Android Spinnerの選択肢をXMLで指定する

Spinnerでは、Adapterを用意しなくてもXMLから選択肢をセットすることができます。

res/values/arrays.xml

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1. <?xml version="1.0" encoding="utf-8"?>  
2. <resources>  
3.   
4.     <string-array name="spinner_values">  
5.         <item>Cupcake</item>  
6.         <item>Donut</item>  
7.         <item>Eclair</item>  
8.         <item>Froyo</item>  
9.         <item>Gingerbread</item>  
10.         <item>Honeycomb</item>  
11.         <item>ICS</item>  
12.         <item>JellyBean</item>  
13.         <item>KitKat</item>  
14.     </string-array>  
15.   
16. </resources>  

<?xml version="1.0" encoding="utf-8"?> <resources> <string-array name="spinner_values"> <item>Cupcake</item> <item>Donut</item> <item>Eclair</item> <item>Froyo</item> <item>Gingerbread</item> <item>Honeycomb</item> <item>ICS</item> <item>JellyBean</item> <item>KitKat</item> </string-array> </resources> res/layout/activity_main.xml

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1. <?xml version="1.0" encoding="utf-8"?>  
2. <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  
3.     android:layout_width="match_parent"  
4.     android:layout_height="match_parent"  
5.     android:orientation="vertical" >  
6.   
7.     <Spinner  
8.         android:id="@+id/spinner1"  
9.         android:layout_width="match_parent"  
10.         android:layout_height="wrap_content"  
11.         android:entries="@array/spinner_values" />  
12.   
13. </LinearLayout>  

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" > <Spinner android:id="@+id/spinner1" android:layout_width="match_parent" android:layout_height="wrap_content" android:entries="@array/spinner_values" /> </LinearLayout> このandroid:entries属性はAbsSpinnerで用意されています。

このように選択肢をセットした場合、Spinner部分のレイアウトには android.R.layout.simple_spinner_item が、ドロップダウンのレイアウトには android.R.layout.simple_spinner_dropdown_item が使われます。

AbsSpinner.java

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1.      67     public AbsSpinner(Context context, AttributeSet attrs, int defStyle) {  
2.      68         super(context, attrs, defStyle);  
3.      69         initAbsSpinner();  
4.      70   
5.      71         TypedArray a = context.obtainStyledAttributes(attrs,  
6.      72                 com.android.internal.R.styleable.AbsSpinner, defStyle, 0);  
7.      73   
8.      74         CharSequence[] entries = a.getTextArray(R.styleable.AbsSpinner_entries);  
9.      75         if (entries != null) {  
10.      76             ArrayAdapter<charsequence> adapter =  
11.      77                     new ArrayAdapter<charsequence>(context,  
12.      78                             R.layout.simple_spinner_item, entries);  
13.      79             adapter.setDropDownViewResource(R.layout.simple_spinner_dropdown_item);  
14.      80             setAdapter(adapter);  
15.      81         }  
16.      82   
17.      83         a.recycle();  
18.      84     }  
19. </charsequence></charsequence>  

67 public AbsSpinner(Context context, AttributeSet attrs, int defStyle) { 68 super(context, attrs, defStyle); 69 initAbsSpinner(); 70 71 TypedArray a = context.obtainStyledAttributes(attrs, 72 com.android.internal.R.styleable.AbsSpinner, defStyle, 0); 73 74 CharSequence[] entries = a.getTextArray(R.styleable.AbsSpinner_entries); 75 if (entries != null) { 76 ArrayAdapter adapter = 77 new ArrayAdapter(context, 78 R.layout.simple_spinner_item, entries); 79 adapter.setDropDownViewResource(R.layout.simple_spinner_dropdown_item); 80 setAdapter(adapter); 81 } 82 83 a.recycle(); 84 }

android.R.layout.simple_spinner_item

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1. <?xml version="1.0" encoding="utf-8"?>  
2. ...  
3. <TextView xmlns:android="http://schemas.android.com/apk/res/android"   
4.     android:id="@android:id/text1"  
5.     style="?android:attr/spinnerItemStyle"  
6.     android:singleLine="true"  
7.     android:layout_width="match_parent"  
8.     android:layout_height="wrap_content"  
9.     android:ellipsize="marquee"  
10.     android:textAlignment="inherit"/>  

