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Adding the Menu
7:04In 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.
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An easy way to do this,
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is to copy the code from
a project that already has a menu.
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Luckily, Android studio
creates lots of those.
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Let's pick this one,
with the three dots in the corner.
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We'll want this menumain.xml file for
ourselves.
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We don't even have a menu folder
under our res directory yet.
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So I'll just copy the whole directory.
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This is the string that will display
when we click the menu button.
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So let's hit Alt+Enter to create this.
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We want it to say clear strokes.
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It would also be nice if it
had a more descriptive name.
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We can go to re-factor, rename, noting
that the keyboard shortcut is shift F6,
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and then name it action clear strokes.
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And we'll do the same thing for the ID.
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Except this time we'll use
the Shift+F6 shortcut.
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All right.
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Now we need to add the code and
main activity to use that menu.
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We can grab that code from the project
we just generated as well.
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And main activity.
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Below onCreate we'll want
the onCreateMenuOptions and
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onOptionsItemSelected file methods.
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And we'll paste them below on pause.
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Recall that we changed our action
settings to be action clear strokes.
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And now we can add the code that we'd like
to execute when that button is pressed.
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What we'd like to happen is for each of
the holes to reset their stroke count
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to zero, as well as to not to have any
saved data with those strokes either.
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So we'll take our editor.
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And we'll hit clear to remove all
the shared preference values,
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and then mEditor.apply
to save our changes.
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After that, we need to set each
of the whole scores to zero.
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Instead of using a for loop, using int
I equals zero, like I have been doing.
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This time I'll use a for
each loop to show something different.
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So four, we're going to be using holes.
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And we're going to call the holes in the
loop hole, from the group called m holes.
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And for each hole,
we wanna set the stroke count to zero.
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Okay.
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That should do it.
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Let's see what happens.
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Well, right off the bat, it's pretty
clear that we don't have a bar up here.
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And we'd like one.
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Let's hop over to Google and
see what that's all about.
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I Googled for list activity,
no action bar.
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And on the second result,
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We learn that only themes after
Holo can get action bars.
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And our theme,
let's double check it against this first,
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is AppCompat.Light.DarkActionBar.
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Which is exactly what he
says might cause us trouble.
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So let's try changing it to
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Android:Theme.Holo.
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All right.
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We've got our action bar.
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And we've got an awfully dark theme,
if you like this theme that's great,
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if you don't we can change
this to Holo.Light.
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Looks good.
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So what happens when we clear the strokes?
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Nothing, nothing happened.
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Three, two, one, zeros, zeros.
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What's going on here is
when we clear the strokes,
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we're clearing them in the data and
the data is correct.
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But what's being shown to
us is not being updated.
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We haven't told the list view to update.
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By scrolling up and down, we can make
it update each of the views, and so
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if we clear the strokes and scroll down,
and then come back up, it'll be zero.
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But it won't be 0 right when we hit Clear
Strokes because we haven't added any code
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to clear that yet.
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This is an easy fix though.
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In MainActivity.java, right after we
set all the hole stroke counts to 0
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All we need to do is call
notifyDataSetChanged on our list adaptor.
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So, mlistadaptor.notifyDataSetChanged.
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And this tells the list adaptor
that the data set changed.
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And the list adaptor knows that when
that happens it needs to update.
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So that should handle that bug.
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Let's run it and find out.
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All right, lets add some scores and
then clear them.
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Looks good.
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And if we leave, and
then come back, still zeros.
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Let's test a rotation just for
good measure.
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Looks good.
And it looks like we're done with the app.
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Great job.
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If you're looking for
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more things to add to this app, a good
place to start would be the app icon.
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Congratulations on finishing
the Golf Scorecard app.
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It was definitely a lot of work.
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But being able to put all
the pieces together and
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create a finished product,
is definitely worth it.
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You’re now well on your way to
becoming an Android developer, and
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I look forward to seeing what
you choose to make next.
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