Baseadapter for Android basic classes

Baseadapter for Android applications Program It is a commonly used basic data adapter. It is mainly used to transmit a set of data to UI display components such as listview, spinner, gallery, and gridview. It inherits from the interface adapter, 1. Adapter class Introduction 1). shows the structure of the relevant adapter class: to customize the adapter subclass, You need to implement the preceding methods. The most important method is the getview () method, it returns the view component after obtaining data, such as textview in each row of listview and imageview in Gallery. 2) Adapter plays a very important role in Android applications and is widely used. It can be seen as a bridge between data sources and UI components, the relationship between the adapter, data, and UI can be expressed as follows: 3), common subclass 2, baseadapter Introduction
Baseadapter implements the listadapter and spinneradapter interfaces. Of course, it can also directly provide data to UI components such as listview and spinner. Shows the related class structure. 3. Example 1: Gallery displays the running results of a group of images:
Note: The above row of images is the gallery. Each time you click a gallery image, the layout file of the image is displayed in an uppercase image below:

 <?  XML version = "1.0" encoding = "UTF-8"  ?>  
 <  Linearlayout  Xmlns: Android  = "Http://schemas.android.com/apk/res/android"  
Android: Orientation  = "Vertical"  
Android: layout_width  = "Fill_parent"  
Android: layout_height  = "Fill_parent"  
  >  
  <  Textview
 Android: layout_width  = "Fill_parent"   
Android: layout_height  = "Wrap_content"   
Android: Text  = "@ String/hello"  
  />  

  <  Gallery
  Android: ID  = "@ + ID/gallery1"   
Android: layout_width  = "Match_parent"  
Android: spacing  = "5px"   
Android: layout_height  = "Wrap_content"   
  > </  Gallery  >  
  <  Imageview
  Android: ID  = "@ + ID/IV"  
Android: layout_gravity  = "Center_vertical" 
Android: layout_margintop  = "20px"  
Android: layout_width  = "320px"  
Android: layout_height  = "320px"  
  > </  Imageview  >  

  </  Linearlayout  > 

Mainactivity class:

 Package Com. magc. Adapter;

  Import  Android. App. activity;
  Import  Android. content. context;
  Import  Android. OS. Bundle;
  Import  Android. util. log;
  Import  Android. View. view;
  Import  Android. View. viewgroup;
  Import Android. View. View. onclicklistener;
  Import  Android. widget. adapterview;
  Import  Android. widget. baseadapter;
  Import  Android. widget. Gallery;
  Import  Android. widget. imageview;
  Import  Android. widget. adapterview. onitemclicklistener;

  Public     Class Mainactivity  Extends  Activity {
  Private  Gallery;
  Private  Imageview imgview;
  Private     Int  [] IMGs  =  {R. drawable. A6, R. drawable. A1, R. drawable. A2, R. drawable. A3, R. drawable. A4, R. drawable. A5 };
  /** Called when the activity is first created.  */  
@ Override
  Public     Void  Oncreate (bundle savedinstancestate ){
  Super  . Oncreate (savedinstancestate );
Setcontentview (R. layout. Main );
Imgview  =  (Imageview) findviewbyid (R. Id. IV );
Gallery  = (Gallery) findviewbyid (R. Id. gallery1 );
Myimgadapter Adapter  =     New  Myimgadapter (  This  );
Gallery. setadapter (adapter );
Gallery. setonitemclicklistener (  New  Onitemclicklistener (){
  //  When you click an image, set the resourceid of the image to the image view below,  
  @ Override
  Public    Void  Onitemclick (adapterview  <?>  Arg0, view,  Int  Position,
  Long  Arg3 ){

Imgview. setimageresource (IMGs [position]);

}
});
}

  Class  Myimgadapter  Extends Baseadapter {
// The custom image adapter contains classes in mainactivity to facilitate access to various variables in mainactivity, especially IMGs arrays.
  Private  Context context;  //  Receives the passed context object.  
    Public  Myimgadapter (context ){
  Super  ();
  This  . Context =  Context;
}


  /*  (Non-javadoc)
* @ See Android. widget. Adapter # getcount ()
  */  
@ Override
  Public     Int  Getcount (){
  Return  IMGs. length;
}

  /* (Non-javadoc)
* @ See Android. widget. Adapter # getitem (INT)
  */  
@ Override
  Public  Object getitem (  Int  Position ){
  Return  Position;
}

  /*  (Non-javadoc)
* @ See Android. widget. Adapter # getitemid (INT)
  */  
@ Override
 Public     Long  Getitemid (  Int  Position ){
  Return  Position;
}

  /*  (Non-javadoc)
* @ See Android. widget. Adapter # getview (INT, Android. View. View, Android. View. viewgroup)
  */  
@ Override
  Public  View getview ( Int  Position, view convertview, viewgroup parent ){
  //  Create an imageview instance for each data (that is, each image ID,  
  Imageview IV  =     New  Imageview (context );  //  For the context variables passed outside,  
  Iv. setimageresource (IMGs [position]);
Log. I ( "  Magc  "  , String. valueof (IMGs [position]);
Iv. setlayoutparams (  New  Gallery. layoutparams (  80  ,  80  ));  //  Set the size of each image in the gallery to 80*80.  
  Iv. setscaletype (imageview. scaletype. fit_xy );
  Return IV;
}

}

} 

Example 2: Use a prompt box to select the Avatar function (gallery and imageswitcher are used together to display the image) To be continued ......