自己写的程序崩溃

Question

自己写的程序崩溃 求大神看看实在不懂那里错了  下面是代码

package com.example.mypptcontrol;

import java.io.IOException;

import java.io.OutputStream;

import java.io.PrintWriter;

import java.net.Socket;

import java.net.UnknownHostException;

import android.app.Activity;

import android.os.Bundle;

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.Toast;

public class MainActivity extends Activity {

private Button loginButton1;

private Button loginButton2;

private Button loginButton3;

private Button loginButton4;

private Button loginButton5;

public String ppt;

PrintWriter pw = null;

Socket socket=null;

OutputStream os=null;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

//初始化连接按钮

loginButton1 =(Button) findViewById(R.id.button2);

loginButton2 =(Button) findViewById(R.id.button5);

loginButton3 =(Button) findViewById(R.id.button6);

loginButton4 =(Button) findViewById(R.id.button4);

loginButton5 =(Button) findViewById(R.id.button1);

EditText et = (EditText)findViewById(R.id.editText1);

//获取edittext文本内容

String value1 = et.getText().toString();

EditText et2 = (EditText)findViewById(R.id.editText2);

loginButton1.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View arg0) {

// TODO 自动生成的方法存根

try {

socket=new Socket("123.150.226.119",7777);

os=socket.getOutputStream();

pw= new PrintWriter(os);

} catch (UnknownHostException e) {

// TODO 自动生成的 catch 块

e.printStackTrace();

} catch (IOException e) {

// TODO 自动生成的 catch 块

e.printStackTrace();

}

}

});

           loginButton2.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View arg0) {

// TODO 自动生成的方法存根

ppt="F6";

}

});

         loginButton3.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View arg0) {

// TODO 自动生成的方法存根

ppt="last";

}

});

         loginButton4.setOnClickListener(new OnClickListener() {

 

  @Override

  public void onClick(View arg0) {

  // TODO 自动生成的方法存根

  ppt="next";

 

  }

  });

         loginButton5.setOnClickListener(new OnClickListener() {

 

  @Override

  public void onClick(View arg0) {

  // TODO 自动生成的方法存根

  ppt="stop";

 

  }

  });

         if(ppt!="stop"){

       

        pw.write(ppt);

        pw.flush();

         

         }else{

        pw.write(ppt);

        pw.flush();

try {

os.close();

} catch (IOException e) {

// TODO 自动生成的 catch 块

e.printStackTrace();

}

try {

socket.close();

} catch (IOException e) {

// TODO 自动生成的 catch 块

e.printStackTrace();

}

         }

}

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;

}

@Override

public boolean onOptionsItemSelected(MenuItem item) {

// Handle action bar item clicks here. The action bar will

// automatically handle clicks on the Home/Up button, so long

// as you specify a parent activity in AndroidManifest.xml.

int id = item.getItemId();

if (id == R.id.action_settings) {

return true;

}

return super.onOptionsItemSelected(item);

}

}

这是Logcat报的错

10-27 23:01:36.390: D/AndroidRuntime(1235): Shutting down VM

10-27 23:01:36.390: W/dalvikvm(1235): threadid=1: thread exiting with uncaught exception (group=0xb3a0fba8)

10-27 23:01:36.400: E/AndroidRuntime(1235): FATAL EXCEPTION: main

10-27 23:01:36.400: E/AndroidRuntime(1235): Process: com.example.mypptcontrol, PID: 1235

10-27 23:01:36.400: E/AndroidRuntime(1235): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.mypptcontrol/com.example.mypptcontrol.MainActivity}: java.lang.NullPointerException

10-27 23:01:36.400: E/AndroidRuntime(1235): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2184)

10-27 23:01:36.400: E/AndroidRuntime(1235): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233)

10-27 23:01:36.400: E/AndroidRuntime(1235): at android.app.ActivityThread.access$800(ActivityThread.java:135)

10-27 23:01:36.400: E/AndroidRuntime(1235): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)

10-27 23:01:36.400: E/AndroidRuntime(1235): at android.os.Handler.dispatchMessage(Handler.java:102)

10-27 23:01:36.400: E/AndroidRuntime(1235): at android.os.Looper.loop(Looper.java:136)

10-27 23:01:36.400: E/AndroidRuntime(1235): at android.app.ActivityThread.main(ActivityThread.java:5001)

10-27 23:01:36.400: E/AndroidRuntime(1235): at java.lang.reflect.Method.invokeNative(Native Method)

10-27 23:01:36.400: E/AndroidRuntime(1235): at java.lang.reflect.Method.invoke(Method.java:515)

10-27 23:01:36.400: E/AndroidRuntime(1235): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)

10-27 23:01:36.400: E/AndroidRuntime(1235): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)

10-27 23:01:36.400: E/AndroidRuntime(1235): at dalvik.system.NativeStart.main(Native Method)

10-27 23:01:36.400: E/AndroidRuntime(1235): Caused by: java.lang.NullPointerException

10-27 23:01:36.400: E/AndroidRuntime(1235): at com.example.mypptcontrol.MainActivity.onCreate(MainActivity.java:102)

10-27 23:01:36.400: E/AndroidRuntime(1235): at android.app.Activity.performCreate(Activity.java:5231)

10-27 23:01:36.400: E/AndroidRuntime(1235): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)

10-27 23:01:36.400: E/AndroidRuntime(1235): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2148)

10-27 23:01:36.400: E/AndroidRuntime(1235): ... 11 more

10-27 23:01:39.910: I/Process(1235): Sending signal. PID: 1235 SIG: 9

求大神看看啊

Answer 1

10-27 23:01:36.400: E/AndroidRuntime(1235): Caused by: java.lang.NullPointerException找 Caused by 关键字