更新ArrayList <task>以反映对数据库的更改</task>

Question

我有一个ListView，其中每个项目都有一个SeekBar。

当我更新Seekbar的进度时，会将其写入数据库，以便在再次使用该应用程序时重新加载。

不幸的是，如果ListView向上或向下滚动以便任何项目从可见屏幕上消失，那么当重绘它们时，它们将使用旧值绘制。

如何在更新SeekBar时使活动“刷新”，以便ListView后面的值与数据库同步，这应该会停止使用陈旧数据重新绘制SeekBar。 / p>

更新

我已经解决了这个问题是由于底层的ArrayList没有被更新，所以当数据库被写入更新进度时，ArrayList处于与最初传递给构造函数时相同的状态。当我更新底层数据库时，如何重新填充ArrayList？

代码

@Override
public View getView(int position, View convertView, ViewGroup parent) {
View view = convertView;
try {
    if (view == null) {
    LayoutInflater vi = (LayoutInflater) mContext
        .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    view = vi.inflate(R.layout.task_list_item, null);
    }
    final Task t = mList.get(position);
    if (t != null) {

    /* assign layout elements */
    final SeekBar seekBar = (SeekBar) view.findViewById(R.id.seek);
    final TextView textViewDescription = (TextView) view
        .findViewById(R.id.task_description_text_view);
    final TextView textViewTaskId = (TextView) view
        .findViewById(fyp.proj.R.id.task_id_text_view);
    final TextView textViewTaskTitle = (TextView) view
        .findViewById(R.id.task_title_text_view);

    /* populate layout with task details */
    textViewTaskId.setText(String.valueOf(t.getTaskId()));
    textViewTaskTitle.setText(t.getTaskTitle());
    textViewDescription.setText(t.getTaskDesc());
    seekBar.setProgress(t.getProgress());
    seekBar.setTag(t.getTaskId());

    /* attach listener */
    attachProgressUpdatedListener(seekBar);

    }
} catch (Exception e) {
    Log.i(TaskAdapter.class.toString(), Log.getStackTraceString(e));
}
return view;
}

private void attachProgressUpdatedListener(SeekBar seekBar) {
seekBar.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {

    public void onStopTrackingTouch(SeekBar seekBar) {
    int progress = seekBar.getProgress();
    int task_id = (Integer) seekBar.getTag();

    // task handler instansiated with zero as parent project id is
    // not needed here.
    TaskHandler taskHandler = new TaskHandler(DBAdapter
        .getDBAdapterInstance(getContext()), 0);

    taskHandler.updateTaskProgress(task_id, progress);

    }

    public void onStartTrackingTouch(SeekBar seekBar) {
    // empty as onStartTrackingTouch listener not being used in
    // current implementation

    }

    public void onProgressChanged(SeekBar seekBar, int progress,
        boolean fromUser) {
    // empty as onProgressChanged listener not being used in
    // current implementation

    }
});

}

Answer 1

解决方案

根据slukian的评论，这个案例的答案是将新的进度值传递给底层的mList。这是解决方案。

private void attachProgressUpdatedListener(SeekBar seekBar,
    final int position) {

seekBar.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {

    public void onStopTrackingTouch(SeekBar seekBar) {
    int progress = seekBar.getProgress();
    int task_id = (Integer) seekBar.getTag();

    // task handler instansiated with zero as parent project id is
    // not needed here.
    TaskHandler taskHandler = new TaskHandler(DBAdapter
        .getDBAdapterInstance(getContext()), 0);

    taskHandler.updateTaskProgress(task_id, progress);

    // update underlying mList
    mList.get(position).setProgress(progress);

    }

    public void onStartTrackingTouch(SeekBar seekBar) {
    // empty as onStartTrackingTouch listener not being used in
    // current implementation

    }

    public void onProgressChanged(SeekBar seekBar, int progress,
        boolean fromUser) {
    // empty as onProgressChanged listener not being used in
    // current implementation

    }
});

}

为attachProgressUpdatedListener方法添加了位置。 检索传递位置的ArrayList中的项目并更新progress属性。