java - ArrayAdapter 中的 android UnsupportedOperationException

Question

我正在尝试为我的应用程序创建一个 onDisimiss 监听器，因为现在这就是我所拥有的

Activity

public class listview_test extends Activity {
ListView list;
String[] web = {
        "Google Plus",
        "Twitter",
        "Windows",
} ;
Integer[] imageId = {
        R.drawable.ic_launcher,
        R.drawable.icon,
        R.drawable.ic_launcher,
};
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.list_test);
    final CustomList adapter = new
            CustomList(listview_test.this, web, imageId);
    list=(ListView)findViewById(R.id.list);
    list.setAdapter(adapter);
    list.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view,
                                int position, long id) {
            Toast.makeText(listview_test.this, "You Clicked at " +web[+ position], Toast.LENGTH_SHORT).show();
        }
    });
    SwipeDismissListViewTouchListener touchListener =
            new SwipeDismissListViewTouchListener(
                    list,
                    new SwipeDismissListViewTouchListener.DismissCallbacks() {
                        @Override
                        public boolean canDismiss(int position) {
                            return true;
                        }

                        @Override
                        public void onDismiss(ListView listView, int[] reverseSortedPositions) {
                            for (int position : reverseSortedPositions) {
                                adapter.remove(adapter.getItem(position));
                            }
                            adapter.notifyDataSetChanged();
                        }
                    }
            );
    list.setOnTouchListener(touchListener);
    // Setting this scroll listener is required to ensure that during ListView scrolling,
    // we don't look for swipes.
    list.setOnScrollListener(touchListener.makeScrollListener());
}
}

和自定义适配器

public class CustomList extends ArrayAdapter<String>{
private final Activity context;
private final String[] web;
private final Integer[] imageId;
public CustomList(Activity context,
                  String[] web, Integer[] imageId) {
    super(context, R.layout.weather_item, web);
    this.context = context;
    this.web = web;
    this.imageId = imageId;
}
@Override
public View getView(int position, View view, ViewGroup parent) {
    LayoutInflater inflater = context.getLayoutInflater();
    View rowView= inflater.inflate(R.layout.weather_item, null, true);
    TextView txtTitle = (TextView) rowView.findViewById(R.id.city);
    ImageView imageView = (ImageView) rowView.findViewById(R.id.info_image);
    txtTitle.setText(web[position]);
    imageView.setImageResource(imageId[position]);
    return rowView;
}

出于某种原因，每次我滑动一个项目以关闭它时，它都会强制关闭并给我这个异常

    java.lang.UnsupportedOperationException

在这一行

adapter.remove(adapter.getItem(position));

Answer 1

java.lang.UnsupportedOperationException

当您通过数组或不可修改的 List 支持 Adapter 时抛出。由于您无法更改它们的大小，因此无法删除。

相反，修改您的适配器，使其接受List 而不是数组，并确保您传递的List 是完全灵活的.

有点像

List <String> web = new ArrayList <String> ();
web.add ("Google Plus");
web.add ("Twitter");
//etc.

足以确保一个灵活的列表。

这意味着您的 CustomList 适配器也应该调用同样接受 List 的父类(super class)构造函数，在本例中是

public ArrayAdapter (Context context, int resource, List<T> objects)

有关更多信息，请参阅 ArrayAdapter文档。