如何为我刚刚创建的新线程获取 Looper？

Question

I'm creating a thread to handle a request. In the thread I must call Looper.prepare() which is require by some other functionality it is using, and then I call Looper.loop() . But when the connection for the request is closed, I get a callback in a different thread. At that point I need to call quit() on the Thread's looper so that loop() will return and the thread will exit. However, I am having a hard time figuring out how to get that thread's looper. I don't see any in Thread to get the Looper for the thread. In the Looper class I see a way to get the looper for the current class, but I'm not able to pass this information from the inner class of the Thread to the class that creates it:

                final Looper l1;
                final Thread thread = new Thread() {
                    @Override
                    public void run() {
                        Looper.prepare();
                        l1 = Looper.myLooper(); // ERROR!
                        // initialization goes here
                        Looper.loop();
                        Log.d(logtag,"The request thread is done.");
                    }
                };
                thread.start();

and in the callback which immediately follows the above line:

webSocket.setClosedCallback(new CompletedCallback() {
    @Override
    public void onCompleted(Exception ex) {
        // other code
        l1.quit();
    }
});

I get a compile time error on the line marked above:

Cannot assign a value to final variable 'l1'.

But I haven't assigned it yet! If I don't make Looper final, then I can't assign to it because it's not final.

Answer 1

This seems like somewhat of a hack, but I created this class (private, in the same file):

class LooperHolder {
    Looper l1 = null;
    void setLooper(Looper looper) {
        l1 = looper;
    }
    Looper getLooper() {
        return l1;
    }
}

Then I modified my code to go through the looper holder:

            final LooperHolder lh = new LooperHolder();
            final Thread thread = new Thread() {
                @Override
                public void run() {
                    Looper.prepare();
                    lh.setLooper(Looper.myLooper());
                    // initialization goes here
                    Looper.loop();
                    Log.d(logtag,"The request thread is done.");
                }
            };
            thread.start();

And then in the callback:

Looper l1 = lh.getLooper();
if (l1 != null) l1.quit();