Here is step by step functionality:
add menu.xml
<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<item
android:id="@+id/actionNotifications"
android:icon="@drawable/ic_info_outline_white_24dp"
android:menuCategory="secondary"
android:orderInCategory="1"
android:title="Cart"
app:actionLayout="@layout/notification_layout"
app:showAsAction="always" />
</menu>
Then add notification_layout.xml, this layout will be used as the notification icons layout
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
style="@android:style/Widget.ActionButton"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:layout_gravity="center"
android:background="@android:color/transparent"
android:clickable="true"
android:gravity="center"
android:orientation="vertical">
<ImageView
android:id="@+id/hotlist_bell"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="0dp"
android:contentDescription="Notification Icon"
android:gravity="center"
android:src="@drawable/ic_info_outline_white_24dp" />
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/txtCount"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="@dimen/x5dp"
android:layout_marginLeft="@dimen/x10dp"
android:layout_marginRight="0dp"
android:background="@drawable/pointer_"
android:gravity="center"
android:minWidth="17sp"
android:text="0"
android:textColor="#ffffffff"
android:textSize="12sp" />
</RelativeLayout>
now inside Activity
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.menu, menu);
final View notificaitons = menu.findItem(R.id.actionNotifications).getActionView();
txtViewCount = (TextView) notificaitons.findViewById(R.id.txtCount);
updateHotCount(count++);
txtViewCount.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
updateHotCount(count++);
}
});
notificaitons.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO
}
});
return true;
}
You can put following function (taken from stackoverflow) inside the activity to update counter:
public void updateHotCount(final int new_hot_number) {
count = new_hot_number;
if (count < 0) return;
runOnUiThread(new Runnable() {
@Override
public void run() {
if (count == 0)
txtViewCount.setVisibility(View.GONE);
else {
txtViewCount.setVisibility(View.VISIBLE);
txtViewCount.setText(Integer.toString(count));
// supportInvalidateOptionsMenu();
}
}
});
}