转轮xml:

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

java:

public class MainActivity extends AppCompatActivity implements AdapterView.OnItemSelectedListener{

    private Spinner spinner;
    private static final String[] paths = {"item 1", "item 2", "item 3"};

    @Override
    protected void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main_layout);

        spinner = (Spinner)findViewById(R.id.spinner);
        ArrayAdapter<String>adapter = new ArrayAdapter<String>(MainActivity.this,
                android.R.layout.simple_spinner_item,paths);

        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spinner.setAdapter(adapter);
        spinner.setOnItemSelectedListener(this);

    }

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

        switch (position) {
            case 0:
                // Whatever you want to happen when the first item gets selected
                break;
            case 1:
                // Whatever you want to happen when the second item gets selected
                break;
            case 2:
                // Whatever you want to happen when the thrid item gets selected
                break;

        }
    }

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

}

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<*>?) {}
    }

转轮xml:

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

java:

public class MainActivity extends AppCompatActivity implements AdapterView.OnItemSelectedListener{

    private Spinner spinner;
    private static final String[] paths = {"item 1", "item 2", "item 3"};

    @Override
    protected void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main_layout);

        spinner = (Spinner)findViewById(R.id.spinner);
        ArrayAdapter<String>adapter = new ArrayAdapter<String>(MainActivity.this,
                android.R.layout.simple_spinner_item,paths);

        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spinner.setAdapter(adapter);
        spinner.setOnItemSelectedListener(this);

    }

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

        switch (position) {
            case 0:
                // Whatever you want to happen when the first item gets selected
                break;
            case 1:
                // Whatever you want to happen when the second item gets selected
                break;
            case 2:
                // Whatever you want to happen when the thrid item gets selected
                break;

        }
    }

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

}

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)

parseInt(binding.inputAge.text.toString()),

新的android资源文件(dropdown_item)在R.layout。Dropdown_item，把textview放在里面。

TextView代码:

`<TextView android:id="@+id/textView"
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:padding="14sp"
 android:text="textView"
 android:textColor="@color/black"
 android:textSize="16sp"
 android:textStyle="bold"
 xmlns:android="http://schemas.android.com/apk/res/android"/>`

//绑定适配器并获取值 binding.ddCity.setAdapter (showCity) binding.ddCity.selectedItem.toString ()

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) { 

                    } 

                } 
        ); 
    }