android 运行不正常,该如何处理

android 运行不正常
啊啊啊 急死我了 主Acitvity中就这几行代码
ListView list;
// Cursor cursor=null;
   
@Override
  public void onCreate(Bundle savedInstanceState) {
//Toast.makeText(this, "进入工程", Toast.LENGTH_SHORT).toString();
  super.onCreate(savedInstanceState);
  setContentView(R.layout.main);

  System.out.println("输出信息"); //检验
  String[] datas=new String[]{"文科查询","理科查询"};
  list=(ListView)findViewById(R.id.list);
// ArrayAdapter adapter=new ArrayAdapter(this,android.R.layout.select_dialog_singlechoice,datas);
//// this.getListView().setAdapter(adapter);
// System.out.println("输出信息list"); 
}

但结果总出不来 总报错

08-03 00:30:51.680: ERROR/AndroidRuntime(836): Uncaught handler: thread main exiting due to uncaught exception
08-03 00:30:51.709: ERROR/AndroidRuntime(836): java.lang.RuntimeException: Unable to start activity ComponentInfo{test.andorid1/test.andorid1.Activity1}: java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'
08-03 00:30:51.709: ERROR/AndroidRuntime(836): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2268)
08-03 00:30:51.709: ERROR/AndroidRuntime(836): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2284)
08-03 00:30:51.709: ERROR/AndroidRuntime(836): at android.app.ActivityThread.access$1800(ActivityThread.java:112)
08-03 00:30:51.709: ERROR/AndroidRuntime(836): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1692)
08-03 00:30:51.709: ERROR/AndroidRuntime(836): at android.os.Handler.dispatchMessage(Handler.java:99)
08-03 00:30:51.709: ERROR/AndroidRuntime(836): at android.os.Looper.loop(Looper.java:123)
08-03 00:30:51.709: ERROR/AndroidRuntime(836): at android.app.ActivityThread.main(ActivityThread.java:3948)
08-03 00:30:51.709: ERROR/AndroidRuntime(836): at java.lang.reflect.Method.invokeNative(Native Method)
08-03 00:30:51.709: ERROR/AndroidRuntime(836): at java.lang.reflect.Method.invoke(Method.java:521)
08-03 00:30:51.709: ERROR/AndroidRuntime(836): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:782)
08-03 00:30:51.709: ERROR/AndroidRuntime(836): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:540)
08-03 00:30:51.709: ERROR/AndroidRuntime(836): at dalvik.system.NativeStart.main(Native Method)
08-03 00:30:51.709: ERROR/AndroidRuntime(836): Caused by: java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'
08-03 00:30:51.709: ERROR/AndroidRuntime(836): at android.app.ListActivity.onContentChanged(ListActivity.java:236)
08-03 00:30:51.709: ERROR/AndroidRuntime(836): at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:312)
08-03 00:30:51.709: ERROR/AndroidRuntime(836): at android.app.Activity.setContentView(Activity.java:1626)
08-03 00:30:51.709: ERROR/AndroidRuntime(836): at test.andorid1.Activity1.onCreate(Activity1.java:24)
08-03 00:30:51.709: ERROR/AndroidRuntime(836): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1123)
08-03 00:30:51.709: ERROR/AndroidRuntime(836): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2231)
08-03 00:30:51.709: ERROR/AndroidRuntime(836): ... 11 more
报错说setContentView(R.layout.main)有问题 这是咋回事啊究竟！！！！


------解决方案--------------------
08-03 00:30:51.709: ERROR/AndroidRuntime(836): Caused by: java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'
LZ 仔细看
你XML布局文件如果写的ListView 的id 是系统的 => Activity extends ListActivity
ListView 的id 是自己定义的 =>Activity就没必要继承ListActivity