Question

当我尝试删除或复制项目时，我的列表视图无法正确更新。数据正确存储在数据库中，但在listview上无法正确显示，我认为这是由于回收视图的问题。

例如，我删除了一个id为87的项目，然后我复制了一个不同的项目，它在listview中显示为id为87，即使它应该是88（并且已正确存储在数据库中为88 ）。

我已经尝试使用视图持有者和自定义适配器查看其他一些代码示例，但我似乎无法弄清楚问题。我是否已将ViewHolder概念正确应用于自定义适配器？

public class WorkoutAdapter extends ArrayAdapter<ExerciseSetModel> {

    private Context context;
    private ArrayList<ExerciseSetModel> exerciseSetList;
    private JSONParser jParser = new JSONParser();
    private String isComplete;
    private String exerciseId;

    public WorkoutAdapter(Context context, ArrayList<ExerciseSetModel> objects) {

        super(context, R.layout.exercise_set_item, objects);

        this.context = context;
        this.exerciseSetList = objects;
        isComplete = "";
    }

    private class ViewHolder{
        TextView tvExerciseSetName;
        TextView tvExerciseSetDetails;
        CheckBox cbIsComplete;
    }

    @Override
    public View getView(final int position, View convertView, ViewGroup parent) {

        RelativeLayout view = (RelativeLayout) convertView;
        ViewHolder holder = null;

        if (view == null) {
            LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            view = (RelativeLayout) inflater.inflate(R.layout.exercise_set_item, parent, false);

            holder = new ViewHolder();
            holder.tvExerciseSetName = (TextView) view.findViewById(R.id.exerciseSetName);
            holder.tvExerciseSetDetails = (TextView) view.findViewById(R.id.exerciseSetDetails);
            holder.cbIsComplete = (CheckBox) view.findViewById(R.id.cbIsComplete);

            if (exerciseSetList.get(position).getIsComplete() == 1) {
                holder.cbIsComplete.setChecked(true);
                isComplete = "1";
            }
            else {
                holder.cbIsComplete.setChecked(false);
                isComplete = "0";
            }

            holder.cbIsComplete.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
                @Override
                public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                    if (isChecked) {
                        exerciseSetList.get(position).setIsComplete(1);
                        exerciseId = exerciseSetList.get(position).getExerciseId() + "";
                        isComplete = "1";
                    } else {
                        exerciseSetList.get(position).setIsComplete(0);
                        exerciseId = exerciseSetList.get(position).getExerciseId() + "";
                        isComplete = "0";
                    }
                    new UpdateExerciseComplete().execute();
                }
            });

            holder.tvExerciseSetName.setText(exerciseSetList.get(position).getExerciseName());
            holder.tvExerciseSetDetails.setText(exerciseSetList.get(position).getExerciseDetails() + " id: " + exerciseSetList.get(position).getExerciseId());

        }
        else{
            holder = (ViewHolder) view.getTag();
        }

        return view;
    }

    class UpdateExerciseComplete extends AsyncTask<String, String, String> {

        private String updateIsCompleteUrl;

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
        }

        protected String doInBackground(String... args) {

            updateIsCompleteUrl = "localhost/android_connect/updateIsComplete.php";

            LinkedHashMap<String, String> params = new LinkedHashMap<String, String>();
            params.put("is_complete", isComplete);
            params.put("exercise_id", exerciseId);
            jParser.makePostRequest(updateIsCompleteUrl, params);

            return null;
        }

        protected void onPostExecute(String file_url) {
        }
    }
}

Answer 1

在onclick()函数中获取正确的位置。您必须在视图holder.cbIsComplete.setTag(position)上标记位置，然后使用onCLick()

在int position=(Integer)buttonView.getTag()内获取此标记

Answer 2

您实施了错误的ViewHolder模式。替换修改后的getView

 @Override
public View getView(final int position, View convertView, ViewGroup parent) {

    RelativeLayout view = (RelativeLayout) convertView;
    ViewHolder holder = null;

    if (view == null) {
        LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        view = (RelativeLayout) inflater.inflate(R.layout.exercise_set_item, parent, false);

        holder = new ViewHolder();
        holder.tvExerciseSetName = (TextView) view.findViewById(R.id.exerciseSetName);
        holder.tvExerciseSetDetails = (TextView) view.findViewById(R.id.exerciseSetDetails);
        holder.cbIsComplete = (CheckBox) view.findViewById(R.id.cbIsComplete);
        view.setTag(holder); 
    }else{
        holder = (ViewHolder) view.getTag();
    }

    if (exerciseSetList.get(position).getIsComplete() == 1) {
        holder.cbIsComplete.setChecked(true);
        isComplete = "1";
    }
    else {
        holder.cbIsComplete.setChecked(false);
        isComplete = "0";
    }

    holder.cbIsComplete.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
            if (isChecked) {
                exerciseSetList.get(position).setIsComplete(1);
                exerciseId = exerciseSetList.get(position).getExerciseId() + "";
                isComplete = "1";
            } else {
                exerciseSetList.get(position).setIsComplete(0);
                exerciseId = exerciseSetList.get(position).getExerciseId() + "";
                isComplete = "0";
            }
            new UpdateExerciseComplete().execute();
        }
    });

    holder.tvExerciseSetName.setText(exerciseSetList.get(position).getExerciseName());
    holder.tvExerciseSetDetails.setText(exerciseSetList.get(position).getExerciseDetails() + " id: " + exerciseSetList.get(position).getExerciseId());

    return view;
}

即使使用视图持有者，ListView项也无法正确删除/复制

2 个答案: