Java 为什么赢了'；我的CardView不会出现在我的片段中吗？

我正在学习如何使用视图寻呼机创建滑动视图的教程，并尝试将其转换为使用片段

我的问题是，当我选择碎片时，卡片没有出现

我认为问题在于这一行代码

adapter = new Adapter(models, getActivity());

（最初的

adapter=newadapter（models，this）；

在教程中），但我可能错了

我是android studio的新手，这是我第一次使用片段，如果有任何帮助，我将不胜感激

这是我的密码：

fragment_cards.xml

值得注意的是，片段本身正在工作，因为其中的按钮显示正确。 唯一的问题是我的卡根本没有出现

任何帮助都将不胜感激，因为这简直让我发疯

非常感谢您抽出时间我非常感谢

---

Roman

充气将在每次使用时创建一个新的布局对象（视图对象），因此这是一个视图布局

viewPager = inflater.inflate(R.layout.fragment_cards, container, false).findViewById(R.id.viewPager);

您将返回一个没有任何内容的新视图对象

return inflater.inflate(R.layout.fragment_cards, container, false);

因此，您需要在充气后存储一个视图引用，然后使用它并返回它，如图所示

View root  = inflater.inflate(R.layout.fragment_cards, container, false).findViewById(R.id.viewPager);
viewPager = root.findViewById(R.id.viewPager);
// ... code
return root;

CardsFragment.java

package com.example.musicassistant;

import android.animation.ArgbEvaluator;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.viewpager.widget.ViewPager;

import java.util.ArrayList;
import java.util.List;
import java.util.Objects;

public class CardsFragment extends Fragment {

    ViewPager viewPager;
    Adapter adapter;
    List<Model> models;
    Integer[] colors = null;
    ArgbEvaluator argbEvaluator = new ArgbEvaluator();

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

        models = new ArrayList<>();
        models.add(new Model(R.drawable.brochure, "Brochure", "oooooo"));
        models.add(new Model(R.drawable.sticker, "Sticker", "oooooo"));
        models.add(new Model(R.drawable.poster, "Poster", "oooooo"));
        models.add(new Model(R.drawable.namecard, "Namecard", "oooooo"));

        adapter = new Adapter(models, getActivity());

        viewPager = inflater.inflate(R.layout.fragment_cards, container, false).findViewById(R.id.viewPager);
        viewPager.setAdapter(adapter);
        viewPager.setPadding(130,0,130,0);

        Integer[] colors_temp = {
                getResources().getColor(R.color.color1),
                getResources().getColor(R.color.color2),
                getResources().getColor(R.color.color3),
                getResources().getColor(R.color.color4)

        };

        colors = colors_temp;

        viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
            @Override
            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
                if (position < (adapter.getCount() -1) && position < (colors.length -1)) {
                    viewPager.setBackgroundColor(
                            (Integer) argbEvaluator.evaluate(
                                    positionOffset,
                                    colors[position],
                                    colors[position + 1]
                            )
                    );
                } else {
                    viewPager.setBackgroundColor(colors[colors.length - 1]);
                }
            }

            @Override
            public void onPageSelected(int position) {

            }

            @Override
            public void onPageScrollStateChanged(int state) {

            }
        });

        return inflater.inflate(R.layout.fragment_cards, container, false);
    }
}

Adapter.java

package com.example.musicassistant;


import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.viewpager.widget.PagerAdapter;

import java.util.List;

public class Adapter extends PagerAdapter {

    private List<Model> models;
    private LayoutInflater layoutInflater;
    private Context context;

    public Adapter(List<Model> models, Context context) {
        this.models = models;
        this.context = context;
    }

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

    @Override
    public boolean isViewFromObject(@NonNull View view, @NonNull Object object) {
        return view.equals(object);
    }

    @NonNull
    @Override
    public Object instantiateItem(@NonNull ViewGroup container, int position) {
        layoutInflater = LayoutInflater.from(context);
        View view = layoutInflater.inflate(R.layout.item, container, false);

        ImageView imageView;
        TextView title, desc;

        imageView = view.findViewById(R.id.image);
        title = view.findViewById(R.id.title);
        desc = view.findViewById(R.id.desc);

        imageView.setImageResource(models.get(position).getImage());
        title.setText(models.get(position).getTitle());
        desc.setText(models.get(position).getDesc());

        container.addView(view, 0);
        return view;
    }

    @Override
    public void destroyItem(@NonNull ViewGroup container, int position, @NonNull Object object) {
        container.removeView((View)object);
    }
}

Model.java

package com.example.musicassistant;

public class Model {

    private int image;
    private String title;
    private  String desc;

    public Model(int image, String title, String desc) {
        this.image = image;
        this.title = title;
        this.desc = desc;
    }

    public int getImage() {
        return image;
    }

    public void setImage(int image) {
        this.image = image;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getDesc() {
        return desc;
    }

    public void setDesc(String desc) {
        this.desc = desc;
    }
}

viewPager = inflater.inflate(R.layout.fragment_cards, container, false).findViewById(R.id.viewPager);

return inflater.inflate(R.layout.fragment_cards, container, false);

View root  = inflater.inflate(R.layout.fragment_cards, container, false).findViewById(R.id.viewPager);
viewPager = root.findViewById(R.id.viewPager);
// ... code
return root;