我正在尝试使用Facebook登录来构建聊天应用程序。登录部分工作正常。我面临的问题是，当我想要移动到面临空指针异常的新活动时，我使用socket.io。请帮我。提前做出来。
public class Second extends Activity {
static SocketIO socket;
Object data;
int t = 0;
Singleton tmp = Singleton.getInstance();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
System.out.println("second activity enntered");
setContentView(R.layout.activity_second);
final TextView tv = (TextView) findViewById(R.id.textView1);
System.out.println(getIntent().getExtras().getString("name")+"secondactivity");
tv.setText("Welcome"+getIntent().getExtras().getString("name"));
final Button bt1 = (Button) findViewById(R.id.button1);
final Button bt2 = (Button) findViewById(R.id.button2);
final EditText et = (EditText) findViewById(R.id.editText1);
bt1.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
if(bt1.getText().equals("Create Room"))
{
System.out.println(bt1.getText());
et.setVisibility(View.VISIBLE);
bt2.setVisibility(View.VISIBLE);
bt1.setText("Cancel Room");
}
else if(bt1.getText().equals("Cancel Room"))
{
System.out.println(bt1.getText());
et.setVisibility(View.INVISIBLE);
bt2.setVisibility(View.INVISIBLE);
bt1.setText("Create Room");
}
}
});
bt2.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
JSONObject b = new JSONObject();
try {
b.put("creator", getIntent().getExtras().getString("name"));
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
b.put("roomName", et.getText()) ;
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
tmp.emit("createroom", b);
}
});
}
public void setData(Object[] args) {
// TODO Auto-generated method stub
System.out.println(args[0]);
data = args[0];
t = 1;
System.out.println(Second.this);
Intent inte = null;
System.out.println(inte+"asdasdasdasdasdasdsa");
System.out.println(new Intent(Second.this,Ownroom.class));
inte= new Intent(Second.this,Ownroom.class);
inte.putExtra("json",data.toString() );
startActivity(inte);
}
}
LogCat是
07-14 16:20:52.050: I/System.out(2353): com.example.lastapp1.Second@40f6b508
07-14 16:20:52.060: I/System.out(2353): nullasdasdasdasdasdasdsa
07-14 16:20:52.070: W/System.err(2353): io.socket.SocketIOException: Exception was thrown in on(String, JSONObject[]).
07-14 16:20:52.070: W/System.err(2353): Message was: 5:::{"name":"receiveroom","args":[{"roomName":"kj","roomId":"be72be30-0b44-11e4-9f8c-4706467ac6c0","creator":"Saikrishna Rangineni","listofusers":["Saikrishna Rangineni"]}]}
07-14 16:20:52.080: W/System.err(2353): at io.socket.IOConnection.transportMessage(IOConnection.java:700)
07-14 16:20:52.090: W/System.err(2353): at io.socket.WebsocketTransport.onMessage(WebsocketTransport.java:82)
07-14 16:20:52.090: W/System.err(2353): at org.java_websocket.client.WebSocketClient.onWebsocketMessage(WebSocketClient.java:361)
07-14 16:20:52.090: W/System.err(2353): at org.java_websocket.WebSocketImpl.deliverMessage(WebSocketImpl.java:565)
07-14 16:20:52.100: W/System.err(2353): at org.java_websocket.WebSocketImpl.decodeFrames(WebSocketImpl.java:331)
07-14 16:20:52.100: W/System.err(2353): at org.java_websocket.WebSocketImpl.decode(WebSocketImpl.java:152)
07-14 16:20:52.120: W/System.err(2353): at org.java_websocket.client.WebSocketClient.interruptableRun(WebSocketClient.java:247)
07-14 16:20:52.120: W/System.err(2353): at org.java_websocket.client.WebSocketClient.run(WebSocketClient.java:193)
07-14 16:20:52.130: W/System.err(2353): at java.lang.Thread.run(Thread.java:856)
07-14 16:20:52.130: W/System.err(2353): Caused by: java.lang.NullPointerException
07-14 16:20:52.140: W/System.err(2353): at android.content.ContextWrapper.getPackageName(ContextWrapper.java:127)
07-14 16:20:52.150: W/System.err(2353): at android.content.ComponentName.<init>(ComponentName.java:75)
07-14 16:20:52.150: W/System.err(2353): at android.content.Intent.<init>(Intent.java:3122)
07-14 16:20:52.150: W/System.err(2353): at com.example.lastapp1.Second.setData(Second.java:104)
07-14 16:20:52.160: W/System.err(2353): at com.example.server.Singleton$1.on(Singleton.java:71)
07-14 16:20:52.160: W/System.err(2353): at io.socket.IOConnection.on(IOConnection.java:907)
07-14 16:20:52.170: W/System.err(2353): at io.socket.IOConnection.transportMessage(IOConnection.java:697)
07-14 16:20:52.170: W/System.err(2353): ... 8 more
自己的代码
package com.example.lastapp1;
import io.socket.IOAcknowledge;
import io.socket.IOCallback;
import io.socket.SocketIO;
import io.socket.SocketIOException;
import java.security.NoSuchAlgorithmException;
import javax.net.ssl.SSLContext;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class Ownroom extends Activity {
SocketIO socket;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_ownroom);
Button bt1 = (Button) findViewById(R.id.button3);
final EditText et = (EditText) findViewById(R.id.editText1);
