Thursday, February 16, 2012

Stop Android SeekBar resetting


I have a ListView in which each item has a SeekBar.



When I update the progress of the Seekbar this is written to a database so it can be reloaded when the application is used again.



Unfortunately if the ListView is scrolled up or down so that any of the items disappear from the visible screen, when they are redrawn they are drawn with the old value.



How do I get the activity to "refresh" when the SeekBar is updated so the values behind the ListView are in sync with the database, this should stop the SeekBar being redrawn with stale data.




@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

}
});

}

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