Question

我有两个列表我将list1中的项目添加到另一个列表中，但是当我点击某个项目时。程序结束时没有任何错误 debug显示异常错误以下是代码： -

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    String lst1[] = {"abdul","yousuf","khalid","john","egor"};
    String   lst2[]= {};
    Double  lp1[]={10.0,5.0,2.0,0.5,1.5};
    Double  lp12[]={};

    ListView lis1= (ListView)findViewById(R.id.lv1);
    ListView lis2= (ListView)findViewById(R.id.lv2);

    ArrayAdapter<String> adapter1 =new ArrayAdapter<String>(MainActivity.this,android.R.layout.simple_list_item_1,lst1);
    final ArrayAdapter<String> adapter2 =new ArrayAdapter<String>(MainActivity.this,android.R.layout.simple_list_item_1,lst2);
    lis1.setAdapter(adapter1);
    lis2.setAdapter(adapter2);

    lis1.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
         String item = ((TextView)view).getText().toString();
         adapter2.add(item);

        }
    });
}

Answer 1

因为当你使用

ArrayAdapter<String> adapter1 =new ArrayAdapter<String>(MainActivity.this,
               android.R.layout.simple_list_item_1,lst2);`
//  Internally a fixed size list will be generated ^^^^

然后lst2数组将转换为固定长度列表，该列表无法接受新条目

public More ...ArrayAdapter(Context context, int resource, int textViewResourceId, T[] objects) {
        init(context, resource, textViewResourceId, Arrays.asList(objects));
        //                                          fixed length array
    }

了解asList

解决方案：

 ArrayAdapter<String> adapter1 =new ArrayAdapter<String>(MainActivity.this,
              android.R.layout.simple_list_item_1,
              new ArrayList<String>(Arrays.asList(lst1));
             //  Pass array as new mutable list
 final ArrayAdapter<String> adapter2 =new ArrayAdapter<String>(MainActivity.this,
              android.R.layout.simple_list_item_1,
              new ArrayList<String>(Arrays.asList(lst2));

Answer 2

试试这个

lis1.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
         String item =lst1[position];
         adapter2.add(item);

        }
    });

Answer 3

这是解决方案

 lis1.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
         String item = ((TextView)view).getText().toString();
         lst2.add(item);
         adapter2.notifyDataSetChanged();

        }
    });

Android添加列表项给出错误

3 个答案: