实现效果:
主要还是ListView的优化:
基本思路:
<1>使用自定义适配器完成操作
<2>将listView进行优化处理
- /* //ListView完成了重用条目的优化操作
- if(convertView==null){
- //2.将布局文件转换成View 对象
- convertView=View.inflate(MainActivity.this,R.layout.person_item,null);
- }
示例代码：
package com.hsj.example.baseadapterdemo05;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;
import com.hsj.example.baseadapterdemo05.com.hsj.domain.Person;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private ListView listView_persons;
private MyAdapter adapter;
private List<Person> personList;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
this.listView_persons= (ListView) this.findViewById(R.id.listView_persons);
this.personList=this.getData();
this.adapter=new MyAdapter(this.personList);
this.listView_persons.setAdapter(this.adapter);
}
private List<Person> getData() {
personList=new ArrayList<>();
for(int i=0;i<24;i++){
Person person=new Person(
(R.drawable.png_01+i),
"小丽"+i,
20+i
);
personList.add(person);
}
return personList;
}
private final class MyAdapter extends BaseAdapter{
private List<Person> personList;
public MyAdapter(List<Person> personList) {
this.personList=personList;
}
@Override
public int getCount() {
return personList.size();
}
@Override
public Object getItem(int position) {
return personList.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
//原始方式:没有重用条目,造成极大的资源浪费
/*//1.得到当前条目对应的数据对象
Person person=personList.get(position);
//2.将布局文件转换成View 对象
View view=View.inflate(MainActivity.this,R.layout.person_item,null);
//3.找到当前条目对象中相应的控件对象
ImageView imageView_header= (ImageView) view.findViewById(R.id.imageView_header);
TextView textView_name= (TextView) view.findViewById(R.id.textView_name);
TextView textView_age= (TextView) view.findViewById(R.id.textView_age);
//4.为控件对象设置相应的值
imageView_header.setImageResource(person.getHeader());
textView_name.setText(person.getName());
//此处报异常:android.content.res.Resources$NotFoundException: String resource ID #0x14
// textView_age.setText(person.getAge());
textView_age.setText(String.valueOf(person.getAge()));*/
//1.得到当前条目对应的数据对象
Person person=personList.get(position);
/* View view=null;
if(convertView==null){
//2.将布局文件转换成View 对象
view=View.inflate(MainActivity.this,R.layout.person_item,null);
}else{
view=convertView;
}
//3.找到当前条目对象中相应的控件对象
ImageView imageView_header= (ImageView) view.findViewById(R.id.imageView_header);
TextView textView_name= (TextView) view.findViewById(R.id.textView_name);
TextView textView_age= (TextView) view.findViewById(R.id.textView_age);
//4.为控件对象设置相应的值
imageView_header.setImageResource(person.getHeader());
textView_name.setText(person.getName());
//此处报异常:android.content.res.Resources$NotFoundException: String resource ID #0x14
// textView_age.setText(person.getAge());
textView_age.setText(String.valueOf(person.getAge()));*/
/* //ListView完成了重用条目的优化操作
if(convertView==null){
//2.将布局文件转换成View 对象
convertView=View.inflate(MainActivity.this,R.layout.person_item,null);
}
//3.找到当前条目对象中相应的控件对象
ImageView imageView_header= (ImageView) convertView.findViewById(R.id.imageView_header);
TextView textView_name= (TextView) convertView.findViewById(R.id.textView_name);
TextView textView_age= (TextView) convertView.findViewById(R.id.textView_age);
//4.为控件对象设置相应的值
imageView_header.setImageResource(person.getHeader());
textView_name.setText(person.getName());
//此处报异常:android.content.res.Resources$NotFoundException: String resource ID #0x14
// textView_age.setText(person.getAge());
textView_age.setText(String.valueOf(person.getAge()));*/
//ListView完成了重用条目的优化操作,继续解决重复查找控件的问题
ViewHolder viewHolder=null;
if(convertView==null){
viewHolder=new ViewHolder();
//2.将布局文件转换成View 对象
convertView=View.inflate(MainActivity.this,R.layout.person_item,null);
//3.找到当前条目对象中相应的控件对象
ImageView imageView_header= (ImageView) convertView.findViewById(R.id.imageView_header);
TextView textView_name= (TextView) convertView.findViewById(R.id.textView_name);
TextView textView_age= (TextView) convertView.findViewById(R.id.textView_age);
viewHolder.imageView_header=imageView_header;
viewHolder.textView_name=textView_name;
viewHolder.textView_age=textView_age;
//将当前条目控件封装成ViewHolder对象并和当前条目进行绑定
convertView.setTag(viewHolder);
}else{
viewHolder= (ViewHolder) convertView.getTag();
}
//4.为控件对象设置相应的值
viewHolder.imageView_header.setImageResource(person.getHeader());
viewHolder.textView_name.setText(person.getName());
viewHolder.textView_age.setText(String.valueOf(person.getAge()));
return convertView;
}
/**
* 声明每一个条目中拥有的控件对象
*/
class ViewHolder{
ImageView imageView_header;
TextView textView_name;
TextView textView_age;
}
}
}