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POAndroid freezes when there is a NullPointerException in OnClickListener.onClick (other tasks cannot start)
 

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  1. POAndroid freezes when there is a NullPointerException in OnClickListener.onClick (other tasks cannot start)
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    <p>I have a simple setup:</p> <ul> <li><code>CrashHandler</code> - a class which implements <code>Thread.UncaughtExceptionHandler</code>;</li> <li><code>CrashActivity</code> - an activity which can send user reports;</li> <li><code>MainActivity</code> - the main app with which the user should interact. </li> </ul> <p>When there is an uncaught exception within the <code>MainActivity</code> or any of it's threads, the <code>CrashHandler</code> intercepts it and creates a notification with an intent to start the <code>CrashActivity</code>:</p> <pre><code>Intent it = new Intent("CrashReporter" + SystemClock.currentThreadTimeMillis()); it.setClass(context, CrashActivity.class); it.setFlags(it.getFlags() | Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TOP); </code></pre> <p>In the mean time Android shows an "Application crashed" message, the user clicks OK, the application is closed, then the user might click the <code>notification</code>. If the <code>notification</code> is clicked, the <code>CrashActivity</code> starts and shows.</p> <p>This code has been working for a long time in many different situations (crash on main thread, crash in a <code>handler</code>, crash on a background <code>thread</code>...). However, I recently discovered that it DOES NOT WORK if the exception is thrown in the <code>OnClickListener.onClick</code> method in a listener attached to a <code>button</code> in the <code>MainActivity</code>. The situation is as follows:</p> <ol> <li>I execute code that deliberately throws a <code>NullPointerException</code>;</li> <li><code>CrashHandler</code> intercepts it and creates a <code>notification</code> (which is shown);</li> <li>Android DOES NOT show any messages (for example, there is no "Application crashed", which should be visible);</li> <li>The <code>MainActivity</code> is frozen;</li> <li>IF the user clicks on the notification to launch the <code>CrashActivity</code>, a black screen is shown and everything freezes (the desired activity is not shown).</li> </ol> <p><code>Logcat</code> shows that there is a timeout on launch, even before <code>OnCreate</code> or any of my code:</p> <pre><code>I/ActivityManager(11826): START u0 {act=CrashHandler1196 flg=0x14000000 cmp=mycompany.myapp/.CrashActivity bnds=[0,102][720,230] (has extras)} from pid -1 W/KeyguardViewMediator(11826): verifyUnlock called when not externally disabled W/ActivityManager(11826): Activity pause timeout for ActivityRecord{41f4d988 u0 mycompany.myapp/.MainActivity} W/ActivityManager(11826): Launch timeout has expired, giving up wake lock! W/ActivityManager(11826): Activity idle timeout for ActivityRecord{4225eeb8 u0 mycompany.myapp/.CrashActivity} </code></pre> <ul> <li>If before clicking the <code>notification</code> I kill the app from <code>ADB</code>, the <code>notification</code> works perfectly.</li> <li><p>If before clicking the <code>notification</code> I make some clicks and gestures on the frozen app, after a few seconds I receive a message about an <code>ANR</code>: </p> <pre><code> E/ActivityManager(11826): ANR in mycompany.myapp (mycompany.myapp/.MainActivity) E/ActivityManager(11826): Reason: keyDispatchingTimedOut E/ActivityManager(11826): Load: 0.63 / 0.57 / 0.49 </code></pre></li> <li><p>If I click "yes, kill it", and then click the <code>notification</code>, it works perfectly.</p></li> <li>If I add <code>System.exit</code>(-1) in the <code>CrashHandler</code> just after creating the notification, the app immediately quits and the notification works perfectly (unfortunately, I can't go with this solution in production). </li> </ul> <p>I have two questions:</p> <ol> <li>Why a <code>NullPointer exception</code> in <code>OnClickListener.onClick</code> doesn't cause the app to crash, instead freezing it together with the OS and preventing other activities from starting?</li> <li>What to do to avoid it in general, or at least, how to make the <code>CrashActivity</code> start in these conditions? </li> </ol>
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    1. USam05mhz
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    1. COI think you should post some of your code from **onClick** so that we can understand.
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      1. USMunim Dibosh
 

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