使用EclipseJava的Android应用程序出现错误

我有一个活动，并在此活动中使用Listview、ImageButton、Edittext和微调器。但我的问题是，每当我运行代码时，它都会显示错误

08-11 06:38:38.433: D/dalvikvm(1012): GC_FOR_ALLOC freed 133K, 7% free 2745K/2940K, paused 172ms, total 206ms
08-11 06:38:38.713: E/TCP Client(1012): C: Connecting...
08-11 06:38:38.723: D/AndroidRuntime(1012): Shutting down VM
08-11 06:38:38.723: W/dalvikvm(1012): threadid=1: thread exiting with uncaught exception (group=0x414c4700)
08-11 06:38:38.973: E/AndroidRuntime(1012): FATAL EXCEPTION: main
08-11 06:38:38.973: E/AndroidRuntime(1012): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.android_examples.com.tabhost/com.android_examples.com.tabhost.MainActivity}: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.android_examples.com.tabhost/com.android_examples.com.tabhost.TabActivity_1}: java.lang.NullPointerException
08-11 06:38:38.973: E/AndroidRuntime(1012):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
08-11 06:38:38.973: E/AndroidRuntime(1012):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
08-11 06:38:38.973: E/AndroidRuntime(1012):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
08-11 06:38:38.973: E/AndroidRuntime(1012):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
08-11 06:38:38.973: E/AndroidRuntime(1012):     at android.os.Handler.dispatchMessage(Handler.java:99)
08-11 06:38:38.973: E/AndroidRuntime(1012):     at android.os.Looper.loop(Looper.java:137)
08-11 06:38:38.973: E/AndroidRuntime(1012):     at android.app.ActivityThread.main(ActivityThread.java:5103)
08-11 06:38:38.973: E/AndroidRuntime(1012):     at java.lang.reflect.Method.invokeNative(Native Method)
08-11 06:38:38.973: E/AndroidRuntime(1012):     at java.lang.reflect.Method.invoke(Method.java:525)
08-11 06:38:38.973: E/AndroidRuntime(1012):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
08-11 06:38:38.973: E/AndroidRuntime(1012):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
08-11 06:38:38.973: E/AndroidRuntime(1012):     at dalvik.system.NativeStart.main(Native Method)
08-11 06:38:38.973: E/AndroidRuntime(1012): Caused by: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.android_examples.com.tabhost/com.android_examples.com.tabhost.TabActivity_1}: java.lang.NullPointerException
08-11 06:38:38.973: E/AndroidRuntime(1012):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
08-11 06:38:38.973: E/AndroidRuntime(1012):     at android.app.ActivityThread.startActivityNow(ActivityThread.java:2054)
08-11 06:38:38.973: E/AndroidRuntime(1012):     at android.app.LocalActivityManager.moveToState(LocalActivityManager.java:135)
08-11 06:38:38.973: E/AndroidRuntime(1012):     at android.app.LocalActivityManager.startActivity(LocalActivityManager.java:347)
08-11 06:38:38.973: E/AndroidRuntime(1012):     at android.widget.TabHost$IntentContentStrategy.getContentView(TabHost.java:749)
08-11 06:38:38.973: E/AndroidRuntime(1012):     at android.widget.TabHost.setCurrentTab(TabHost.java:413)
08-11 06:38:38.973: E/AndroidRuntime(1012):     at android.widget.TabHost.addTab(TabHost.java:240)
08-11 06:38:38.973: E/AndroidRuntime(1012):     at com.android_examples.com.tabhost.MainActivity.onCreate(MainActivity.java:44)
08-11 06:38:38.973: E/AndroidRuntime(1012):     at android.app.Activity.performCreate(Activity.java:5133)
08-11 06:38:38.973: E/AndroidRuntime(1012):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
08-11 06:38:38.973: E/AndroidRuntime(1012):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
08-11 06:38:38.973: E/AndroidRuntime(1012):     ... 11 more
08-11 06:38:38.973: E/AndroidRuntime(1012): Caused by: java.lang.NullPointerException
08-11 06:38:38.973: E/AndroidRuntime(1012):     at com.android_examples.com.tabhost.TabActivity_1.onCreate(TabActivity_1.java:50)
08-11 06:38:38.973: E/AndroidRuntime(1012):     at android.app.Activity.performCreate(Activity.java:5133)
08-11 06:38:38.973: E/AndroidRuntime(1012):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
08-11 06:38:38.973: E/AndroidRuntime(1012):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
08-11 06:38:38.973: E/AndroidRuntime(1012):     ... 21 more
08-11 06:38:46.273: I/Process(1012): Sending signal. PID: 1012 SIG: 9

我的活动代码是

public  class TabActivity_1 extends Activity {
private ListView mList;
private ArrayList<String> arrayList;
private MyCustomAdapter mAdapter;
private TCPClient mTcpClient;
Spinner sp1;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_tab_activity_1);

    sp1=(Spinner) findViewById(R.id.spinner1);
    ArrayAdapter<CharSequence> ar=ArrayAdapter.createFromResource(this,R.array.Type1,android.R.layout.simple_list_item_1);
    ar.setDropDownViewResource(android.R.layout.simple_dropdown_item_1line);
    sp1.setAdapter(ar);

     arrayList = new ArrayList<String>();

     final EditText editText = (EditText) findViewById(R.id.editText1);
        ImageButton startt = (ImageButton)findViewById(R.id.imageButton1);

