Android 为什么我的ListActivity卡在/empty元素上?
Android 为什么我的ListActivity卡在/empty元素上?,android,listview,android-arrayadapter,listactivity,notifydatasetchanged,Android,Listview,Android Arrayadapter,Listactivity,Notifydatasetchanged,我正在尝试在我的Android应用程序上使用ListActivity,但它没有按应有的方式工作。 以下是我的活动: public class MainActivity extends ListActivity { public void onCreate(Bundle savedInstanceState){ super.onCreate(savedInstanceState); setContentView(R.layout.activity_term
我正在尝试在我的Android应用程序上使用ListActivity,但它没有按应有的方式工作。
以下是我的活动:
public class MainActivity extends ListActivity {
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_terminals_list); //The special layout
TerminalsArrayAdapter adapter = new TerminalsArrayAdapter(this); // A custom adapter
setListAdapter(adapter);
RequestTask task = new RequestTask(adapter); // An Async task
task.execute("/terminals/all");
}
}
这是我的布局:<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<ListView
android:id="@android:id/list"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
</ListView>
<TextView
android:id="@android:id/empty"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Loading..." />
</LinearLayout>
这是我的自定义适配器:
public class TerminalsArrayAdapter extends ArrayAdapter<String[]> {
private Activity mContext;
private ArrayList<String[]> mObjects = new ArrayList<String[]>();
public TerminalsArrayAdapter(Activity context) {
super(context, R.layout.terminals_listview_item);
this.mContext = context;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View elementView;
if(convertView==null){
LayoutInflater inflater = mContext.getLayoutInflater();
elementView = inflater.inflate(R.layout.terminals_listview_item, parent);
...
// Some things with my view
} else {
elementView = convertView;
}
...
// Some things with my view
return elementView;
}
public void updateTerminals(ArrayList<String[]> newObject){
mObjects.clear();
mObjects.addAll(newObject);
notifyDataSetChanged();
Log.d("TerminalsArrayAdapter", "Dataset Changed !");
}
}
public类TerminalsArrayAdapter扩展了ArrayAdapter{
私人活动mContext;
private ArrayList mObjects=new ArrayList();
公共终端阵列适配器(活动上下文){
超级(上下文、右布局、终端\列表视图\项目);
this.mContext=上下文;
}
@凌驾
公共视图getView(int位置、视图转换视图、视图组父视图){
视图元素视图;
if(convertView==null){
LayoutInflater充气器=mContext.getLayoutInflater();
elementView=充气机。充气(R.layout.terminals\u listview\u项目,父项);
...
//有些事情与我的观点一致
}否则{
elementView=convertView;
}
...
//有些事情与我的观点一致
返回元素视图;
}
public void updateTerminals(ArrayList newObject){
mObjects.clear();
mObjects.addAll(newObject);
notifyDataSetChanged();
d(“TerminalArrayAdapter”,“数据集已更改!”);
}
}
下面是我的异步任务:
public class RequestTask extends AsyncTask<String, Void, ArrayList<String[]>>{
private final TerminalsArrayAdapter mAdapter;
public RequestTask(TerminalsArrayAdapter adapter) {
mAdapter = adapter;
}
@Override
protected ArrayList<String[]> doInBackground(String... params) {
...
// retrieve some data from my server
return response;
}
@Override
protected void onPostExecute(ArrayList<String[]> response) {
Log.d("response_server","GOT IT !");
mAdapter.updateTerminals(response);
}
}
公共类RequestTask扩展了AsyncTask{
专用最终终端阵列适配器;
公共请求任务(TerminalArrayAdapter适配器){
mAdapter=适配器;
}
@凌驾
受保护的ArrayList doInBackground(字符串…参数){
...
