Android AppWidget TextView: How to set background color at run time

Question

I am trying to create an AppWidget, in which the background color of a TextView changes at random at specified periodic interval.

The TextView is defined in layout xml file as

<?xml version="1.0" encoding="utf-8" ?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/widget"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical" >
    <TextView  
        android:id="@+id/message"
        android:background="#ff99ff"
        android:text="Hello Widget" />
</LinearLayout>

In update method, i have loaded the layout as

RemoteViews remoteView=new RemoteViews(context.getPackageName(),R.layout.widget_message);

To change the background of TextView i used the following statement

remoteView.setInt(R.id.message, "setBackgroundResource", R.color.col_1);

But i am getting a widget saying problem loading widget. If i remove the above line everything works fine.

LogCat says:

updateAppWidget couldn't find any view, using error view

android.widget.RemoteViews$ActionException: view: android.widget.TextView can't use method with RemoteViews: setBackgroundResource(int)

Answer 1

The reason is that via RemoteViews you can call just limited amount of methods. In case that it is prohibited you get message like this.

Tom

Answer 2

Tomas is correct. My solution is to make two views with the respective backgrounds and make one INVISIBLE and the other one VISIBLE. Of course this only works with a small number of backgrounds, e.g., "green" and "red" that might indicate some state.

Answer 3

What i find weird about this is that it works great on my nexus one ( 2.2 ), but not at all on an HTC Tattoo ( 1.6 ). I'm going to try and run some emulator tests and see if it's not just another case of HTC lazily implementing some underlying UI rendering code, which i already found with the Tattoo ( Layouts render differently than on stock Android 1.6 ).

What device were you testing this on?

Answer 4

Is there a workaround for this problem on all devices?