在Kotlin中，您可以这样做:

首先，将这些代码放入布局中

   <Spinner
            android:id="@+id/spinner"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"/>

然后你可以在onCreate()在活动作为->

   val spinner = findViewById<Spinner>(R.id.spinner)
    val items = arrayOf("500g", "1kg", "2kg")
    val adapter = ArrayAdapter<String>(
        this,
        android.R.layout.simple_spinner_dropdown_item,
        items
    )
    spinner.setAdapter(adapter)

你可以从下拉菜单中获取listener:

 spinner.onItemSelectedListener = object : OnItemSelectedListener {
        override fun onItemSelected(
            arg0: AdapterView<*>?,
            arg1: View?,
            arg2: Int,
            arg3: Long
        ) {
            // Do what you want
            val items = spinner.selectedItem.toString()
            
        }

        override fun onNothingSelected(arg0: AdapterView<*>?) {}
    }

在Kotlin中，您可以这样做:

首先，将这些代码放入布局中

   <Spinner
            android:id="@+id/spinner"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"/>

然后你可以在onCreate()在活动作为->

   val spinner = findViewById<Spinner>(R.id.spinner)
    val items = arrayOf("500g", "1kg", "2kg")
    val adapter = ArrayAdapter<String>(
        this,
        android.R.layout.simple_spinner_dropdown_item,
        items
    )
    spinner.setAdapter(adapter)

你可以从下拉菜单中获取listener:

 spinner.onItemSelectedListener = object : OnItemSelectedListener {
        override fun onItemSelected(
            arg0: AdapterView<*>?,
            arg1: View?,
            arg2: Int,
            arg3: Long
        ) {
            // Do what you want
            val items = spinner.selectedItem.toString()
            
        }

        override fun onNothingSelected(arg0: AdapterView<*>?) {}
    }

简单的/优雅的/我怎么做的:

预览:

XML:

<Spinner
    android:id="@+id/spinner1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@android:drawable/btn_dropdown"
    android:spinnerMode="dropdown"/>

spinnerMode设置为dropdown是android的下拉方式。(https://developer.android.com/reference/android/widget/Spinner attr_android: spinnerMode)

Java:

//get the spinner from the xml.
Spinner dropdown = findViewById(R.id.spinner1);
//create a list of items for the spinner.
String[] items = new String[]{"1", "2", "three"};
//create an adapter to describe how the items are displayed, adapters are used in several places in android.
//There are multiple variations of this, but this is the basic variant.
ArrayAdapter<String> adapter = new ArrayAdapter<>(this, android.R.layout.simple_spinner_dropdown_item, items);
//set the spinners adapter to the previously created one.
dropdown.setAdapter(adapter);

文档:

这是基础知识，但还有更多的东西可以通过实验自学。 https://developer.android.com/guide/topics/ui/controls/spinner.html

你可以使用setOnItemSelectedListener。(https://developer.android.com/guide/topics/ui/controls/spinner.html # SelectListener) 您可以从xml中添加字符串列表。(https://developer.android.com/guide/topics/ui/controls/spinner.html #填充) 这个视图有一个appCompat版本。(https://developer.android.com/reference/androidx/appcompat/widget/AppCompatSpinner)

你也可以使用AppCompatSpinner小部件:

<android.support.v7.widget.AppCompatSpinner
    android:id="@+id/spinner_order_type"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    app:backgroundTint="@color/red"/>

在Activity类内部:

AppCompatSpinner spinOrderType = (AppCompatSpinner) findViewById(R.id.spinner_order_type);
List<String> categories = new ArrayList<String>();
        categories.add(getString(R.string.label_table_order));
        categories.add(getString(R.string.label_take_away));

        ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(mContext,
                R.layout.layout_spinner_item, categories);
        dataAdapter.setDropDownViewResource(R.layout.layout_spinner_item);
        spinOrderType.setAdapter(dataAdapter);
        spinOrderType.setSelection(0);

        spinOrderType.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long l) {
                String item = parent.getItemAtPosition(position).toString();
                Log.d(TAG, item);
            }

            @Override
            public void onNothingSelected(AdapterView<?> adapterView) {

            }
        });

layout_spinner_item.xml

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    xmlns:tools="http://schemas.android.com/tools"
    android:gravity="left"
    android:textSize="@dimen/text.size.large"
    android:textColor="@color/text.link"
    android:padding="@dimen/margin.3" />

下面是它的代码。

activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >

<Spinner
    android:id="@+id/static_spinner"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_marginBottom="20dp"
    android:layout_marginTop="20dp" />

<Spinner
    android:id="@+id/dynamic_spinner"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content" />

strings.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="app_name">Ahotbrew.com - Dropdown</string> 
<string-array name="brew_array">
    <item>Cappuccino</item>
    <item>Espresso</item>
    <item>Mocha</item>
    <item>Caffè Americano</item>
    <item>Cafe Zorro</item>
</string-array> 

MainActivity

Spinner staticSpinner = (Spinner) findViewById(R.id.static_spinner);

    // Create an ArrayAdapter using the string array and a default spinner
    ArrayAdapter<CharSequence> staticAdapter = ArrayAdapter
            .createFromResource(this, R.array.brew_array,
                    android.R.layout.simple_spinner_item);

    // Specify the layout to use when the list of choices appears
    staticAdapter
            .setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

    // Apply the adapter to the spinner
    staticSpinner.setAdapter(staticAdapter);

    Spinner dynamicSpinner = (Spinner) findViewById(R.id.dynamic_spinner);

    String[] items = new String[] { "Chai Latte", "Green Tea", "Black Tea" };

    ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
            android.R.layout.simple_spinner_item, items);

    dynamicSpinner.setAdapter(adapter);

    dynamicSpinner.setOnItemSelectedListener(new OnItemSelectedListener() {
        @Override
        public void onItemSelected(AdapterView<?> parent, View view,
                int position, long id) {
            Log.v("item", (String) parent.getItemAtPosition(position));
        }

        @Override
        public void onNothingSelected(AdapterView<?> parent) {
            // TODO Auto-generated method stub
        }
    });

这个例子来自 http://www.ahotbrew.com/android-dropdown-spinner-example/

试试这个…

<string-array name="names">

        <item></item>
        <item>By Bus</item>
        <item>By Train</item>
        <item>By Van</item>
        <item>By Bike</item>
    </string-array>


String travel_type;


ArrayAdapter<String> myAdapter = new ArrayAdapter(AddNew_Trip.this,android.R.layout.simple_list_item_1, getResources().getStringArray(R.array.names)); 
        myAdapter.setDropDownViewResource(android.R.layout.simple_dropdown_item_1line); 
        mySpinner.setAdapter(myAdapter); 

        mySpinner.setOnItemSelectedListener( 
                new AdapterView.OnItemSelectedListener() { 

                    @Override 
                    public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) { 
                        travel_type = String.valueOf(adapterView.getItemAtPosition(i)); 
                        //Toast.makeText(Plan_Trip.this, travel_type, Toast.LENGTH_SHORT).show(); 
                    } 

                    @Override 
                    public void onNothingSelected(AdapterView<?> adapterView) { 

                    } 

                } 
        ); 
    }