Question

我在Android应用中创建了动态数量的复选框（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。

但我想从这个列表中获取已检查项目的数组。

所以我使用 present_array [] varible来获取 simple_list_item_checked 列表中已检查项目的列表。

它可以在烤面包中显示项。但是将此项添加到显示ArryIndexOutOfBoundException的 present_array [item] 。

感谢你的帮助..

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

您的String数组String [] present_array;的长度为1。你必须用长度

初始化它

  public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
            long arg3) {
        // TODO Auto-generated method stub
        int len = lv.getCount();
        SparseBooleanArray checked = lv.getCheckedItemPositions();
        present_array = new String[len]; //added this line
        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 //

         }          
    }

Answer 2

请改用ArrayList。它不需要具有固定的大小，并且每次添加或删除项目时都会更改。

实例化一个空数组列表，如下所示：

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

然后在add()中使用onItemClick()：

presentlist.add(item)

[编辑]： 并使用以下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);
}

Answer 3

如果我错了，请纠正我，但似乎你正在循环ListView中的所有元素。

而你（可能）想要的是从getCheckedItemPositions()循环元素。

您应该将代码更改为：

public class Tab1 extends Activity {
    String [] student_array={"party","sport","music","café","education"};
    List<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);
        final 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

                SparseBooleanArray checked = lv.getCheckedItemPositions();
                int len = checked.size();
                for (int i = 0; i < len; i++) {
                    // Check if it's indeed checked
                    if (checked.get(i)) {
                        int idx = checked.keyAt(i);
                        // Add str
                        String item = (String) adapter.getItem(idx);
                        present_array.add(item);  // ERROR WHEN ADDING STRING ARRAY //
                    }
                }
            }

        });
    }

注意我是如何检查是否实际检查了checked数组中的项目。那是因为：

然而，该功能有一个未记录的陷阱，即使是这样您选择一个项目然后取消选择，该项目仍包含在中数组

以上是Stanley Siu's blog

的摘录

ArrayIndexOutOfBoundException simple_list_item_checked中的错误

3 个答案: