Android Threads and Throwables

Question

I have a class (let's call it ABC) that executes I/O. Some things like FileOutputStream.close make you use try catch blocks around them. In addition, I created my own throwable objects that help the user and me know what is going on.

In the this class I passed in the context of the activity that creates it and made it such that I create and alert dialog box with the throwable text.

So here is my problem I need to run this class off of a new thread, but still want to get the information from the text of the throwable.

So for example this is what a typical catch clause looks like in my class.

new AlertDialog.Builder(myContext)
                        .setTitle("Error Message")
                        .setMessage(
                                "Error Code: #006" + "\n" + T.toString())
                        .setNeutralButton("OK",
                                new DialogInterface.OnClickListener() {

                                    @Override
                                    public void onClick(
                                            DialogInterface dialog,
                                            int which) {
                                        // TODO: Add Ability to Email
                                        // Developer

                                    }
                                }).show();

Would I just do something like

throw new Throwable(throwable);

this inside the ABC class in place of the alert dialog? Then would I move the alert dialog to a try catch where my the Runnable interface run method is called or the do in background for an asynchtask?

Answer 1

Use Java's Thread.UncaughtExceptionHandler to save the text / display a dialog. So you would make a new class extending Thread.UncaughtExceptionHandler, like this:

public class myThreadExceptionHandler implements Thread.UncaughtExceptionHandler
{
    private DataTargetClass dataTarget;
    public myThreadExceptionHandler(DataTargetClass c)
    { 
        dataTarget = c;
    }
    public void uncaughtException(Thread t, Throwable e)
    {
        dataTarget.exceptionObject = e;
        dataTarget.onException();
        // Just substitute in whatever method your thread uses to return information.
    }
}

In your code that started the thread, you would do this:

foo = new DataTargetClass();
Thread t = new Thread(myIoRunnable(foo));
t.setUncaughtExceptionHandler(new myThreadExceptionHandler(foo));
t.start();