无法在未调用 Looper.prepare() 的线程内创建处理程序

Can not create handler inside thread that has not called Looper.prepare()

我试图在延迟一段时间后显示警告对话框:

Thread thread = new Thread() {
                    @Override
                    public void run() {
                        try {
                            synchronized (this) {
                                wait(3000);
                            }
                        } catch (InterruptedException ex) {
                        }

                        final AlertDialog.Builder builder = new AlertDialog.Builder(stop_watch.fa);
                        builder.setMessage("Want to exit?");
                        builder.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int which) {
                                locator_activity.fa.finish();
                            }
                        });
                        AlertDialog alertDialog = builder.create();
                        alertDialog.show();
                    }
                };
                thread.start();

启动应用程序后。当显示 alertdialog 时,应用程序停止工作。它显示问题:-

java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()

AlertDialogs 是 UI 元素,因此需要在 UI 线程上执行工作:

new Thread() {
    public void run() {
        activity.this.runOnUiThread(new Runnable() {
            public void run() {
                // Show dialog..
            }
        });
    }
}.start();