安卓：ListView控件不刷新的notifyDataSetChanged（）; [英] Android: ListView not refreshing on notifyDataSetChanged();
问题描述
我有一个自定义的BaseAdapter和主要活动的Add按钮。该按钮会打开一个文本框，一个对话框，您可以添加新的元素列表的方式。现在的问题是，该清单是不是令人耳目一新。在onActivityResult（）函数，我打印列表中的元素的每一次我在对话框中的数量增加点击OK的数量和，所以我知道它只是不工作的清爽。我BaseAdapter和我的活动：
I've got a custom BaseAdapter and an add button in the main activity. The button opens a dialog with a textbox and you can add new elements to the list that way. The problem is that the list is not refreshing. In the onActivityResult() function I print the number of elements in the list and each time I hit OK in the dialog box the number increases, so I know it's just the refreshing that doesn't work. My BaseAdapter and my activity:
class ListaOrase extends BaseAdapter{
private Activity context;
ArrayList<String> orase;
public ListaOrase(Activity context){
this.context=context;
orase=new ArrayList<String>();
}
public void add(String string){
orase.add(string);
this.notifyDataSetChanged();
}
public View getView (int position, View convertView, ViewGroup list) {
View element;
if (convertView == null)
{
LayoutInflater inflater = context.getLayoutInflater();
element = inflater.inflate(R.layout.lista, null);
}
else element = convertView;
TextView elementLista=(TextView)element.findViewById(R.id.elementLista);
elementLista.setText(orase.get(position));
return element;
}
}
public class WeatherAppActivity extends ListActivity {
Button buton;
ListaOrase lista;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
lista=new ListaOrase(this);
buton=(Button)findViewById(R.id.buton);
lista.add("Bucuresti");
lista.add("Sibiu");
setListAdapter(lista);
}
public void add(View view){
Intent intent=new Intent();
intent.setClass(this, Adauga.class);
startActivityForResult(intent, 0);
}
public void onActivityResult (int requestCode, int responseCode, Intent data){
System.out.println("Apelata");
if(responseCode==1){
lista.add(data.getStringExtra("oras")); // e chiar getText()
System.out.println(lista.getCount());
lista.notifyDataSetChanged();
}
}
}
正如你所看到的，我想刷新（notifyDataSetChanged（）;）两个加时，一个新的元素（在BaseAdapter扩展类）和方法onActivityResult，该对话框通过该新元素的主要活动后。我再说一遍，元素被添加到列表中，因为数量的增加，它只是不刷新。
As you can see, I'm trying to refresh (notifyDataSetChanged();) both when adding a new element (in the BaseAdapter extending class) and in method onActivityResult, after the dialog passes the new element to the main Activity. I repeat, the element IS added to the list because the count increases, it just doesn't refresh.
谢谢您的回答！
推荐答案
这是正常的，它不刷新，您要添加到LISTA但适配器，保留自己的单各一份，所以也设置项目再次列表中的适配器，然后调用notifyDataChanged或者新的项目添加到适配器。
It's normal that it doesn't refresh, you are adding an item to "lista" but the adapter keeps its own copy of that list, so or you set again the list in the adapter and then you call notifyDataChanged or you add the new item to the adapter.
反正我看到几个奇怪的事情，我的事情你可以使用一个数组适配器semplify一切，你并不需要实现添加，等等。我写了一些code simplyfing你：
Anyway I see couple of weird things, I thing you could semplify everything using an array adapter, you don't need to implement add,etc. I wrote some code simplyfing yours:
public class WeatherAppActivity extends ListActivity {
Button buton;
ItemsAdapter lista;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
List<String> initialList = new ArrayList<String>();
initialList.add("Bucuresti");
initialList.add("Sibiu");
lista=new ItemsAdapter(this, initialList);
buton=(Button)findViewById(R.id.button1);
buton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
lista.add(""+System.currentTimeMillis()); // e chiar getText()
lista.notifyDataSetChanged();
}
});
setListAdapter(lista);
}
class ItemsAdapter extends ArrayAdapter<String> {
public ItemsAdapter(Context context, List<String> list) {
super(context, R.layout.lista, list);
}
@Override
public View getView(final int position, View row, final ViewGroup parent) {
final String item = getItem(position);
ItemWrapper wrapper = null;
if (row == null) {
row = getLayoutInflater().inflate(R.layout.lista, parent, false);
wrapper = new ItemWrapper(row);
row.setTag(wrapper);
} else {
wrapper = (ItemWrapper) row.getTag();
}
wrapper.refreshData(item);
return row;
}
class ItemWrapper {
TextView text;
public ItemWrapper(View row) {
text = (TextView) row.findViewById(R.id.elementLista);
}
public void refreshData(String item) {
text.setText(item);
}
}
}
}
这些都是我所使用的XML：
These are the xml that I have used:
main.xml中
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:layout_marginBottom="63dp"
android:text="Button" />
<ListView
android:id="@id/android:list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true" >
</ListView>
</RelativeLayout>
lista.xml
lista.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/elementLista"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Medium Text"
android:textAppearance="?android:attr/textAppearanceMedium" />
</LinearLayout>
这是适配器的使用baseadapter版本：
This is the version of the adapter using a baseadapter:
class ItemsBaseAdapter extends BaseAdapter {
private List<String> items;
private Context mContext;
public ItemsBaseAdapter(Context context, List<String> list) {
items = list;
mContext = context;
}
public void addItem(String str) {
items.add(str);
}
@Override
public View getView(final int position, View row, final ViewGroup parent) {
final String item = (String) getItem(position);
ItemWrapper wrapper = null;
if (row == null) {
row = getLayoutInflater().inflate(R.layout.lista, parent, false);
wrapper = new ItemWrapper(row);
row.setTag(wrapper);
} else {
wrapper = (ItemWrapper) row.getTag();
}
wrapper.refreshData(item);
return row;
}
class ItemWrapper {
TextView text;
public ItemWrapper(View row) {
text = (TextView) row.findViewById(R.id.elementLista);
}
public void refreshData(String item) {
text.setText(item);
}
}
@Override
public int getCount() {
return items.size();
}
@Override
public Object getItem(int position) {
return items.get(position);
}
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return 0;
}
}
这是列表项的版本还至极包括左边的ImageView的：
And this is the version of the list item wich also include an imageview on the left:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal" >
<ImageView
android:layout_height="wrap_content"
android:src="@android:drawable/btn_star_big_on"
android:scaleType="fitCenter"
android:layout_width="wrap_content"
/>
<TextView
android:id="@+id/elementLista"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Medium Text"
android:textAppearance="?android:attr/textAppearanceMedium"
/>
</LinearLayout>
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