Android控件ListView使用方法詳解

2019-12-12 02:27:18

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Android控件ListView使用方法介紹，具體如下

一、ListView的簡單用法

首先新建一個ListViewTest項目，并讓Android Studio自動創建好活動。然后修改activity_main.xml中的代碼，如下：

<?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>

接下來修改MainActivity中的代碼：

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); }}

數組中的數據無法直接傳遞給ListView，需要借助適配器來實現。

ArrayAdapter的構造函數中依次傳入當前上下文，ListView子項布局的id，以及要適配的數據；

調用ListView的setAdapter()方法，將構建好的適配器對象傳遞進去，這樣ListView和數據之間的關聯就建立完成。

運行程序，可以通過滾動的方式來查看屏幕外的數據。

二、定制ListView的界面

首先準備一組圖片，分別對應上面提供的每一種水果（注意圖片大小盡量一致），放在drawable目錄下，注意命名不能出現大寫字母（比如Apple不合法）；

在com.example.administrator.listviewtest下新建.java文件，定義一個實體類Fruit，作為ListView適配器的適配類型。

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; }}

然后為ListView的子項指定一個自定義布局，在layout目錄下新建fruit_item.xml。

<?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>

接下來創建一個自定義的適配器，同樣在com.example.administrator.listviewtest下新建.java文件，重寫了父類的一組構造函數，用于將上下文、ListView子項布局的id和數據都傳遞進來，命名為FruitAdapter，代碼如下：

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);   //獲取當前項的實例  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中的代碼：

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();     //初始化水果數據  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);  } }}

運行程序后，效果圖如下（圖片大小后來才意識到，懶得換了……）：