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lec 03. Intents Explicit Intents Implicit Intents. ADB (Android Device Bridge) adb kill-server adb start-server adb get-state adb devices Use kill-server / start-server to reboot the adb if your device/emulator is not communicating with your dev-machine. Flip teaching

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Lec 03

lec 03

Intents

Explicit Intents

Implicit Intents


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ADB (Android Device Bridge)

adb kill-server

adb start-server

adb get-state

adb devices

Use kill-server / start-server to reboot the adb if your device/emulator is not communicating with your dev-machine.


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Flip teaching

http://www.youtube.com/watch?v=HkMS6Glswig

http://en.wikipedia.org/wiki/Flip_teaching

Partially Flipped

1/ Videos are required

2/ There will still be lectures and slides but less emphasis on these.

3/ More emphasis on lab: doing exercises together in class (laptop to class is required)


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Activated by Intents

Activities

Services

Broadcast Receivers (aka Receivers)

(http://developer.android.com/guide/components/intents-filters.html)


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ComponentName

name : Adam Gerber

Action

email : [email protected]

Data

ret : something...

Scheme

Categories

Intent Architecture::Action/Data/etc

//Explicit; all you need is the ComponentName and optionally the bundle.

//Implicit; usually Action/Data and then optionally the bundle.

Explicit

Implicit


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Explicit Intents: intra-app call by name

//********************************

//This method works great for intra-app calls between activities

//********************************

//use the calling class and the called class as params to constructor.

Intent itn = new Intent(this, Second.class);

startActivity(itn);

//********************************

//You can use this method as well

//notice that all you need is the component name for explicit

// calls

//********************************

//instantiate with zero params and add the component this way

Intent itn = new Intent();

itn.setComponent(new ComponentName("edu.uchicago.cs", "edu.uchicago.cs.Second"));

startActivity(itn);


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Explicit Intents: intra-app call by name

// this is inside the another method, such as the onClick method

Intent itnThird = new Intent();

itnThird.setComponent(new ComponentName("edu.uchicago.cs", "edu.uchicago.cs.Third"));

//********************************

// or you could do this -> Intent itnThird = new Intent(this, Third.class);

//********************************

itnThird.putExtra("name", "Adam Gerber");

itnThird.putExtra("email", "[email protected]");

startActivity(itnThird);


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Implicit Intents: inter-app call

Implicit intents are anonymous and loosely-coupled.

You request the component like a service of the operating system.

Intent itn = new Intent(Intent.ACTION_VIEW, Uri.parse("http://www.google.com/"));

startActivity(itn);


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Implicit Intents: Action/Data pairs

ACTION_VIEW content://contacts/people/1 -- Display information about the person whose identifier is "1".

ACTION_DIAL content://contacts/people/1 -- Display the phone dialer with the person filled in.

ACTION_VIEW tel:123 -- Display the phone dialer with the given number filled in. Note how the VIEW action does what what is considered the most reasonable thing for a particular URI.

ACTION_DIAL tel:123 -- Display the phone dialer with the given number filled in.

ACTION_EDIT content://contacts/people/1 -- Edit information about the person whose identifier is "1".

ACTION_VIEW content://contacts/people/ -- Display a list of people, which the user can browse through. This example is a typical top-level entry into the Contacts application, showing you the list of people.


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ComponentName

name : Adam Gerber

Action

email : [email protected]

Data

ret : something...

Scheme

Categories

Intent Architecture::Bundle (aka extras)

//The bundle is a data structure inside the Intent.

//It holds key/value pairs.

//You can use predefined keys as well.

//If you don't place the extras in there


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Intents

Intent messaging is a facility for late run-time binding between components in the same or different applications. 

Intents are handled by the Android OS. In order for the OS to know about a component, it must be declared in the application manifest file.

If a component does not define Intent filters, it can only be called by explicit Intents. A component with filters can receive both explicit and implicit intents.

6/12/12


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AndroidManifest.xml file

Is an inventory of all the components in an application.

If the component is not listed there, the Android OS won't know it's there. Not even intra-app component communication will resolve.

6/12/12


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Android OS

M

M

*A

I

A

R

S

A

*A

CP


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Intent Filters::Two purposes

1/ inventory of components used by the OS that are callable given certain criteria.

2/ filter requests.

You can define from course to fine

Beware, there is a slight mis-matching between the java and xml:

ACTION_WEB_SEARCH corresponds to android.intent.action.WEB_SEARCH

ACTION_EDIT corresponds to android.intent.action.EDIT

ACTION_EDIT corresponds to android.intent.action.EDIT

CATEGORY_BROWSABLE corresonds to android.intent.category.BROWSABLE


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Categories

//Use Categories to further refine your Intent

//Most important is CATEGORY_DEFAULT

<intent-filter>

<actionandroid:name="android.intent.action.MAIN"/>

<categoryandroid:name="android.intent.category.LAUNCHER"/>

</intent-filter>


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From Google: An Intent object is a bundle of information. It contains information of interest to the component that receives the intent (such as the action to be taken and the data to act on) plus information of interest to the Android system (such as the category of component that should handle the intent and instructions on how to launch a target activity)


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Only three aspects of an Intent object are consulted when the object is tested against an intent filter:

>action >data (both URI and data type) >category

must pass all three tests.

A component can have multiple intent filters.

a filter must contain at least one <action> element, or it will block all intents


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Adapters


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AdapterViews


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