Java – How do you make custom widgets?

When developing widgets for Android use, it seems that you cannot add your own custom View classes to the AppWidgetProvider.

For example, I created a custom class that extends the View, which works fine when used in an activity, but when I add it to the widget, I get a “ClassNotFoundException” because Android seems to only allow a specific set of system widgets to be added.

I’ve seen some apps look like they made their own custom widgets in them. For example, there is a radial menu that pops up when clicked showing the application shortcut. How are these achieved? Can I use my own custom widget? They seem to have a block canvas that can be drawn inside the widget.

Good quick example https://market.android.com/details?id=zombiesinthelab.widgets.droidpetwidget&feature=top-paid
So this widget is done by drawing ImageView and updating them regularly instead of using the Canvas drawing frame?

Android widgets can only contain Layout-Widgets supported by RemoteViews.

A RemoteViews object (and,
consequently, an App Widget) can
support the following layout classes:

FrameLayout
LinearLayout
RelativeLayout

And the following widget classes:

AnalogClock
Button
Chronometer
ImageButton
ImageView
ProgressBar
TextView

> Descendants of these classes are not
supported.

Pay attention to the last sentence. You cannot change this behavior, it is hardcoded in Android.