如何从 viewpager 和 pageradapter 中删除项目 [英] How to delete item from viewpager and pageradapter

问题描述

我正在使用 pageradapter 和 viewpager 来显示 imageview 数组、textview 数组.但是如何在按钮单击时删除寻呼机.下面代码中的整个代码，但是我在 xml 中添加了按钮 onclick 应该删除页面.

I am using pageradapter and viewpager to display imageview array,textview array .But how do I delete pager on button click .Entire code in the code below ,but I have added button in xml onclick should delete the page.

https://www.swipetips.com/android-viewpager-gallery-images-and-texts-tutorial/

 package com.androidbegin.viewpagertutorial;

    import android.content.Context;
    import android.support.v4.view.PagerAdapter;
    import android.support.v4.view.ViewPager;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.View.OnClickListener;
    import android.view.ViewGroup;
    import android.widget.Button;
    import android.widget.ImageView;
    import android.widget.RelativeLayout;
    import android.widget.TextView;

    public class ViewPagerAdapter extends PagerAdapter {
        // Declare Variables
        Context context;
        String[] rank;
        String[] country;
        String[] population;
        int[] flag;
        LayoutInflater inflater;

        public ViewPagerAdapter(Context context, String[] rank, String[] country,
                String[] population, int[] flag) {
            this.context = context;
            this.rank = rank;
            this.country = country;
            this.population = population;
            this.flag = flag;
        }

        @Override
        public int getCount() {
            return rank.length;
        }

        @Override
        public boolean isViewFromObject(View view, Object object) {
            return view == ((RelativeLayout) object);
        }

        @Override
        public Object instantiateItem(final ViewGroup container, final int position) {

            // Declare Variables
            TextView txtrank;
            TextView txtcountry;
            TextView txtpopulation;
            ImageView imgflag;

            Button b;

            inflater = (LayoutInflater) context
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            View itemView = inflater.inflate(R.layout.viewpager_item, container,
                    false);

            // Locate the TextViews in viewpager_item.xml
            txtrank = (TextView) itemView.findViewById(R.id.rank);
            txtcountry = (TextView) itemView.findViewById(R.id.country);
            txtpopulation = (TextView) itemView.findViewById(R.id.population);
            b=(Button)itemView.findViewById(R.id.button1);


            b.setOnClickListener(new OnClickListener() {

                @Override
                public void onClick(View v) {



                }
            });

            // Capture position and set to the TextViews
            txtrank.setText(rank[position]);
            txtcountry.setText(country[position]);
            txtpopulation.setText(population[position]);

            // Locate the ImageView in viewpager_item.xml
            imgflag = (ImageView) itemView.findViewById(R.id.flag);
            // Capture position and set to the ImageView
            imgflag.setImageResource(flag[position]);

            // Add viewpager_item.xml to ViewPager
            ((ViewPager) container).addView(itemView);

            return itemView;
        }

        @Override
        public void destroyItem(ViewGroup container, int position, Object object) {
            // Remove viewpager_item.xml from ViewPager
            ((ViewPager) container).removeView((RelativeLayout) object);

        }
    }

//////////////////

////////////////////

// Locate the ViewPager in viewpager_main.xml
        viewPager = (ViewPager) findViewById(R.id.pager);
        // Pass results to ViewPagerAdapter Class
        adapter = new ViewPagerAdapter(MainActivity.this, rank, country, population, flag);
        // Binds the Adapter to the ViewPager
        viewPager.setAdapter(adapter);

推荐答案

首先需要使用List，因为动态删除对象.第二个你需要

first you need to use List because of dynamically deleting objects. second you need

    @Override
    public int getItemPosition(Object object){
        return PagerAdapter.POSITION_NONE;
    }

强制适配器每次创建新页面，而不是在内存页面中使用.

to force the adapter to create new page each time and not using in memory pages.

 public class ViewPagerAdapter extends PagerAdapter {
    // Declare Variables
    Context context;
    List<String> rank;
    List<String> country;
    List<String> population;
    List<Integer> flag = new ArrayList<Integer>();
    LayoutInflater inflater;

    public ViewPagerAdapter(Context context, String[] rank, String[] country,
            String[] population, int[] flag) {
        this.context = context;
        this.rank = new ArrayList<String>(Arrays.asList(rank));
        this.country = new ArrayList<String>(Arrays.asList(country));
        this.population = new ArrayList<String>(Arrays.asList(population));
        for (int i : flag){ 
            this.flag.add(i);
        }

    }

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

    @Override
    public boolean isViewFromObject(View view, Object object) {
        return view == ((RelativeLayout) object);
    }

    @Override
    public Object instantiateItem(ViewGroup container, int position) {

        // Declare Variables
        TextView txtrank;
        TextView txtcountry;
        TextView txtpopulation;
        ImageView imgflag;

        inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View itemView = inflater.inflate(R.layout.viewpager_item, container,
                false);

        // Locate the TextViews in viewpager_item.xml
        txtrank = (TextView) itemView.findViewById(R.id.rank);
        txtcountry = (TextView) itemView.findViewById(R.id.country);
        txtpopulation = (TextView) itemView.findViewById(R.id.population);
         Button b=(Button)itemView.findViewById(R.id.button1);

         final int delPosition = position;

         b.setOnClickListener(new OnClickListener() {

             @Override
             public void onClick(View v) {
                 rank.remove(delPosition);
                 country.remove(delPosition);
                 population.remove(delPosition);
                 flag.remove(delPosition);
                 notifyDataSetChanged();
             }
         });
        // Capture position and set to the TextViews
        txtrank.setText(rank.get(position));
        txtcountry.setText(country.get(position));
        txtpopulation.setText(population.get(position));

        // Locate the ImageView in viewpager_item.xml
        imgflag = (ImageView) itemView.findViewById(R.id.flag);
        // Capture position and set to the ImageView
        imgflag.setImageResource(flag.get(position));

        // Add viewpager_item.xml to ViewPager
        ((ViewPager) container).addView(itemView);

        return itemView;
    }

    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        // Remove viewpager_item.xml from ViewPager
        ((ViewPager) container).removeView((RelativeLayout) object);

    }
    @Override
    public int getItemPosition(Object object){
        return PagerAdapter.POSITION_NONE;
    }
}

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