How to get the error log from android process and when to call the get error log method?

Question

I have implemented the try catch on the exception possible places. There are different other exception will be thrown by android OS[Database Exception, Permission and other exception]. I want to write those error log data into file{only there is a crash on our application}.

Already I have code to write the given data into file. I just want to know how to get the error log from android process.

If there is any crash the app instance is not available. And I don't know the exact place where to call the get the error log method. on this. Please help me on this.

Answer 1

In your application class you can initialize for an unhandled exception. The callback method will have an throwable object. From this object we can get the crash log data and then the same data to be written to the file.

Application Class:

public class MyApplication extends Application {
    // uncaught exception handler variable
    private UncaughtExceptionHandler defaultUEH;

    public MyApplication() {
        defaultUEH = Thread.getDefaultUncaughtExceptionHandler();

        // setup handler for uncaught exception
        Thread.setDefaultUncaughtExceptionHandler(_unCaughtExceptionHandler);
    }

    // handler listener
    private Thread.UncaughtExceptionHandler _unCaughtExceptionHandler = new Thread.UncaughtExceptionHandler() {
        @Override
        public void uncaughtException(Thread thread, Throwable ex) {
                        //To write the crash log data to file
            AppUtil.getInstance().writeActivityLogToFile(true,
                    getErrorMessgae(ex));

            // re-throw critical exception further to the os (important) to handle
            defaultUEH.uncaughtException(thread, ex);
            // System.exit(2);
        }
    };

    /**
     * To get the crash log message from throwable object
     * 
     * @param e
     *            - throwable exception object
     * @return - the crash log
     */
    private String getErrorMessgae(Throwable e) {
        StackTraceElement[] stackTrackElementArray = e.getStackTrace();
        String crashLog = e.toString() + "\n\n";
        crashLog += "--------- Stack trace ---------\n\n";
        for (int i = 0; i < stackTrackElementArray.length; i++) {
            crashLog += "    " + stackTrackElementArray[i].toString() + "\n";
        }
        crashLog += "-------------------------------\n\n";

        // If the exception was thrown in a background thread inside
        // AsyncTask, then the actual exception can be found with getCause
        crashLog += "--------- Cause ---------\n\n";
        Throwable cause = e.getCause();
        if (cause != null) {
            crashLog += cause.toString() + "\n\n";
            stackTrackElementArray = cause.getStackTrace();
            for (int i = 0; i < stackTrackElementArray.length; i++) {
                crashLog += "    " + stackTrackElementArray[i].toString()
                        + "\n";
            }
        }
        crashLog += "-------------------------------\n\n";
        return crashLog;
    }
}

Declare your application class in your manifest in the following tag:

<application
    android:name=".application.FleetLOCApplication"
    ......>