3-Implicit Intents.pptx
- 1. Android Developer Fundamentals V2 This work is licensed under a Creative Commons Attribution 4.0 International License. Implicit Intents Android Developer Fundamentals V2 This work is licensed under a Creative Commons Attribution 4.0 International License. Implicit Intents 1 1 Activities and Intents 1 Android Developer Fundamentals V2 Lesson 2
- 2. Android Developer Fundamentals V2 This work is licensed under a Creative Commons Attribution 4.0 International License. Implicit Intents 2.3 Implicit Intents 2
- 3. Android Developer Fundamentals V2 This work is licensed under a Creative Commons Attribution 4.0 International License. Implicit Intents Contents ● Intent—recap ● Implicit Intent overview ● Sending an implicit Intent ● Receiving an implicit Intent 3
- 4. Android Developer Fundamentals V2 Recap: Intent 4
- 5. Android Developer Fundamentals V2 This work is licensed under a Creative Commons Attribution 4.0 International License. Implicit Intents What is an Intent? 5 An Intent is: ● Description of an operation to be performed ● Messaging object used to request an action from another app component via the Android system. App component Originator Intent Action Android System
- 6. Android Developer Fundamentals V2 This work is licensed under a Creative Commons Attribution 4.0 International License. Implicit Intents What can an Intent do? An Intent can be used to: ● start an Activity ● start a Service ● deliver a Broadcast Services and Broadcasts are covered in other lessons 6
- 7. Android Developer Fundamentals V2 This work is licensed under a Creative Commons Attribution 4.0 International License. Implicit Intents Explicit vs. implicit Intent 7 Explicit Intent — Starts an Activity of a specific class Implicit Intent — Asks system to find an Activity class with a registered handler that can handle this request
- 8. Android Developer Fundamentals V2 Implicit Intent overview 8
- 9. Android Developer Fundamentals V2 This work is licensed under a Creative Commons Attribution 4.0 International License. Implicit Intents What you do with an implicit Intent ● Start an Activity in another app by describing an action you intend to perform, such as "share an article", "view a map", or "take a picture" ● Specify an action and optionally provide data with which to perform the action ● Don't specify the target Activity class, just the intended action 9
- 10. Android Developer Fundamentals V2 This work is licensed under a Creative Commons Attribution 4.0 International License. Implicit Intents What system does with implicit Intent 10 ● Android runtime matches the implicit intent request with registered intent handlers ● If there are multiple matches, an App Chooser will open to let the user decide
- 11. Android Developer Fundamentals V2 This work is licensed under a Creative Commons Attribution 4.0 International License. Implicit Intents How does implicit Intent work? 11 1. The Android Runtime keeps a list of registered Apps 2. Apps have to register via AndroidManifest.xml 3. Runtime receives the request and looks for matches 4. Android runtime uses Intent filters for matching 5. If more than one match, shows a list of possible matches and lets the user choose one 6. Android runtime starts the requested activity
- 12. Android Developer Fundamentals V2 This work is licensed under a Creative Commons Attribution 4.0 International License. Implicit Intents App Chooser 12 When the Android runtime finds multiple registered activities that can handle an implicit Intent, it displays an App Chooser to allow the user to select the handler
- 13. Android Developer Fundamentals V2 Sending an implicit Intent 13
- 14. Android Developer Fundamentals V2 This work is licensed under a Creative Commons Attribution 4.0 International License. Implicit Intents Sending an implicit Intent 14 1. Create an Intent for an action Intent intent = new Intent(Intent.ACTION_CALL_BUTTON); User has pressed Call button — start Activity that can make a call (no data is passed in or returned) 1. Start the Activity if (intent.resolveActivity(getPackageManager()) != null) { startActivity(intent); }
- 15. Android Developer Fundamentals V2 This work is licensed under a Creative Commons Attribution 4.0 International License. Implicit Intents Avoid exceptions and crashes 15 Before starting an implicit Activity, use the package manager to check that there is a package with an Activity that matches the given criteria. Intent myIntent = new Intent(Intent.ACTION_CALL_BUTTON); if (intent.resolveActivity(getPackageManager()) != null) { startActivity(intent); }
- 16. Android Developer Fundamentals V2 This work is licensed under a Creative Commons Attribution 4.0 International License. Implicit Intents Sending an implicit Intent with data URI 16 1. Create an Intent for action Intent intent = new Intent(Intent.ACTION_DIAL); 1. Provide data as a URI intent.setData(Uri.parse("tel:8005551234")); 1. Start the Activity if (intent.resolveActivity(getPackageManager()) != null) { startActivity(intent); }
- 17. Android Developer Fundamentals V2 This work is licensed under a Creative Commons Attribution 4.0 International License. Implicit Intents Providing the data as URI 17 Create an URI from a string using Uri.parse(String uri) ● Uri.parse("tel:8005551234") ● Uri.parse("geo:0,0?q=brooklyn%20bridge%2C%20brooklyn%2C%20ny") ● Uri.parse("http://www.android.com"); Uri documentation
- 18. Android Developer Fundamentals V2 This work is licensed under a Creative Commons Attribution 4.0 International License. Implicit Intents Implicit Intent examples 18 Show a web page Uri uri = Uri.parse("http://www.google.com"); Intent it = new Intent(Intent.ACTION_VIEW,uri); startActivity(it); Dial a phone number Uri uri = Uri.parse("tel:8005551234"); Intent it = new Intent(Intent.ACTION_DIAL, uri); startActivity(it);
- 19. Android Developer Fundamentals V2 This work is licensed under a Creative Commons Attribution 4.0 International License. Implicit Intents Sending an implicit Intent with extras 19 1. Create an Intent for an action Intent intent = new Intent(Intent.ACTION_WEB_SEARCH); 1. Put extras String query = edittext.getText().toString(); intent.putExtra(SearchManager.QUERY, query)); 1. Start the Activity if (intent.resolveActivity(getPackageManager()) != null) { startActivity(intent); }
- 20. Android Developer Fundamentals V2 This work is licensed under a Creative Commons Attribution 4.0 International License. Implicit Intents Category 20 Additional information about the kind of component to handle the intent. ● CATEGORY_OPENABLE Only allow URIs of files that are openable ● CATEGORY_BROWSABLE Only an Activity that can start a web browser to display data referenced by the URI
- 21. Android Developer Fundamentals V2 This work is licensed under a Creative Commons Attribution 4.0 International License. Implicit Intents Sending an implicit Intent with type and category 21 1. Create an Intent for an action Intent intent = new Intent(Intent.ACTION_CREATE_DOCUMENT); 1. Set mime type and category for additional information intent.setType("application/pdf"); // set MIME type intent.addCategory(Intent.CATEGORY_OPENABLE); continued on next slide...
