自定义ListView的几种方法

先创建好自定义的layout布局 item.xml

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

<ImageView android:id="@+id/lv_imageview"
android:layout_width="60dp"
android:layout_height="60dp"
android:src="@drawable/ic_launcher"/>

<TextView android:id="@+id/tv_title"
android:layout_width="match_parent"
android:layout_height="30dp"
android:layout_toEndOf="@+id/lv_imageview"
android:layout_toRightOf="@+id/lv_imageview"
android:text="Title"
android:gravity="center"
android:textSize="25sp"/>

<TextView android:id="@+id/tv_content"
android:layout_width="match_parent"
android:layout_height="30dp"
android:layout_toEndOf="@+id/lv_imageview"
android:layout_toRightOf="@+id/lv_imageview"
android:layout_below="@+id/tv_title"
android:text="Content"
android:gravity="center_vertical"
android:textSize="20sp"/>
</RelativeLayout>
 

自定义实体类 ItemBean

package com.example.baseadapter;

public class ItemBean {
public int ImageResid;
public String title;
public String ItemContent;
public ItemBean(int imageResid, String title, String itemContent) {
super();
ImageResid = imageResid;
this.title = title;
this.ItemContent = itemContent;
}

}

自定义适配器，此代码中有三种方法，分别是效率由高到低

package com.example.baseadapter;

import java.util.List;

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;

public class MyAdapter extends BaseAdapter{
private List<ItemBean> mList;
private LayoutInflater mLayoutInflater;
private long mSumTime = 0;
public MyAdapter(Context context,List<ItemBean> list){
mLayoutInflater = LayoutInflater.from(context);
mList = list;
}

@Override
public int getCount() {
// TODO Auto-generated method stub
return mList.size();
}

@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return mList.get(position);
}

@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
/**
* 效率最低
* 没有利用到listview的缓存机制，没有任何的优化处理，效率低，浪费资源 23409907
*
* */
long start = System.nanoTime();//获取系统的纳秒事件
View view = mLayoutInflater.inflate(R.layout.item, null);
ImageView mImageView = (ImageView)view.findViewById(R.id.lv_imageview);
TextView mTextViewTitle = (TextView) view.findViewById(R.id.tv_title);
TextView mTextViewContent = (TextView) view.findViewById(R.id.tv_content);

ItemBean itemBean = mList.get(position);

mImageView.setImageResource(itemBean.ImageResid);
mTextViewContent.setText(itemBean.ItemContent);
mTextViewTitle.setText(itemBean.title);
long end = System.nanoTime();
long mValue = end - start;
mSumTime += mValue;
System.out.println(mSumTime);
return view;

/**
*效率第二创建方法  1472730
* 充分的利用了李斯特view的缓存特性，如果没有缓存才创建新的View
*/
/*long start = System.nanoTime();//获取系统的纳秒事件
if (convertView == null){
convertView = mLayoutInflater.inflate(R.layout.item, null);
}
ImageView mImageView = (ImageView)convertView.findViewById(R.id.lv_imageview);
TextView mTextViewTitle = (TextView) convertView.findViewById(R.id.tv_title);
TextView mTextViewContent = (TextView) convertView.findViewById(R.id.tv_content);

ItemBean itemBean = mList.get(position);

mImageView.setImageResource(itemBean.ImageResid);
mTextViewContent.setText(itemBean.ItemContent);
mTextViewTitle.setText(itemBean.title);
long end = System.nanoTime();
long mValue = end - start;
mSumTime += mValue;
System.out.println(mSumTime);
return convertView;*/

/*
* 效率较高创建listView  7376228
*

long start = System.nanoTime();//获取系统的纳秒事件
if (convertView == null){
VieweHolder vieweHolder = new VieweHolder();
convertView = mLayoutInflater.inflate(R.layout.item, null);
vieweHolder.mImageView = (ImageView) convertView.findViewById(R.id.lv_imageview);
vieweHolder.mTextViewContent = (TextView)convertView.findViewById(R.id.tv_content);
vieweHolder.mTextViewTitle = (TextView) convertView.findViewById(R.id.tv_title);
convertView.setTag(vieweHolder);
}else{
VieweHolder 	VieweHolder = (VieweHolder)convertView.getTag();
}
ItemBean itemBean = mList.get(position);

VieweHolder.mImageView.setImageResource(itemBean.ImageResid);
VieweHolder.mTextViewContent.setText(itemBean.ItemContent);
VieweHolder.mTextViewTitle.setText(itemBean.title);
long end = System.nanoTime();
long mValue = end - start;
mSumTime += mValue;
System.out.println(mSumTime);
return convertView;*/
}
static class VieweHolder{
public static ImageView mImageView;
public static  TextView mTextViewTitle;
public static  TextView mTextViewContent;
}

}

最后就是MainActivity的代码和其布局文件

MainActivity

package com.example.baseadapter;

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

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ListView;

public class MainActivity extends Activity {
private ListView mListView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
List<ItemBean> itembeanList = new ArrayList<ItemBean>();
for (int i = 0; i < 20; i++){
itembeanList.add(new ItemBean(R.drawable.ic_launcher,
"TITLE"+i+"",
"CONTENT"+i+""));
}
mListView = (ListView)findViewById(R.id.listview);
mListView.setAdapter(new MyAdapter(MainActivity.this, itembeanList));
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}

MainActivity_Layout

<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:paddingLeft="16dp"
android:paddingRight="16dp"
android:paddingTop="16dp"
android:paddingBottom="16dp"
tools:context="com.example.baseadapter.MainActivity" >

<ListView
android:id="@+id/listview"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true" >
</ListView>

</RelativeLayout>

如有不对，望大家指教，谢谢