Android控件之Spinner简单使用

0x00 效果图

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0x01 定义Spinner视图

在drawable包下, 新建一个xml文件spinner_background.xml, 自定义Spinner的背景:

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item>
        <layer-list>
            <item>
                <shape>
                    <gradient android:angle="90"
                              android:endColor="@color/moccasin"
                              android:startColor="#E8EBEF"
                              android:type="linear" />

                    <stroke android:width="1dp"
                            android:color="#000000" />

                    <corners android:radius="2dp" />

                    <padding android:bottom="3dp"
                             android:left="3dp"
                             android:right="3dp"
                             android:top="3dp" />
                </shape>
            </item>
        </layer-list>
    </item>
</selector>

(渐变色效果)效果如下:

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0x02 定义一个Theme

在res/values/styles.xml中添加一个style, 然后在Spinner添加这个Theme:

<style name="spinnerstyle">
    <item name="android:background">@drawable/spinner_background</item>
    <item name="android:layout_marginLeft">10dp</item>
    <item name="android:layout_marginRight">10dp</item>
    <item name="android:layout_marginBottom">10dp</item>
    <item name="android:paddingLeft">0dp</item>
    <item name="android:paddingTop">3dp</item>
    <item name="android:paddingBottom">5dp</item>
    <item name="android:popupBackground">@color/lemon_chiffon</item>
</style>

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0x03 添加Spinner控件

在想要添加Spinner控件的layout里添加Spinner控件:

<Spinner
    android:id="@+id/spinner_service"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginTop="20dp"
    android:focusableInTouchMode="true"
    android:scrollbars="vertical"
    android:theme="@style/spinnerstyle">
</Spinner>

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0x04 添加Spinner里的选项字符串数组

这里我在res/values中添加了一个str_array_services.xml:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string-array name="services_array">
        <item>@string/str_select_service</item>
        <item>@string/str_health_self</item>
        <item>@string/str_hs_project</item>
        <item>@string/str_com_care</item>
        <item>@string/str_find_people</item>
        <item>@string/str_dormitory</item>
    </string-array>
</resources>

那些@string/xxx在strings.xml定义这些字符串.(这里为了更好的耦合性, 可以设置成多个语言版本)

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0x05 在Activity或Fragment中实例化Spinner

public class LoginActivity extends AppCompatActivity implements AdapterView.OnItemSelectedListener {
    private Spinner mSpinner;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);
        mSpinner = findViewById(R.id.spinner_service);
        mSpinner.setOnItemSelectedListener(this);
        ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this,
                R.array.services_array, android.R.layout.simple_spinner_item);
        adapter.setDropDownViewResource(android.R.layout.simple_dropdown_item_1line);
        mSpinner.setAdapter(adapter);
    }

    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {

    }

    @Override
    public void onNothingSelected(AdapterView<?> parent) {
        // Another interface callback
    }
}

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