Android's listview cache mechanism

Activity_main.xml:

<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:paddingbottom= "@dimen/activity_vertical_margin"
android:paddingleft= "@dimen/activity_horizontal_margin"
android:paddingright= "@dimen/activity_horizontal_margin"
android:paddingtop= "@dimen/activity_vertical_margin"
tools:context= "Com.example.day_05_06.MainActivity" >


<listview
Android:id= "@+id/lvgenerals"
Android:layout_width= "Match_parent"
android:layout_height= "Match_parent"
Android:divider= "#ccc"
android:dividerheight= "20DP"/>


</RelativeLayout>

Mainactivity.java:

Package com.example.day_05_06;


Import java.util.ArrayList;
Import java.util.List;


Import com.litsoft.General.General;


Import android.support.v7.app.ActionBarActivity;
Import Android.content.Context;
Import Android.os.Bundle;
Import Android.util.Log;
Import Android.view.Menu;
Import Android.view.MenuItem;
Import Android.view.View;
Import Android.view.ViewGroup;
Import Android.widget.Adapter;
Import Android.widget.BaseAdapter;
Import Android.widget.ImageView;
Import Android.widget.ListView;
Import Android.widget.TextView;


public class Mainactivity extends Actionbaractivity {
Private ListView Lvgenerals;//listview Object
Private list<general> Generals;//Data collection
Private Baseadapter adapter;//Adapter
@Override
protected void OnCreate (Bundle savedinstancestate) {
Super.oncreate (savedinstancestate);
Setcontentview (R.layout.activity_main);
InitData ();
Initview ();
}
private void Initview () {
TODO auto-generated Method Stub
Lvgenerals = (ListView) Findviewbyid (r.id.lvgenerals);
adapter = new Generaladapter (this,generals);
Lvgenerals.setadapter (adapter);
}
private void InitData () {
TODO auto-generated Method Stub
Generals = new ArrayList ();

int [] images = new int[] {
R.drawable.baiqi,r.drawable.caocao,r.drawable.chengjisihan,
R.drawable.hanxin,r.drawable.lishimin,r.drawable.nuerhachi,
R.drawable.sunbin,r.drawable.sunwu,r.drawable.yuefei,
R.drawable.zhuyuanzhang
};
String [] names = Getresources (). Getstringarray (R.array.generals);
for (int i=0;i<images.length;i++) {
General general = new General (Images[i],names[i]);
Generals.add (General);
}
}
Class Generaladapter extends baseadapter{
Private context context;
Private list<general> innergenerals;
Public Generaladapter (context context, list<general> innergenerals) {//The context object and the General collection object of the external class are passed here in the form of a constructor
Super ();
This.context = context;
This.innergenerals = innergenerals;
}

@Override
public int GetCount () {
TODO auto-generated Method Stub
return Generals.size ();
}





@Override
Public General GetItem (int position) {
TODO auto-generated Method Stub
return Generals.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
LOG.I ("main", position+ "");
Viewholder viewholder = null;

if (Convertview = = null) {//When a list item has not been created in the first screen
Viewholder = new Viewholder ();
Convertview = view.inflate (context, r.layout.general, null);
Viewholder.ivgerneral = (ImageView) Convertview.findviewbyid (R.ID.IVTHUMB);
Viewholder.tvname = (TextView) Convertview.findviewbyid (r.id.tvname);
Convertview.settag (Viewholder);//This is equivalent to initializing a layout for adaptation at a time, which is used in the future, that is, when scrolling, it is not necessary to initialize the layout for adaptation.
}else{//after scrolling, other list items appear
Viewholder = (Viewholder) convertview.gettag ();
}
General general = This.innerGenerals.get (position);
ViewHolder.ivGerneral.setImageResource (GENERAL.GETIMAGESRC ());
ViewHolder.tvName.setText (General.getname ());
return convertview;
}

}
Class viewholder{//is used to fit the layout of a specific item
ImageView ivgerneral;
TextView Tvname;
}


}

Matching page layouts: general.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= "Match_parent"
android:orientation= "Horizontal" >

<imageview
Android:id= "@+id/ivthumb"
Android:layout_width= "60DP"
android:layout_height= "60DP"
android:src= "@drawable/baiqi"/>
<textview
Android:id= "@+id/tvname"
Android:layout_width= "Match_parent"
android:layout_height= "60DP"
android:text= "White"
/>
</LinearLayout>

General.java:

Package com.litsoft.General;


public class General {
private int imagesrc;
private String name;
public int getimagesrc () {
return imagesrc;
}
public void setimagesrc (int imagesrc) {
THIS.IMAGESRC = IMAGESRC;
}
Public String GetName () {
return name;
}
public void SetName (String name) {
THIS.name = name;
}
Public General (int imagesrc, String name) {
Super ();
THIS.IMAGESRC = IMAGESRC;
THIS.name = name;
}

}

Strings.xml:

<?xml version= "1.0" encoding= "Utf-8"?>
<resources>


<string name= "App_name" >Day_05_06</string>
<string name= "Hello_world" >hello world!</string>
<string name= "Action_settings" >Settings</string>
<string-array name= "Generals" >
<item> White </item>
<item> Caocao </item>
<item> Genghis Khan </item>
<item> Han </item>
<item> Li Shimin </item>
<item> Noor Nurhachi </item>
<item> Sun Bin </item>
<item> Sun Wu </item>
<item> Zhu Yuanzhang </item>
<item> Yue Fei </item>
</string-array>
</resources>

Effect:

650) this.width=650; "src=" http://img.blog.csdn.net/20141201141918770 "/>

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Android's listview cache mechanism