Android控件ListView使用方法介绍,具体如下
一、ListView的简单用法
首先新建一个ListViewTest项目,并让Android Studio自动创建好活动。然后修改activity_main.xml中的代码,如下:
代码语言:javascript复制<?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"
<ListView
android:id="@ id/list_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
</ListView
</LinearLayout
接下来修改MainActivity中的代码:
代码语言:javascript复制public class MainActivity extends AppCompatActivity {
private String[] data={"Apple","Banana","Orange","Watermelon","Pear","Grape","Pineapple","Strawberry","Cherry","Mango","Apple","Banana","Orange","Watermelon","Pear","Grape","Pineapple","Strawberry","Cherry","Mango"};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ArrayAdapter<String adapter=new ArrayAdapter<String (MainActivity.this,android.R.layout.simple_list_item_1,data);
ListView listview=(ListView)findViewById(R.id.list_view);
listview.setAdapter(adapter);
}
}
数组中的数据无法直接传递给ListView,需要借助适配器来实现。
ArrayAdapter的构造函数中依次传入当前上下文,ListView子项布局的id,以及要适配的数据;
调用ListView的setAdapter()方法,将构建好的适配器对象传递进去,这样ListView和数据之间的关联就建立完成。
运行程序,可以通过滚动的方式来查看屏幕外的数据。
二、定制ListView的界面
首先准备一组图片,分别对应上面提供的每一种水果(注意图片大小尽量一致),放在drawable目录下,注意命名不能出现大写字母(比如Apple不合法);
在com.example.administrator.listviewtest下新建.java文件,定义一个实体类Fruit,作为ListView适配器的适配类型。
代码语言:javascript复制public class Fruit{
private String name;
private int imageId;
public Fruit(String name,int imageId){
this.name=name;
this.imageId=imageId;
}
public String getName(){
return name;
}
public int getImageId(){
return imageId;
}
}
然后为ListView的子项指定一个自定义布局,在layout目录下新建fruit_item.xml。
代码语言:javascript复制<?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="wrap_content"
<ImageView
android:id="@ id/fruit_image"
android:layout_width="wrap_content"
android:layout_height="wrap_content" /
<TextView
android:id="@ id/fruit_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:layout_marginLeft="10dp"
/
</LinearLayout
接下来创建一个自定义的适配器,同样在com.example.administrator.listviewtest下新建.java文件,重写了父类的一组构造函数,用于将上下文、ListView子项布局的id和数据都传递进来,命名为FruitAdapter,代码如下:
代码语言:javascript复制public class FruitAdapter extends ArrayAdapter<Fruit {
private int resourceId;
public FruitAdapter(Context context, int textViewResourceId, List<Fruit objects){
super(context,textViewResourceId,objects);
resourceId=textViewResourceId;
}
@Override
public View getView(int position,View convertView,ViewGroup parent){
Fruit fruit=getItem(position); //获取当前项的实例
View view= LayoutInflater.from(getContext()).inflate(resourceId,parent,false);
ImageView fruitImage=(ImageView)view.findViewById(R.id.fruit_image);
TextView fruitName=(TextView) view.findViewById(R.id.fruit_name);
fruitImage.setImageResource(fruit.getImageId());
fruitName.setText(fruit.getName());
return view;
}
}
下面修改MainActivity中的代码:
代码语言:javascript复制package com.example.administrator.listviewtest;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private List<Fruit fruitList=new ArrayList< ();
// private String[] data={"Apple","Banana","Orange","Watermelon","Pear","Grape","Pineapple","Strawberry","Cherry","Mango","Apple","Banana","Orange","Watermelon","Pear","Grape","Pineapple","Strawberry","Cherry","Mango"};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initFruits(); //初始化水果数据
FruitAdapter adapter=new FruitAdapter(MainActivity.this,R.layout.fruit_item,fruitList);
// ArrayAdapter<String adapter = new ArrayAdapter<String (MainActivity.this, android.R.layout.simple_list_item_1, data);
ListView listview = (ListView) findViewById(R.id.list_view);
listview.setAdapter(adapter);
}
private void initFruits(){
for(int i=0;i<2;i ){
Fruit apple=new Fruit("Apple",R.drawable.apple);
fruitList.add(apple);
Fruit orange=new Fruit("Orange",R.drawable.orange);
fruitList.add(orange);
Fruit banana=new Fruit("Banana",R.drawable.banana);
fruitList.add(banana);
Fruit waterlenmo=new Fruit("Waterlemon",R.drawable.waterlemon);
fruitList.add(waterlenmo);
Fruit pear=new Fruit("Pear",R.drawable.pear);
fruitList.add(pear);
Fruit grape=new Fruit("Grape",R.drawable.grape);
fruitList.add(grape);
Fruit pineapple=new Fruit("Pineapple",R.drawable.pineapple);
fruitList.add(pineapple);
Fruit strawberry=new Fruit("Strawberry",R.drawable.straw);
fruitList.add(strawberry);
Fruit cherry=new Fruit("Cherry",R.drawable.cherry);
fruitList.add(cherry);
Fruit mango=new Fruit("mango",R.drawable.mango);
fruitList.add(mango);
}
}
}
运行程序后,效果图如下(图片大小后来才意识到,懒得换了……):
以上就是本文的全部内容,希望对大家的学习有所帮助。