我有一个应用程序使用ActionBarSherlock,在主fragment中有一个ViewPager,它使用多个fragment来显示列表中不同对象。
主Fragment:
public class CollectionDemoFragment extends SherlockFragment {
DemoCollectionPagerAdapter mDemoCollectionPagerAdapter;
ViewPager mViewPager;
public CollectionDemoFragment() {
setTitle(R.string.title);
setHasOptionsMenu(true);
}
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.demo_fragment, container, false);
mDemoCollectionPagerAdapter = new DemoCollectionPagerAdapter(getFragmentManager());
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mDemoCollectionPagerAdapter);
return view;
}
@Override
public void onPause() {
//This runs when the fragment goes to backstack
super.onPause();
}
@Override
public void onResume() {
//This runs when the fragment returns from backstack
super.onResume();
}
}
ViewPagerAdapter:
public class DemoCollectionPagerAdapter extends
FragmentStatePagerAdapter {
public DemoCollectionPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int i) {
Fragment fragment = new DemoObjectFragment();
Bundle args = new Bundle();
args.putInt(DemoObjectFragment.ARG_OBJECT, i + 1);
fragment.setArguments(args);
return fragment;
}
@Override
public int getItemPosition(Object object) {
return POSITION_NONE;
}
@Override
public int getCount() {
return 100;
}
@Override
public CharSequence getPageTitle(int position) {
return "OBJECT " + (position + 1);
}
}
在每个片段中,我都可以创建一个新的主片段,并在ViewPager中显示一个新列表,并用这个新片段替换内容。
ViewPager片段:
public static class DemoObjectFragment extends Fragment {
public static final String ARG_OBJECT = "object";
@Override
public View onCreateView(LayoutInflater inflater,
ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(
R.layout.fragment_collection_object, container, false);
Bundle args = getArguments();
((TextView) rootView.findViewById(android.R.id.text1)).setText(
Integer.toString(args.getInt(ARG_OBJECT)));
//Setup components
return rootView;
}
@Override
public void setMenuVisibility(final boolean visible) {
if (visible) {
//Do something
}
super.setMenuVisibility(visible);
}
@Override
public void onPause() {
//This should run when the fragment goes to backstack
super.onPause();
}
@Override
public void onResume() {
//This should run when the fragment returns from backstack
super.onResume();
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.someComponent:
Fragment newContent = new CollectionDemoFragment();
switchContent(newContent, true);
break;
}
}
public void switchContent(Fragment newContent, boolean addToBackStack) {
if (newContent != null) {
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.setCustomAnimations(android.R.anim.fade_in, android.R.anim.fade_out);
ft.replace(R.id.content_frame, newContent);
if (addToBackStack) {
ft.addToBackStack("" + newContent.getId());
}
ft.commit();
}
}
}
这个功能运行良好,直到我按下“后退”按钮并且之前的主要片段从后堆栈返回。
屏幕是空的(因为onCreateView没有被调用所以布局没有被充气),当主要片段进入后堆栈时,ViewPager中的片段的生命周期方法也从未被调用,也不会在其返回时被调用。 ViewPager中片段中唯一被调用的方法是setMenuVisibility(),因此只有其中的代码运行。
有人知道如何解决这个问题以及为什么会发生吗?
不确定是否重要,但我必须支持Android 2.3以上版本。