Question

android 自定义adapter什么时候用

Answer 1

　　Adapter是用来帮助填充数据的中间桥梁，比如通过它将数据填充到ListView, GridView, Gallery等，而android的adapter又有很多种（ArrayAdapter, BaseAdapter, CursorAdapter, HeaderViewListAdapter, ListAdapter, ResourceCursorAdapter, SimpleAdapter, SimpleCursorAdapter, SpinnerAdapter, WrapperListAdap

1用BaseAdapter实现如下效果：

Item  的activity_main.xml文件：

[java] view plain copy 

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"  

    xmlns:tools="http://schemas.android.com/tools"  

    android:layout_width="match_parent"  

    android:layout_height="match_parent"  

    android:orientation="vertical"  

     >  

  

    <ImageView  

        android:id="@+id/im_greens"  

        android:layout_width="wrap_content"  

        android:layout_height="wrap_content"  

        android:src="@drawable/safe"  

        android:layout_marginTop="3px"  

        android:text="@string/hello_world" />  

    <TextView   

        android:layout_below="@id/im_greens"  

        android:id="@+id/tv_greens"  

        android:layout_width="wrap_content"  

        android:layout_height="wrap_content"  

        android:text="剁椒鱼头"  

        android:textSize="16sp"  

        />  

    <TextView   

        android:id="@+id/tv_price"  

        android:layout_width="wrap_content"  

          android:layout_height="wrap_content"  

          android:layout_toRightOf="@id/im_greens"  

          android:layout_marginLeft="35px"  

          android:layout_marginTop="30px"  

          android:text="价格:"  

          android:textSize="22sp"  

        />  

  

    <TextView   

        android:id="@+id/tv_price_2"  

        android:layout_width="wrap_content"  

          android:layout_height="wrap_content"  

          android:layout_marginTop="30px"  

          android:layout_toRightOf="@id/tv_price"  

          android:layout_marginLeft="55px"  

          android:textColor="#E00703"  

          android:text="58元"  

          android:textSize="22sp"  

        />  

  

</RelativeLayout>  

greens_listview.xml文件：

[java] view plain copy 

<?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" >  

    <LinearLayout   

        android:layout_width="match_parent"  

        android:layout_height="40dip"       

        android:gravity="center_vertical|center_horizontal"  

        android:background="#619854"  

        android:orientation="vertical"      

        >   

        <TextView   

            android:layout_width="wrap_content"  

            android:layout_height="wrap_content"  

            android:textSize="20sp"  

            android:textColor="#E8F2FE"  

            android:text="菜谱"                 

            />          

    </LinearLayout>  

    <ListView   

        android:id="@+id/listview_greens"  

        android:layout_width="wrap_content"  

        android:layout_height="wrap_content"  

        android:horizontalSpacing="10dip"  

        android:verticalSpacing="10dip"  

        ></ListView>  

</LinearLayout>  

Activity代码：

[java] view plain copy 

package com.example.adapter;  

  

import android.app.Activity;  

import android.os.Bundle;  

import android.view.LayoutInflater;  

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 lsitview_greens;  

    @Override  

    protected void onCreate(Bundle savedInstanceState) {  

        super.onCreate(savedInstanceState);  

        setContentView(R.layout.greens_listview);     

          

        MyApater adapter = new MyApater();  

        lsitview_greens  = (ListView) findViewById(R.id.listview_greens);  

        lsitview_greens.setAdapter(adapter);  

          

          

    }  

  

    //自定义Adapter  

    class MyApater extends BaseAdapter{  

          

        //用于显示菜品的图片  

        int[] images = {R.drawable.safe,R.drawable.safe,R.drawable.safe,R.drawable.safe,R.drawable.safe,R.drawable.safe,R.drawable.safe,R.drawable.safe,R.drawable.safe};  

        //用于显示菜名  

        String[]  name = new String[]{  

            "宫保鸡丁","糖醋排骨","麻婆豆腐","红烧鱼","回锅肉","辣椒炒肉","醋溜土豆丝","大蒜腊牛肉","红烧排骨"  

        };  

        //用于显示价格  

        String[] price = new String[]{  

            "32￥","22￥","15￥","94￥","45￥","15￥","20￥","45￥","85￥"     

        };  

        @Override  

        public int getCount() {  

            // TODO Auto-generated method stub  

            return name.length;  

        }  

  

        @Override  

        public Object getItem(int arg0) {  

            // TODO Auto-generated method stub  

            return null;  

        }  

  

        @Override  

        public long getItemId(int position) {  

            // TODO Auto-generated method stub  

            return position;  

        }  

  

        @Override  

        public View getView(int position, View convertView, ViewGroup parent) {  

            if(convertView == null){  

                //根据布局文件获取View返回值  

                convertView = LayoutInflater.from(getApplicationContext()).inflate(R.layout.activity_main, null);                 

            }  

            ImageView imageview = (ImageView) convertView.findViewById(R.id.im_greens);  

            TextView greens_name = (TextView) convertView.findViewById(R.id.tv_greens);  

            TextView greens_price = (TextView) convertView.findViewById(R.id.tv_price_2);  

              

            imageview.setImageResource(images[position]);  

            greens_name.setText(name[position]);  

            greens_price.setText(price[position]);  

            return convertView;  

        }  

          

    }  

}