<?xml version="1.0" encoding="utf-8"?> ... <TextView xmlns:android="http://schemas.android.com/apk/res/android" android:id="@android:id/text1" style="?android:attr/spinnerItemStyle" android:singleLine="true" android:layout_width="match_parent" android:layout_height="wrap_content" android:ellipsize="marquee" android:textAlignment="inherit"/>

android.R.layout.simple_spinner_dropdown_item

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1. <?xml version="1.0" encoding="utf-8"?>  
2. ...  
3. <CheckedTextView xmlns:android="http://schemas.android.com/apk/res/android"   
4.     android:id="@android:id/text1"  
5.     style="?android:attr/spinnerDropDownItemStyle"  
6.     android:singleLine="true"  
7.     android:layout_width="match_parent"  
8.     android:layout_height="?android:attr/dropdownListPreferredItemHeight"  
9.     android:ellipsize="marquee"  
10.     android:textAlignment="inherit"/>  

<?xml version="1.0" encoding="utf-8"?> ... <CheckedTextView xmlns:android="http://schemas.android.com/apk/res/android" android:id="@android:id/text1" style="?android:attr/spinnerDropDownItemStyle" android:singleLine="true" android:layout_width="match_parent" android:layout_height="?android:attr/dropdownListPreferredItemHeight" android:ellipsize="marquee" android:textAlignment="inherit"/> このレイアウトを見るとわかりますが、それぞれandroid:spinnerItemStyleとandroid:spinnerDropDownItemStyleに指定されているスタイルを適用しています。
この属性に独自のスタイルをセットすれば、Spinner部分とドロップダウンの文字サイズや文字色を一括で変えることができます。

• Widget.TextView.SpinnerItem
• Widget.Holo.TextView.SpinnerItem
• Widget.Holo.Light.TextView.SpinnerItem

• Widget.DropDownItem
• Widget.Holo.DropDownItem
• Widget.Holo.Light.DropDownItem

文字サイズを小さくする例

res/values/styles.xml

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1. <resources>  
2.   
3.     <style name="AppTheme" parent="android:Theme.Holo.Light.DarkActionBar">  
4.         <item name="android:spinnerItemStyle">@style/SpinnerItemStyle</item>  
5.         <item name="android:spinnerDropDownItemStyle">@style/SpinnerDropDownItemStyle</item>  
6.     </style>  
7.       
8.     <style name="SpinnerItemStyle" parent="android:Widget.Holo.Light.TextView.SpinnerItem">  
9.         <item name="android:textSize">12sp</item>  
10.     </style>  
11.       
12.     <style name="SpinnerDropDownItemStyle" parent="android:Widget.Holo.Light.DropDownItem">  
13.         <item name="android:textSize">12sp</item>  
14.     </style>  
15.   
16. </resources>  

<resources> <style name="AppTheme" parent="android:Theme.Holo.Light.DarkActionBar"> <item name="android:spinnerItemStyle">@style/SpinnerItemStyle</item> <item name="android:spinnerDropDownItemStyle">@style/SpinnerDropDownItemStyle</item> </style> <style name="SpinnerItemStyle" parent="android:Widget.Holo.Light.TextView.SpinnerItem"> <item name="android:textSize">12sp</item> </style> <style name="SpinnerDropDownItemStyle" parent="android:Widget.Holo.Light.DropDownItem"> <item name="android:textSize">12sp</item> </style> </resources>



この方法のときも、setOnItemSelectedListener()を使って選択項目が変わったことを検知でき、Adapterが保持しているObjectはStringになります。

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1. public class MainActivity extends Activity {  
2.   
3.     @Override  
4.     protected void onCreate(Bundle savedInstanceState) {  
5.         super.onCreate(savedInstanceState);  
6.         setContentView(R.layout.activity_main);  
7.   
8.         Spinner spinner = (Spinner) findViewById(R.id.spinner1);  
9.         spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {  
10.   
11.             @Override  
12.             public void onItemSelected(AdapterView<?> adapter,   
13.                 View v, int position, long id) {  
14.   
15.                 Toast.makeText(MainActivity.this,   
16.                     (String) adapter.getItemAtPosition(position),   
17.                     Toast.LENGTH_SHORT).show();  
18.             }  
19.   
20.             @Override  
21.             public void onNothingSelected(AdapterView<?> adapter) {  
22.             }  
23.         });  
24.     }  
25. }  

public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Spinner spinner = (Spinner) findViewById(R.id.spinner1); spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() { @Override public void onItemSelected(AdapterView<?> adapter, View v, int position, long id) { Toast.makeText(MainActivity.this, (String) adapter.getItemAtPosition(position), Toast.LENGTH_SHORT).show(); } @Override public void onNothingSelected(AdapterView<?> adapter) { } }); } }