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

I am trying to create 开发者_运维问答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)

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Try this it will work fine.

remoteView.setInt(R.id.message, "setBackgroundColor", 
        android.graphics.Color.BLACK);

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If you have some shape as the background of the textview, where the background is defined in some drawable resource, then you can use

remoteViews.setInt(R.id.change,"setBackgroundResource", R.drawable.my_drawable_new);

In above code statement, R.id.change is the TextView with some background resource and you have defined some resources (my_drawable and my drawable_new) in your drawable folder.

<TextView
    android:id="@+id/change"
    android:background="@drawable/my_drawable">
</TextView

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If you want to set the color of the text itself, use

remoteViews.setInt(R.id.tvAmountThisYear, "setTextColor",
                android.graphics.Color.RED);

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contentView.setInt(R.id.tv_contactText, "setBackgroundColor", Color.parseColor(hexColor));

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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.

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As of android 2.2 this method can be called, not before.

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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

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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?

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The emulator will let this go through when you run a 2.2 emulator, so I guess the restriction is lifted as of 2.2.