Question

I would like to create a notification icon view that looks similar to the Google+ app’s notification. The difference will be that I need to be able to change the color at runtime where as the Google+ icons gray or red so I’m assuming they are using a StateListDrawable.

What is the best approach for this? I’d prefer to have the rounded clipped corners and have the option to have a drawable inside. This custom view will be placed in the Action Bar as well. I still need the view to respond to android:background state list drawables so I can have the click and selected accordance working.

This custom view will be placed in the action bar as well.

Answer 1

I solved this by doing the following.

Created this to make the rounded corner shape with a solid color. This also adds a translucent black to give it a pressed look against a blackground.
res/drawable/shape_notification.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" 
    android:shape="rectangle">
    <stroke android:color="#33000000" android:width="2dp"/>
    <corners android:radius="4dp" />
    <solid android:color="#99333333"/>
</shape>

The layer drawable will be used as the actual drawable on the action bar item. It has the background (written above) overlayed with the wrench icon.
res/drawable/layer_customizer.xml

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
    <item android:drawable="@drawable/shape_notification" />
    <item android:drawable="@drawable/ic_menu_preferences" />
</layer-list>

Java code to change the color. The target view is the object that is assigned the layer_customizer drawable. The color passed in will change the shape_notification.xml’s solid tag color.

public static void setCustomizerDrawableColor(final View target, final int color) {
  final Drawable d = target.getDrawable();
  LayerDrawable layer = (LayerDrawable)d;
  GradientDrawable gradient = (GradientDrawable)layer.getDrawable(0);
  gradient.setColor(color);
  gradient.invalidateSelf();
  layer.invalidateSelf();
  target.invalidate();
}

Create a layout using these layers.
res/layout/actionview_customizer.xml

<?xml version="1.0" encoding="utf-8"?>
<ImageButton xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/ActionViewCustomizer"
    android:src="@drawable/layer_customizer"
    android:contentDescription="@string/customize"
    style="@style/ActionBarButton" />

To get the custom layout to put into the ActionBar add this menu item into it:
res/menu/actionbar_main.xml

<item android:id="@+id/MenuItemCustomize"
  android:icon="@drawable/layer_customizer"
  android:title="@string/customize"
  android:showAsAction="always"
  android:actionLayout="@layout/actionview_customizer"
   />

Then after loading the Action Bar use this code to get the handle to the button. This happens in your Activity.

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.actionbar_main, menu);
    final ActionBar actionBar = getActionBar();
    final MenuItem customizerItem = menu.findItem(R.id.MenuItemCustomize);
    View v = customizerItem.getActionView();
    customizerActionView = (ImageButton) v;
    customizerActionView.setOnClickListener(new OnClickListener() {
        public void onClick(View v) {
            onOptionsItemSelected(customizerItem);
        }
    });
}

If you want to see the full source working together look at the app source code I use this in. http://code.google.com/p/motivatormaker-android/source/browse/MakeMotivator/src/com/futonredemption/makemotivator/activities/MainActivity.java