        //relate the listView from java to the one created in xml
        mList = (ListView)findViewById(R.id.listView1);
        mAdapter = new MyCustomAdapter(this, arrayList);
        mList.setAdapter(mAdapter);

        // connect to the server
        new connectTask().execute("");

       startt.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View view) {

                String message = editText.getText().toString();

                //add the text in the arrayList
                arrayList.add("c: " + message);

                //refresh the list
                mAdapter.notifyDataSetChanged();
                editText.setText("");
            }
        });
}

        public class connectTask extends AsyncTask<String,String,TCPClient> {

            @Override
            protected TCPClient doInBackground(String... message) {

                //we create a TCPClient object and
                mTcpClient = new TCPClient(new TCPClient.OnMessageReceived() {
                    @Override
                    //here the messageReceived method is implemented
                    public void messageReceived(String message) {
                        //this method calls the onProgressUpdate
                        publishProgress(message);
                    }
                });
                mTcpClient.run();

                return null;
            }

            @Override
            protected void onProgressUpdate(String... values) {
                super.onProgressUpdate(values);

                //in the arrayList we add the messaged received from server
                arrayList.add(values[0]);
                // notify the adapter that the data set has changed. This means that new message received
                // from server was added to the list
                mAdapter.notifyDataSetChanged();
            }

        }            

         public void buttonClickMethod(View v){
              Intent i= new Intent(TabActivity_1.this,PageAjout.class);
              startActivity(i);
          }
        }

公共类选项卡活动\u 1扩展活动{
私有ListView-mList；
私有ArrayList ArrayList；
私人MyCustomAdapter mAdapter；
私有TCP客户端mTcpClient；
Spinner sp1；
@凌驾
创建时受保护的void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
setContentView（R.layout.activity_选项卡_activity_1）；
sp1=（微调器）findViewById（R.id.spinner1）；
ArrayAdapter ar=ArrayAdapter.createFromResource（这是R.array.Type1，android.R.layout.simple\u list\u item\u 1）；
ar.setDropDownViewResource（android.R.layout.simple\u dropdown\u item\u 1line）；
设置适配器（ar）；
arrayList=新的arrayList（）；
final EditText EditText=（EditText）findViewById（R.id.editText1）；
ImageButton startt=（ImageButton）findViewById（R.id.imageButton1）；
//将java中的listView与xml中创建的listView关联起来
mList=（ListView）findViewById（R.id.listView1）；
mAdapter=新的MyCustomAdapter（此为arrayList）；
mList.setAdapter（mAdapter）；
//连接到服务器
新建connectTask（）。执行（“”）；
startt.setOnClickListener（新视图.OnClickListener（）{
@凌驾
公共void onClick（视图）{
String message=editText.getText（）.toString（）；
//在arrayList中添加文本
添加（“c:+消息”）；
//刷新列表
mAdapter.notifyDataSetChanged（）；
editText.setText（“”）；
}
});
}
公共类connectTask扩展了AsyncTask{
@凌驾
受保护的TCPClient doInBackground（字符串…消息）{
//我们创建一个TCPClient对象并
mTcpClient=新的TCPClient（新的TCPClient.OnMessageReceived（）{
@凌驾
//这里实现了messageReceived方法
已接收公共无效消息（字符串消息）{
//此方法调用onProgressUpdate
出版进度（信息）；
}
});
mTcpClient.run（）；
返回null；
}
@凌驾
受保护的void onProgressUpdate（字符串…值）{
super.onProgressUpdate（值）；
//在arrayList中，我们添加从服务器接收的消息
arrayList.add（值[0]）；
//通知适配器数据集已更改。这意味着收到新消息
//从服务器添加到列表中
mAdapter.notifyDataSetChanged（）；
}
}            
公共无效按钮单击方法（视图五）{
意图i=新意图（TabActivity_1.this，PageAjout.class）；
星触觉（i）；
}
}

---

我很困惑，我哪里做错了。指导我。

您将空的arrayList设置为adapter，这就是代码给出NullPointerException的原因

从

onCreate（）

并重写

AsyncTask的
onPostExecute（）
方法，并将arrayList设置为adapter。您还可以设置一个条件来检查arrayList是否不应为null

@Override
protected void onProgressUpdate(String... values) {
      super.onProgressUpdate(values);

       //in the arrayList we add the messaged received from server
      arrayList.add(values[0]);
}
protected void onPostExecute (TCPClient result) {
     mAdapter = new MyCustomAdapter(this, arrayList);
     mList.setAdapter(mAdapter);
}

希望有帮助。
具体哪一行？请不要将错误作为图片发布。另外，请更详细地描述该问题。您确定已正确初始化编辑文本吗？请输入tabActivity_1代码，因为此错误发生在您忘记任何初始化时，如edirText=（EditText）findViewById（R.id.EditText）；或者为startt-alsodebug-debug-debug检查相同的代码。。。。。。请在此更新您的日志和代码
@Override
protected void onProgressUpdate(String... values) {
      super.onProgressUpdate(values);

       //in the arrayList we add the messaged received from server
      arrayList.add(values[0]);
}
protected void onPostExecute (TCPClient result) {
     mAdapter = new MyCustomAdapter(this, arrayList);
     mList.setAdapter(mAdapter);
}