《通信業(yè)務(wù)開發(fā)》課程OnItemSelected選項(xiàng)OnItemSelectedListenerPART18-4事件特性監(jiān)聽接口實(shí)例演示事件特性示例選項(xiàng)選擇事件，如Spinner、ListView……接口：OnItemSelectedListener.

onItemSelected()onNothingSelected()實(shí)現(xiàn)步驟：獲取監(jiān)聽對(duì)象：如Spinner創(chuàng)建監(jiān)聽器類,實(shí)現(xiàn)OnItemSelectedListener注冊(cè)監(jiān)聽器：

setOnItemSelectedListener()規(guī)則監(jiān)聽接口publicstaticinterfaceAdapterView.OnItemSelectedListener(){publicvoidonItemSelected(AdapterView<?>parent,Viewview,intposition,longid){}publicvoidonNothingSelected(AdapterView<?>parent){}}voidsetOnItemSelectedListener(AdapterView.OnItemSelectedListener

l)實(shí)例演示<resources>

<stringname="planet_prompt">太陽系行星：</string>

<string-array

name="planets_arry">

<item>Mercury</item>

<item>Venus</item>

<item>Earth</item>

<item>Mars</item>

<item>Jupiter</item>

<item>Saturn</item>

<item>Uranus</item>

<item>Neptune</item>

</string-array>

</resources><LinearLayout…>

<TextView…/>

<Spinnerandroid:id="@+id/spinner1"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:prompt="@string/planet_prompt"/>

</LinearLayout>XML布局實(shí)例演示public

class

MainActivity

extends

Activity

{

@Override

protected

void

onCreate(Bundle

savedInstanceState)

{

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

Spinnerspin=(Spinner)findViewById(R.id.spinner1);

ArrayAdapter<CharSequence>adapter=

ArrayAdapter.createFromResource(this,

R.array.planets_arry,android.R.layout.simple_spinner_item);

adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

spin.setAdapter(adapter);

sp.setOnItemSelectedListener(newOnPlanetItemSelectedListener());

}

publicclassOnPlanetItemSelectedListener

implementsOnItemSelectedListener{

@Override

publicvoid

onItemSelected(AdapterView<?>parent,Viewarg1,intpos,longarg3){

Toast.makeText(parent.getContext(),

"Theplanetis"+

parent.getItemAtPosition(pos).toString(),

Toast.LENGTH_LONG).show