GetView ListFragment 复选框问题

Question

我有一个 Activity，它扩展了一个包含 2 个文本框和一个复选框的片段列表。我的列表填充得很好，但是当我选中复选框时，它引用了 getView() 调用的最后一个片段，而不是其相关片段（当我选中框 2 时，如果框 8 是 getView 调用的最后一个项目，则框 8 将展开（ ）在名单上） 我该如何解决？代码如下：

 package com.bango.chdebug;

import java.util.ArrayList;
import java.util.UUID;

import android.os.Bundle;
import android.support.v4.app.ListFragment;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.CompoundButton.OnCheckedChangeListener;
import android.widget.ListView;
import android.widget.TextView;

public class VoteListFragment extends ListFragment {
    private ArrayList<MediaItem> myML;
    public static boolean myCheckBoxState = false;
    private ArrayList<UUID> voteList;
    private MediaItem temp;
    private int maxVote = 0;
    private CheckBox voteBox;
    public static String VOTE_KEY = "vote";
    public String TAG = "NewMediaList";

    @Override
    public void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        temp = new MediaItem();
        if(savedInstanceState != null){
        myCheckBoxState = savedInstanceState.getBoolean(VOTE_KEY, false);
        }
        getActivity().setTitle("New Movie List");
        voteList = new ArrayList<UUID>();
        myML = MediaDB.get(getActivity()).getVoteMediaItems();
        MediaAdapter medAdapt = new MediaAdapter(myML);
        setListAdapter(medAdapt);
    }

    private class MediaAdapter extends ArrayAdapter<MediaItem> {
        public MediaAdapter(ArrayList<MediaItem> mediaItems) {
            super(getActivity(), 0, mediaItems);
            // mediaItems = parseOfficialList(mediaItems);
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            // TODO Auto-generated method stub
            if (convertView == null) {
                convertView = getActivity().getLayoutInflater().inflate(
                        R.layout.new_media_list_item, null);
            }
            temp = getItem(position);
            TextView medTitle = (TextView) convertView
                    .findViewById(R.id.vote_media_title);
            TextView medDate = (TextView) convertView
                    .findViewById(R.id.vote_media_date);
            voteBox = (CheckBox) convertView
                    .findViewById(R.id.vote_media_cb);
            medTitle.setText(temp.getMyTitle());
            voteBox.setEnabled(true);
            voteBox.setOnCheckedChangeListener(new OnCheckedChangeListener(){
                @Override
                public void onCheckedChanged(CompoundButton buttonView,
                        boolean isChecked) {
                    // TODO Auto-generated method stub
                    Log.d("onresume", "On Check called for " + temp.getMyTitle());  
                }
            });
            return convertView;
        }   
    }   
    }

Answer 1

这个问题已经被问过很多次了，请参考listview-checkbox-trouble、listview-with-checkbox-and-all-clickable 或get-selected-item-using-checkbox-in-listview。

绝对不能保证最后一次调用getView() 应该发生在单击的复选框上。任何文档/示例中都没有提到它，所以你不应该依赖它。 您的列表只是 查看 来显示数据。数据本身应该存储在不同的实体中。在您的代码中未使用该实体。您应该在其中存储已检查/未检查状态并将反向引用存储在视图中（例如存储中的数据位置）。

下面是稍微修改的片段。请注意，我已将新的 checked 字段添加到 MediaItem 以存储复选框状态。如果需要，您可以使用单独的数组来存储该状态。

public class VoteListFragment extends ListFragment {
    private ArrayList<MediaItem> myML;
    public static boolean myCheckBoxState = false;
    private ArrayList<UUID> voteList;
    private MediaItem temp;
    private int maxVote = 0;
    private CheckBox voteBox;
    public static String VOTE_KEY = "vote";
    public String TAG = "NewMediaList";

    @Override
    public void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        temp = new MediaItem("item");
        if(savedInstanceState != null){
            myCheckBoxState = savedInstanceState.getBoolean(VOTE_KEY, false);
        }
        getActivity().setTitle("New Movie List");
        voteList = new ArrayList<UUID>();
        myML = getVoteMediaItems(getActivity());
        MediaAdapter medAdapt = new MediaAdapter(myML);
        setListAdapter(medAdapt);
    }

    private ArrayList<MediaItem> getVoteMediaItems(final Activity activity) {
        final ArrayList<MediaItem> items = new ArrayList<MediaItem>();

        for (int i = 0; i < 100; i++) {
            items.add(new MediaItem(String.valueOf(i) + " item"));
        }

        return items;
    }

    private class MediaAdapter extends ArrayAdapter<MediaItem> {

        private CompoundButton.OnCheckedChangeListener mCheckedListener = new CompoundButton.OnCheckedChangeListener(){
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                Integer position = (Integer) buttonView.getTag();

                if (position != null) {
                    Toast.makeText(getActivity(), "On Check called for " + getItem(position).getMyTitle(), Toast.LENGTH_LONG).show();
                    getItem(position).checked = isChecked;
                }
            }
        };

        public MediaAdapter(ArrayList<MediaItem> mediaItems) {
            super(getActivity(), 0, mediaItems);
            // mediaItems = parseOfficialList(mediaItems);
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            // TODO Auto-generated method stub
            if (convertView == null) {
                convertView = getActivity().getLayoutInflater().inflate(
                        R.layout.new_media_list_item, null);
            }

            temp = getItem(position);

            // Consider using of ViewHolder pattern instead of call findViewById() to improve performance
            TextView medTitle = (TextView) convertView
                    .findViewById(R.id.vote_media_title);
            TextView medDate = (TextView) convertView
                    .findViewById(R.id.vote_media_date);
            voteBox = (CheckBox) convertView
                    .findViewById(R.id.vote_media_cb);
            medTitle.setText(temp.getMyTitle());
            voteBox.setEnabled(true);
            voteBox.setOnCheckedChangeListener(null);
            voteBox.setChecked(temp.checked);
            voteBox.setTag(position);

            voteBox.setOnCheckedChangeListener(mCheckedListener);
            return convertView;
        }
    }

    public class MediaItem {
        private String myTitle;
        // Newly added field
        private boolean checked = false;

        MediaItem(String title) {
            myTitle = title;
        }

        public String getMyTitle() {
            return myTitle;
        }
    }
}