Question

我正在使用ScrollView中的ListView。每当我对ListView执行删除操作时，数据都是删除但问题是在删除数据后不幸应用程序停止了。我正在使用领域来存储数据并从领域中删除数据。这是我的代码。

listViewSearchCity.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
            PostUserItinerary item = (PostUserItinerary) listViewSearchCity.getItemAtPosition(i);
            view.setBackgroundColor(Color.parseColor("#a9a9a9"));
            // change1();
            h=item.getSearchCity();
            onclick();
            // onitemclick();

        }
    });
public void onclick()
{

    imgDelete.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            //PostItinerarySearchCityAdapter adapter = new PostItinerarySearchCityAdapter(PostUserItineraryActivity.this,helper.justRefresh());
            String type =h ;
            final RealmResults<PostUserItinerary> students = realm.where(PostUserItinerary.class).findAll();

            PostUserItinerary postUserItinerary = students.where().equalTo("searchCity", type).findFirst();

            if (postUserItinerary != null) {

                if (!realm.isInTransaction()) {
                    realm.beginTransaction();
                }

                postUserItinerary.deleteFromRealm();
                realm.commitTransaction();
                adapter.notifyDataSetChanged();
               // listViewSearchCity.setAdapter(adapter);

            }
        }
        //final int position2 = holder.getAdapterPosition();



    });

}

这是我的日志节目。

10-17 10：51：09.717 6586-6586 / com.xitiz.xitizmobile E / AndroidRuntime：致命异常：主要处理：com.xitiz.xitizmobile，PID：6586 显示java.lang.NullPointerException at com.xitiz.xitizmobile.PostUserItineraryActivity $ 7.onClick（PostUserItineraryActivity.java:327）在android.view.View.performClick（View.java:4444）在android.view.View $ PerformClick.run（View.java:18440）在android.os.Handler.handleCallback（Handler.java:733）在android.os.Handler.dispatchMessage（Handler.java:95）在android.os.Looper.loop（Looper.java:136）在android.app.ActivityThread.main（ActivityThread.java:5052） at java.lang.reflect.Method.invokeNative（Native Method）在java.lang.reflect.Method.invoke（Method.java:515）在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:796）在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:612）在dalvik.system.NativeStart.main（本地方法）

Answer 1

执行此操作的简单方法是制作PostItinerarySearchCityAdapter extends RealmBaseAdapter<PostUserItinerary>，直接使用RealmResults<PostUserItinerary>初始化，然后将您直接拨打的所有电话移至adapter.notifyDataSetChanged();。

您可以在Realm的示例中看到示例Activity和Adapter。

class MyListAdapter extends RealmBaseAdapter<PostUserItinerary> implements ListAdapter {

    private static class ViewHolder {
        TextView countText;
        CheckBox deleteCheckBox;
    }

    MyListAdapter(OrderedRealmCollection<Counter> realmResults) {
        super(realmResults);
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder viewHolder;
        if (convertView == null) {
            convertView = LayoutInflater.from(parent.getContext())
                    .inflate(R.layout.row, parent, false);
            viewHolder = new ViewHolder();
            viewHolder.countText = (TextView) convertView.findViewById(R.id.textview);
            viewHolder.deleteCheckBox = (CheckBox) convertView.findViewById(R.id.checkBox);
            convertView.setTag(viewHolder);
        } else {
            viewHolder = (ViewHolder) convertView.getTag();
        }

        final PostUserItinerary item = getItem(position);
        ...
        return convertView;
    }
}

和

public class ListViewExampleActivity extends AppCompatActivity {

    private Realm realm;
    private MyListAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_listview);
        realm = Realm.getDefaultInstance();

        // RealmResults are "live" views, that are automatically kept up to date, even when changes happen
        // on a background thread. The RealmBaseAdapter will automatically keep track of changes and will
        // automatically refresh when a change is detected.
        adapter = new MyListAdapter(realm.where(PostUserItinerary.class).findAllAsync());

如何在使用Realm删除ListView数据后刷新scrollView中的ListView？

1 个答案: