Question

我正在加载日志数据。它运行顺利。但是，我在工具栏下面添加了一个不确定的进度条，每次调用Asynctask时都会显示。

当数据加载速度如此之快时，是否可以避免显示？
这是推荐thread.sleep吗？
或者甚至不需要加载500及以上记录的进度条？

这是我的代码：

public void refreshList(String status) {
    String id = String.valueOf(getArguments().getInt("ID"));

    String paramsValue[] = new String[2];
    paramsValue[0] = id;
    paramsValue[1] = status;
    new LogsTask(this).execute(paramsValue);

}

private static class LogsTask extends AsyncTask<String[], Integer, LinkedHashMap<Integer, ValuesExtension>> {
    String paramsValue[];

    LogsFragment logsFragment;
    WeakReference<LogsFragment> fragmentWeakReference;

    LogsTask(LogsFragment logsFragment) {
        fragmentWeakReference = new WeakReference<>(logsFragment);
    }


    @Override
    protected void onPreExecute() {
        logsFragment = fragmentWeakReference.get();
        logsFragment.pbLogs.setVisibility(View.VISIBLE);    
    }

    @Override
    protected LinkedHashMap<Integer, ValuesExtension> doInBackground(String[]... params) {
        Cursor dbReader = null;

        DBHelper dbHelper = new DBHelper(logsFragment.getContext());
        LinkedHashMap<Integer, ValuesExtension> logsMap = new LinkedHashMap<>();

        try {              
            dbHelper.open();

            if (dbReader.getCount() > 0) {
                while (dbReader.moveToNext()) {
                    try {
                        /* LOADING OF DATA */
                        logsMap.put("values", value);

                        Thread.sleep(250); // is this important when loading data?
                    } catch (InterruptedException | ParseException e) {
                        e.printStackTrace();
                    }
                }
            }
        } catch (SQLException e) {
            return null;
        } finally {
            if (dbReader != null) {
                dbReader.close();
            }
            dbHelper.close();
        }
        return logsMap;
    }


    @Override
    protected void onPostExecute(LinkedHashMap<Integer, ValuesExtension> logsMap) {           
        logsFragment.pbLogs.setVisibility(View.GONE);

        if (logsMap != null) {
            logsFragment.refreshLog();
        }

    }
}

Answer 1

作为一种解决方法，您可以将进度条的开始延迟300毫秒，具体取决于数据的加载速度

private boolean completed = false;
@Override
    protected void onPreExecute() {
        logsFragment = fragmentWeakReference.get();
        //below code won't display progress if your task completes within 300 ms and longer tasks it will be shown after 300 ms
        logsFragment.pbLogs.postDelayed(new Runnable(){
          @Override
          public void run(){
               if(!completed)
               logsFragment.pbLogs.setVisibility(View.VISIBLE);  
         }, 300);  
    }

 @Override
    protected void onPostExecute(LinkedHashMap<Integer, ValuesExtension> logsMap) {      
        completed = true;     
        logsFragment.pbLogs.setVisibility(View.GONE);

        if (logsMap != null) {
            logsFragment.refreshLog();
        }

    }

如何使用asynctask处理数据加载

1 个答案: