我正在开发一个包含ViewPager视图的应用程序,
我创建了一个PagerAdapter,它有视图,PagerAdapter的instantiateItem()方法在create()中被调用两次我不知道为什么,任何人都可以帮我这个吗？
我创建了一个PagerAdapter,它有视图,PagerAdapter的instantiateItem()方法在create()中被调用两次我不知道为什么,任何人都可以帮我这个吗？
这是我的代码,
View PagerView;
MyPagerAdapter adapter;
ViewPager pager;
adapter = new MyPagerAdapter();
pager.setAdapter(adapter);
pager.setCurrentItem(0);
public class MyPagerAdapter extends PagerAdapter {
@Override
public Object instantiateItem(final View collection,final int position) {
Log.d("Inside","Pager");
PagerView = new View(collection.getContext());
LayoutInflater inflater = (LayoutInflater) collection.getContext()
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
PagerView = inflater.inflate(R.layout.tablemenu,null,false);
tbMenuDetails = (TableLayout) PagerView
.findViewById(R.id.Menutable1);
scrollview = (ScrollView) PagerView.findViewById(R.id.scrollView1);
tbMenuDetails.removeAllViews();
removeTableRows();
createTableLayout(position);
String str[][] = datasource.GetSubMenuDetailsFromMenuId(MenuIdlst
.get(position).trim());
Log.d("Str","" + str.length);
for (int i = 0; i < str.length; i++) {
addRows(str[i][1],str[i][2],str[i][0],str[i][3],position);
Log.d("Message","Pos " + position + " SubMenuName" + str[i][2]
+ " SubMenuId" + " " + str[i][0] + " TypeID" + " "
+ str[i][3]);
}
// View view = inflater.inflate(resId,null);
((ViewPager) collection).addView(PagerView,0);
return PagerView;
}
@Override
public void destroyItem(final View arg0,final int arg1,final Object arg2) {
((ViewPager) arg0).removeView((View) arg2);
}
@Override
public boolean isViewFromObject(final View arg0,final Object arg1) {
return arg0 == ((View) arg1);
}
@Override
public void finishUpdate(View arg0) {
// TODO Auto-generated method stub
}
@Override
public void restoreState(Parcelable arg0,ClassLoader arg1) {
// TODO Auto-generated method stub
}
@Override
public Parcelable saveState() {
// TODO Auto-generated method stub
return null;
}
@Override
public void startUpdate(View arg0) {
// TODO Auto-generated method stub
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return MenuIdlst.size();
}
}
请帮忙
解决方法
如果您决定使用Fragments,请不要实现PagerAdapter.相反,扩展FragmentPagerAdapter或FragmentStatePagerAdapter：
private class MyPagerAdapter extends FragmentStatePagerAdapter {
public MyPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public int getCount() {
return NUMBER_OF_PAGES_IN_PAGER;
}
@Override
public Fragment getItem(int position) {
// Implement the static method newInstance in MyFragment.java yourself.
// It should return you a brand new instance of MyFragment,basically using
// the code you had in your original instantiateItem method.
return MyFragment.newInstance(position,... etc ...);
}
}
然后在你的活动中：
myPagerAdapter = new MyPagerAdapter(getFragmentManager()); // or myPagerAdapter = new MyPagerAdapter(getSupportFragmentManager()); myViewPager.setAdapter(myPagerAdapter);
要获得有关如何使用Fragments和ViewPagers的更多信息：
https://developer.android.com/reference/android/app/Fragment.html
https://developer.android.com/reference/android/support/v4/view/ViewPager.html
https://developer.android.com/reference/android/support/v4/app/FragmentStatePagerAdapter.html
