高级控件

1.下拉列表

package com.tiger.chapter08;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Spinner;

public class SpinnerDropdownActivity extends AppCompatActivity implements AdapterView.OnItemSelectedListener {

    // 定义下拉列表需要显示的文本数组
    private final static String[] starArray = {"水星", "金星", "地球", "火星", "木星", "土星"};
    private Spinner sp_dropdown;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_spinner_dropdown);
        sp_dropdown = findViewById(R.id.sp_dropdown);
        // 声明一个下拉列表的数组适配器
        ArrayAdapter<String> startAdapter = new ArrayAdapter<>(this, R.layout.item_select, starArray);
        sp_dropdown.setAdapter(startAdapter);
        // 设置下拉框默认显示第一项
        sp_dropdown.setSelection(0);
        // 给下拉框设置选择监听器，一旦用户选中某一项，就触发监听器的onItemSelected方法
        sp_dropdown.setOnItemSelectedListener(this);
    }

    //不用静态因为 是对象绑定的所以垃圾回收机制回收不了

    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
        ToastUtil.show(this, "您选择的是" + starArray[position]);
    }

    @Override
    public void onNothingSelected(AdapterView<?> parent) {

    }

}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".SpinnerDropdownActivity">

    
    
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="下拉模式的列表框"
        android:textSize="17sp"/>
    
    <Spinner
        android:id="@+id/sp_dropdown"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:spinnerMode="dropdown"/>
<!--    dropdown  dialog-->
    
    
    
    
    
    
    
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="50dp"
    android:gravity="center"
    android:textColor="#0000ff"
    android:textSize="17sp"
    tools:text="火星" />

dialog模式设置标题

      //设置 下拉框标题。对话框模式才显示标题，下拉模式不显示
        sp_dropdown.setPrompt("请选择行星");

2.SimpleIconAdapter

package com.dongnaoedu.chapter08;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.SimpleAdapter;
import android.widget.Spinner;

import com.dongnaoedu.chapter08.util.ToastUtil;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class SpinnerIconActivity extends AppCompatActivity implements AdapterView.OnItemSelectedListener {

    // 定义下拉列表需要显示的行星图标数组
    private static final int[] iconArray = {
            R.drawable.shuixing, R.drawable.jinxing, R.drawable.diqiu,
            R.drawable.huoxing, R.drawable.muxing, R.drawable.tuxing
    };
    // 定义下拉列表需要显示的行星名称数组
    private static final String[] starArray = {"水星", "金星", "地球", "火星", "木星", "土星"};


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_spinner_icon);
        // 声明一个映射对象的列表，用于保存行星的图标与名称配对信息
        List<Map<String, Object>> list = new ArrayList<>();
        // iconArray是行星的图标数组，starArray是行星的名称数组
        for (int i = 0; i < iconArray.length; i++) {
            Map<String, Object> item = new HashMap<>();
            item.put("icon", iconArray[i]);
            item.put("name", starArray[i]);
            list.add(item);
        }

        // 声明一个下拉列表的简单适配器，其中指定了图标与文本两组数据
        SimpleAdapter startAdapter = new SimpleAdapter(this, list,
                R.layout.item_simple,
                new String[]{"icon", "name"},
                new int[]{R.id.iv_icon, R.id.tv_name});

        Spinner sp_icon = findViewById(R.id.sp_icon);
        sp_icon.setAdapter(startAdapter);
        sp_icon.setSelection(0);
        sp_icon.setOnItemSelectedListener(this);
    }

    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
        ToastUtil.show(this, "您选择的是" + starArray[position]);
    }

    @Override
    public void onNothingSelected(AdapterView<?> parent) {

    }
}

3.BaseAdapter

package com.dongnaoedu.chapter08.entity;

import com.dongnaoedu.chapter08.R;

