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)

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
        }

}

您可以通过以下简单的步骤创建旋转器

首先在XML中创建旋转器

<Spinner
        android:id="@+id/select"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:textColor="#070707"></Spinner>

现在在值中创建字符串arary

 <string-array name="itemselect">
    <item>Repurchase</item>
    <item>Coupons</item>
</string-array>

现在在Java文件中初始化

public class MemberCart_Activity extends AppCompatActivity {

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

 
    select=findViewById(R.id.select);
 ArrayAdapter<String> myadapter=new ArrayAdapter<String>(Main_Activity.this,android.R.layout.simple_list_item_1,getResources().getStringArray(R.array.itemselect));
    myadapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    select.setAdapter(myadapter);

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" />

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:

package example.spin.spinnerexample;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity implements AdapterView.OnItemSelectedListener{

    String[] bankNames={"BOI","SBI","HDFC","PNB","OBC"};
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //Getting the instance of Spinner and applying OnItemSelectedListener on it
        Spinner spin = (Spinner) findViewById(R.id.simpleSpinner);
        spin.setOnItemSelectedListener(this);

        //Creating the ArrayAdapter instance having the bank name list
        ArrayAdapter aa = new ArrayAdapter(this,android.R.layout.simple_spinner_item,bankNames);
        aa.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        //Setting the ArrayAdapter data on the Spinner
        spin.setAdapter(aa);
    }


    //Performing action onItemSelected and onNothing selected
    @Override
    public void onItemSelected(AdapterView<?> arg0, View arg1, int position,long id) {
        Toast.makeText(getApplicationContext(), bankNames[position], Toast.LENGTH_LONG).show();
    }

    @Override
    public void onNothingSelected(AdapterView<?> arg0) {
        // TODO Auto-generated method stub

    }
}

activity_main.xml: -

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity">

    <Spinner
        android:id="@+id/simpleSpinner"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="100dp" />

</RelativeLayout>