我正在创建一个Android聊天应用程序，其中我使用WebSockets，除此之外，我还想创建应用程序协议的自定义实现。
我陷入了困境。
从本质上讲，我想要的是一种方法，知道在另一个类中调用了事件处理程序方法，在此基础上在我的类中启动我自己的方法，然后在我的类中获得该事件处理程序的结果。
这怎么可能？
我研究了很多，发现了绑定、事件发射器等。有人能为我指明正确的方向，并为我提供一些可以学习这项技术的资源吗？
这就是我迄今为止所做的：
public void connect(){
try {
setUpWebSocketHandler(handler);
mConnection.connect(wsuri, handler);
}
catch (WebSocketException e) {
Log.d("exception", e.toString());
}
}
public void setUpWebSocketHandler(WebSocketHandler handler)
{
handler = new WebSocketHandler(){
//first method for websockethandler
@Override
public void onOpen() {
//here i create a json format string to be sent to my server that returns something afterwards
String output = json.toString();
Log.d("OUTPUT+" , output);
Log.d("onOpen", "Status: Connected to " + wsuri);
mConnection.sendTextMessage(output);
}
//second method for websockethandler
@Override
public void onTextMessage(final String payload) {
Log.d("onTextMessage", "Response: " + payload);
JSONObject jsonObj = null;
try {
jsonObj = new JSONObject(payload);
} catch (JSONException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
try {
String type = jsonObj.getString("type");
switch (type) {
case "xxx":
//authEvent
System.out.println("xxx");
break;
case "yyy":
//userOnlineEvent
System.out.println("yyy");
break;
case "zzz":
System.out.println("zzz");
break;
case "userListToken":
userList = getUserList(payload);
break;
default:
System.out.println("DefaultCase");
break;
}
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
//third method for websockethandler
@Override
public void onClose(int code, String reason) {
Log.d("onClose", "Connection lost.");
}
};
}
public String getUserList(final String payload)
{
final Thread connectthread;
connectthread = new Thread(
new Runnable()
{
public void run()
{
try {
//here i create a URL, send post request to it and i get a response with userlist
HttpClient client = new DefaultHttpClient();
HttpGet post = new HttpGet(url);
HttpResponse response = client.execute(post);
BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
while ((userList = rd.readLine()) != null) {
System.out.println(userList);
Log.d("HTTP GET RESPONSE", "Response: " + userList);
}
} catch (JSONException | IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
);
connectthread.start();
try
{
connectthread.join();
}
catch (Exception e)
{
Log.i("error","Error!!");
}
System.out.println("userListToken");
return userList;
}
我还有一个问题。我使用回调获得了userList。。。。现在的问题是：
private class ProcessLogin extends AsyncTask<String, Void, String> {
private ProgressDialog pDialog;
String uname,password;
@Override
protected void onPreExecute() {
super.onPreExecute();
uname = txtUsername.getText().toString();
password = txtPassword.getText().toString();
pDialog = new ProgressDialog(LoginActivity.this);
pDialog.setTitle("Contacting Servers");
pDialog.setMessage("Logging in ...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
@Override
protected String doInBackground(String... args) {
String user = null;
ifly.connect();
user = userList;
return user;
}
@Override
protected void onPostExecute(String user) {
try {
if(user != null){
//Intent i = new Intent("com.example.tabmainactivity");
Log.d("Got it", "Response: " + userList);
pDialog.dismiss();
//startService(new Intent(getApplicationContext(),iFlyChatMessage.class));
//startActivity(i);
//finish();
}else{
// username / password doesn't match
pDialog.dismiss();
Toast.makeText(getApplicationContext(),
"Incorrect username/password", Toast.LENGTH_SHORT).show();
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
public void processMessage(String userList)
{
this.userList = userList;
}
我想要postExecute中的userList，这样我就可以将这个userList发送到另一个活动。如何停止doinbackground()以等待回调完成。如果我使用thread.sleep，整个过程就会停止，甚至连连接都无法工作。
感谢
您可以在某个地方声明一个接口，使事件处理程序接受该接口的实例，然后创建一个实现该接口的匿名类，同时在处理程序的事件源注册中传递该实例。
如下所示：
public class MyClass{
...
...
component.addXXXListener(new EventHandler(new MyInterface() {
@Override
public void doSomething() {
callMethod();
}
}));
...
...
public void callMethod() {
...
...
}
我希望你明白了。
我不确定我是否正确理解了你。
您应该使用回调对象。
类似于：
public interface MessageProcesor{
public void processMessage(String message);
}
您的活动应该实现此接口。并且您的"客户端"类中应该有MessageProcesor字段。你的代码应该是这样的：
private MessageProcesor callback;
public void setUpWebSocketHandler(WebSocketHandler handler)
{
handler = new WebSocketHandler(){
//first method for websockethandler
@Override
public void onOpen() {
//here i create a json format string to be sent to my server that returns something afterwards
String output = json.toString();
Log.d("OUTPUT+" , output);
Log.d("onOpen", "Status: Connected to " + wsuri);
mConnection.sendTextMessage(output);
}
//second method for websockethandler
@Override
public void onTextMessage(final String payload) {
Log.d("onTextMessage", "Response: " + payload);
JSONObject jsonObj = null;
try {
jsonObj = new JSONObject(payload);
} catch (JSONException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
try {
String type = jsonObj.getString("type");
switch (type) {
case "xxx":
//authEvent
System.out.println("xxx");
break;
case "yyy":
//userOnlineEvent
System.out.println("yyy");
break;
case "zzz":
System.out.println("zzz");
break;
case "userListToken":
userList = getUserList(payload);
callback.processMessage(userList);
break;
default:
System.out.println("DefaultCase");
break;
}
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
//third method for websockethandler
@Override
public void onClose(int code, String reason) {
Log.d("onClose", "Connection lost.");
}
};
}
public String getUserList(final String payload)
{
final Thread connectthread;
connectthread = new Thread(
new Runnable()
{
public void run()
{
try {
//here i create a URL, send post request to it and i get a response with userlist
HttpClient client = new DefaultHttpClient();
HttpGet post = new HttpGet(url);
HttpResponse response = client.execute(post);
BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
while ((userList = rd.readLine()) != null) {
System.out.println(userList);
Log.d("HTTP GET RESPONSE", "Response: " + userList);
}
} catch (JSONException | IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
);
connectthread.start();
try
{
connectthread.join();
}
catch (Exception e)
{
Log.i("error","Error!!");
}
System.out.println("userListToken");
return userList;
}
您可以将"callback"作为构造函数参数或通过setter方法传递。
希望这能有所帮助。