- 22. Android Developer Fundamentals V2 This work is licensed under a Creative Commons Attribution 4.0 International License. Implicit Intents Sending an implicit Intent with type and category 22 3. Start the Activity if (intent.resolveActivity(getPackageManager()) != null) { startActivityForResult(myIntent,ACTIVITY_REQUEST_CREATE_FILE); } 4. Process returned content URI in onActivityResult()
- 23. Android Developer Fundamentals V2 This work is licensed under a Creative Commons Attribution 4.0 International License. Implicit Intents Common actions for an implicit Intent 23 Common actions include: ● ACTION_SET_ALARM ● ACTION_IMAGE_CAPTURE ● ACTION_CREATE_DOCUMENT ● ACTION_SENDTO ● and many more
- 24. Android Developer Fundamentals V2 This work is licensed under a Creative Commons Attribution 4.0 International License. Implicit Intents Apps that handle common actions 24 Common actions are usually handled by installed apps (both system apps and other apps), such as: ● Alarm Clock, Calendar, Camera, Contacts ● Email, File Storage, Maps, Music/Video ● Notes, Phone, Search, Settings ● Text Messaging and Web Browsing ➔ List of common actions for an implicit intent ➔ List of all available actions
- 25. Android Developer Fundamentals V2 Receiving an Implicit Intent 25
- 26. Android Developer Fundamentals V2 This work is licensed under a Creative Commons Attribution 4.0 International License. Implicit Intents Register your app to receive an Intent 26 ● Declare one or more Intent filters for the Activity in AndroidManifest.xml ● Filter announces ability of Activity to accept an implicit Intent ● Filter puts conditions on the Intent that the Activity accepts
- 27. Android Developer Fundamentals V2 This work is licensed under a Creative Commons Attribution 4.0 International License. Implicit Intents Intent filter in AndroidManifest.xml 27 <activity android:name="ShareActivity"> <intent-filter> <action android:name="android.intent.action.SEND"/> <category android:name="android.intent.category.DEFAULT"/> <data android:mimeType="text/plain"/> </intent-filter> </activity>
- 28. Android Developer Fundamentals V2 This work is licensed under a Creative Commons Attribution 4.0 International License. Implicit Intents Intent filters: action and category 28 ● action — Match one or more action constants ○ android.intent.action.VIEW — matches any Intent with ACTION_VIEW ○ android.intent.action.SEND — matches any Intent with ACTION_SEND ● category — additional information (list of categories) ○ android.intent.category.BROWSABLE—can be started by web browser ○ android.intent.category.LAUNCHER—Show activity as launcher icon
- 29. Android Developer Fundamentals V2 This work is licensed under a Creative Commons Attribution 4.0 International License. Implicit Intents Intent filters: data 29 ● data — Filter on data URIs, MIME type ○ android:scheme="https"—require URIs to be https protocol ○ android:host="developer.android.com"—only accept an Intent from specified hosts ○ android:mimeType="text/plain"—limit the acceptable types of documents
- 30. Android Developer Fundamentals V2 This work is licensed under a Creative Commons Attribution 4.0 International License. Implicit Intents 30 An Activity can have multiple filters <activity android:name="ShareActivity"> <intent-filter> <action android:name="android.intent.action.SEND"/> ... </intent-filter> <intent-filter> <action android:name="android.intent.action.SEND_MULTIPLE"/> ... </intent-filter> </activity> An Activity can have several filters
- 31. Android Developer Fundamentals V2 This work is licensed under a Creative Commons Attribution 4.0 International License. Implicit Intents A filter can have multiple actions & data <intent-filter> <action android:name="android.intent.action.SEND"/> <action android:name="android.intent.action.SEND_MULTIPLE"/> <category android:name="android.intent.category.DEFAULT"/> <data android:mimeType="image/*"/> <data android:mimeType="video/*"/> </intent-filter> 31
- 32. Android Developer Fundamentals V2 Learn more 32
- 33. Android Developer Fundamentals V2 This work is licensed under a Creative Commons Attribution 4.0 International License. Implicit Intents Learn more ● Intent class documentation ● Uri documentation ● List of common apps that respond to implicit intents ● List of available actions ● List of categories ● Intent Filters 33
- 34. Android Developer Fundamentals V2 This work is licensed under a Creative Commons Attribution 4.0 International License. Implicit Intents What's Next? 34 ● Concept Chapter: 2.3 Implicit Intents ● Practical: 2.3 Implicit Intents
- 35. Android Developer Fundamentals V2 END 35