StackOverflow2013

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copied!<p>The call to <code>getSystemService(...)</code> will not work before <code>onCreate()</code> is called by the Android framework. This happens when the service is started (i.e. by [Context#bindService(...)][1] or <a href="http://d.android.com/reference/android/content/Context.html#startService(android.content.Intent)" rel="noreferrer">Context#startService(...)</a>). I've seen the same NPE when trying to call <code>getSystemService()</code> from a constructor (i.e. before <code>onCreate()</code> is called).</p> <p>You're simply calling <code>(new TMLService()).ManageIncomingCall(incomingNumber)</code>, which doesn't allow Android to initialize your service, which is the root cause of this NPE.</p> <p>In order to get it working, you'll have to start the service and then call a method on the service. To call a method, I think you have to expose it using <a href="http://developer.android.com/guide/developing/tools/aidl.html" rel="noreferrer">AIDL</a>. It might be more complicated than you need for this (maybe?). </p> <p>I've heard that <a href="http://developer.android.com/reference/android/app/IntentService.html" rel="noreferrer">IntentService</a> is an easier way to do stuff in a service without the complexity of AIDL. Here's a sample of how I think IntentService should work. Haven't tested it, but hopefully its useful to get started.</p> <p>CallReceiver</p> <pre><code>public class CallReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { MyPhoneStateListener phoneListener = new MyPhoneStateListener(context); TelephonyManager telephony = (TelephonyManager)context.getSystemService(Context.TELEPHONY_SERVICE); telephony.listen(phoneListener, PhoneStateListener.LISTEN_CALL_STATE); } } </code></pre> <p>MyPhoneStateListener</p> <pre><code>public class MyPhoneStateListener extends PhoneStateListener { private final Context mContext; public MyPhoneStateListener(Context context) { this.mContext = context; } public void onCallStateChanged(int state, String incomingNumber){ if (state == TelephonyManager.CALL_STATE_RINGING) { Log.d("DEBUG", "RINGING"); // OPTION 1: Do it on the main thread (might be bad :) ) //AudioManager audioManage = (AudioManager)mContext.getSystemService(Context.AUDIO_SERVICE); //audioManage.setRingerMode(AudioManager.RINGER_MODE_SILENT); // OPTION 2: Use an IntentService (a bit easier than AIDL) Intent intent = new Intent(TMLIntentService.ACTION_SILENCE_RINGER); mContext.startService(intent); } } } </code></pre> <p>TMLIntentService</p> <pre><code>public class TMLIntentService extends IntentService { public static final String ACTION_SILENCE_RINGER = "org.example.intentservice.ACTION_SILENCE_RINGER"; @Override public void onHandleIntent(Intent intent) { if(ACTION_SILENCE_RINGER.equals( intent.getAction() ) { AudioManager audioManage = (AudioManager)getSystemService(Context.AUDIO_SERVICE); audioManage.setRingerMode(AudioManager.RINGER_MODE_SILENT); } } } </code></pre> <p>AndroidManifest.xml</p> <pre><code><service android:name=".TMLIntentService"> <intent-filter> <action android:name="org.example.intentservice.ACTION_SILENCE_RINGER" /> </intent-filter> </service> </code></pre> <p>[1]: <a href="http://d.android.com/reference/android/content/Context.html#bindService(android.content.Intent" rel="noreferrer">http://d.android.com/reference/android/content/Context.html#bindService(android.content.Intent</a>, android.content.ServiceConnection, int)</p>

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