Java 正在尝试更新ListView项

我正在开发一个

列表视图

，它首先包含4项：事件a、事件B、事件C和事件D

这四个事件存储在名为

mEvents

的

ArrayList

中，单击一个按钮，我想从

ArrayList

中筛选出事件B，并通过适配器使用

notifyDataSetChanged（）

相应地更新

ListView

我正在使用另一个名为

newEvents

的

ArrayList

存储应该显示的事件（事件a/C/D），然后清除

mEvents

，然后将其设置为等于

newEvents

当按下按钮时，由于某种原因，最后一个列表项总是被删除（事件D），无论我尝试过滤哪个事件

以下是相关代码，如有任何帮助，将不胜感激

列表视图代码：

public class ListActivity extends FragmentActivity {

private UserCustomFilters mUserCustomFilters = new UserCustomFilters();

// Our database hostname and the credentials
String url = ; //
String user = ;
String pass =;

SQLUtils sqlu ; //The SQLUtil object type that will be initialized later depending on the credentials given above.
ArrayList<Event> mEvents;       //The Array that will hold the Events that we will pass around(to Adapter,the List...)
List<Event> Even;

//Change Even to static if intent is used to refresh
ArrayList<Event> newEvent =new ArrayList<>();
ListviewAdapter adapter;

//Default Constructor for the class ListActivity
public ListActivity()
{
    sqlu = new SQLUtils(url, user, pass); //Creating Object type SQLUtils using credentials needed
    Even = sqlu.Events();  //Imports the List of Events from the Database.

    mEvents = new ArrayList<>();  //Assigning the new array where the events go.

    //Setting it into the new Array.
    for(int i=0;i<Even.size();i++)
    {
        mEvents.add(Even.get(i));
    }
}

//Injecting Buttons using ButterKnife Library
@InjectView(android.R.id.list) ListView mListView;

private void setUpFilters(){

    // Calling the FilterView class to set the layout for the filters

    FilterView filterView = new FilterView(this);
    mUserCustomFilters = filterView.init();
}

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_list2);

    setUpFilters();

    adapter=new ListviewAdapter(this, mEvents); 

    mListView.setAdapter(adapter);

    //Swipe stuff
    adapter.setMode(Attributes.Mode.Single);
}

..........

@OnClick(R.id.filterSaveButton)
public void ImplementingButton(View view)  {

    for(int i =0; i< mEvents.size();i++){

        if(mEvents.get(i).getEventName().equals("Event B")){

        }
        else{
            newEvent.add(mEvents.get(i));
        }
    }

    adapter.getData().clear();

    adapter.getData().addAll(newEvent);

    adapter.notifyDataSetChanged();

}

public class ListviewAdapter extends BaseSwipeAdapter {

private Activity mActivity;
private ArrayList<Event> mEvents;
public static int Clicks=0;

//the Constructor for the class.
public ListviewAdapter(Activity activity, ArrayList<Event> events) {
    mActivity = activity;
    mEvents = events;
}

@Override
public int getCount() {
    return mEvents.size();  //Returns length of the array of Events
}

@Override
public Object getItem(int position) {
    return mEvents.get(position);  //Returns the Item being accessed in the the array}
}

@Override
public long getItemId(int position) {
    return 0;   //Id of the Item being accessed in the view
}

public ArrayList<Event> getData() {

    return mEvents;
}

@Override
public int getSwipeLayoutResourceId(int i) {
    return R.id.swipe;
}

@Override
public View generateView(int position, ViewGroup parent) {

    //Inflates the view to be used
    View convertView = LayoutInflater.from(mActivity).inflate(R.layout.list_item, parent, false);

    ViewHolder holder = new ViewHolder(); //Making variable of class type ViewHolder def

    convertView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            //Assigning the Relative Layout that contains the detailed description.
            RelativeLayout layout = (RelativeLayout) v.findViewById(R.id.DescriptionLayout);

            //Assigning the summary description stuff that will hide and reappear depending on the clicks.
            ImageView Bubble = (ImageView) v.findViewById(R.id.EventImageBubble);

            TextView EventName = (TextView) v.findViewById(R.id.TextEventName);
            TextView EventDate = (TextView) v.findViewById(R.id.TextEventDate);
            TextView EventPrice = (TextView) v.findViewById(R.id.TextEventPrice);
            TextView EventDistance = (TextView) v.findViewById(R.id.TextEventDistance);

            if (Clicks % 2 == 0) {
                //Popping the detailed description into view.
                layout.setVisibility(View.VISIBLE);

                //Hiding the summary Description from view to display the detailed description.
                Bubble.setVisibility(View.INVISIBLE);
                EventName.setVisibility(View.INVISIBLE);
                EventDate.setVisibility(View.INVISIBLE);
                EventPrice.setVisibility(View.INVISIBLE);
                EventDistance.setVisibility(View.INVISIBLE);
            } else {
                //Hiding the detailed description upon the 2nd click.
                layout.setVisibility(View.INVISIBLE);

                //Displaying the summary description back upon the 2nd click.
                Bubble.setVisibility(View.VISIBLE);
                EventName.setVisibility(View.VISIBLE);
                EventDate.setVisibility(View.VISIBLE);
                EventPrice.setVisibility(View.VISIBLE);
                EventDistance.setVisibility(View.VISIBLE);
            }

