Android - Intents - Mazenet Solution
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The document explains the concept of intents in Android development, highlighting their role as asynchronous messages that facilitate interaction between components. It describes two types of intents: explicit intents, which invoke a specific component, and implicit intents, which specify an action to be performed, along with any accompanying data. Additionally, it covers how to start activities and retrieve results from sub-activities, with examples of code implementation.
Android - Intents - Mazenet Solution
- 2. • Intents are asynchronous messages • It allow you to interact with components • Types of Intent – Implicit Intent – Explicit Intent
- 4. Starting Activities • To start an activity, use the method startActivity(intent) • This method is defined on the Context object which Activity extends.
- 6. • Activities which are started by other Android activities are called sub-activities. Intent i = new Intent(this, ActivityTwo.class); startActivity(i);
- 9. Explicit Intents • It explicitly define the component which should be called by the Android system, by using the Java class as identifier. Intent i = new Intent(this, ActivityTwo.class); i.putExtra("Value1", "This value one for ActivityTwo "); i.putExtra("Value2", "This value two ActivityTwo");
- 11. Implicit Intents • Implicit intents specify the action which should be performed and optionally data which provides content for the action. • For Example: the following tells the Android System to view a web page. Intent i = new Intent(Intent.ACTION_VIEW, Uri.parse("http://www.mazenetsolution.com")); startActivity(i);
- 12. Retrieving result data from a sub-activity
- 15. Example
- 16. startActivityForResult() public void onClick(View view) { Intent i = new Intent(this, ActivityTwo.class); i.putExtra("Value1", "This value one for ActivityTwo "); i.putExtra("Value2", "This value two ActivityTwo"); startActivityForResult(i, REQUEST_CODE); }
- 17. Intent Filter
- 18. • Intents are used to signal to the Android system that a certain event has occurred. • Intents often describe the action which should be performed and provide data upon which such an action should be done.
- 19. String url = "http://www.mazenetsolution.com"; Intent i = new Intent(Intent.ACTION_VIEW); i.setData(Uri.parse(url)); startActivity(i);
- 20. Example: Register an activity as browser <activity android:name=".BrowserActivitiy" android:label="@string/app_name"> <intent-filter> <action android:name="android.intent.action.VIEW" /> <category android:name="android.intent.category.DEFAULT" /> <data android:scheme="http"/> </intent-filter> </activity>