android developer android developer - 4 months ago 24
Android Question

How to add a clickable "events" action item to actionBarSherlock?

Background



many apps (including google plus and facebook) have an action bar item showing the number of in-app-events (or "notifications").

This action item has a number within it and you can click it in order to show the events the app has for the user.

something like that (taken from here) :

enter image description here

The problem



I wish to make it work on old android versions, so i use actionBarSherlock.

Sadly, each solution i use has its disadvantages, and i couldn't find any solution here (on stackOverflow) that handles this with actionBarSherlock (found other solutions, but not with this library).

I've also found a post about it (here) , claiming it's an issue on this library, but it's very old and seems to be closed and marked as fixed, but I can't find out how to use it now.

What I've tried



i've tried the next solutions:


  • actionLayout . it showed fine, but clicking on it didn't show the clicking effect.

  • actionViewClass - it didn't even work for some reason.

  • adding the menu item and its view programmatically.



The question



What's the best way to achieve this ?




EDIT: this is what i've tried using actionLayout :

"action_item_notification.xml" - for now it's the same as "abs__action_menu_item_layout.xml" (here). later i will add a textView to hold the number of notifications.

in the menu xml file, i have this as one of the items:

<item
android:id="@+id/activity_main__menuItem_notifications"
android:actionLayout="@layout/action_item_notification"
android:icon="@drawable/notification_button"
android:showAsAction="always"
android:title="@string/notifications"/>


not only it doesn't show the icon, but long clicking on the item will crash the app, with a NPE on the ActionMenuItemView.java file.




EDIT:ok, so i've found a solution that is almost perfect.

it shows the action item nicely and it even reacts to clicking as the other action items.

I've sadly had one missing feature - long clicking on action item to show the toast of its title. sadly, i couldn't find a way to overcome this so what i did (that works) is handling the long clicking on the view itself, and call a similar code that is used for ActionMenuItemView::onLongClick .

if anyone has a better and nicer solution, please write it down.

i've written this solution in a new answer here.

Answer

here's my solution, but it's a bit messy and calls the same code of showing a toast for the action item as the one of actionBarSherlock.

if anyone has a better, cleaner solution, please write it down.

menu file (activity_main.xml) :

...
<item
    android:id="@+id/activity_main__menuItem_notifications"
    android:showAsAction="always"
    android:title="@string/notifications"/>
...

MainActivity.java :

public boolean onCreateOptionsMenu(...){
...
getSupportMenuInflater().inflate(R.menu.activity_main, menu);
//
final MenuItem notificationsMenuItem = menu.findItem(R.id.activity_main__menuItem_notifications);
notificationsMenuItem.setActionView(R.layout.action_item_notification);
setEnableLongClickOnCustomActionItem(notificationsMenuItem,true);
...
public static void setEnableLongClickOnCustomActionItem(final MenuItem menuItem, final boolean enable) {
    final View actionView = menuItem.getActionView();
    if (actionView == null)
        return;
    final CharSequence title = menuItem.getTitle();
    if (!enable || Strings.isEmpty(title))
        actionView.setOnLongClickListener(null);
    actionView.setOnLongClickListener(new OnLongClickListener() {

        @Override
        public boolean onLongClick(final View v) {
            final int[] screenPos = new int[2];
            final Rect displayFrame = new Rect();
            actionView.getLocationOnScreen(screenPos);
            actionView.getWindowVisibleDisplayFrame(displayFrame);

            final Context context = actionView.getContext();
            final int width = actionView.getWidth();
            final int height = actionView.getHeight();
            final int midy = screenPos[1] + height / 2;
            final int screenWidth = context.getResources().getDisplayMetrics().widthPixels;

            final Toast cheatSheet = Toast.makeText(context, title, Toast.LENGTH_SHORT);
            if (midy < displayFrame.height()) {
                // Show along the top; follow action buttons
                cheatSheet.setGravity(Gravity.TOP | Gravity.RIGHT, screenWidth - screenPos[0] - width / 2, height);
            } else {
                // Show along the bottom center
                cheatSheet.setGravity(Gravity.BOTTOM | Gravity.CENTER_HORIZONTAL, 0, height);
            }
            cheatSheet.show();
            return true;
        }
    });

layout file of the action item ( action_item_notification.xml) :

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    style="?attr/actionButtonStyle"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:addStatesFromChildren="true"
    android:focusable="true" >

    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:adjustViewBounds="true"
        android:background="@null"
        android:focusable="false"
        android:scaleType="fitCenter"
        android:src="@drawable/notification_button" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBottom="@+id/imageView1"
        android:layout_alignRight="@+id/imageView1"
        android:background="@drawable/action_item_notification_counter_background"
        android:paddingLeft="1dp"
        android:paddingRight="1dp"
        android:text="88"
        android:textColor="#FFffffff"
        tools:ignore="HardcodedText" />

</RelativeLayout>

and a nice drawable for the background of the textView ("action_item_notification_counter_background.xml") :

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="oval" >

    <solid android:color="#FFff0000" />

</shape>