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, ie make widgets update and respond to user interaction, refer the solution here: Widgets don't respond when re-added through code