android - simple_list_item_checked 中的 ArrayIndexOutOfBoundException 错误

Question

我在 Android 应用程序中创建动态数量的复选框(这取决于数组的长度)。我使用 student_array[] 添加了动态数量的复选框。它工作正常。

但我想从此列表中获取选中项的数组。

所以我使用 present_array[] 变量从 simple_list_item_checked 列表中获取选中的项目列表。

它在 toast 中用于显示 item。但是将此项目添加到 present_array[item] 显示 ArryIndexOutOfBoundException。

预先感谢您的帮助..

这是我的java文件

public class Tab1 extends Activity {
String [] student_array={"party","sport","music","café","education"};
String [] present_array;
/** Called when the activity is first created. */
  ArrayList<String> presentlist;
  @Override
  public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.tab1);
      ArrayAdapter<String> adapter= new ArrayAdapter<String>(this, android.R.layout.simple_list_item_checked, student_array);
      final ListView lv= (ListView)findViewById(R.id.listView1);
      lv.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);
      lv.setAdapter(adapter);


      lv.setOnItemClickListener(new android.widget.AdapterView.OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
                long arg3) {
            // TODO Auto-generated method stub
            int len = lv.getCount();
            SparseBooleanArray checked = lv.getCheckedItemPositions();
            for (int i = 0; i < len; i++)
             if (checked.get(i)) {
          String item =(String) lv.getItemAtPosition(checked.keyAt(i));

         present_array[i]=item;  // ERROR WHEN ADDING STRING ARRAY //

             }          
        }
    });


      }  

我的 LogCat

 07-06 06:26:49.329: E/AndroidRuntime(1328): FATAL EXCEPTION: main
 07-06 06:26:49.329: E/AndroidRuntime(1328): Process: info.androidhive.slidingmenu,    PID: 1328

 07-06 06:26:49.329: E/AndroidRuntime(1328): java.lang.ArrayIndexOutOfBoundsException: length=1; index=3
 07-06 06:26:49.329: E/AndroidRuntime(1328):    at    android.util.SparseBooleanArray.keyAt(SparseBooleanArray.java:176)
  07-06 06:26:49.329: E/AndroidRuntime(1328):   at com.androidexample.tabbar.Tab1$1.onItemClick(Tab1.java:45)
 07-06 06:26:49.329: E/AndroidRuntime(1328):    at android.widget.AdapterView.performItemClick(AdapterView.java:299)
 07-06 06:26:49.329: E/AndroidRuntime(1328):    at android.widget.AbsListView.performItemClick(AbsListView.java:1113)
 07-06 06:26:49.329: E/AndroidRuntime(1328):    at android.widget.AbsListView$PerformClick.run(AbsListView.java:2904)
 07-06 06:26:49.329: E/AndroidRuntime(1328):    at android.widget.AbsListView$3.run(AbsListView.java:3638)
 07-06 06:26:49.329: E/AndroidRuntime(1328):    at android.os.Handler.handleCallback(Handler.java:733)
 07-06 06:26:49.329: E/AndroidRuntime(1328):    at android.os.Handler.dispatchMessage(Handler.java:95)
 07-06 06:26:49.329: E/AndroidRuntime(1328):    at android.os.Looper.loop(Looper.java:137)
 07-06 06:26:49.329: E/AndroidRuntime(1328):    at android.app.ActivityThread.main(ActivityThread.java:4998)
 07-06 06:26:49.329: E/AndroidRuntime(1328):    at java.lang.reflect.Method.invokeNative(Native Method)
 07-06 06:26:49.329: E/AndroidRuntime(1328):    at java.lang.reflect.Method.invoke(Method.java:515)
 07-06 06:26:49.329: E/AndroidRuntime(1328):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:777)
 07-06 06:26:49.329: E/AndroidRuntime(1328):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:593)
 07-06 06:26:49.329: E/AndroidRuntime(1328):    at dalvik.system.NativeStart.main(Native Method)

Answer 1

改用ArrayList。它不需要固定大小，每次添加或删除项目时都会更改。

实例化一个空数组列表如下:

ArrayList<String> presentlist = new ArrayList<String>();

然后在 onItemClick() 中使用 add() :

presentlist.add(item)

[编辑]:并使用下面的循环获取列表中所有选中项目的列表:

for (int i = 0; i<checked.size(); i++){
    if(checked.valueAt(i) == false) continue;
    String item =(String) lv.getItemAtPosition(checked.keyAt(i));
    presentlist.add(item);
}