第十八篇-Spinner下拉列表的使用

MainActivity.java

package com.example.aimee.spinnertest;

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 {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Spinner spinner=findViewById(R.id.spinner);
        ArrayAdapter<?>adapter=ArrayAdapter.createFromResource(this,R.array.color,android.R.layout.simple_list_item_1);
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spinner.setAdapter(adapter);
        AdapterView.OnItemSelectedListener itemSelectedListener=new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                Toast.makeText(MainActivity.this,"选择的色彩"+parent.getItemAtPosition(position).toString(),Toast.LENGTH_LONG).show();
            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {
                Toast.makeText(MainActivity.this,"Nothing is selected",Toast.LENGTH_LONG).show();

            }
        };
        spinner.setOnItemSelectedListener(itemSelectedListener);
    }
}

 main_activity.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">
    
    <Spinner
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/spinner"
        android:entries="@array/color"
        >
    </Spinner>

</android.support.constraint.ConstraintLayout>

 arrays.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string-array name="color">
        <item>red</item>
        <item>blue</item>
        <item>yellow</item>
        <item>pink</item>
        <item>orange</item>
    </string-array>
</resources>