设备进入待机状态后,如果我打电话, getSupportFragmentManager()
我会得到一个FragmentManager
包含未初始化的片段,其所有变量都设置为null
.
这里有一些代码:
this.mAdapter = new MyAdapter(getSupportFragmentManager());
this.mPager = (ViewPager) findViewById(R.id.pager);
this.mPager.setAdapter(mAdapter);
TabPageIndicator titleIndicator = (TabPageIndicator) findViewById(R.id.titles);
titleIndicator.setViewPager(mPager);
titleIndicator.setOnPageChangeListener(new OnPageChangeListener()
{
@Override
public void onPageSelected(int position)
{
mAdapter.getItem(position).onFocus();
}
@Override
public void onPageScrolled(int arg0, float arg1, int arg2)
{
}
@Override
public void onPageScrollStateChanged(int arg0)
{
}
});
这是 MyAdapter 类:
public static class MyAdapter extends FragmentStatePagerAdapter
{
ArrayList<ExtendedFragment> tabs = new ArrayList<ExtendedFragment>();
String[] titles = new String[] { "FRAG1", "FRAG2", "FRAG3", "FRAG4", "FRAG5", "FRAG6"};
public MyAdapter(FragmentManager fm)
{
super(fm);
tabs.add(new frag1());
tabs.add(new frag2());
tabs.add(new frag3());
tabs.add(new frag4());
tabs.add(new frag5());
tabs.add(new frag6());
}
@Override
public int getCount()
{
return tabs.size();
}
@Override
public ExtendedFragment getItem(int position)
{
return tabs.get(position);
}
@Override
public CharSequence getPageTitle(int position)
{
return titles[position];
}
}
实现该ExtendedFragment
方法onFocus()
,每个片段都覆盖,因为当标签获得焦点时,我需要采取一些操作。当我从待机状态恢复设备onFocus()
并被解雇时,如果我尝试View
使用getView()
我得到null
.
为什么我的观点是空的?