//从我的服务器检索一些数据
返回响应;
}
@凌驾
受保护的void onPostExecute(ArrayList响应){
Log.d(“response_server”,“明白了!”);
mAdapter.updateTerminals(响应);
}
}
据我所知,仅当适配器不为空时才会显示ListView。如果为空,将显示文本视图。
这就是我的应用程序的工作方式:
我试图找出我的代码出了什么问题,但我没能找到。我很想听听你的建议/解决方案!谢谢
PS:请告诉我您是否需要任何东西来更好地理解我的问题。您的
列表视图
高度应该是match\u parent
尝试使用setVisibility(View.go)
和setVisibility(View.VISIBLE)
来:
- 显示文本视图&隐藏列表视图
- 显示列表视图和隐藏文本视图
公共类MainActivity扩展了ListActivity{
创建时的公共void(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_terminals_list);//特殊布局
//用特定的方法创建你的列表,以便能够多次给她打电话
//宁愿创建新数据,然后用新数据刷新
CreateList(Passanydata);
RequestTask任务=新的RequestTask(适配器);//异步任务
task.execute(“/terminals/all”);
}
}
公共void CreateList(ArrayList响应){
TerminalArrayAdapter=新的TerminalArrayAdapter(此,响应);//自定义适配器
setListAdapter(适配器);
}
@凌驾
受保护的void onPostExecute(ArrayList响应){
Log.d(“response_server”,“明白了!”);
//获得新数据后,将其传递到列表中
创建列表(响应);
}
公共类TerminalsArrayAdapter扩展了ArrayAdapter{
私人活动mContext;
private ArrayList mObjects=new ArrayList();
公共终端ArrayAdapter(活动上下文、ArrayList对象){
超级(上下文、右布局、终端\列表视图\项目);
this.mContext=上下文;
//当你有你的数据,它将能够使用它在这里
this.mObjects=对象;
}
@凌驾
公共视图getView(int位置、视图转换视图、视图组父视图){
视图元素视图;
if(convertView==null){
LayoutInflater充气器=mContext.getLayoutInflater();
elementView=充气机。充气(R.layout.terminals\u listview\u项目,父项);
...
//有些事情与我的观点一致
}否则{
elementView=convertView;
}
...
//有些事情与我的观点一致
返回元素视图;
}
}
|移除终端阵列适配器=新终端阵列适配器(此);//自定义适配器setListAdapter(适配器)代码>fom onCreate并将其放入onPostExecute。直接在onPostExecute中添加对象。从onPost | EExecute中删除mAdapter.updateTerminals(response)
。尝试在列表视图中使用invalidate方法查看此消息:嗨!您在哪里定义CreateList?在一个单独的文件中?如果是,它是什么类型的文件?CraeteList是MainActivity中的方法
public class MainActivity extends ListActivity {
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_terminals_list); //The special layout
// create your list with specific method to be able call her many time
// prefer to create then refresh with new data
CreateList(Passanydata);
RequestTask task = new RequestTask(adapter); // An Async task
task.execute("/terminals/all");
}
}
public void CreateList(ArrayList<String[]> response){
TerminalsArrayAdapter adapter = new TerminalsArrayAdapter(this,response); // A custom adapter
setListAdapter(adapter);
}
@Override
protected void onPostExecute(ArrayList<String[]> response) {
Log.d("response_server","GOT IT !");
// after you got your new data , pass it to your list
CreateList(response);
}
public class TerminalsArrayAdapter extends ArrayAdapter<String[]> {
private Activity mContext;
private ArrayList<String[]> mObjects = new ArrayList<String[]>();
public TerminalsArrayAdapter(Activity context,ArrayList<String[]> objects) {
super(context, R.layout.terminals_listview_item);
this.mContext = context;
// when you have your data it will be able to use it here
this.mObjects = objects;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View elementView;
if(convertView==null){
LayoutInflater inflater = mContext.getLayoutInflater();
elementView = inflater.inflate(R.layout.terminals_listview_item, parent);
...
// Some things with my view
} else {
elementView = convertView;
}
...
// Some things with my view
return elementView;
}
}