INTENTS
Babylon University , IT College , SW Dep. , Android
Assist. Lecturer : Wadhah R. Baiee
(2014)
Ref: Wei-Meng Lee, “BEGINNING ANDROID™ 4 APPLICATION
DEVELOPMENT “, Ch2 , John Wiley & Sons , 2012
Resolving Intent Filter Collision
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In the previous section, you learned that the <intentfilter> element defines how your activity can be
invoked by another activity.
What happens if another activity (in either the same
or a separate application) has the same filter
name?
For example, suppose your application has another
activity named Activity3, with the following entry in
the AndroidManifest.xml file:
Resolving Intent Filter Collision
Resolving Intent Filter Collision
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If you call the startActivity() method with the
following intent, then the Android OS will display a
selection of activities :
If you check the “Use by default for this action” item
and then select an activity, then the next time the
intent “net.learn2develop.SecondActivity” is called
again, it will launch the previous activity that you
have selected.
Resolving Intent Filter Collision
Returning Results from an Intent
The startActivity() method invokes another
activity but does not return a result to the
current activity.
 If you need to pass data back from an activity,
you should instead use the
startActivityForResult() method.
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Returning Results from an Intent
Returning Results from an Intent
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Add the following statements in bold to the
secondactivity.xml file
Returning Results from an Intent
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Add the following statements in bold to the SecondActivity.java
Returning Results from an Intent
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Add the following statements in bold to the UsingIntentActivity.java
Returning Results from an Intent
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In addition to passing in an Intent object, you need to pass
in a request code as well.
The request code is simply an integer value that identifies
an activity you are calling.
This is needed because when an activity returns a value,
you must have a way to identify it.
Returning Results from an Intent
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In order for an activity to return a value to the calling
activity, you use an Intent object to send data back via the
setData() method:
The setResult() method sets a result code (either
RESULT_OK or RESULT_CANCELLED) and the data (an
Intent object) to be returned back to the calling activity.
The finish() method closes the activity and returns control
back to the calling activity.
Returning Results from an Intent
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In the calling activity, you need to implement the onActivityResult()
method, which is called whenever an activity returns
Here, you check for the appropriate request and result codes and
display the result that is returned.
The returned result is passed in via the data argument and you
obtain its details through the getData() method.
Returning Results from an Intent
Intent
Uri
getData()
setData()
Passing Data Using an Intent Object
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Besides returning data from an activity, it is also common
to pass data to an activity.
you can use the Intent object to pass the data to the
target activity.
Add Button to the first activity (main) xml .
Passing Data Using an Intent Object
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Add a TextView and Button to the SecondActivity xml .
Passing Data Using an Intent Object
.setData(Uri)
[Uri.parse()]
IntentObject.
Passing data with
Intent
StartActivity()
.getData(Uri)
.putExtra()
Direct
IntentObject.
StartResultActivity()
.getStringExtra()
.getIntExtra()
getIntent()
Bundle
putExtras()
getExtras()
BundleObject.
.putString()
.putInt()
.getString()
.getInt()
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Modify SecondActivity java file to be as follow:
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Modify SecondActivity java file to be as follow:
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Modify MainActivity java file to be as follow:
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Modify MainActivity java file to be as follow:
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For more details , please go to “How it works” P-67 on your text book .