如何在处理程序中使用ApplicationContext

发布于 2025-02-06 03:00:35 字数 1258 浏览 2 评论 0原文

我真的是Android的新手，我试图将线程类与消息处理程序一起使用，在那里，我需要使用ApplicationContext，但是当我尝试运行它时，这是使应用程序崩溃的

   if (!connected.isState()) {
                client = new MqttAndroidClient(myContext.context, SERVERURI, CLIENTID);
                try {
                    IMqttToken token = client.connect();
                    token.setActionCallback(new IMqttActionListener() {
                        @Override
                        public void onSuccess(IMqttToken asyncActionToken) {
                            //we are connected
                            connected.setState(true);
                        }

                        @Override
                        public void onFailure(IMqttToken asyncActionToken, Throwable exception) {
                            //we are not connected
                        }
                    });
                } catch (Exception e) {
                    e.printStackTrace();
                }
                return;    
           }

代码mycontext类

class myContext extends Application {

    public static Context context;

    @Override
    public void onCreate() {
        super.onCreate();
        context = getApplicationContext();
    }

} 我该怎么办来解决这个问题？

原文

i am really new to Android and i was trying to use the Thread class with a message handler, in there i need to use the ApplicationContext but when i try to run it it crashes, here is the code that makes the application crash

   if (!connected.isState()) {
                client = new MqttAndroidClient(myContext.context, SERVERURI, CLIENTID);
                try {
                    IMqttToken token = client.connect();
                    token.setActionCallback(new IMqttActionListener() {
                        @Override
                        public void onSuccess(IMqttToken asyncActionToken) {
                            //we are connected
                            connected.setState(true);
                        }

                        @Override
                        public void onFailure(IMqttToken asyncActionToken, Throwable exception) {
                            //we are not connected
                        }
                    });
                } catch (Exception e) {
                    e.printStackTrace();
                }
                return;    
           }

here is the myContext class

class myContext extends Application {

    public static Context context;

    @Override
    public void onCreate() {
        super.onCreate();
        context = getApplicationContext();
    }

}
what can i do to fix the problem?

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终陌 2025-02-13 03:00:36

您可能没有告诉Android使用您的自定义application类，因此myContext.oncreate（）未被调用。为此

android:name=".myContext"

You probably haven't told Android to use your custom Application class, so myContext.onCreate() isn't being called. To do this you need to add this to your <application> declaration in your manifest:

android:name=".myContext"

回复收藏 0 原文

温柔一刀 2025-02-13 03:00:36

OP在这里。
最后，我通过发送包含message.obj中applicationContext的消息来解决它，这是现在的代码，

if (!connected.isState()) {
            client = new MqttAndroidClient((Context) msg.obj, SERVERURI, CLIENTID);
            try {
                IMqttToken token = client.connect();
                token.setActionCallback(new IMqttActionListener() {
                    @Override
                    public void onSuccess(IMqttToken asyncActionToken) {
                        //we are connected
                        connected.setState(true);
                    }

                    @Override
                    public void onFailure(IMqttToken asyncActionToken, Throwable exception) {
                        //we are not connected
                    }
                });
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return;
    }

感谢大家的建议并跟上我的不经验

:--)

OP here.
in the end i solved it by sending a message containing the applicationContext in message.obj, here is the code now

if (!connected.isState()) {
            client = new MqttAndroidClient((Context) msg.obj, SERVERURI, CLIENTID);
            try {
                IMqttToken token = client.connect();
                token.setActionCallback(new IMqttActionListener() {
                    @Override
                    public void onSuccess(IMqttToken asyncActionToken) {
                        //we are connected
                        connected.setState(true);
                    }

                    @Override
                    public void onFailure(IMqttToken asyncActionToken, Throwable exception) {
                        //we are not connected
                    }
                });
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return;
    }

thanks to everybody for the suggestions and for keeping up with my inexperience

:-)

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