final TextView tv = (TextView) findViewById(R.id.textView1);
//System.out.println(getIntent().getExtras().get);
try {
final JSONObject obj = new JSONObject(getIntent().getStringExtra("json"));
tv.setText("Welcome to "+obj.get("roomName")+"room");
bt1.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
System.out.println("helllo in click");
// TODO Auto-generated method stub
JSONObject a = new JSONObject();
try {
a.put("message", et.getText());
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
a.put("name", obj.get("creator"));
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
a.put("roomName", obj.get("roomName"));
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
a.put("roomId", obj.get("roomId"));
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println(obj+"in click");
socket.emit("send message",a );
}
});
} catch (JSONException e2) {
// TODO Auto-generated catch block
e2.printStackTrace();
}
}
}
单吨级
package com.example.server;
import io.socket.IOAcknowledge;
import io.socket.IOCallback;
import io.socket.SocketIO;
import io.socket.SocketIOException;
import java.net.Socket;
import java.security.NoSuchAlgorithmException;
import javax.net.ssl.SSLContext;
import org.json.JSONObject;
import com.example.lastapp1.MainActivity;
import com.example.lastapp1.MainActivity.MainFragment;
import com.example.lastapp1.Second;
import android.content.Intent;
import android.sax.StartElementListener;
import android.util.Log;
public class Singleton {
String name = "No name";
private static Singleton Single= new Singleton();
static SocketIO socket;
static MainFragment mianee1 = new MainFragment();
static Second mianee2 = new Second();
/* A private Constructor prevents any other
* class from instantiating.
*/
private Singleton (){ }
/* Static 'instance' method */
public static Singleton getInstance( ) {
System.out.println("login");
try {
SocketIO.setDefaultSSLSocketFactory(SSLContext.getDefault());
} catch (NoSuchAlgorithmException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
try {
socket = new SocketIO("http://10.0.2.2:3000/");
System.out.println("asdasdasd");
} catch (Exception e) {
//TODO Auto-generated catch block
System.out.println(e);
e.printStackTrace();
}
socket.connect(new IOCallback() {
public void on(String event, IOAcknowledge ack, Object... args) {
if ("socket1".equals(event) && args.length > 0) {
Log.e("received",""+args[0]);
mianee1.setData(args);
System.out.println("yes yes yes"+args[0]);
}
if ("receiveroom".equals(event) && args.length > 0) {
Log.e("receiveroom",""+args[0]);
// mianee2.setData(args);
System.out.println("received socket from second room"+args[0]);
}
}
public void onMessage(JSONObject json, IOAcknowledge ack) {
System.out.println("Server said:" + json);
}
public void onMessage(String data, IOAcknowledge ack) {
System.out.println("Server said:" + data);
}
public void onError(SocketIOException socketIOException) { socketIOException.printStackTrace();}
public void onDisconnect() {
System.out.println("connected sucesfully");
}
public void onConnect() {
System.out.println("connected");
}
});
return Single;
}
public void run() {
// TODO Auto-generated method stub
}
//public static void run() {
//
//
// try {
// SocketIO.setDefaultSSLSocketFactory(SSLContext.getDefault());
// } catch (NoSuchAlgorithmException e1) {
// // TODO Auto-generated catch block
// e1.printStackTrace();
// }
//try {
//SocketIO socket = new SocketIO("http://10.0.2.2:3000/");
//System.out.println("asdasdasd");
//} catch (Exception e) {
//// TODO Auto-generated catch block
//System.out.println(e);
//e.printStackTrace();
//}
//SocketIO socket = null;
//socket.connect(new IOCallback() {
//
//public void on(String event, IOAcknowledge ack, Object... args) {
// if ("socket1".equals(event) && args.length > 0) {
// Log.e("received",""+args[0]);
// MainFragment mai = new MainFragment();
// mai.nextActvity(args[0]);
// }
//}
//
//public void onMessage(JSONObject json, IOAcknowledge ack) {
// System.out.println("Server said:" + json);
//}
//public void onMessage(String data, IOAcknowledge ack) {
// System.out.println("Server said:" + data);
//}
//
//public void onError(SocketIOException socketIOException) { socketIOException.printStackTrace();}
//
//public void onDisconnect() {
//System.out.println("connected sucesfully");
//}
//
//public void onConnect() {
// System.out.println("connected");
//}
//});
//}
public void setName(String a)
{
name = a;
}
public String getname() {
return name;
}
public void emit(String string, String abc) {
// TODO Auto-generated method stub
socket.emit(string,abc);
}
public void emit(String string, JSONObject b) {
// TODO Auto-generated method stub
socket.emit(string,b);
}
}
答案 0 :(得分：1)
您正在打印 NULL
Intent inte = null;
System.out.println(inte+"asdasdasdasdasdasdsa");