Android对象输出流
我需要向我的服务器发送java程序(它在PC上运行)的电子邮件地址和安卓应用程序的密码,但当我点击登录按钮时,服务器并没有收到我的消息,应用程序崩溃 这是android代码:Android对象输出流,android,objectoutputstream,Android,Objectoutputstream,我需要向我的服务器发送java程序(它在PC上运行)的电子邮件地址和安卓应用程序的密码,但当我点击登录按钮时,服务器并没有收到我的消息,应用程序崩溃 这是android代码: public class MainActivity extends Activity { private TextView tv; private Button button; private EditText editText1; private EditText editTex
public class MainActivity extends Activity {
private TextView tv;
private Button button;
private EditText editText1;
private EditText editText2;
Socket client;
private class myTask extends AsyncTask<String, String, String> {
@Override
protected void onPreExecute() {
super.onPreExecute();
}
@Override
protected String doInBackground(String... params) {
try {
client = new Socket("192.168.1.3", 4444); //connect to server
}catch (UnknownHostException e){
return "Host not found";
}catch (IOException e) {
return "Exception Caught";
}
return null;
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
if ("Host not found".equalsIgnoreCase(result)){
Toast.makeText(getApplicationContext(), "Host not found" ,Toast.LENGTH_LONG).show();
}else if("Exception Caught".equalsIgnoreCase(result)){
Toast.makeText(getApplicationContext(), "Connection error" ,Toast.LENGTH_LONG).show();
}else{
Toast.makeText(getApplicationContext(), "Connection established" ,Toast.LENGTH_LONG).show();
}
}
}
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tv = (TextView)findViewById(R.id.register);
button = (Button)findViewById(R.id.login);
new myTask().execute();
tv.setOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View arg0) {
startActivity(new Intent(MainActivity.this, Register.class));
}
});
button.setOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View arg0) {
ObjectInputStream ois = null;
ObjectOutputStream oos = null;
try {
oos = new ObjectOutputStream(client.getOutputStream());
oos.writeUTF("LOGIN");
String emailText = editText1.getText().toString();
oos.writeUTF(emailText);
oos.flush();
String passwordText = editText2.getText().toString();
oos.writeUTF(passwordText);
oos.flush();
client.close();
} catch (IOException ex) {
Logger.getLogger(MainActivity.class.getName()).log(Level.SEVERE, null, ex);
}
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
android应用程序日志:
06-02 10:42:56.948: E/AndroidRuntime(5383): FATAL EXCEPTION: main
06-02 10:42:56.948: E/AndroidRuntime(5383): java.lang.NullPointerException
06-02 10:42:56.948: E/AndroidRuntime(5383): at com.example.social_network.MainActivity$2.onClick(MainActivity.java:106)
06-02 10:42:56.948: E/AndroidRuntime(5383): at android.view.View.performClick(View.java:4240)
06-02 10:42:56.948: E/AndroidRuntime(5383): at android.view.View$PerformClick.run(View.java:17721)
06-02 10:42:56.948: E/AndroidRuntime(5383): at android.os.Handler.handleCallback(Handler.java:730)
06-02 10:42:56.948: E/AndroidRuntime(5383): at android.os.Handler.dispatchMessage(Handler.java:92)
06-02 10:42:56.948: E/AndroidRuntime(5383): at android.os.Looper.loop(Looper.java:137)
06-02 10:42:56.948: E/AndroidRuntime(5383): at android.app.ActivityThread.main(ActivityThread.java:5103)
06-02 10:42:56.948: E/AndroidRuntime(5383): at java.lang.reflect.Method.invokeNative(Native Method)
06-02 10:42:56.948: E/AndroidRuntime(5383): at java.lang.reflect.Method.invoke(Method.java:525)
06-02 10:42:56.948: E/AndroidRuntime(5383): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
06-02 10:42:56.948: E/AndroidRuntime(5383): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
06-02 10:42:56.948: E/AndroidRuntime(5383): at dalvik.system.NativeStart.main(Native Method)
我需要使用ObjectOutputStream,因为服务器已设置为接收此对象。我错在哪里?
谢谢虽然我不完全确定它为什么会因NullPointerException崩溃,但我不认为ObjectOutputStream设计为在同一个流上发送多个对象。我建议使用单个类来保存数据,而不是使用多个字符串 另外,我不使用默认的ObjectOutputStream,而是使用KryoNet序列化库,因为它节省了使用AsyncTasks的工作量(默认情况下是异步的,基于侦听器),并且使这个过程更加容易。它也是桌面和Android之间的跨平台平台
它的工作方式是,必须在服务器和客户端的Kryo对象中注册要发送的类,然后可以使用sendTCP(object)命令发送数据。反序列化为对象是自动的,有关详细信息,请参阅网站。使用起来真的很简单!:) 请发布崩溃的堆栈跟踪。我已经用logcatWhat更新了代码:(MainActivity.java:106)???请写这行,问题是当我发送oos.writeUTF(“登录”)时;服务器应该让我打印这个字符串,但它崩溃了,给了我那个错误。服务器工作正常,因为我的pc客户端工作正常问题是android客户端到目前为止运气如何?您没有使用进度条更新,因此我推荐的解决方案可以工作。如果你在让KryoNet工作方面需要更多帮助,请留下评论。很高兴这有帮助!几天后我在这里举了一个例子,所以我在这里链接:
06-02 10:42:56.948: E/AndroidRuntime(5383): FATAL EXCEPTION: main
06-02 10:42:56.948: E/AndroidRuntime(5383): java.lang.NullPointerException
06-02 10:42:56.948: E/AndroidRuntime(5383): at com.example.social_network.MainActivity$2.onClick(MainActivity.java:106)
06-02 10:42:56.948: E/AndroidRuntime(5383): at android.view.View.performClick(View.java:4240)
06-02 10:42:56.948: E/AndroidRuntime(5383): at android.view.View$PerformClick.run(View.java:17721)
06-02 10:42:56.948: E/AndroidRuntime(5383): at android.os.Handler.handleCallback(Handler.java:730)
06-02 10:42:56.948: E/AndroidRuntime(5383): at android.os.Handler.dispatchMessage(Handler.java:92)
06-02 10:42:56.948: E/AndroidRuntime(5383): at android.os.Looper.loop(Looper.java:137)
06-02 10:42:56.948: E/AndroidRuntime(5383): at android.app.ActivityThread.main(ActivityThread.java:5103)
06-02 10:42:56.948: E/AndroidRuntime(5383): at java.lang.reflect.Method.invokeNative(Native Method)
06-02 10:42:56.948: E/AndroidRuntime(5383): at java.lang.reflect.Method.invoke(Method.java:525)
06-02 10:42:56.948: E/AndroidRuntime(5383): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
06-02 10:42:56.948: E/AndroidRuntime(5383): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
06-02 10:42:56.948: E/AndroidRuntime(5383): at dalvik.system.NativeStart.main(Native Method)