Back to Small Clever Rooms
RSS Feed

An Amendment to an Android Widget Tutorial

I’m trying to make an Android widget, and Google turned up a pretty straightforward and well-presented tutorial that I decided to follow to get a feel for things.

The tutorial was fairly easy to follow aside from the text boxes that were too narrow for the code samples, but it had some bits that were either out of date or, more likely, just wrong. So without further ado, I present some errata:

• In step 4, you edit the widget’s main.xml file, which the tutorial doesn’t explain should be located in res/layout in your project. Most of it works, but:

  • The android:id attribute of the LinearLayout tag is wrong, which is unfortunate. The tutorial mentions in step 3 that Eclipse will complain about R.id.widget_textview and that it will be created shortly. It also mentions in step 4 that “the important thing is the id of our TextView, which we used earlier in the WatchWidget class.” But then it still gets it wrong. Oh well. The value of the android:id attribute should actually be "@+id/widget_textview.
  • I’m fairly certain the widget background stuff is out of date. The background given is a single image, but the link to the Android docs take you to a page where the only available download is a whole folder of stuff. I don’t know how to use the single image provided, so I used the download instead. It contains a res folder with a bunch of folders starting with drawable in it. Their names were similar to those in my Android project’s res directory, so I copied the icons generated by ADT when I set up my project into the downloaded drawable folders and then copied them wholesale into my project, replacing the ones that already existed.
  • If you use the downloaded resources from the Android docs like I did, you have to change the android:background attribute of the LinearLayout tag of main.xml to @drawable/appwidget_bg. Without knowing too much about it, I believe the downloaded folder contains different resources for different screen sizes. This seems to be the relevant part of the Android docs.

• Step 5 has you edit AndroidManifest.xml. But it refers to a receiver named WatchWidgetActivity, which doesn’t exist because in step 1 you unchecked “Create Activity”. It should instead refer to your AppWidgetProvider subclass. So change .WatchWidgetActivity to WatchWidget.

• I think it’s a minor issue, but in step 4, Eclipse will complain about your setting the attribute android:text to a string literal. It should instead point to a string resource, because this aids greatly in localization. So to fix the warning, change the value of android:text to (say) @string/test_time. Then open the file res/values/strings.xml and add a new String resource whose name should be test_time. Its value can be whatever you want.

• In step 6, android:updatePeriodMillis is set to 1000. Having any widget refresh once every second is probably a terrible idea. I set mine to 600000.