2
我试图创建一个具有多种类型的视图的ListView适配器。我下面的下面的教程：Android ListView - 奇怪的回收行为
http://android.amberfog.com/?p=296
然而，第一轮建设下面的代码后：
public class MultipleItemList extends Activity
{
private MyCustomAdapter mAdapter;
private ListView mListView;
private String mTag = "MultipleItemList";
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mListView = (ListView)findViewById(R.id.main_list);
mAdapter = new MyCustomAdapter();
for(int i = 0; i < 50; i++)
{
mAdapter.addItem("Item: " + i);
}
mListView.setAdapter(mAdapter);
}
private class MyCustomAdapter extends BaseAdapter
{
private ArrayList<String> mData = new ArrayList<String>();
private LayoutInflater mInflater;
public MyCustomAdapter()
{
mInflater = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
public void addItem(final String item)
{
mData.add(item);
notifyDataSetChanged();
}
public int getCount()
{
return mData.size();
}
public String getItem(int position)
{
return mData.get(position);
}
public long getItemId(int position)
{
return position;
}
public View getView(int position, View convertView, ViewGroup parent)
{
Log.e(mTag, "getView: " + position + " " + convertView);
ViewHolder holder = null;
if(convertView == null)
{
convertView = mInflater.inflate(R.layout.list_item, null);
holder = new ViewHolder();
holder.textView = (TextView)convertView.findViewById(R.id.item_text);
convertView.setTag(holder);
}
else
{
holder = (ViewHolder)convertView.getTag();
}
holder.textView.setText(mData.get(position));
return convertView;
}
}
public static class ViewHolder
{
public TextView textView;
}
}
凡的main.xml是：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<ListView
android:id="@+id/main_list"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
</ListView>
</LinearLayout>
而list_item.xml是：
<?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/item_text"
android:layout_width="fill_parent"
android:layout_height="50dp"
android:text="TextView"
android:gravity="center_vertical"
android:paddingLeft="25dp"/>
</LinearLayout>
我期望的输出类似于他的预期输出：
02-05 13:47:32.559: INFO/System.out(947): getView 0 null
02-05 13:47:32.570: INFO/System.out(947): getView 1 null
02-05 13:47:32.589: INFO/System.out(947): getView 2 null
02-05 13:47:32.599: INFO/System.out(947): getView 3 null
02-05 13:47:32.619: INFO/System.out(947): getView 4 null
02-05 13:47:32.629: INFO/System.out(947): getView 5 null
02-05 13:47:32.708: INFO/System.out(947): getView 6 null
02-05 13:47:32.719: INFO/System.out(947): getView 7 null
02-05 13:47:32.729: INFO/System.out(947): getView 8 null
而是没有用户交互，只需加载屏幕，我得到以下几点：
05-09 15:24:00.347: E/MultipleItemList(11109): getView: 0 null
05-09 15:24:00.357: E/MultipleItemList(11109): getView: 1 [email protected]
05-09 15:24:00.357: E/MultipleItemList(11109): getView: 2 [email protected]
05-09 15:24:00.357: E/MultipleItemList(11109): getView: 3 [email protected]
05-09 15:24:00.357: E/MultipleItemList(11109): getView: 4 [email protected]
05-09 15:24:00.357: E/MultipleItemList(11109): getView: 5 [email protected]
05-09 15:24:00.367: E/MultipleItemList(11109): getView: 6 [email protected]
05-09 15:24:00.367: E/MultipleItemList(11109): getView: 7 [email protected]
05-09 15:24:00.367: E/MultipleItemList(11109): getView: 8 [email protected]
05-09 15:24:00.367: E/MultipleItemList(11109): getView: 9 [email protected]
05-09 15:24:00.407: E/MultipleItemList(11109): getView: 0 [email protected]
05-09 15:24:00.407: E/MultipleItemList(11109): getView: 1 null
05-09 15:24:00.407: E/MultipleItemList(11109): getView: 2 null
05-09 15:24:00.417: E/MultipleItemList(11109): getView: 3 null
05-09 15:24:00.417: E/MultipleItemList(11109): getView: 4 null
05-09 15:24:00.417: E/MultipleItemList(11109): getView: 5 null
05-09 15:24:00.427: E/MultipleItemList(11109): getView: 6 null
05-09 15:24:00.427: E/MultipleItemList(11109): getView: 7 null
05-09 15:24:00.437: E/MultipleItemList(11109): getView: 8 null
05-09 15:24:00.437: E/MultipleItemList(11109): getView: 9 null
05-09 15:24:00.457: E/MultipleItemList(11109): getView: 0 null
05-09 15:24:00.457: E/MultipleItemList(11109): getView: 1 [email protected]
05-09 15:24:00.457: E/MultipleItemList(11109): getView: 2 [email protected]
05-09 15:24:00.457: E/MultipleItemList(11109): getView: 3 [email protected]
05-09 15:24:00.457: E/MultipleItemList(11109): getView: 4 [email protected]
05-09 15:24:00.457: E/MultipleItemList(11109): getView: 5 [email protected]
05-09 15:24:00.467: E/MultipleItemList(11109): getView: 6 [email protected]
05-09 15:24:00.467: E/MultipleItemList(11109): getView: 7 [email protected]
05-09 15:24:00.467: E/MultipleItemList(11109): getView: 8 [email protected]
05-09 15:24:00.467: E/MultipleItemList(11109): getView: 9 [email protected]
为什么地球上有很多工作要呈现列表中的前10个项目？发生
我可以在代码和教程中的代码之间看到的唯一真正区别是本教程使用“ListActivity”而不是“Activity”。 “Activity”和“ListActivity”中的ListView行为之间可能存在细微的差异。如果你完全按照教程做，你会得到相同的结果吗？ – Louth
@Louth：我不确定。我不打算在我的应用程序中使用ListActivity，所以我不知道这太值得探索了。我认为不管ListActivity“活着”在哪里，行为都不应该偏离。 – Josh
可能的重复：http://stackoverflow.com/questions/2618272/custom-listview-adapter-getview-method-being-called-multiple-times-and-in-no-co –