Android CONTROLS: Use the drop-down list box--spinner

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First, the previous paragraph code

<SpinnerAndroid:id= "@+id/spin"Android:paddingtop= "10px"Android:layout_width= "Fill_parent"Android:layout_height= "50SP"/><ButtonAndroid:id= "@+id/addlist"Android:layout_width= "Wrap_content"Android:layout_height= "Wrap_content"Android:text= "Add" />

Second, next create a new drop-down list of view resources, that is, each item's TextView, we named it dropdown.xml, we put it in drawable, the code is:

<?XML version= "1.0" encoding= "Utf-8"?><TextViewxmlns:android= "Http://schemas.android.com/apk/res/android"Android:id= "@+id/tv1"Android:layout_width= "Fill_parent"Android:layout_height= "20SP"Android:singleline= "true"style= "? Android:attr/spinnerdropdownitemstyle"    />

Iii. creation of Adapter

Here are the next two functions:

1.arrayadapter.arrayadapter (Context context,int textviewresourcid,list<string> objects)

We can create a new adapter object from it, which requires three parameters:

(1) Contextual context, which is the adapter belongs to which activity, belongs to which application.

(2) Resource ID of Textviewresourcid TextView

(3) The last parameter is the data you want to add to the drop-down list, which can be a static String array or a dynamic list<string>;

2.adapterview.setonitemselectedlistener (Onitemselectedlistener Listener), use this method to set the listener for the spinner object. Here the parameter is the Onitemselectedlistener interface, implementation of this interface requires rewriting two methods:

(1) public void onitemselected (adapterview<?> parent, view view,int position, long ID)

This method allows you to do the processing that you want to do when the selected item is chosen. The meaning of the four parameters:

• Adapterview<?> parent, this kind of context, is just a range comparison, referring to your current operation of the Adapterview
• View view, this parameter is the TextView object you clicked on specifically
• int position This parameter means that the view you clicked is in the entire Adaterview position.
• Long ID Click the ID of the view

(2) public void onnothingselected (adapterview<?> parent)

This callback function is called when there are no options in Adapterview.

The complete code is as follows:

    PrivateSpinner Spinner; PrivateTextView TV; PrivateArrayadapter<string>adapter; Private Static FinalString[] years = {"Less than 1 Years", "1 years-3 years", "3 years-5 years", "5 years or more" }; Privatearraylist<string> array =NewArraylist<string>(); @Overrideprotected voidonCreate (Bundle savedinstancestate) {Super. OnCreate (savedinstancestate);        Setcontentview (R.layout.activity_main); if(Savedinstancestate = =NULL) {Getsupportfragmentmanager (). BeginTransaction (). Add (R.id.container,Newplaceholderfragment ()). commit (); } Spinner=(Spinner) Findviewbyid (R.id.spin); TV=(TextView) Findviewbyid (R.ID.TEXTVIEW1);  for(inti = 0; i < years.length; i++) {Array.add (years[i]); } Adapter=NewArrayadapter<string> ( This, Android.        R.layout.simple_spinner_item, array);                Adapter.setdropdownviewresource (R.drawable.dropdown);        Spinner.setadapter (adapter); Spinner.setonitemselectedlistener (NewOnitemselectedlistener () {@Override Public voidOnitemselected (adapterview<?>Parent, view view,intPositionLongID) {//TODO Auto-generated method stubsString seleted =Array.get (position);                Tv.settext (seleted);            Parent.setvisibility (view.visible); } @Override Public voidOnnothingselected (adapterview<?>arg0) {                //TODO Auto-generated method stubsTv.settext ("You don't have a choice"); }        });

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