宁静的API服务 [英] Restful API service
问题描述
我正在寻找一种服务，我可以用它来调用基于网络的 REST API.
I'm looking to make a service which I can use to make calls to a web-based REST API.
基本上我想在 app init 上启动一个服务，然后我希望能够要求该服务请求一个 url 并返回结果.与此同时，我希望能够显示一个进度窗口或类似的东西.
Basically I want to start a service on app init then I want to be able to ask that service to request a url and return the results. In the meantime I want to be able to display a progress window or something similar.
我目前已经创建了一个使用 IDL 的服务，我在某处读到过你只需要它来进行跨应用程序通信，所以认为这些需要剥离但不确定如何在没有它的情况下进行回调.此外，当我点击 post(Config.getURL("login"), values) 应用程序似乎暂停了一段时间(看起来很奇怪 - 认为服务背后的想法是它在不同的线程！)
I've created a service currently which uses IDL, I've read somewhere that you only really need this for cross app communication, so think these needs stripping out but unsure how to do callbacks without it. Also when I hit the post(Config.getURL("login"), values) the app seems to pause for a while (seems weird - thought the idea behind a service was that it runs on a different thread!)
目前我有一个带有 post 和 get http 方法的服务，几个 AIDL 文件(用于双向通信)，一个 ServiceManager 处理服务的启动、停止、绑定等，我正在动态创建一个处理程序根据需要为回调提供特定代码.
Currently I have a service with post and get http methods inside, a couple of AIDL files (for two way communication), a ServiceManager which deals with starting, stopping, binding etc to the service and I'm dynamically creating a Handler with specific code for the callbacks as needed.
我不希望任何人给我一个完整的代码库来处理，但我会非常感谢您的指点.
I don't want anyone to give me a complete code base to work on, but some pointers would be greatly appreciated.
代码(大部分)完整:
public class RestfulAPIService extends Service {
final RemoteCallbackList<IRemoteServiceCallback> mCallbacks = new RemoteCallbackList<IRemoteServiceCallback>();
public void onStart(Intent intent, int startId) {
super.onStart(intent, startId);
}
public IBinder onBind(Intent intent) {
return binder;
}
public void onCreate() {
super.onCreate();
}
public void onDestroy() {
super.onDestroy();
mCallbacks.kill();
}
private final IRestfulService.Stub binder = new IRestfulService.Stub() {
public void doLogin(String username, String password) {
Message msg = new Message();
Bundle data = new Bundle();
HashMap<String, String> values = new HashMap<String, String>();
values.put("username", username);
values.put("password", password);
String result = post(Config.getURL("login"), values);
data.putString("response", result);
msg.setData(data);
msg.what = Config.ACTION_LOGIN;
mHandler.sendMessage(msg);
}
public void registerCallback(IRemoteServiceCallback cb) {
if (cb != null)
mCallbacks.register(cb);
}
};
private final Handler mHandler = new Handler() {
public void handleMessage(Message msg) {
// Broadcast to all clients the new value.
final int N = mCallbacks.beginBroadcast();
for (int i = 0; i < N; i++) {
try {
switch (msg.what) {
case Config.ACTION_LOGIN:
mCallbacks.getBroadcastItem(i).userLogIn( msg.getData().getString("response"));
break;
default:
super.handleMessage(msg);
return;
}
} catch (RemoteException e) {
}
}
mCallbacks.finishBroadcast();
}
public String post(String url, HashMap<String, String> namePairs) {...}
public String get(String url) {...}
};
几个 AIDL 文件:
A couple of AIDL files:
package com.something.android
oneway interface IRemoteServiceCallback {
void userLogIn(String result);
}
和
package com.something.android
import com.something.android.IRemoteServiceCallback;
interface IRestfulService {
void doLogin(in String username, in String password);
void registerCallback(IRemoteServiceCallback cb);
}
和服务经理:
public class ServiceManager {
final RemoteCallbackList<IRemoteServiceCallback> mCallbacks = new RemoteCallbackList<IRemoteServiceCallback>();
public IRestfulService restfulService;
private RestfulServiceConnection conn;
private boolean started = false;
private Context context;
public ServiceManager(Context context) {
this.context = context;
}
public void startService() {
if (started) {
Toast.makeText(context, "Service already started", Toast.LENGTH_SHORT).show();
} else {
Intent i = new Intent();
i.setClassName("com.something.android", "com.something.android.RestfulAPIService");
context.startService(i);
started = true;
}
}
public void stopService() {
if (!started) {
Toast.makeText(context, "Service not yet started", Toast.LENGTH_SHORT).show();
} else {
Intent i = new Intent();
i.setClassName("com.something.android", "com.something.android.RestfulAPIService");
context.stopService(i);
started = false;
}
}
public void bindService() {
if (conn == null) {
conn = new RestfulServiceConnection();
Intent i = new Intent();
i.setClassName("com.something.android", "com.something.android.RestfulAPIService");
context.bindService(i, conn, Context.BIND_AUTO_CREATE);
} else {
Toast.makeText(context, "Cannot bind - service already bound", Toast.LENGTH_SHORT).show();
}
}
protected void destroy() {
releaseService();
}
private void releaseService() {
if (conn != null) {
context.unbindService(conn);
conn = null;
Log.d(LOG_TAG, "unbindService()");
} else {
Toast.makeText(context, "Cannot unbind - service not bound", Toast.LENGTH_SHORT).show();
}
}
class RestfulServiceConnection implements ServiceConnection {
public void onServiceConnected(ComponentName className, IBinder boundService) {
restfulService = IRestfulService.Stub.asInterface((IBinder) boundService);
try {
restfulService.registerCallback(mCallback);
} catch (RemoteException e) {}
}
public void onServiceDisconnected(ComponentName className) {
restfulService = null;
}
};
private IRemoteServiceCallback mCallback = new IRemoteServiceCallback.Stub() {
public void userLogIn(String result) throws RemoteException {
mHandler.sendMessage(mHandler.obtainMessage(Config.ACTION_LOGIN, result));
}
};
private Handler mHandler;
public void setHandler(Handler handler) {
mHandler = handler;
}
}
服务初始化和绑定:
// this I'm calling on app onCreate
servicemanager = new ServiceManager(this);
servicemanager.startService();
servicemanager.bindService();
application = (ApplicationState)this.getApplication();
application.setServiceManager(servicemanager);
服务函数调用:
// this lot i'm calling as required - in this example for login
progressDialog = new ProgressDialog(Login.this);
progressDialog.setMessage("Logging you in...");
progressDialog.show();
application = (ApplicationState) getApplication();
servicemanager = application.getServiceManager();
servicemanager.setHandler(mHandler);
try {
servicemanager.restfulService.doLogin(args[0], args[1]);
} catch (RemoteException e) {
e.printStackTrace();
}
...later in the same file...
Handler mHandler = new Handler() {
public void handleMessage(Message msg) {
switch (msg.what) {
case Config.ACTION_LOGIN:
if (progressDialog.isShowing()) {
progressDialog.dismiss();
}
try {
...process login results...
}
} catch (JSONException e) {
Log.e("JSON", "There was an error parsing the JSON", e);
}
break;
default:
super.handleMessage(msg);
}
}
};
推荐答案
如果您的服务将成为您应用程序的一部分，那么您将使它变得比实际需要的更加复杂.由于您有一个从 RESTful Web 服务获取一些数据的简单用例，您应该查看 ResultReceiver 和 IntentService.
If your service is going to be part of you application then you are making it way more complex than it needs to be. Since you have a simple use case of getting some data from a RESTful Web Service, you should look into ResultReceiver and IntentService.
此服务 + ResultReceiver 模式通过使用 startService() 当你想做一些动作时.您可以指定要执行的操作，并通过 Intent 中的附加项传入您的 ResultReceiver(活动).
This Service + ResultReceiver pattern works by starting or binding to the service with startService() when you want to do some action. You can specify the operation to perform and pass in your ResultReceiver (the activity) through the extras in the Intent.
在您实现的服务中 onHandleIntent 执行 Intent 中指定的操作.操作完成后，您使用传入的 ResultReceiver 到 发送消息给活动，此时 onReceiveResult 将被调用.
In the service you implement onHandleIntent to do the operation that is specified in the Intent. When the operation is completed you use the passed in ResultReceiver to send a message back to the Activity at which point onReceiveResult will be called.
例如，您想从 Web 服务中提取一些数据.
So for example, you want to pull some data from your Web Service.
- 您创建意图并调用 startService.
- 服务中的操作开始并向活动发送一条消息说它已开始
- 活动处理消息并显示进度.
- 服务完成操作并将一些数据发送回您的活动.
- 您的活动处理数据并放入列表视图
- 该服务会向您发送一条消息，说它已完成，然后它会自行终止.
- 活动获取完成消息并隐藏进度对话框.
我知道您提到您不想要代码库，而是想要开源 Google I/O 2010 应用以我描述的方式使用服务.
I know you mentioned you didn't want a code base but the open source Google I/O 2010 app uses a service in this way I am describing.
更新以添加示例代码:
活动.
public class HomeActivity extends Activity implements MyResultReceiver.Receiver {
public MyResultReceiver mReceiver;
public void onCreate(Bundle savedInstanceState) {
mReceiver = new MyResultReceiver(new Handler());
mReceiver.setReceiver(this);
...
final Intent intent = new Intent(Intent.ACTION_SYNC, null, this, QueryService.class);
intent.putExtra("receiver", mReceiver);
intent.putExtra("command", "query");
startService(intent);
}
public void onPause() {
mReceiver.setReceiver(null); // clear receiver so no leaks.
}
public void onReceiveResult(int resultCode, Bundle resultData) {
switch (resultCode) {
case RUNNING:
//show progress
break;
case FINISHED:
List results = resultData.getParcelableList("results");
// do something interesting
// hide progress
break;
case ERROR:
// handle the error;
break;
}
}
服务:
public class QueryService extends IntentService {
protected void onHandleIntent(Intent intent) {
final ResultReceiver receiver = intent.getParcelableExtra("receiver");
String command = intent.getStringExtra("command");
Bundle b = new Bundle();
if(command.equals("query") {
receiver.send(STATUS_RUNNING, Bundle.EMPTY);
try {
// get some data or something
b.putParcelableArrayList("results", results);
receiver.send(STATUS_FINISHED, b)
} catch(Exception e) {
b.putString(Intent.EXTRA_TEXT, e.toString());
receiver.send(STATUS_ERROR, b);
}
}
}
}
ResultReceiver 扩展 - 编辑以实现 MyResultReceiver.Receiver
ResultReceiver extension - edited about to implement MyResultReceiver.Receiver
public class MyResultReceiver implements ResultReceiver {
private Receiver mReceiver;
public MyResultReceiver(Handler handler) {
super(handler);
}
public void setReceiver(Receiver receiver) {
mReceiver = receiver;
}
public interface Receiver {
public void onReceiveResult(int resultCode, Bundle resultData);
}
@Override
protected void onReceiveResult(int resultCode, Bundle resultData) {
if (mReceiver != null) {
mReceiver.onReceiveResult(resultCode, resultData);
}
}
}
这篇关于宁静的API服务的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
