Tìm hiểu về Spinner trong android

Spinner là gì

Nếu bạn đã từng lập trình vb.net, C Sharp thì Spinner giống như ComboBox. Trong Java ta có JComboBox cũng tương tự nhu spinner

Trong android cách sử dụng Spinner và ListView gần như nhau, Spinner chỉ khác ListView là bạn phải set Resource cho DropDownView, xem code bên dưới để hiểu hơn về spinner

Code Clas MainActivity

package com.example.macbookpro.dtsondcspinner2;

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 {
    Spinner spn;
    String arr[] = {"Cocacola", "Pepsi","Redbull","C2","Other"};
    @Override    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //==== anh xa        spn = (Spinner) findViewById(R.id.spinnerNuocUong);

        // === tao ArrayAdapter        ArrayAdapter<String > adapter = new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item,arr);
        // thiet lap Resource cho  DropDown        adapter.setDropDownViewResource(android.R.layout.simple_list_item_single_choice);
        // gan adapter cho spinner        spn.setAdapter(adapter);

        //=== Thiet lap su kien select tren cac Item cua spinner        spn.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            //Khi select vao 1 Item bat ky            @Override            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                String nuocUong = arr[position];
                Toast.makeText(MainActivity.this,"Ban vua chon nuoc uong: "+nuocUong,Toast.LENGTH_SHORT).show();
            }
            // khi Khong select vao bat ky Item nao            @Override            public void onNothingSelected(AdapterView<?> parent) {
                Toast.makeText(MainActivity.this,"Ban chua chon nuoc uong!",Toast.LENGTH_SHORT).show();
            }
        });
    }
}

Code Xml giao diện

<?xml version="1.0" encoding="utf-8"?><LinearLayout 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"    android:orientation="vertical"    tools:context="com.example.macbookpro.dtsondcspinner2.MainActivity">

    <TextView        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:textAppearance="?android:attr/textAppearanceLarge"        android:text="DANH SACH NUOC UONG"        android:background="#1941c6"        android:textColor="#FF0000"        android:gravity="center"        android:id="@+id/textView"        android:layout_gravity="center_horizontal" />

    <Spinner        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:id="@+id/spinnerNuocUong"        android:layout_gravity="center_horizontal" />
</LinearLayout>