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[英]How to send JSON data as parameter from Android to Jersey RESTful Service
[英]Send JSON data from a service to UI in Android
要求是:我有一个后台服务,在该服务中,我正在执行REST调用以获取JSON数据。 我想将JSON数据发送到UI并更新内容。
我可以使用一种方法,即将整个JSON字符串存储在SharedPreferences中并在UI中进行检索,但我认为这样做并不高效。
有想法吗? 我在UI中添加了一个Handler来更新元素,但是我对使用它并不熟悉。
样本REST调用代码:
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(DATA_URL);
httpPost.setHeader("Content-Type", "application/json");
//passes the results to a string builder/entity
StringEntity se = null;
try {
se = new StringEntity(RequestJSON.toString());
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
//sets the post request as the resulting string
httpPost.setEntity(se);
//Handles what is returned from the page
ResponseHandler responseHandler = new BasicResponseHandler();
try {
HttpResponse response = (HttpResponse) httpClient.execute(httpPost, responseHandler);
// response will have JSON data that I need to update in UI
//Show notification
showNotification("Update Complete");
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
// httpClient = null;
}
在UI活动中
Handler myHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
Bundle Recevied = msg.getData();
String resp = Recevied.getString("Mkey");
}
};
messenger = new Messenger(myHandler);
}
将信息传递给服务人员并准备好结果:
Message msg = Message.obtain();
Bundle data = new Bundle();
data.putString("Mkey",
Smsg);
msg.setData(data);
try {
// Send the Message back to the client Activity.
messenger.send(msg);
} catch (RemoteException e) {
e.printStackTrace();
}
像这样的东西可能适合您。 TL; DR:在更新活动的服务中创建一个侦听器。
在服务中,创建一个静态函数和一个静态字段:
private static BlaBlaService _instance;
public static BlaBlaService getInstance() {
return _instance;
}
在onCreate函数上填充_instance字段:
public void onCreate() {
super.onCreate();
_instance = this;
...
}
public void addRESTCompleteListener(RESTCompleteListener l) {...}
REST调用完成后,调用:
listener.RESTCompleted(JSON.whatever)
现在,在您的活动中,只需在服务启动后将其添加到服务中即可:
BlaBlaService.getInstance().addRESTCompleteListener(listener)
不要忘记在需要时释放所有指针。
希望这可以帮助 :)
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