android—wifi

1.       什么是wifi？

     Wifi是一种无线联网的技术，以前通过网线连接电脑，现在通过无线电波来连网，常见的就是一个无限路由器，那么这个无限路由器的电波覆盖的有效范围都可以采用wifi连接方式进行连网，如果无线路由器连接了一条ADSL线路或者别的上网线路，则又被称为热点。

 

 

2.       获取wifi网卡的状态

 

是由一系列的整形常量来表示的，

WIFI_STATE_DISABLED: 网卡不可用             constant value        1

WIFI_STATE_DISABLING：WIFI正在关闭         constant value        0

WIFI_STATE_ENABLED:   WIFI网卡可用         constant value        3       

WIFI_STATE_ENABLING : WIFI网卡正在打开      constant value        2

WIFI_STATE_UNKNOWN:未知网卡状态

       

 

3.       操作wifi所需要的权限

 

<uses-permission android:name="android.permission.CHANGE_NETWORK_STATE"></uses-permission>

    <uses-permission android:name="android.permission.CHANGE_WIFI_STATE"></uses-permission>

    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"></uses-permission>

    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE"></uses-permission>

 

4.       改变wifi网卡的状态

 

改变wifi网卡的状态，

对wifi网卡进行操作，需要通过WifiManager对象来进行，获取该对象的方法如下:

WifiManger

WifiManger =( WifiManger)Context.getSystemService(Service.WIFI_SERVICE);

 

   打开wifi网卡

WifiManger.setWifiEnabled(ture);

  关闭wifi网卡

WifiManger.setEnable(false);

获取网卡当前的状态：

WifiManger.getWifiState();

代码如下：

package com.wbk.wifi.activity;

import android.app.Activity;
import android.content.Context;
import android.net.wifi.WifiManager;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;

public class Wifi_wbkActivity extends Activity
{
    private Button startButton = null;
    private Button stopButton = null;
    private Button checkButton = null;

    private WifiManager wifiManager = null;

    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        startButton = (Button) findViewById(R.id.startButton);
        stopButton = (Button) findViewById(R.id.stopButton);
        checkButton = (Button) findViewById(R.id.checkButton);
        startButton.setOnClickListener(new startWifiListener());
        stopButton.setOnClickListener(new stopWifiListener());
        checkButton.setOnClickListener(new checkWifiListener());
    }

    // 内部类，需要的是Wifi_wbkActivity的对象，所以Wifi_wbkActivity.this
    class startWifiListener implements OnClickListener
    {

        @Override
        public void onClick(View v)
        {
            wifiManager = (WifiManager) Wifi_wbkActivity.this.getSystemService(Context.WIFI_SERVICE);
            wifiManager.setWifiEnabled(true);
            System.out.println("wifi start ----->" + wifiManager.getWifiState());
            Toast.makeText(Wifi_wbkActivity.this, "当前wifi网卡状态为", wifiManager.getWifiState());
        }
    }

    class stopWifiListener implements OnClickListener
    {

        @Override
        public void onClick(View v)
        {
            wifiManager=(WifiManager)Wifi_wbkActivity.this.getSystemService(Context.WIFI_SERVICE);
            wifiManager.setWifiEnabled(false);
            System.out.println("wifi stop --->"+wifiManager.getWifiState());
            Toast.makeText(Wifi_wbkActivity.this, "当前的wifi状态为", wifiManager.getWifiState());
            
        }

    }
    class checkWifiListener implements OnClickListener{

        @Override
        public void onClick(View v)
        {
            wifiManager=(WifiManager)Wifi_wbkActivity.this.getSystemService(Context.WIFI_SERVICE);
            System.out.println("wifi state ----->"+wifiManager.getWifiState());
            Toast.makeText(Wifi_wbkActivity.this, "当前的wifi状态为",  wifiManager.getWifiState());
        }
        
    }

}