Learning notes for Android: Use Cases in the Spinner drop-down list

Learning notes for Android: Use Cases in the Spinner drop-down list

 

(1) Two methods are used to extract the data source from the Spinner: using the list set or configuring through the xml file

(2) The layout code is as follows:

 

(2)

Package com. example. spinners; import java. util. arrayList; import java. util. list; import android. app. activity; import android. OS. bundle; import android. view. menu; import android. view. view; import android. widget. adapterView; import android. widget. adapterView. onItemSelectedListener; import android. widget. arrayAdapter; import android. widget. spinner; import android. widget. toast;/*** use the OnItemSelectedListener interface to implement the selected event * @ author xuliugen **/public class MainActivity extends Activity implements OnItemSelectedListener {private Spinner spinner1; private Spinner spinner2; // private SpinnerAdapter spinnerAdapter; private ArrayAdapter
 
  
Adapter; @ Overrideprotected void onCreate (Bundle savedInstanceState) {super. onCreate (savedInstanceState); setContentView (R. layout. activity_main); spinner1 = (Spinner) this. findViewById (R. id. spinner1); spinner2 = (Spinner) this. findViewById (R. id. spinner2); // the first type of manually input listadapter = new ArrayAdapter
  
   
(MainActivity. this, android. r. layout. simple_spinner_item, getDataSource (); spinner1.setAdapter (adapter); // register the listener spinner1.setOnItemSelectedListener (this); // Method 2: ArrayAdapter adapter2 = ArrayAdapter by loading the data source configured in the xml file. createFromResource (this, R. array. planets_array, android. r. layout. simple_spinner_item); adapter2.setDropDownViewResource (android. r. layout. simple_spinner_dropdown_item); spinner2.setAdapter (adapter2);}/** use the first method: manually input list */public List
   
    
GetDataSource () {List
    
     
List = new ArrayList
     
      
(); List. add (beijing); list. add (beida); list. add (shahai); list. add (shangjing); list. add (shanglian); list. add (chengdu); return list;} @ Overridepublic boolean onCreateOptionsMenu (Menu menu) {getMenuInflater (). inflate (R. menu. main, menu); return true;} @ Overridepublic void onItemSelected (AdapterView
      Parent, View view, int position, long id) {String itemString = spinner1.getItemAtPosition (position ). toString (); Toast. makeText (this, you selected + itemString, 1 ). show () ;}@ Overridepublic void onNothingSelected (AdapterView
      Parent ){}}
     
    
   
  
 

 

(4) The configuration in the resource file is as follows:

 

 
     
  
   Spinners
      
  
   Settings
      
  
   Hello world!
      
          
   
    Mercury
           
   
    Venus
           
   
    Earth
           
   
    Mars
           
   
    Jupiter
           
   
    Saturn
           
   
    Uranus
           
   
    Neptune
       
  
 

(5) The running result is as follows: