Question

我使用listview显示下载列表的进度。我通过在处理程序中调用notifyDataSetChanged来使用线程来每秒更新进度。一切正常，直到我尝试使用setOnItemClickListener来获取列表中单击的项目。当更新线程运行时，onItemClick的结果是不可预测的，我点击列表中的第一项但是onItemClick的结果显示我点击了第二个。我认为这是因为点击项目时数据会发生变化，但我该如何防止呢？我试图在单击项时将isListItemBeenClicked标志设置为true，并且当isListItemBeenClicked为false时更新线程仅调用notifyDataSetChanged，但它不起作用。任何人都可以帮我吗？

PS：对不起我的蹩脚英语

代码：

1.Refresh handler

    listViewRefreshHandler = new Handler() {
        @Override
        public void handleMessage(Message msg){
            if(!isListItemBeenClicked){
                System.out.println("start refresh");
                downloadingTaskList.clear();
                uploadingTaskList.clear();
                completedTaskList.clear();
                downloadingTaskList.addAll(transferService.getDownloadingTaskList());
                uploadingTaskList.addAll(transferService.getUploadingTaskList());
                completedTaskList.addAll(transferService.getCompletedTaskList());
                Collections.sort(completedTaskList, new Comparator<TransferTask>(){
                    @Override
                    public int compare(TransferTask transferTask1, TransferTask transferTask2) {
                        int ret=0;
                        long result=transferTask2.getCompletedDate().getTime()-transferTask1.getCompletedDate().getTime();
                        if(result==0){
                            ret=0;
                        }else if(result>0){
                            ret=1;
                        }else{
                            ret=-1;
                        }
                        return ret;
                    }

                });
                downloadingTaskListAdapter.notifyDataSetChanged();
                completedTaskListAdapter.notifyDataSetChanged();
                uploadingTaskListAdapter.notifyDataSetChanged();
                System.out.println("refresh end");
            }
        }
    };

2.OnItemClickListener

        list.setOnItemClickListener(new OnItemClickListener(){
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            isListItemBeenClicked=true;
            System.out.println("click start");
            TransferTask downloadTask=(TransferTask)view.getTag();
            System.out.println("click "+downloadTask.getFileName());
            System.out.println("click end");
            isListItemBeenClicked=false;

        }
    });

3.更新线程

        new Thread() {
        public void run() {
            while (!isStop) {
                try {
                    Thread.sleep(1000);
                    listViewRefreshHandler.sendEmptyMessage(1);
                } catch (Exception ex) {
                    ex.printStackTrace();
                }
            }
        }
    }.start();

4.TransferTaskListAdapter

public class TransferTaskListAdapter extends BaseAdapter {   

    private Context context;   
    private List<TransferTask> transeferTaskList;

    public TransferTaskListAdapter(Context context, List<TransferTask> downloadTaskList ) {    
        this.context = context;   
        this.transeferTaskList = downloadTaskList;   
    }   

    public int getCount() {                           
        return transeferTaskList.size();   
    }   

    public TransferTask getItem(int position) {        
        return transeferTaskList.get(position);   
    }   

    public long getItemId(int position) {     
        return position;   
    }   
    public View getView(int position, View convertView, ViewGroup parent) {
        System.out.println("get view called");
        TransferTask transferTask=getItem(position);
        if(convertView==null){
            convertView= LayoutInflater.from(context).inflate(R.layout.transfering_task, null);
        }
        convertView.setTag(transferTask);
        ImageView taskStatusImageView=(ImageView)convertView.findViewById(R.id.taskStatus);
        TransferTaskStatus tastStatus=transferTask.getStatus();
        switch(tastStatus){
            case DOWNLOADING:
                taskStatusImageView.setImageResource(R.drawable.icon_status_download);
                break;
            case UPLOADING:
                taskStatusImageView.setImageResource(R.drawable.icon_status_upload);
                break;
            case PAUSED :
                taskStatusImageView.setImageResource(R.drawable.icon_status_paused);
                break;
            case COMPLETED:
                if(transferTask.getType().equals(TaskType.DONWLOAD)){
                    taskStatusImageView.setImageResource(R.drawable.icon_status_download);
                }else{
                    taskStatusImageView.setImageResource(R.drawable.icon_status_upload);
                }

                break;
            case WAITING:
                taskStatusImageView.setImageResource(R.drawable.icon_status_waiting);
                break;
            case STARTING:
                taskStatusImageView.setImageResource(R.drawable.icon_status_waiting);
                break;
            case STOPPING:
                taskStatusImageView.setImageResource(R.drawable.icon_status_waiting);
                break;
            default:
                taskStatusImageView.setImageResource(R.drawable.icon_status_failed);
        }

        String fileName=transferTask.getFileName();
        TextView fileNameTextView=(TextView)convertView.findViewById(R.id.fileName);
        fileNameTextView.setText(fileName);

        long size=transferTask.getSize();
        long transferedSize=transferTask.getTransferedSize();
        FileTransferProgressBar progressBar=(FileTransferProgressBar)convertView.findViewById(R.id.downloadProgress);
        progressBar.setTotalFileSize(size);
        progressBar.setTransferedFileSize(transferedSize);
        System.out.println("get view end");
        return convertView;   
    }   

}

Answer 1

尝试使用以下内容：

TransferTask downloadTask = (TransferTask)parent.getItemAtPosition(position);

而不是你当前的：

TransferTask downloadTask=(TransferTask)view.getTag();

调用adapter.notifyDataSetChanged时，ListView setOnItemClickListener获取错误的项目

1 个答案: