how to make my phonegap android app crash?

Question

I am developing a crash reporter plugin for phonegap android apps. For the testing purpose, I have to make my application crash & "Unfortunately, application has stopped" window has to be invoked. When I make an unhandled exception in the javascript, the app is not crashing. Instead its showing the same screen. I made the app screen stop respond to user input by executing some infinite loop in javascript & waited around 1 hour, still the app was not crashing. Is the phonegap library by default handling the exceptions ? how I can make my app crash by making exception in javascript level ?

I tried the below code,added a java method to generate crash in the 'CordovaActivity' class.

public static void generateCrash()
   {
     int a = 0;
     int b = 10;
     int c = b/a ;
    }

The app is crashing when I call this method from java (from the 'onCreate' in the activity class) . But when I invoke the same method from the javascript using plugin, the app is not crashing. I want my app to crash by calling/invoking some function from the javascript.

Answer 1

Crash by pressing menu button:

You cannot make the app crash from a plugin or javascript call as the exceptions are handled internally. If you want to make the app crash in android you can edit CordovaActivity.java in Android platform. Change onCreateOptionsMenu as shown:

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    this.postMessage("onCreateOptionsMenu", menu);
    throw new RuntimeException();
} 

Press the menu button and app will crash & "Unfortunately, application has stopped" window will be displayed.

Crash by calling some native function from Javascript:

Write an Android native plugin for Phonegap. Refer http://docs.phonegap.com/en/3.0.0/guide_platforms_android_plugin.md.html#Android%20Plugins for plugin creation. Throw exception inside execute method. This will be handled in the parent layer(Thats why you can see logs about crash in the console), So please do following changes to make the app crash.(Both the classes belong to org.apache.cordova package)

• Remove catch (Exception e){} block in execHelper method of pluginManager classs.

• Remove catch (Throwable e) {} block in exec method of ExposedJsApi class.

  With this change I am able to crash the application from javascript call.

Answer 2

If an app would run like a webpage, a infinite loop might take some time to cause a crash, but should work. Just remember to remove it after testing. Because it causes an exception, and times out the program, the crash should be properly invoked if something possible harmful is used in it. Do something like this:

while(true){ eval("9.99999e+5000 / Infinity"); }

Because we aren't editing a variable, we will prevent the out of memory error.

If this doesn't work, refer to @Aaron D's answer, and if that doesn't work, refer to @kumar's answer.

Answer 3

Unfortunately, JS exceptions are handled by the WebView and even native plugins run in their own separate thread, and will not crash the main Application thread if you raise an exception there (this may not be true for hybrid applications). So you need to hook into the main activity and cause it to throw an Exception on the main thread.

Subclass the CordovaActivity class and override the plugin messaging method:

@Override
public Object onMessage(String id, Object data) {
    if ("crashApp".equals(id)) {
        throw new Exception();
    }
    super(id, data);
}

Write an Android native plugin for Phonegap as per this answer. What it does doesn't matter, but when you message it from the Javascript you should use the id 'crashApp' which should be picked up by your overridden method in the CordovaActivity subclass, and raise the Exception on the main thread.

. Then you can message your plugin using this id whenever you have a Javascript exception by overriding the window.onerror function:

window.onerror = function myFunction(errorMsg, url, lineNumber) { 
/* call Android native function to throw Exception */ ; 
return false; }

This will throw all Javascript errors down into your Java code where they can raise the ANR dialog (and you can pass debugging information with it too).

Answer 4

1. try download any file more that 100MB(my app got stuck in low end androids). You can even do that in loops.

2. Use canvas and drop some random 3d figures.

3. app an alert message in a loop of 1000.

Answer 5

You can make your cordova/ phonegap application crash by removing the permissions from the AndroindManifest.xml file but still using them inside the app, these kind of exceptions mostly crash your application.

please note that (depending on your project structure) modifying the AndroindManifest.xml file itself, it may be regenerated and change back to its correct state so you're gonna need to remove permission lines and then change the Androind.json file in the plugins folder befor build, appropriately to make your changes take effect.

I tested this process and it definitely works! :D

hope it helps, mim ;)

Answer 6

I strongly believe infinite loops won't work in this case. When you use it with PhoneGap, javascript is only a (safe) script language that cannot generate system-driven exceptions.

The best method is to run some native codes (problematic codes) under the help of another PhoneGap plugin. For example, you can do division by zero in objective-c and java native codes.

Answer 7

Usually a halt in execution, intentional or not, can cause android to think the app has crashed. Try wrapping your code in something like setTimeout(function() { your code }, 60000) to delay execution by a minute.

Or, try making an ajax request that will time out.

Answer 8

how I can make my app crash by making exception in javascript level ?

You cannot handle js errors that causes the "Unfortunately, application has stopped" message, because they don't exist and are not javascript-related but Webview/plugin-related.

If yous see this kind of message after a js call, then it comes from the web view's javascript implementation, AKA Chrome's one or the plugin's native part. Javascript is sandboxed and should not produce such behaviours.

Answer 9

You can try to do a infinity loop incrementally appending a string as the app starts:

onDeviceReady: function() {
    var test = "test";
    while (true) {
        test += "--------------------";
        console.log(test);
    }
},

This will do the trick.