如何解决在ViewPager 2中动态删除片段时,它总是删除最后一个片段
在ViewPager 2中动态删除片段时,它总是删除最后一个片段,但在添加片段期间没有问题,我尝试为每个Fragment条目指定一个ID,但该方法无效,但getItemPosition覆盖方法在Viewpager中有效,但在Viewpager2中不可用>
请帮助我解决这个问题,困扰我很多天
ViewPagerFragmentAdapter
public class ViewPagerFragmentAdapter extends FragmentStateAdapter {
private ArrayList<Fragment> arrayList = new ArrayList<>();
public ViewPagerFragmentAdapter(@NonNull FragmentManager fragmentManager,@NonNull Lifecycle lifecycle) {
super(fragmentManager,lifecycle);
}
@NonNull
@Override
public Fragment createFragment(int position) {
return Test_FRAG.newinstance(position);
}
@Override
public int getItemCount() {
return arrayList.size();
}
public void addFragment(Test_FRAG test_frag) {
arrayList.add(test_frag);
notifyDataSetChanged();
}
public void removefragment(int position) {
arrayList.remove(position);
notifyDataSetChanged();
}}
主要活动
public class MainActivity extends AppCompatActivity {
ViewPager2 myViewPager2;
TabLayout tabLayout;
ViewPagerFragmentAdapter myAdapter;
int P;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tabLayout = findViewById(R.id.tabs);
myViewPager2 = findViewById(R.id.view_pager);
myViewPager2.setOffscreenPageLimit(5);
myAdapter = new ViewPagerFragmentAdapter(getSupportFragmentManager(),getLifecycle());
myAdapter.addFragment(new Test_FRAG());
myAdapter.addFragment(new Test_FRAG());
myViewPager2.setAdapter(myAdapter);
myViewPager2.setUserInputEnabled(false);
new TabLayoutMediator(tabLayout,myViewPager2,new TabLayoutMediator.TabConfigurationStrategy() {
@Override
public void onConfigureTab(@NonNull TabLayout.Tab tab,int position) {
tab.setText("Tab " + (position + 1));
}
}).attach();
myViewPager2.registerOnPageChangeCallback(new ViewPager2.OnPageChangeCallback() {
@Override
public void onPageScrolled(int position,float positionOffset,int positionOffsetPixels) {
super.onPageScrolled(position,positionOffset,positionOffsetPixels);
}
@Override
public void onPageSelected(int position) {
super.onPageSelected(position);
Log.e("Selected_Page",String.valueOf(position));
String info = String.valueOf(position);
P = position;
}
@Override
public void onPageScrollStateChanged(int state) {
super.onPageScrollStateChanged(state);
}
});
// set Orientation in ViewPager2
myViewPager2.setOrientation(ViewPager2.ORIENTATION_HORIZONTAL);
// myViewPager2.setPageTransformer(new MarginPageTransformer(1500));
}
public void ADD_Fragment(View view) {
myAdapter.addFragment(new Test_FRAG());
myAdapter.notifyDataSetChanged();
myViewPager2.setCurrentItem(tabLayout.getTabCount());
tabLayout.setSelected(true);
}
public void Close_Fragment(View view) {
int pos = myViewPager2.getCurrentItem();
myAdapter.removefragment(pos);
myAdapter.notifyDataSetChanged();
}
}
解决方法
您定位的片段错误!
arrayList.remove(getItemCount())
将始终删除您的最后一个片段(恰好与您的片段计数相对应)。
改为使用该职位。类似于:arrayList.remove(position)
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