foodcheck/ListActivity.java

package com.example.health.foodlist;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.widget.AdapterView;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.Toast;

import com.example.health.Bean.FoodBean;
import com.example.health.Bean.Foodinfo;
import com.example.health.R;
import com.example.health.food_grid.FoodDescActivity;
import com.example.health.food_grid.FoodGridActivity;

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

public class ListActivity extends AppCompatActivity implements View.OnClickListener {
    EditText list_edit;
    ImageView list_refresh,list_serach;
    ListView list_foodlist;
//Listview的内部数据源
    List<FoodBean> mDatas;
    List<FoodBean> allFoodList;
    private ListAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_list);
//查找控件
        intiView();
//找到Listview对应的数据源
        mDatas = new ArrayList<>();
        allFoodList = Foodinfo.getAllFoodList();
        mDatas.addAll(allFoodList);
//创建适配器  BaseAdapter的子类
        adapter = new ListAdapter(this, mDatas);
        list_foodlist.setAdapter(adapter);//设置适配器
//设置单向点击监听功能
        setListener();
    }

    private void setListener() {
        list_foodlist.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                FoodBean foodBean = mDatas.get(position);
                Intent intent = new Intent(ListActivity.this, FoodDescActivity.class);
                intent.putExtra("food",foodBean);
                startActivity(intent);
            }
        });
    }


    private void intiView() {
        list_edit=findViewById(R.id.info_edit);
        list_refresh=findViewById(R.id.info_refresh);
        list_serach=findViewById(R.id.info_search);
        list_foodlist=findViewById(R.id.info_foodlistview);
        list_refresh.setOnClickListener(this);//添加点击事件的监听器
        list_serach.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.info_refresh://刷新点击
                list_edit.setText("");
                mDatas.clear();
                mDatas.addAll(allFoodList);
                adapter.notifyDataSetChanged();
                break;

            case R.id.info_search://搜索点击
//               获取输入内容，判断不为空
                String input = list_edit.getText().toString().trim();
                if (TextUtils.isEmpty(input)) {
                    Toast.makeText(this, "输入内容不能为空!", Toast.LENGTH_SHORT).show();
                    return;
                }
//                判断所有食物列表的标题是否包含输入内容，如果包含，就添加到小集合中
                List<FoodBean>list = new ArrayList<>();
                for (int i = 0; i < allFoodList.size(); i++) {
                    String foodName = allFoodList.get(i).getFoodName();
                    if (foodName.contains(input)) {
                      list.add(allFoodList.get(i));
                    }
                    mDatas.clear();//清空Listview的适配器的内容
                    mDatas.addAll(list);//添加新的数据到数据源中
                    adapter.notifyDataSetChanged();//提升适配器更新
                }
                break;
        }
    }
}