时间:2022-07-31 09:18:35 | 栏目:Android代码 | 点击:次
activity_main.xml
在res/layout文件中,放置一个TextView控件用于显示购物商城界面的标题,放置一个ListView控件用于显示购物商场界面的列表
<?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" tools:context=".MainActivity" android:orientation="vertical"> <TextView android:layout_width="match_parent" android:layout_height="45dp" android:text="购物商城" android:textSize="18sp" android:textColor="#FFFFFF" android:background="#FF8F03" android:gravity="center"/> <ListView android:id="@+id/lv" android:layout_width="match_parent" android:layout_height="wrap_content" android:listSelector="@color/colorAccent" /> </LinearLayout>
list_Item.xml
在res/layout文件中创建一个列表条目界面的布局文件list_item.xml,在该文件中放置一个Image View控件用于显示商品的图片;放置2个TextView控件分别用于显示商品的名称和价格!
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:padding="16dp"> <ImageView android:id="@+id/iv" android:layout_width="120dp" android:layout_height="90dp" android:layout_centerVertical="true" /> <RelativeLayout android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerVertical="true" android:layout_marginLeft="10dp" android:layout_toRightOf="@+id/iv"> <TextView android:id="@+id/title" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="桌子" android:textColor="#000000" android:textSize="20sp" /> <TextView android:id="@+id/tv_price" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@+id/title" android:layout_marginTop="10dp" android:text="价格:" android:textColor="#FF8F03" android:textSize="20sp" /> <TextView android:id="@+id/price" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@+id/title" android:layout_marginTop="10dp" android:layout_toRightOf="@+id/tv_price" android:text="1000" android:textColor="#FF8F03" android:textSize="20sp" /> </RelativeLayout> </RelativeLayout>
MainActivity.java
12-14行代码定义了数组titles,prices,icons,分别用于存储商品列表中的商品名称,价格和图片,并且3个数组的长度一致。
19行创建MyBaseAdpter的实例
20行设置数据适配器List View上
23-34行代码返回条目的长度,价格,数据对象
37行找到list_item.xml中创建的TextView控件
创建一个View Holder类,将需要加载的控件变量放在该类中
最后调用id属性,set实现!
package com.example.dymemory1; import android.app.Activity; import android.os.Bundle; import android.view.View; import android.view.ViewGroup; import android.widget.BaseAdapter; import android.widget.ImageView; import android.widget.ListView; import android.widget.TextView; public class MainActivity extends Activity { private ListView mListView; private String[] titles = {"苹果","蛋糕","修罗壁纸","桌子","猕猴桃","毛衣"}; private String[] prices = {"10元/kg","100元/个","50元/张","45元/把","10元/kg","110元/件"}; private int[] icons = {R.drawable.apple,R.drawable.cake,R.drawable.juyoujing,R.drawable.table,R.drawable.kiwifruit,R.drawable.wireclothes}; protected void onCreate(Bundle saveInstanceState){ super.onCreate(saveInstanceState); setContentView(R.layout.activity_main); mListView=(ListView)findViewById(R.id.lv); MyBaseAdaPter mAdapter = new MyBaseAdaPter(); mListView.setAdapter(mAdapter); } class MyBaseAdaPter extends BaseAdapter{ @Override public int getCount( ){ return titles.length; } @Override public Object getItem(int position){ return titles[position]; } @Override public long getItemId(int position){ return position; } @Override public View getView(int position,View convertView,ViewGroup parent){ ViewHolder holder =null; if(convertView == null){ convertView = View.inflate( MainActivity.this,R.layout.list_item,null); holder= new ViewHolder(); holder.title=(TextView) convertView.findViewById(R.id.title); holder.price=(TextView) convertView.findViewById(R.id.price); holder.iv=(ImageView) convertView.findViewById(R.id.iv); convertView.setTag(holder); } else { holder = (ViewHolder) convertView.getTag(); } holder.title.setText(titles[position]); holder.price.setText(prices[position]); holder.iv.setBackgroundResource(icons[position]); return convertView; } } static class ViewHolder{ TextView title; TextView price; ImageView iv; } }