Android Complex Custom ListView implementation

In the implementation of the ListView in Android is more difficult to understand the newcomer, I read a number of articles that can use the following ideas to let new people better understand (also do a good record, lest they forget later).

Refer to the blog: http://cinderella7.blog.51cto.com/7607653/1281696 (here with the idea of MVC to understand the ListView, personally think it is good)

http://blog.csdn.net/jueblog/article/details/11857281 (a complete implementation)

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First, straighten out the whole idea.

The custom ListView contains three important concepts, which are understood in the form of MVC:

ListView is equivalent to V (view) in the MVC framework

Adapter equivalent to C (Controller) in the MVC framework

　　The data source is equivalent to M (model) in the MVC framework

Two or one step-by-step implementation

1. Customize the layout of each item subkey in the ListView first

Listitem.xml

<?XML version= "1.0" encoding= "Utf-8"?><LinearLayoutxmlns:android= "Http://schemas.android.com/apk/res/android"android:orientation= "vertical"Android:layout_width= "Match_parent"Android:layout_height= "Match_parent">    <ImageViewAndroid:layout_width= "Fill_parent"Android:layout_height= "100DP"Android:id= "@+id/imageview"/>    <TextViewAndroid:layout_width= "Fill_parent"Android:layout_height= "Wrap_content"android:textappearance= "? Android:attr/textappearancelarge"Android:text= "Large Text"Android:id= "@+id/textview"/></LinearLayout>

2. Define the main layout

<?XML version= "1.0" encoding= "Utf-8"?><LinearLayoutxmlns:android= "Http://schemas.android.com/apk/res/android"android:orientation= "vertical"Android:layout_width= "Fill_parent"Android:layout_height= "Fill_parent"        >    <ListViewAndroid:layout_width= "Wrap_content"Android:layout_height= "Wrap_content"Android:id= "@+id/listview"/></LinearLayout>

3. Then, define the data source, view, adapter

    Private List// M    Private ListView ListView;  // V    Private Myadapter Myadapter;  // C

4. Get the data source

PrivateListGetData () {ArrayList<HashMap<String,Object>> arrayList =NewArraylist(); HashMap<String,Object> HashMap =NULL;  for(inti=0;i<10;i++) {HashMap=NewHashmap<string, object>(); Hashmap.put ("Index", integer.tostring (i+1)); Hashmap.put ("IMG", r.drawable.my); Arraylist.add (HASHMAP); //add to Data source        }        returnarrayList; }

5. Custom adapter, add data source to adapter

//Create a custom adapter    Private classMyadapterextendsbaseadapter{PrivateLayoutinflater Mlayoutinflater;
　　　　　　         PublicMyadapter (Context context) {Mlayoutinflater= Layoutinflater.from (context);//Dynamic Layout Mapping} @Override Public intGetCount () {returnmdata.size (); } @Override PublicObject GetItem (intposition) {            return NULL; } @Override Public LongGetitemid (intposition) {            return0; } @Override PublicView GetView (intposition, View Convertview, ViewGroup parent) {Convertview= Mlayoutinflater.inflate (R.layout.listitem,NULL);//instantiate view based on layout fileTextView TV =(TextView) Convertview.findviewbyid (R.id.textview); Tv.settext (Mdata.get (position). Get ("Index"). toString ()); ImageView img=(ImageView) Convertview.findviewbyid (R.id.imageview); Img.setbackgroundresource ((Integer) mdata.get (position). Get ("IMG")); returnConvertview; }    }

6. Implement in the OnCreate function

        ListView = (ListView) Findviewbyid (R.id.listview);         // ----        Mdata = getData ();         New Myadapter (this);        Listview.setadapter (myadapter);

Iii. Summary

The entire implementation process is strictly in accordance with the MVC pattern, first of all to customize your own element layout, then get the data source, then rewrite the adapter, load the data source into the adapter, and display the adapter contents through the ListView.

The full version of the Java code is attached below:

 Packagecom.example.ListViewTest;Importandroid.app.Activity;ImportAndroid.content.Context;ImportAndroid.os.Bundle;ImportAndroid.view.LayoutInflater;ImportAndroid.view.View;ImportAndroid.view.ViewGroup;ImportAndroid.widget.BaseAdapter;ImportAndroid.widget.ImageView;ImportAndroid.widget.ListView;ImportAndroid.widget.TextView;Importjava.util.ArrayList;ImportJava.util.HashMap;Importjava.util.List; Public classMyActivityextendsActivity {/*** Called when the activity is first created. */@Override Public voidonCreate (Bundle savedinstancestate) {Super. OnCreate (savedinstancestate);        Setcontentview (R.layout.main); ListView=(ListView) Findviewbyid (R.id.listview); //----Mdata =GetData (); Myadapter=NewMyadapter ( This);    Listview.setadapter (Myadapter); }    PrivateList//M    PrivateListView ListView;//V    PrivateMyadapter Myadapter;//C    PrivateListGetData () {ArrayList<HashMap<String,Object>> arrayList =NewArraylist(); HashMap<String,Object> HashMap =NULL;  for(inti=0;i<10;i++) {HashMap=NewHashmap<string, object>(); Hashmap.put ("Index", integer.tostring (i+1)); Hashmap.put ("IMG", r.drawable.my); Arraylist.add (HASHMAP); //add to Data source        }        returnarrayList; }    //Create a custom adapter    Private classMyadapterextendsbaseadapter{PrivateLayoutinflater Mlayoutinflater;  PublicMyadapter (Context context) {Mlayoutinflater= Layoutinflater.from (context);//Dynamic Layout Mapping} @Override Public intGetCount () {returnmdata.size (); } @Override PublicObject GetItem (intposition) {            return NULL; } @Override Public LongGetitemid (intposition) {            return0; } @Override PublicView GetView (intposition, View Convertview, ViewGroup parent) {Convertview= Mlayoutinflater.inflate (R.layout.listitem,NULL);//instantiate view based on layout fileTextView TV =(TextView) Convertview.findviewbyid (R.id.textview); Tv.settext (Mdata.get (position). Get ("Index"). toString ()); ImageView img=(ImageView) Convertview.findviewbyid (R.id.imageview); Img.setbackgroundresource ((Integer) mdata.get (position). Get ("IMG")); returnConvertview; }    }}