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In this video I find a way to get back the ActionBar, implement the Menu, and add functionality to the 'Clear Strokes' MenuItem.
The last thing we need to is add a menu.
0:00
An easy way to do this,
0:03
is to copy the code from
a project that already has a menu.
0:05
Luckily, Android studio
creates lots of those.
0:09
Let's pick this one,
with the three dots in the corner.
0:12
We'll want this menumain.xml file for
ourselves.
0:26
We don't even have a menu folder
under our res directory yet.
0:30
So I'll just copy the whole directory.
0:35
This is the string that will display
when we click the menu button.
0:43
So let's hit Alt+Enter to create this.
0:49
We want it to say clear strokes.
0:53
It would also be nice if it
had a more descriptive name.
0:57
We can go to re-factor, rename, noting
that the keyboard shortcut is shift F6,
1:02
and then name it action clear strokes.
1:10
And we'll do the same thing for the ID.
1:18
Except this time we'll use
the Shift+F6 shortcut.
1:20
All right.
1:30
Now we need to add the code and
main activity to use that menu.
1:33
We can grab that code from the project
we just generated as well.
1:39
And main activity.
1:46
Below onCreate we'll want
the onCreateMenuOptions and
1:48
onOptionsItemSelected file methods.
1:53
And we'll paste them below on pause.
2:01
Recall that we changed our action
settings to be action clear strokes.
2:09
And now we can add the code that we'd like
to execute when that button is pressed.
2:17
What we'd like to happen is for each of
the holes to reset their stroke count
2:21
to zero, as well as to not to have any
saved data with those strokes either.
2:27
So we'll take our editor.
2:33
And we'll hit clear to remove all
the shared preference values,
2:37
and then mEditor.apply
to save our changes.
2:42
After that, we need to set each
of the whole scores to zero.
2:50
Instead of using a for loop, using int
I equals zero, like I have been doing.
2:55
This time I'll use a for
each loop to show something different.
3:01
So four, we're going to be using holes.
3:05
And we're going to call the holes in the
loop hole, from the group called m holes.
3:09
And for each hole,
we wanna set the stroke count to zero.
3:18
Okay.
3:25
That should do it.
3:27
Let's see what happens.
3:29
Well, right off the bat, it's pretty
clear that we don't have a bar up here.
3:32
And we'd like one.
3:37
Let's hop over to Google and
see what that's all about.
3:39
I Googled for list activity,
no action bar.
3:42
And on the second result,
3:46
We learn that only themes after
Holo can get action bars.
3:53
And our theme,
let's double check it against this first,
3:58
is AppCompat.Light.DarkActionBar.
4:07
Which is exactly what he
says might cause us trouble.
4:11
So let's try changing it to
4:15
Android:Theme.Holo.
4:20
All right.
4:32
We've got our action bar.
4:33
And we've got an awfully dark theme,
if you like this theme that's great,
4:35
if you don't we can change
this to Holo.Light.
4:39
Looks good.
4:44
So what happens when we clear the strokes?
4:46
Nothing, nothing happened.
4:49
Three, two, one, zeros, zeros.
4:56
What's going on here is
when we clear the strokes,
5:05
we're clearing them in the data and
the data is correct.
5:08
But what's being shown to
us is not being updated.
5:12
We haven't told the list view to update.
5:15
By scrolling up and down, we can make
it update each of the views, and so
5:18
if we clear the strokes and scroll down,
and then come back up, it'll be zero.
5:23
But it won't be 0 right when we hit Clear
Strokes because we haven't added any code
5:29
to clear that yet.
5:35
This is an easy fix though.
5:39
In MainActivity.java, right after we
set all the hole stroke counts to 0
5:43
All we need to do is call
notifyDataSetChanged on our list adaptor.
5:49
So, mlistadaptor.notifyDataSetChanged.
5:57
And this tells the list adaptor
that the data set changed.
6:02
And the list adaptor knows that when
that happens it needs to update.
6:05
So that should handle that bug.
6:10
Let's run it and find out.
6:11
All right, lets add some scores and
then clear them.
6:15
Looks good.
6:20
And if we leave, and
then come back, still zeros.
6:21
Let's test a rotation just for
good measure.
6:31
Looks good.
And it looks like we're done with the app.
6:37
Great job.
6:41
If you're looking for
6:42
more things to add to this app, a good
place to start would be the app icon.
6:43
Congratulations on finishing
the Golf Scorecard app.
6:48
It was definitely a lot of work.
6:51
But being able to put all
the pieces together and
6:53
create a finished product,
is definitely worth it.
6:55
You’re now well on your way to
becoming an Android developer, and
6:58
I look forward to seeing what
you choose to make next.
7:01
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