我在填写listview时遇到问题。我以为我相应地修改了我的XML和适配器，但显然没有。加载活动后，会弹出对话框，说明正在加载，然后应用程序强制关闭。如果我删除说明listview.setText（名称）的3行编码，那么它只是加载我的XML文件中的默认文本的所有项目。我的代码如下所示：
public class DisplayServiceActivity extends ListActivity {
private ListView listOfServices;
//JSONArrays?
JSONArray directory;
//JSON Node names
private static String TAG_ID = "id";
private static String TAG_NAME= "name";
private static String TAG_DIRECTORY = "Categories";
private final static String url= "API LINK HERE";
JSONObject json;
jsonParser jParser = new jsonParser();
ArrayList<HashMap<String, String>> directoryList;
@SuppressLint("NewApi")
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.service);
directoryList = new ArrayList<HashMap<String, String>>();
Request request = new Request();
request.execute();
listOfServices = getListView(); //get builtin listView
// Make sure we're running on Honeycomb or higher to use ActionBar APIs
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
// Show the Up button in the action bar.
getActionBar().setDisplayHomeAsUpEnabled(true);
setTitle("Home Service Categories");
}
}// end of onCreate Method
@SuppressWarnings("unused")
public class Request extends AsyncTask<String, Void, JSONObject> {
private static final int REGISTRATION_TIMEOUT = 3 * 1000;
private static final int WAIT_TIMEOUT = 30 * 1000;
private ProgressDialog dialog =
new ProgressDialog(DisplayServiceActivity.this);
protected void onPreExecute() {
dialog = new ProgressDialog(DisplayServiceActivity.this);
dialog.setMessage("Getting your info real quick... Please wait...");
dialog.show();
}
protected JSONObject doInBackground(String... params) {
json = jParser.getJSONfromURL(url);
return json;
}
protected void onPostExecute(JSONObject s) {
super.onPostExecute(s);
String name = null;
String id = null;
dialog.dismiss();
try {
directory = s.getJSONArray("Categories");
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
for(int i = 0; i< directory.length(); i++){;
try {
id = directory.getJSONObject(i).getString(TAG_ID);
name = directory.getJSONObject(i).getString(TAG_NAME);
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
displayCatList(id, name);
}
}
}
public void displayCatList(String id, String name){
//create new HashMap
HashMap<String,String> map = new HashMap<String, String>();
//add each child node to HashMap key
//map.put(TAG_ID, id);
map.put(TAG_NAME, name);
//adding HashList to ArrarList
directoryList.add(map);
// set Adapter for ListView here
ListAdapter adapter = new SimpleAdapter(this,
directoryList,
R.layout.list_item,
new String[] { name },
new int[] { android.R.id.text1});
LayoutInflater inflator = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View v = inflator.inflate(R.layout.list_item, null);
TextView listName = (TextView) v.findViewById(R.id.listName);
listName.setText(name);
setListAdapter(adapter);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
NavUtils.navigateUpFromSameTask(this);
return true;
}
return super.onOptionsItemSelected(item);
}
}
List_item.xml
<?xml version="1.0" encoding="utf-8"?>
<!-- Single List Item Design -->
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/listName"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:text="rubble rubble rubble"
android:textColor="#FFFFFF"
android:padding="10dip"
android:textSize="20dip"
android:textStyle="bold" >
</TextView>
的services.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:background="@drawable/gradient"
android:orientation="vertical" >
<ListView
android:id="@android:id/list"
android:layout_width="match_parent"
android:layout_height="match_parent" >
</ListView>
<TextView
android:id="@+id/listName"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:padding="10dip"
android:text="rubble rubble rubble"
android:textColor="#FFFFFF"
android:textSize="20dip"
android:textStyle="bold" >
</TextView>
</LinearLayout>
答案 0 :(得分：1)
//更改显示方法
public void displayCatList(String id, String name){
//create new HashMap
HashMap<String,String> map = new HashMap<String, String>();
//add each child node to HashMap key
//map.put(TAG_ID, id);
map.put(TAG_NAME, name);
//adding HashList to ArrarList
directoryList.add(map);
MySimpleAdapter adapter = new MySimpleAdapter(this, R.layout.list_item, android.R.id.text1, directoryList);
setListAdapter(adapter);
adapter.notifyDataSetChanged();
}
//在活动中添加folloowing类
public class MySimpleAdapter extends ArrayAdapter<HashMap<String, String>> {
List<HashMap<String, String>> listItems;
public MySimpleAdapter(Context context, int resource,
int textViewResourceId, List<HashMap<String, String>> objects) {
super(context, resource, textViewResourceId, objects);
listItems = objects;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
if(convertView == null) {
LayoutInflater inflator = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflator.inflate(R.layout.list_item, null);
}
TextView listName = (TextView) convertView.findViewById(R.id.listName);
listName.setText(listItems.get(position).get(TAG_NAME));
return convertView;
}
}
答案 1 :(得分：0)
您正在将视图设置为R.layout.service。但是在displayCatList中，你为listitem.xml中的一个视图调用了findViewById。这不起作用 - 它不在你看来。如果该文本视图应该在列表中，则需要在调用适配器的getView时进行设置。或者让simpleAdaptor为您完成。如果您不希望它成为行的一部分，则不要将其添加到listitem.xml
中答案 2 :(得分：0)
您的listName为空，因为TextView R.id.listName不在主布局中。要获得TextView的值，请执行以下操作： -
LayoutInflator li = getLayoutInflator();
View listItems = li.inflate(R.layout.list_item, null);
// set Adapter for ListView here
ListAdapter adapter = new SimpleAdapter(this,
directoryList,
listItems ,
new String[] { id,name },
new int[] { android.R.id.text1,android.R.id.text2 });
TextView listName = (TextView) listItems .findViewById(R.id.listName);
Log.e("XML Variable", name);
listName.setText(name);
这里我改变的是我在一个名为listItems的视图中夸大了R.layout.list_item，并用它来查找TextView listName。
希望这有帮助。
答案 3 :(得分：0)
在你的代码中，你首先调用asynck任务，它正在处理包括setAdapter for listview在内的所有内容，然后再调用带有directoryList的setAdapter，当你在异步任务之后初始化时，该目录是空白的。最好的解决方案是初始化你的directoryList关于asynctask调用。
directoryList = new ArrayList<HashMap<String, String>>();
Request request = new Request();
request.execute();
然后你的整个代码试试这个。我认为它会解决你的问题...... 我希望它有效。