Android：ListView在Fragment中的使用

一、前言：

因为工作一直在用mvvm框架，因此这篇文章是基于mvvm框架写的。在Fragment复制之前一定要谨记项目可以跑起来。确保能跑起来之后直接复制就行。

二、代码展示：

页面布局

?xml version="1.0" encoding="utf-8"?>


    

        
    

    
        
        
    

item的页面布局：

在java代码中的使用：

新建一个UserBean.java

public class UserBean {
    private String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

public class RegistFragment extends Fragment {
    private RegistViewModel viewModel;
    private FragmentRegistBinding binding;
    private ListView myListView;

    @Override
    public void onStart() {
        super.onStart();
     
    }

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        viewModel = new ViewModelProvider(this).get(RegistViewModel.class);
    }

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        if (binding == null) {
            binding = FragmentRegistBinding.inflate(inflater,container,false);
            binding.setViewModel(viewModel);//一定要在xml的中申明好才可以setViewModel
            binding.setLifecycleOwner(this);

            myListView = binding.lv;
            myListView.setAdapter(new myAdapter(viewModel.userList,getContext()));
            myListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
                @Override
                public void onItemClick(AdapterView adapterView, View view, int i, long l) {
                    Log.d("TAG", "onItemClick: "+i);
                }
            });
        }
        View rootView = binding.getRoot();
        return rootView;
    }


    /**
     * 给ListView设置适配器
     */
    public class myAdapter extends BaseAdapter{

        private List list;
        private Context context;//下面把数据显示到平台上会有用到这个参数

        public myAdapter(List list, Context context) {//创建构造方法
            this.list = list;
            this.context = context;
        }

        @Override
        public int getCount() {//listView能够显示多少数据，，一般是list有多少数据就会显示多少数据
            return list.size();
        }

        @Override
        public Object getItem(int i) {
            return null;
        }

        @Override
        public long getItemId(int i) {
            return i;
        }

        @Override
        public View getView(int i, View view, ViewGroup viewGroup) {//把数据显示到界面上
            //1.拿到布局文件,为了方式view不停创建我们需要做一个判断，当view为空的时候再去创建
            ViewHoder viewHoder;
            if (view == null) {
                //每次都要去找这个控件比较耗时，如何解决呢？我们需要创建一个viewHoder
               viewHoder = new ViewHoder();
                view = LayoutInflater.from(context).inflate(R.layout.item_home,viewGroup,false);
                viewHoder.textView = view.findViewById(R.id.tv);
                view.setTag(viewHoder);
            }else {
                viewHoder = (ViewHoder) view.getTag();
            }
            //2.拿到textView，把值传给textView
//            TextView textView = view.findViewById(R.id.tv);
            viewHoder.textView.setText(list.get(i).getName());
            Log.i("TAG", "getView: "+i);
            //3.把view返回出去
            return view;
        }
    }
    private final class ViewHoder{
        TextView textView;
    }
}

Fragmennt对应的view Model

public class RegistViewModel extends ViewModel {
    public List userList = new ArrayList<>();

    public void setData(){
        for (int i = 0; i < 100; i++) {
            UserBean ub = new UserBean();
            ub.setName("流沔"+i);
            userList.add(ub);
        }
    }
}

三、效果展示：