我正在尝试使用Fragment,ViewPager和co。来自Android支持库v4。当我从寻呼机听页面更改事件时,片段似乎在滚动,但是内容不可见。我基本上拥有的是:
FragmentActivity:
public class MyActivity extends FragmentActivity
{
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
FragmentPagerAdapter fpa = new MyPagerAdapter(this, createFragments());
ViewPager vp = (ViewPager) findViewById(R.id.pager);
vp.setAdapter(fpa);
}
private List<Fragment> createFragments() {
List<Fragment> list = new ArrayList<Fragment>();
list.add(Fragment.instantiate(this, First.class.getName()));
list.add(Fragment.instantiate(this, Second.class.getName()));
list.add(Fragment.instantiate(this, Third.class.getName()));
return list;
}
@Override
protected void onSaveInstanceState(Bundle outState) {
}
FragmentPagerAdapter:
public class MyPagerAdapter extends FragmentPagerAdapter {
private List<Fragment> fragments;
public MyPagerAdapter(FragmentActivity activity, List<Fragment> fragments) {
super(activity.getSupportFragmentManager());
this.fragments = fragments;
}
@Override
public Fragment getItem(int i) {
return fragments.get(i);
}
@Override
public int getCount() {
return fragments.size();
}
@Override
public boolean isViewFromObject(View view, Object o) {
return view.equals(o);
}
}
还有三个看起来像这样的片段:
public class First extends Fragment {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.first, container, false);
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
}
}
它们具有如下布局:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView android:layout_height="fill_parent"
android:layout_width="fill_parent"
android:text="First Fragment"
android:id="@+id/firstText"/>
</LinearLayout>
我最初忘了添加主要布局,它来了:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<android.support.v4.view.ViewPager
android:id="@+id/pager"
android:layout_height="wrap_content"
android:layout_weight="1"
android:layout_width="fill_parent"/>
</LinearLayout>
如果有人可以告诉我我在做什么错,我将不胜感激。
最佳答案
这是因为您已在isViewFromObject
中覆盖了MyPagerAdapter
。FragmentPagerAdapter
处理isViewFromObject
,因此您不应覆盖它。
和我一样,我认为这篇文章的大多数访问者都是从基本的PagerAdapter
开始的,然后意识到他们需要分页片段并更改基类,而没有意识到后果。不幸的是,但是我不能为此批评Android团队。
关于android - 带有FragmentPagerAdapter的ViewPager不显示内容,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/9567741/