();
    Intent pickIntent = new Intent(AppWidgetManager.ACTION_APPWIDGET_PICK);
    pickIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);
    addEmptyData(pickIntent);
    startActivityForResult(pickIntent, REQUEST_PICK_APPWIDGET);
}

// For some reason you have to add this empty data, else it won't work
public void addEmptyData(Intent pickIntent)
{
    ArrayList<AppWidgetProviderInfo> customInfo = 
        new ArrayList<AppWidgetProviderInfo>();
    pickIntent.putParcelableArrayListExtra(
        AppWidgetManager.EXTRA_CUSTOM_INFO, customInfo);
    ArrayList<Bundle> customExtras = new ArrayList<Bundle>();
    pickIntent.putParcelableArrayListExtra(
        AppWidgetManager.EXTRA_CUSTOM_EXTRAS, customExtras);
};

@Override
protected void onActivityResult(int requestCode, int resultCode, 
                                Intent data) {
    if (resultCode == RESULT_OK ) {
        if (requestCode == REQUEST_PICK_APPWIDGET) {
            configureWidget(data);
        }
        else if (requestCode == REQUEST_CREATE_APPWIDGET) {
            createWidget(data);
        }
    }
    else if (resultCode == RESULT_CANCELED && data != null) {
        int appWidgetId = 
            data.getIntExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, -1);
        if (appWidgetId != -1) {
            appWidgetHost.deleteAppWidgetId(appWidgetId);
        }
    }
}

// Show configuration activity of the widget picked by the user
private void configureWidget(Intent data) {
    Bundle extras = data.getExtras();
    int appWidgetId = extras.getInt(AppWidgetManager.EXTRA_APPWIDGET_ID, -1);
    AppWidgetProviderInfo appWidgetInfo = 
            appWidgetManager.getAppWidgetInfo(appWidgetId);
    if (appWidgetInfo.configure != null) {
        Intent intent = 
            new Intent(AppWidgetManager.ACTION_APPWIDGET_CONFIGURE);
        intent.setComponent(appWidgetInfo.configure);
        intent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);
        startActivityForResult(intent, REQUEST_CREATE_APPWIDGET);
    } else {
        createWidget(data);
    }
}

// Get an instance of the selected widget as a AppWidgetHostView
public void createWidget(Intent data) {
    Bundle extras = data.getExtras();
    int appWidgetId = extras.getInt(AppWidgetManager.EXTRA_APPWIDGET_ID, -1);
    AppWidgetProviderInfo appWidgetInfo = appWidgetManager.getAppWidgetInfo(appWidgetId);

    AppWidgetHostView hostView = appWidgetHost.createView(this, appWidgetId, appWidgetInfo);
    hostView.setAppWidget(appWidgetId, appWidgetInfo);
    // Add  it on the layout you want
    myLayout.addView(hostView);
}

// Call this when you want to remove one from your layout
public void removeWidget(AppWidgetHostView hostView) {
    appWidgetHost.deleteAppWidgetId(hostView.getAppWidgetId());

    // Remove from your layout
    myLayout.removeView(hostView);
}

@Override
protected void onStart() {
    super.onStart();
    appWidgetManager = AppWidgetManager.getInstance(this);
    appWidgetHost = new AppWidgetHost(this, APPWIDGET_HOST_ID);

    // Start listening to pending intents from the widgets
    appWidgetHost.startListening();
}

@Override
protected void onStop() {
    super.onStop();
    appWidgetHost.stopListening();
}

All you've got to do is call the method selectWidget() whenever you want to show a list of AppWidgets installed on the device to pick from.

This code is a bit of a modified version of the stock Android launcher.

EDIT:

To bind widget IDs, i.e. make widgets update and respond to user interaction, refer the solution here: Widgets don't respond when re-added through code

Answer 2

I know I am a bit late but things have changed and the code provided by Leonardo Garcia Fischer doesn't work anymore.

Here is the updated version:

final int appWidgetHostId = 23456;
final int REQUEST_BIND_APPWIDGET = 12345;
AppWidgetHost widgetHost;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    widgetHost = new AppWidgetHost(getApplicationContext(), appWidgetHostId);
    widgetHost.startListening();
}

@Override
protected void onDestroy() {
    widgetHost.stopListening();
    super.onDestroy();
}

void configureWidget(int appWidgetId) {
    widgetHost.startAppWidgetConfigureActivityForResult(this, appWidgetId, 0, 0, null);
}

AppWidgetProviderInfo getWidgetProviderInfo(String packageName, int widgetPosition) {
    AppWidgetManager manager = AppWidgetManager.getInstance(this);
    List<AppWidgetProviderInfo> infos = manager.getInstalledProvidersForPackage(packageName, Process.myUserHandle());
    return infos.get(widgetPosition);
}

AppWidgetHostView getWidgetHostView(AppWidgetProviderInfo info) {
    int appWidgetId = widgetHost.allocateAppWidgetId();
    AppWidgetManager manager = AppWidgetManager.getInstance(getApplicationContext());

    boolean canBindWidgets = manager.bindAppWidgetIdIfAllowed(appWidgetId, info.provider);
    if(!canBindWidgets) {
        Intent intent = new Intent(AppWidgetManager.ACTION_APPWIDGET_BIND);
        intent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);
        intent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_PROVIDER, info.provider);
        startActivityForResult(intent, REQUEST_BIND_APPWIDGET);
    }

    AppWidgetHostView widgetHostView = widgetHost.createView(getApplicationContext(), appWidgetId, info);
    
    if(info.configure != null) {
        configureWidget(appWidgetId);
    }

    return widgetHostView;
}

Now, if you want to create an app widget, first you call getWidgetProviderInfo() by specifying which package you want to get your app widgets from and which widget you want (because there may be more than one). Then, you pass the result to getWidgetHostView which will create the widget and launch the configure activity if there is one. Then, you can use the AppWidgetHostView it returns and put it in a linear layout for example. Here is a more complete example:

void createMyWidget() {
    String packageName = com.xxx.xxx;
    AppWidgetProviderInfo widgetInfo = getWidgetProviderInfo(packageName, 0);
    AppWidgetHostView widgetHostView = getWidgetHostView(widgetInfo);
    //Add the widgetHostView to your container.
}
    

Finally, if you want to reconfigure your app widget, you can do so by calling configureWidget and passing its app widget id as a parameter. It will relauch the configure activity (if there is one; that's why you should verify if it exists first by looking at the widget's provider info, just like in the getWidgetHostView function).