android: how to add a customized image to widgets?

Question

i'm new to creating/altering images of any kind in android. what i'm trying to do is the following:

i have a widget, that gets updated periodically from a broadcast receiver. thing is, i want to display a self-made (i.e. programmatically created) image in this widget. and i actually don't know how to ADD the image to the widgets layout. can anyone help me out? heres the code that updates the widget:

public class MyReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(context.getApplicationContext());

        int[] allWidgetIds = intent.getIntArrayExtra(AppWidgetManager.EXTRA_APPWIDGET_IDS);

        // DO SOME THINGS...

        ComponentName myWidget = new ComponentName(context.getApplicationContext(), MyWidgetProvider.class);

        int[] allMyWidgetIds = appWidgetManager.getAppWidgetIds(myWidget);  

        for (int widgetId : allMyWidgetIds) {
            RemoteViews rViews = new RemoteViews(context.getPackageName(), R.layout.widget_layout);
            rViews.setTextViewText(R.id.TextView01, "xyz"); // this works just fine, i.e. it gets updated as intended :)

            appWidgetManager.updateAppWidget(widgetId, rViews);
        }

        // set next update
        Calendar c = Calendar.getInstance();
        c.add(Calendar.SECOND, Config.UPDATE_RATE);

        Date d = new Date(c.getTimeInMillis());
        Intent i = new Intent(context.getApplicationContext(), MyReceiver.class);

        i.putExtra(AppWidgetManager.EXTRA_APPWIDGET_IDS, allWidgetIds);
        PendingIntent sender = PendingIntent.getBroadcast(context.getApplicationContext(), 0, i, PendingIntent.FLAG_UPDATE_CURRENT);

        AlarmManager aManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
        aManager.set(AlarmManager.RTC, d.getTime(), sender);
    }
}

so this works just fine. in the line where "xyz" is written to the TextView, the data i assembled earlier (in the broadcastreceiver) is displayed as intended, i.e. gets updated. at this very point, i want to "draw" this data, i.e. create a graph that should be displayed in the widget.

but: how do i do this? i guess i'll have a drawable in the end. how do i actually get this to be displayed in the widget (and of course updated as well)?

UPDATE:

This is the view-class that should do the graphics. so far it just draws a short line. this works if i set this as a view via setContentView() in an activity:

public class Chart extends View {   
    public Chart(Context context) {
        super(context);
    }

    @Override
    public void onDraw(Canvas canvas) {
        canvas.drawColor(Color.WHITE);

        Paint paint = new Paint();
        paint.setFlags(Paint.ANTI_ALIAS_FLAG);
        paint.setColor(Color.BLACK);

        canvas.drawLine(0, 0, 30, 30, paint);
    }
}

the layout of the widget is pretty boring:

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/widget_layout"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_margin="8dip"
    android:background="@drawable/traffic_shape" >
    <TextView
        android:id="@+id/TextView01"
        android:text="test"
        android:layout_width="match_parent"
        android:layout_height="match_parent" >
    </TextView>
    <ImageView 
        android:id="@+id/graph"
        android:contentDescription="blah"
        android:src="@drawable/icon"
        android:layout_width="match_parent"
        android:layout_height="match_parent" >
    </ImageView>
</LinearLayout>

no how do i get the view i create in my Chart-class to be displayed in the widget? Unfortunately RemoteViews does not offer any functionality to set a view as it seems... :(

Answer 1

looks like i have to answer my own question. found the answer after painfull hours of struggling with the code >:(

for (int widgetId : allWidgetIds)
{
    RemoteViews rViews = new RemoteViews(context.getPackageName(), R.layout.widget_layout);

    Graph graph = new Graph();
    rViews.setImageViewBitmap(R.id.graph, graph.getBitmap());

    appWidgetManager.updateAppWidget(widgetId, rViews);
}

with Graph.java being sth like this:

public class Graph {
    public Bitmap getBitmap() {
        Bitmap bitmap = Bitmap.createBitmap(128, 128, Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmap);

        canvas.drawColor(Color.WHITE);

        Paint paint = new Paint();

        paint.setFlags(Paint.ANTI_ALIAS_FLAG);
        paint.setColor(Color.RED);
        canvas.drawLine(0, 0, 128, 128, paint);
        return bitmap;
    }
}