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Android - Intents and Broadcast Receivers
The document discusses the implementation of Android components, particularly focusing on intents and broadcast receivers. It provides code snippets and instructions for creating activities, managing actions between them, and handling system events through broadcast receivers. Additionally, it covers methods for data sharing between activities and responding to custom events.
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Android - Intents and Broadcast Receivers
- 1. Intents & Broadcast Receivers 2014/9/9 Copyright © 2014 MingHo Chang
- 2. 張明禾 • C • Android App • NodeJS • Sencha Touch • Unity 2014/9/9 Copyright © 2014 MingHo Chang
- 3. AndroidManifest.xml <manifest xmlns:android=hLp://schemas.android.com/apk/res/android package="com.example.test" android:versionCode="1" android:versionName="1.0"> <uses-‐sdk android:minSdkVersion="8" android:targetSdkVersion="17" /> <applicaUon android:icon="@drawable/icon"> <acUvity android:name=".FirstAcUvity" android:label="@string/app_name"> <intent-‐filter> <acUon android:name="android.intent.acUon.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-‐filter> </acUvity> </applicaUon> 2014/9/9 </manifest> Copyright © 2014 MingHo Chang
- 4. AndroidManifest.xml <applicaUon android:icon="@drawable/icon"> <acUvity android:name=".FirstAcUvity" android:label="@string/app_name"> <intent-‐filter> <acUon android:name="android.intent.acUon.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-‐filter> </acUvity> <acUvity android:name=".SecondAcUvity" > </acUvity> </applicaUon> 2014/9/9 Copyright © 2014 MingHo Chang
- 5. 1st implementaUon •New an acUvity named "SecondAcUvity." – File -‐> New -‐> Other… -‐> Android AcUvity • Check if AndroidManifest.xml is updated. • Put two TextViews, one EditText & two buLons named "Dial" & "Update" in the layout. 2014/9/9 Copyright © 2014 MingHo Chang
- 6. Intent • startAcUvity(intent); – Open another acUvity in the same app. – Open another app (and do something). • Ex: Open browser, show map, take picture, call someone… • startService(intent); 2014/9/9 Copyright © 2014 MingHo Chang
- 7. Intent -‐ startAcUvity • Open another acUvity in the same app. Context context = getApplicaUonContext(); Intent i = new Intent(context , SecondAcUvity.class); i.putExtra("Name", "Mary"); startAcUvity(i); 2014/9/9 Copyright © 2014 MingHo Chang
- 8. Intent -‐ startAcUvity • Get data from intent. Bundle extras = getIntent().getExtras(); if (extras == null) { return; } String name = extras.getString("Name"); if (name != null) { // TODO Change the text in the textview } 2014/9/9 Copyright © 2014 MingHo Chang
- 9. Intent -‐ startAcUvity • Open browser. Uri webpage = Uri.parse("hLp://www.android.com"); Intent i = new Intent(Intent.ACTION_VIEW, webpage); startAcUvity(i); • Dial someone’s number Uri number = Uri.parse("tel:12345789"); Intent i = new Intent(Intent.ACTION_DIAL); i.setData(number); startAcUvity(i); 2014/9/9 Copyright © 2014 MingHo Chang
- 10. Intent -‐ startAcUvity • Share messages Intent i = new Intent(Intent.ACTION_SEND); i.setType("text/plain"); i.putExtra(android.content.Intent.EXTRA_TEXT, "How are you?"); startAcUvity(i); 2014/9/9 Copyright © 2014 MingHo Chang
- 11. 2nd implementaUon •Show SecondAcUvity with the selected classmate’s name and descripUon aqer clicking an item on the list. • Dial the number aqer clicking the buLon in SecondAcUvity. 2014/9/9 Copyright © 2014 MingHo Chang
- 12. Intent -‐ startAcUvityForResult • startAcUvityForResult(intent) • onAcUvityResult(requestCode, resultCode, intent) – requestCode – resultCode – intent 2014/9/9 Copyright © 2014 MingHo Chang
- 13. Intent -‐ startAcUvityForResult • FirstAcUvity.java private staUc final int REQUEST_SECOND = 1; Intent i = new Intent(this, SecondAcUvity.class); i.putExtra("Name", "Mary"); i.putExtra("DescripUon", "A girl"); startAcUvityForResult(i, REQUEST_SECOND); 2014/9/9 Copyright © 2014 MingHo Chang
