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[英]ListView with customAdapter not updated when notifyDataSetChanged is called?
[英]My listview is not being updated even after calling notifydatasetchanged()
我不知道為什么,但是我的列表視圖沒有更新...我在調用notifyDataSetChanged(),並且在他們要求這樣做的地方也嘗試了另一個答案:
private void editTransaction(int position) {
h = historyItems.get(position);
historyItems.remove(position);
this.position = position;
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == 5 && resultCode == RESULT_OK) {
String description = data.getStringExtra("description");
if (description == null) description = "no description";
double amount = Double.parseDouble(data.getStringExtra("amount"));
h.setDescription(description);
h.setAmount(amount);
//h.setTimestamp(System.currentTimeMillis());
//this is where I am updating my arraylist....
historyItems.add(position,h);
adapter.notifyDataSetChanged();
user.makeEdit(h);
}
}
這是在我的自定義適配器中。
public class HistoryCustomAdapter extends BaseAdapter {
Context context;
ArrayList<HistoryItem> historyItems;
HashMap<String,String> iconMapper;
private static LayoutInflater inflater=null;
public HistoryCustomAdapter(Context context, ArrayList<HistoryItem> historyItems, HashMap<String, String> iconMapper) {
this.context=context;
this.historyItems=historyItems;
this.iconMapper=iconMapper;
inflater = ( LayoutInflater )context.
getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
@Override
public int getCount() {
return historyItems != null ? historyItems.size() : 0;
}
@Override
public Object getItem(int position) {
return historyItems.get(position);
}
@Override
public long getItemId(int position) {
return 0;
}
@Override
@Override
public View getView(int position, View convertView, ViewGroup parent) {
Holder holder;
if (convertView == null) {
holder = new Holder();
LayoutInflater vi = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = vi.inflate(R.layout.history_item, parent, false);
holder.tvCat = (TextView)convertView.findViewById(R.id.tv_category);
holder.tvAmt = (TextView)convertView.findViewById(R.id.tv_amount);
holder.tvDate = (TextView)convertView.findViewById(R.id.tv_date);
holder.img = (ImageView)convertView.findViewById(R.id.iv);
convertView.setTag(holder);
}
holder=(Holder)convertView.getTag();
HistoryItem historyItem;
historyItem = historyItems.get(position);
holder.tvCat.setText(historyItem.getCategory());
holder.tvAmt.setText(historyItem.getAmount()+"");
DateFormat df = new SimpleDateFormat("yyyy/MM/dd kk:mm:ss");
Calendar c = Calendar.getInstance();
c.setTimeInMillis(historyItem.getTimestamp());
Date day = c.getTime();
holder.tvDate.setText(df.format(day));
Resources res = context.getResources();
String mDrawableName = iconMapper.get(historyItem.getCategory());
int resID = res.getIdentifier(mDrawableName , "drawable", context.getPackageName());
holder.img.setImageResource(resID);
return convertView;
}
public void refresh(ArrayList<HistoryItem> historyItems)
{
this.historyItems.clear();
this.historyItems.addAll(historyItems);
//notifyDataSetChanged();
}
public class Holder
{
TextView tvCat,tvAmt,tvDate;
ImageView img;
}
}
我不知道為什么我的列表視圖沒有立即更新...我應該切換到ArrayAdapters嗎?
嘗試先清除this.historyItems
然后清除this.historyItems.addAll(historyItems)
。 希望它能起作用!
無論如何,如果您嘗試使用ViewHolder Pattern,則應該重用它:
if (rowView == null) {
// init view, holder
rowView.setTag(holder)
} else {
holder = (Holder) rowView.getTag();
}
// fill data
也許這就是您的列表視圖沒有立即反映出來的原因。
當您向this.historyItems
分配新的ArrayList時,將不再通知數據,因為您丟失了對最初指定的Arraylist的引用。
如果希望該方法起作用,則需要重寫getCount
和getItem
。
但是你還需要
this.historyItems.clear();
this.historyItems.addAll(historyItems);
或者,如果使用ArrayAdapter,則不需要將列表作為成員變量
clear();
addAll(historyItems);
然后,notifyDatasetChanged應該工作
在調用adapter.notifyDataSetChanged();
之前嘗試.setAdapter(adapter)
adapter.notifyDataSetChanged();
請檢查此方法
public void refresh(ArrayList<HistoryItem> historyitems)
{
this.historyItems=historyitems;
notifyDataSetChanged();
}
做這個。 會工作的
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