如何在Android ViewPager中删除页面? [英] How to remove pages in Android ViewPager?

问题描述

我试图在单击按钮后在ViewPager中动态添加/删除fragments，但是如果我通过单击后退按钮remove片段(表单)，然后再次添加该片段，表单保留了其数据(EditText不为空).

I'm trying to add/remove dynamically fragments in a ViewPager following a button click, but if I remove the fragment (a form) by clicking on back button, and add the fragment again, the form has kept its data (EditText not empty).

这是我的适配器:

package com.thomas.playlists.viewPager;

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;

import java.util.ArrayList;

public class ViewPagerAdapter extends FragmentPagerAdapter
{
    ArrayList<Fragment> mList = null;

    public ViewPagerAdapter(FragmentManager fm)
    {
        super(fm);
        mList = new ArrayList<Fragment>();
    }

    public void add(Fragment fragment)
    {
        mList.add(fragment);
    }

    public void removeLast()
    {
        if(mList.size() > 1)
            mList.remove(getCount() - 1);
    }

    @Override
    public Fragment getItem(int i)
    {
        return mList.get(i);
    }

    @Override
    public int getCount()
    {
        return mList.size();
    }
}

两次使用添加过程(在主活动中):

Adding proccess used twice (in main Activity) :

PlaylistFragment playlistFragment = new PlaylistFragment();

mViewPagerAdapter.add(playlistFragment);
mViewPagerAdapter.notifyDataSetChanged();
mViewPager.setCurrentItem(mViewPagerAdapter.getCount() - 1, true);

删除页面(仍在主活动中):

Removing a page (still in main Activity) :

mViewPagerAdapter.removeLast();
mViewPagerAdapter.notifyDataSetChanged();
mViewPager.setCurrentItem(mViewPagerAdapter.getCount() - 1, true);

如何正确删除碎片?

:我尝试了这个，但是表单没有重置；

EDIT : I tried this but the form isn't reseted;

实例化第二个片段后，未调用其onCreate()方法.

EDIT 2 : After instanciating the second fragment, its onCreate() method isn't called.

推荐答案

扩展 FragmentStatePagerAdapter ，并覆盖getItemPosition方法:

public class ViewPagerAdapter extends FragmentStatePagerAdapter
{
    //... your existing code

    @Override
    public int getItemPosition(Object object) {
        int position = mList.indexOf(object);
        return position == -1 ? POSITION_NONE : position;
    }
}

这篇关于如何在Android ViewPager中删除页面?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！