- 14. Intent -‐ startAcUvityForResult • FirstAcUvity.java @Override protected void onAcUvityResult(int requestCode, int resultCode, Intent data) { if (resultCode == RESULT_OK && requestCode == REQUEST_SECOND) { if (data.hasExtra("Dialed")) { String hasDialed = data.getExtras().getString("Dialed"); Toast.makeText(this, hasDialed, Toast.LENGTH_SHORT).show(); } } 2}0 14/9/9 Copyright © 2014 MingHo Chang
- 15. Intent -‐ startAcUvityForResult • SecondAcUvity.java @Override public void finish() { Intent data = new Intent(); data.putExtra("Dialed", "Yes"); setResult(RESULT_OK, data); super.finish(); } 2014/9/9 Copyright © 2014 MingHo Chang
- 16. 3rd implementaUon •Send data(dialed or not) back to FirstAcUvity and toast. 2014/9/9 Copyright © 2014 MingHo Chang
- 17. Common Intents URI Ac'on Descrip'on hLp(s):web_address ACTION_VIEW Open the website tel:phone_number ACTION_CALL Call the phone number tel:phone_number ACTION_DIAL Dial the phone number geo:laUtude,longitude ACTION_VIEW Open map MediaStore.ACTION_IMAGE_CAPTURE Open camera People.CONTENT_URI ACTION_VIEW Open contact list market:search? q=pname:pkg_name ACTION_VIEW Search in Google Play 2014/9/9 Copyright © 2014 MingHo Chang
- 18. Broadcast Receiver 2014/9/9 Copyright © 2014 MingHo Chang
- 19. Broadcast Receiver – System Events • android.intent.acUon.______ – BOOT_COMPLETED • Requires android.permission.RECEIVE_BOOT_COMPLETED – ACTION_POWER_CONNECTED – ACTION_POWER_DISCONNECTED – BATTERY_LOW – BATTERY_OKAY • android.net.conn.CONNECTIVITY_CHANGE • android.provider.Telephony.SMS_RECEIVED 2014/9/9 Copyright © 2014 MingHo Chang
- 20. Broadcast Receiver •MyReceiver.java public class MyReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { // Toast } } 2014/9/9 Copyright © 2014 MingHo Chang
- 21. Broadcast Receiver -‐ Register • AndroidManifest.xml <receiver android:name=”.MyReceiver" > <intent-‐filter> <acUon android:name="android.intent.acUon.BOOT_COMPLETED" /> </intent-‐filter> </receiver> • In java Context.registerReceiver(myReceiver, intentFilter); 2014/9/9 Copyright © 2014 MingHo Chang
- 22. 4th implementaUon •Define a broadcast receiver (toast a message) for power connected. 2014/9/9 Copyright © 2014 MingHo Chang
- 23. Broadcast Receiver – Custom Event • AndroidManifest.xml <receiver android:name=".MyReceiver" > <intent-‐filter> <acUon android:name="com.example.test.custom_receiver" /> </intent-‐filter> </receiver> Intent intent = new Intent(); intent.setAcUon("com.example.test.custom_receiver"); sendBroadcast(intent); 2014/9/9 Copyright © 2014 MingHo Chang
- 24. 5th implementaUon •Toast "Updated." while the broadcast receiver gets custom event, clicking "Update" buLon. 2014/9/9 Copyright © 2014 MingHo Chang
- 25. Broadcast Receiver – Custom Event • FirstAcUvity.java public class CustomReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { // TODO } } 2014/9/9 Copyright © 2014 MingHo Chang
- 26. Broadcast Receiver – Custom Event • FirstAcUvity.java private void registerCustomReceiver() { IntentFilter filter = new IntentFilter(); filter.addAcUon("com.example.test.custom_receiver"); if (mCustomReceiver == null) { mCustomReceiver = new CustomReceiver(); } registerReceiver(mCustomReceiver, filter); } 2014/9/9 Copyright © 2014 MingHo Chang
- 27. Broadcast Receiver – Custom Event • FirstAcUvity.java private CustomReceiver mCustomReceiver = null; @Override protected void onCreate(Bundle savedInstanceState) { … registerCustomReceiver(); } 2014/9/9 Copyright © 2014 MingHo Chang
- 28. Broadcast Receiver – Custom Event • FirstAcUvity.java @Override protected void onDestroy() { super.onDestroy(); if (mCustomReceiver != null) { try { unregisterReceiver(mCustomReceiver); } catch(ExcepUon e) { e.printStackTrace(); } mCustomReceiver = null; } 2014/9/9} Copyright © 2014 MingHo Chang
- 29. 6th implementaUon •Update the descripUon in FirstAcUvity aqer clicking "Update" buLon in SecondAcUvity. • Tip: – Use listAdapter.noUfyDataSetChanged(); when data in list change. 2014/9/9 Copyright © 2014 MingHo Chang