            Clicks++; //Adds to the number of times the user has tapped on an item.
        }
    });

    convertView.setTag(holder); //sets the tag

    //Summary Description of the events.
    holder.EventPicture= (ImageView) convertView.findViewById(R.id.ImageEventPicture);
    holder.EventIcon = (ImageView) convertView.findViewById(R.id.ImageEventIcon);
    holder.EventName = (TextView) convertView.findViewById(R.id.TextEventName);
    holder.EventDate = (TextView) convertView.findViewById(R.id.TextEventDate);
    holder.EventPrice= (TextView) convertView.findViewById(R.id.TextEventPrice);
    holder.EventDistance= (TextView) convertView.findViewById(R.id.TextEventDistance);

    //Initializing each item to the required type
    Event event = mEvents.get(position);

    //Detailed Description of the events.
    holder.EventDName=(TextView) convertView.findViewById(R.id.DesEventName);
    holder.EventDPrice= (TextView) convertView.findViewById(R.id.DesEventPrice);
    holder.EventLocName=(TextView) convertView.findViewById(R.id.DesEventLocName);
    holder.EventLocSt=(TextView) convertView.findViewById(R.id.DesEventLocStreet);
    holder.EventLocAdd=(TextView) convertView.findViewById(R.id.DesEventLocAddress);
    holder.EventStartDate=(TextView) convertView.findViewById(R.id.DesEventStartDate);
    holder.EventStartTime=(TextView) convertView.findViewById(R.id.DesEventStartTime);
    holder.EventEndDate=(TextView) convertView.findViewById(R.id.DesEventEndDate);
    holder.EventEndTime= (TextView) convertView.findViewById(R.id.DesEventEndTime);

    //Setting the text boxes to the information retrieved from the arrays of events

    //Setting the summary description
    holder.EventDistance.setText(event.getEventDistance()+"km");
    holder.EventName.setText(event.getEventName());
    holder.EventDate.setText(event.getEventDate());
    holder.EventPrice.setText("$"+event.getEventPrice());
    //holder.EventIcon.setImageResource(event.getEventIcon());
    //holder.EventPicture.setImageResource(event.getEventPicture());

    //Setting the detailed description.
    holder.EventDName.setText(event.getEventName());
    holder.EventDPrice.setText("$"+event.getEventPrice());
    holder.EventLocName.setText(event.getEventLocName());
    holder.EventLocSt.setText(event.getEventLocSt());
    holder.EventLocAdd.setText(event.getEventLocAdd());
    holder.EventStartDate.setText(event.getEventDate());
    holder.EventStartTime.setText(event.getEventStartTime());
    holder.EventEndDate.setText(event.getEventEndDate());
    holder.EventEndTime.setText(event.getEventEndTime());

    //Swipe methods being Implemented
    SwipeLayout swipeLayout = (SwipeLayout)convertView.findViewById(getSwipeLayoutResourceId(position));

    swipeLayout.setShowMode(SwipeLayout.ShowMode.PullOut);

    swipeLayout.addDrag(SwipeLayout.DragEdge.Left, convertView.findViewById(R.id.bottom_wrapper));

    swipeLayout.addDrag(SwipeLayout.DragEdge.Right, convertView.findViewById(R.id.mLinear));

    swipeLayout.addSwipeListener(new SimpleSwipeListener() {

        @Override
        public void onOpen(SwipeLayout layout) {

        }
    });

    return convertView;
}

@Override
public void fillValues(int position, View convertView) {

}

private static class ViewHolder{
    //The values holding summary description of the event.
    ImageView EventPicture;
    ImageView EventIcon;
    TextView EventName;
    TextView EventDate;
    TextView EventPrice;
    TextView EventDistance;

    //The Values holding detailed description of the event.
    TextView EventDName;
    TextView EventDPrice;
    TextView EventLocName;
    TextView EventLocSt;
    TextView EventLocAdd;
    TextView EventStartDate;
    TextView EventStartTime;
    TextView EventEndDate;
    TextView EventEndTime;
}

公共类ListActivity扩展了FragmentActivity{
private UserCustomFilters mUserCustomFilters=new UserCustomFilters（）；
//我们的数据库主机名和凭据
字符串url=//
字符串user=；
字符串传递=；
SQLUtils sqlu；//稍后将根据上述凭据初始化的SQLUtil对象类型。
ArrayList mEvents；//将保存我们将传递的事件的数组（到适配器、列表…）
并列；
//如果使用意图刷新，则更改为静态
ArrayList newEvent=新的ArrayList（）；
ListviewAdapter适配器；
//类ListActivity的默认构造函数
公开上市活动（）
{
sqlu=新SQLUtils（url、用户、过程）；//使用所需凭据创建对象类型SQLUtils
偶数=sqlu.Events（）；//从数据库导入事件列表。
mEvents=new ArrayList（）；//指定事件所在的新数组。
//将其设置到新数组中。
对于（int i=0；i您正在使用“NewEvent”而不是“NewEvent”
在进一步尝试后，我了解到将
适配器.notifyDataSetChanged（）
行替换为：
mListView.setAdapter（适配器）
确实给了我预期的行为，除了listview将滚动到列表顶部，因为我正在重置适配器。
对不起，这是我文章中的一个输入错误，在我的实现中它被更正了。您还可以为ListviewAdapter添加代码吗？任何特定的函数或整个类？不妨执行整个类，只是为了看看it为了实现滑动功能，使用了一个库，这导致适配器与通常的适配器不一样。当您分配新事件时？行
newEvent=new ArrayList（）
？当您向该数组添加新值时，该数组是否可能不是空的？能否在
ImplementingButton（）的开头为其分配一个新的ArrayList
？