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

public class Planet {
    public int image; // 行星图标
    public String name; // 行星名称
    public String desc; // 行星描述

    public Planet(int image, String name, String desc) {
        this.image = image;
        this.name = name;
        this.desc = desc;
    }

    private static int[] iconArray = {R.drawable.shuixing, R.drawable.jinxing, R.drawable.diqiu,
            R.drawable.huoxing, R.drawable.muxing, R.drawable.tuxing};
    private static String[] nameArray = {"水星", "金星", "地球", "火星", "木星", "土星"};
    private static String[] descArray = {
            "水星是太阳系八大行星最内侧也是最小的一颗行星，也是离太阳最近的行星",
            "金星是太阳系八大行星之一，排行第二，距离太阳0.725天文单位",
            "地球是太阳系八大行星之一，排行第三，也是太阳系中直径、质量和密度最大的类地行星，距离太阳1.5亿公里",
            "火星是太阳系八大行星之一，排行第四，属于类地行星，直径约为地球的53%",
            "木星是太阳系八大行星中体积最大、自转最快的行星，排行第五。它的质量为太阳的千分之一，但为太阳系中其它七大行星质量总和的2.5倍",
            "土星为太阳系八大行星之一，排行第六，体积仅次于木星"
    };

    public static List<Planet> getDefaultList() {
        List<Planet> planetList = new ArrayList<Planet>();
        for (int i = 0; i < iconArray.length; i++) {
            planetList.add(new Planet(iconArray[i], nameArray[i], descArray[i]));
        }
        return planetList;
    }
}

package com.dongnaoedu.chapter08.adapter;

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

import com.dongnaoedu.chapter08.R;
import com.dongnaoedu.chapter08.entity.Planet;

import java.util.List;

public class PlanetBaseAdapter extends BaseAdapter {

    private Context mContext;
    private List<Planet> mPlaneList;

    public PlanetBaseAdapter(Context mContext, List<Planet> mPlaneList) {
        this.mContext = mContext;
        this.mPlaneList = mPlaneList;
    }

    // 获取列表项的个数
    @Override
    public int getCount() {
        return mPlaneList.size();
    }

    @Override
    public Object getItem(int position) {
        return mPlaneList.get(position);
    }

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

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder;
        if (convertView == null){
            // 根据布局文件item_list.xml生成转换视图对象
            convertView = LayoutInflater.from(mContext).inflate(R.layout.item_list, null);
            holder = new ViewHolder();
            holder.iv_icon = convertView.findViewById(R.id.iv_icon);
            holder.tv_name = convertView.findViewById(R.id.tv_name);
            holder.tv_desc = convertView.findViewById(R.id.tv_desc);
            // 将视图持有者保存到转换视图当中
            convertView.setTag(holder);
        }else{
            holder = (ViewHolder) convertView.getTag();
        }

        // 给控制设置好数据
        Planet planet = mPlaneList.get(position);
        holder.iv_icon.setImageResource(planet.image);
        holder.tv_name.setText(planet.name);
        holder.tv_desc.setText(planet.desc);

        return convertView;
    }

    public final class ViewHolder {
        public ImageView iv_icon;
        public TextView tv_name;
        public TextView tv_desc;
    }
}

package com.dongnaoedu.chapter08;

import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.Spinner;

import androidx.appcompat.app.AppCompatActivity;

import com.dongnaoedu.chapter08.adapter.PlanetBaseAdapter;
import com.dongnaoedu.chapter08.entity.Planet;
import com.dongnaoedu.chapter08.util.ToastUtil;

import java.util.List;

public class BaseAdapterActivity extends AppCompatActivity implements AdapterView.OnItemSelectedListener {

    private List<Planet> planetList;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_base_adapter);
        Spinner sp_planet = findViewById(R.id.sp_planet);
        // 获取默认的行星列表，即水星、金星、地球、火星、木星、土星
        planetList = Planet.getDefaultList();
        // 构建一个行星列表的适配器
        PlanetBaseAdapter adapter = new PlanetBaseAdapter(this, planetList);
        sp_planet.setAdapter(adapter);
        sp_planet.setSelection(0);
        sp_planet.setOnItemSelectedListener(this);
    }

    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
        ToastUtil.show(this, "您选择的是" + planetList.get(position).name);
    }

    @Override
    public void onNothingSelected(AdapterView<?> parent) {

    }
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="行星的基本适配器"
        android:textSize="17sp" />

    <Spinner
        android:id="@+id/sp_planet"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:spinnerMode="dropdown" />

</LinearLayout>