您不能使用应用程序[或服务]上下文。如果你真的想告诉你从一个应用程序diallog，你将有一个活动范围内传递给它。您也可以存储在活动范围内，但我的做不是 的建议。活动背景下是无效的光洁度，所以你会打破你的计划。正如@LeoLink说，只是直接从你的Activity调用它。

You can't use an application [or service] context. If you really want to show you diallog from an application, you will have to pass an Activity context to it. You could also store the Activity context, but I do not recommend that. The activity context is voided on finish, so you will break your program. As @LeoLink said, just call it directly from your Activity.

编辑例如：

class MyDialog {
    public Dialog show(Context context) {
        Dialog d = new Dialog(context);
        d.setTitle("I'm a dialog");
        d.setMessage("I'm a message");
        return d.show();
    }
}