Android ListView项目不会加载到屏幕上
用例如下所示: 我想在ViewPager中加载一个ListView,同时在列表上设置一个ListView监听器 有人能告诉我为什么ListView没有加载,即屏幕一直是黑色的吗。连传呼机上的带子都不起作用 布局: 一些代码:Android ListView项目不会加载到屏幕上,android,android-layout,listview,Android,Android Layout,Listview,用例如下所示: 我想在ViewPager中加载一个ListView,同时在列表上设置一个ListView监听器 有人能告诉我为什么ListView没有加载,即屏幕一直是黑色的吗。连传呼机上的带子都不起作用 布局: 一些代码: public static class HeaderFragment extends ListFragment { List<Message> messages = new ArrayList<Message>(); String
public static class HeaderFragment extends ListFragment {
List<Message> messages = new ArrayList<Message>();
String topic;
public HeaderFragment(List<Message> messages, String topic) {
this.messages = messages;
this.topic = topic;
}
public HeaderFragment() {
// TODO Auto-generated constructor stub
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.submain, container, false);
final ListView listView = (ListView) v.findViewById(android.R.id.list);
final MessageItemAdapter adapter = new MessageItemAdapter(inflater,
R.layout.headers, messages, 1);
//the click listener.
listView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
Message message = adapter.getItem(position);
Intent intent = new Intent();
intent.setClassName(
"main",
"NewsActivity");
intent.putExtra("title", message.getTitle());
intent.putExtra("description", message.getDescription());
intent.putExtra("source", message.getLink().toString());
intent.putExtra("language", location);
startActivity(intent);
}
});
listView.setAdapter(adapter);
return v;
}
提前感谢
编辑:
调用片段的代码:
public class HeadersActivityPagerAdapter extends FragmentStatePagerAdapter {
public HeadersActivityPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int i) {
int k = 0;
String topic = null;
List<Message> messages = new ArrayList<Message>();
for (Entry<String, List<Message>> elem : fragmentsData.entrySet()) {
if (k==i)
{
topic = elem.getKey();
messages = elem.getValue();
break;
}
k++;
}
return new HeaderFragment(messages, topic);
}
@Override
public int getCount() {
return fragmentsData.size();
}
@Override
public CharSequence getPageTitle(int position) {
int k = 0;
String topic = "";
for (Entry<String, List<Message>> elem : fragmentsData.entrySet()) {
if (k==position)
{
topic = elem.getKey();
break;
}
k++;
}
return topic;
}
}
它是这样工作的,但我失去了ListView的侦听器:
main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center_horizontal"
android:orientation="vertical"
android:padding="4dip" >
<android.support.v4.view.ViewPager
android:id="@+id/pager"
android:layout_width="match_parent"
android:layout_height="0px"
android:layout_weight="1" >
<android.support.v4.view.PagerTitleStrip
android:id="@+id/pager_title_strip"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="top"
android:background="#33b5e5"
android:paddingBottom="4dp"
android:paddingTop="4dp"
android:textColor="#fff" />
</android.support.v4.view.ViewPager>
submin.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" >
<FrameLayout
android:layout_width="match_parent"
android:layout_height="0dip"
android:layout_weight="1" >
<ListView
android:id="@android:id/list"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:drawSelectorOnTop="false" />
</FrameLayout>
一些代码:
public static class HeaderFragment extends ListFragment {
List<Message> messages = new ArrayList<Message>();
String topic;
public HeaderFragment(List<Message> messages, String topic) {
this.messages = messages;
this.topic = topic;
}
public HeaderFragment() {
// TODO Auto-generated constructor stub
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.submain, container, false);
final ListView listView = (ListView) v.findViewById(android.R.id.list);
final MessageItemAdapter adapter = new MessageItemAdapter(inflater,
R.layout.headers, messages, 1);
//the click listener.
listView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
Message message = adapter.getItem(position);
Intent intent = new Intent();
intent.setClassName(
"main",
"NewsActivity");
intent.putExtra("title", message.getTitle());
intent.putExtra("description", message.getDescription());
intent.putExtra("source", message.getLink().toString());
intent.putExtra("language", location);
startActivity(intent);
}
});
listView.setAdapter(adapter);
return v;
}
问题是我失去了我的倾听者,不会触发。
我找到的解决方案让我的应用程序慢了很多
我将侦听器放置在适配器内,用于每个项目。您的ViewPager设置为高度0px。给它一个更大的高度,你应该能够看到它。也许:
<android.support.v4.view.ViewPager
android:id="@+id/pager"
android:layout_width="match_parent"
android:layout_height="match_parent" >
编辑:
显示创建此片段并将其添加到屏幕的代码。还要将一些日志记录添加到此构造函数:
public HeaderFragment(List<Message> messages, String topic) {
this.messages = messages;
Log.i("TAG", "messages size: " + this.messages.size(); // <- add this
this.topic = topic;
}
确保消息在传递到此处时包含某些项。此片段从不向消息中添加任何项,因此,如果在创建片段时它没有任何项,则不会在ListView中显示任何项。问题仍然存在。显示条带,但ListView不显示任何数据…将代码发布到创建片段的位置,然后查看我的编辑。消息不是空的,这是肯定的。这是肯定的。你怎么能肯定?您没有将其记录到任何地方。因为此代码已重构,并且我在2分钟前已对此进行了调试。因为您在ViewPager中有它,所以我假设您在其中显示了其他内容。这些东西能正常显示吗?另外,请发布MessageItemAdapter类的代码。
public HeaderFragment(List<Message> messages, String topic) {
this.messages = messages;
Log.i("TAG", "messages size: " + this.messages.size(); // <- add this
this.topic = topic;
}