- Using an Implicit Intent 4:13
- Unmatched Implicit Intents 5:30
- Review: Implicit Intents 5 questions
- Intent Filters 3:58
- Handling an Intent from a Filter 4:24
- Creating Intent Filters 1 objective
- Sharing Songs with a Custom Intent 5:06
- Using a Custom Intent Filter 6:57
- Review: Custom Intent Filters 5 questions
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Using a Custom Intent Filter
6:57Let's finish up our custom intent and filter combo by creating a new intent filter in a second app.
So now we just need to create a new
App to receive this custom intent.
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Let's create a new project.
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File, new, new project and
let's name this CustomIntentTester.
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Just leave all the defaults click Next,
Next,
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select empty activity, next and finish.
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Okay so all we want to do here
is add a new intent filter.
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Let's open up the manifest.
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So here in manifest,
double click on it, and
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we can just add a second intent
filter to main activity.
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Activities can filter as many
intents as we can throw them.
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So under the first one let's add
a line in the new intent filter.
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And now let's add an action element,
action and then enter a name and
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for the name, we want to use the exact
value we defined in our other app.
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I'm going to copy and
paste it to make sure I don't get a typo.
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So let's switch over here and in detail
activity, we defined it at the top.
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I'm gonna copy the string value, switch
back, and paste it here as the name.
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All I need to do is end my action,
and now I'm set.
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For the category,
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remember that implicit intents require
us to use the default category.
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So let's add category, and recall name and
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then it's already at the top
of my list category default.
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All right, so now we need to do
something with it in main activity.
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Let's go back there and let's just
display the song details in a TextView.
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First will need an ID for the TextView.
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So let's open up the layout file.
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And we have a Hello World TextView.
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I'm going to delete the text and then add
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android:id=@+/textView.
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Let's go back to main activity and
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now we can create a text
view named text view.
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And set it equal to a cast to text
view FindViewById(R.id.textview).
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Next we can get the intent
used to start this activity.
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Intent intent equals getIntent.
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So first we want to check the action to
make sure that this is the right intent.
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So like before, we wanna lead with
the string in case the action is null.
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So we say if string value, which I
happened still have in my clipboard,
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that equals then we pass
in intent.getAction.
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That's in curly braces and
now we need a song class again.
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There are actually
a couple ways to do this.
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I wanna show you how to make it
work with a parcelable class, but
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that means we need to copy
the song class into this app.
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That's fine for now but
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we should always be wary of having
the same code in two places.
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If we really wanna share
models across apps,
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we should package them into a jar file.
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Anyhow, let's go back to Music Machine.
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Open up the Songs class in the Models
package, right-click on it and
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select Copy.
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Go back to our custom intent tester,
right click on the main package here and
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select paste.
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Click OK and
here's our song class once again.
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So now we can use this
back in main activity.
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We'll say song
song=intent.getParcelableExtra.
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And for the name we will use EXTRA_SONG.
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Notice that we need to be really careful
to use the exact same value that we have
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in our other app.
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It's starting to feel a little brittle.
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Perhaps these both should be
defined in the song class itself.
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I'll leave that as an exercise for
you if you want to clean it up.
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Now we can print the song
details in the text view.
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TextView.setText(song.toString).
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I overwrote the to string method to
print the details out line after line.
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So let's try this out.
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Let's run the app.
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Pick the same emulator.
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OK and then when it loads let's
switch back to Music Machine.
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Let's tap on a song and try to share.
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Go to the menu tap on share song and
ouch we get an error
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if we scroll up in logcat,
let's see what it says.
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Okay, this says, BadParcelableException:
ClassNotFound when unmarshalling.
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If you Google this error you can
read about problems trying to share
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a parcelable object across apps.
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Each app has its own Java class loader and
parceling in one app and
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then unparceling in
another causes problems.
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Fortunately, we can address that by
putting the class in the same exact
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package on both apps.
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So let's get rid of this log view and
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right-click on Java here
in the project navigator.
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Select New then Package
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select the main package that's
already in here and click OK.
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Now we want to type the package name
of our custom class from the other app.
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So we have
com.teamtreehouse.musicmachine.models.
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Click OK and there we go,
we have our new package.
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So we can drag the song class in here now.
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So I'm going to drag song in here.
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Click on the re-factor button and
now let's try it again.
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This time if we switch back to Music
Machine, and let's try sharing this again.
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Click on the menu, share song,
and this time it worked.
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Look we can see all the details of
the song in our custom intent tester.
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I should point out another way to share
complex data from one app to another.
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We can choose to implement
a content provider
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which is used to provide different types
of content to other apps that ask for it.
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The classic example is the Photos
app which provides images or
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videos when other apps
prompt the user to pick one.
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Now we won't cover content
providers in this course but
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check the teacher's notes for
more information if you're interested.
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All right.
We've built up a solid understanding of
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intents.
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We've used both explicit and implicit
intents and now understand why you can set
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a specific activity for an intent and
sometimes let Android find a handler.
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We've also seen how to
be good listeners and
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set up an activity to
handle certain intents.
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Will take this further in the next
section where we'll learn how to
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listen across the entire Android system
with a tool called broadcast receivers.
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See you there.
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