Android SDK 提供了 WIFI 开发的相关 API，被保存在 android.net.wifi 和 android.net.wifi.p2p 包下。借助于 Android SDK 提供的相关开发类，可以方便地在 Android 系统的手机上开发基于 WIFI 的应用程序。
实例 WIFIDemo 演示了使用 WIFI 进行连接设备搜索并获取相应信息的过程，运行效果如图 1 所示。
图 1 WIFIDemo 运行结果
实例 WIFIDemo 中所使用的布局文件 main.xml 的内容如下：
android:id="@+id/mScrollView"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:scrollbars="vertical">
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal">
android:id="@+id/open_bt"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="打开wifi" />
android:id="@+id/close_bt"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="关闭wifi" />
android:id="@+id/check_bt"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="检查wifi" />
android:id="@+id/search_bt"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="扫描wifi" />
android:id="@+id/text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="null" />
实例 WIFIDemo 中 AndroidManifest.xml 文件的代码如下：
package="introduction.android.wifidemo">
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
实例 WIFIDemo 中主 Activity 文件 MainActivity.java 的代码如下：
package introduction.android.wifidemo;
import java.util.List;
import android.R.string;
import android.app.Activity;
import android.content.Context;
import android.net.wifi.ScanResult;
import android.net.wifi.WifiInfo;
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.ScrollView;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends Activity {
private Button open_bt, close_bt, check_bt, search_bt;
private TextView textView;
private WifiManager wifiManager;
private WifiInfo wifiInfo;
private ScrollView scrollView;
private List WifiConfiguration;
private ScanResult scanResult;
private List WifiList;
private StringBuffer stringBuffer = new StringBuffer();
/**
* Called when the activity is first created.
*/
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
scrollView = (ScrollView) findViewById(R.id.mScrollView);
open_bt = (Button) findViewById(R.id.open_bt);
close_bt = (Button) findViewById(R.id.close_bt);
check_bt = (Button) findViewById(R.id.check_bt);
search_bt = (Button) findViewById(R.id.search_bt);
textView = (TextView) findViewById(R.id.text);
open_bt.setOnClickListener(new open_btListener());
close_bt.setOnClickListener(new close_btListener());
check_bt.setOnClickListener(new check_btListener());
search_bt.setOnClickListener(new search_btListener());
}
class search_btListener implements OnClickListener {
public void onClick(View v) {
// TODO Auto-generated method stub
wifiManager.startScan();
WifiList = wifiManager.getScanResults();
wifiInfo = wifiManager.getConnectionInfo();
if (stringBuffer != null) {
stringBuffer = new StringBuffer();
}
stringBuffer = stringBuffer.append("Wifi名").append(" ").append("Wifi地址").append(" ")
.append("Wifi频率").append("").append("Wifi信号")
.append("\n");
if (WifiList != null) {
for (int i = 0; i < WifiList.size(); i++) {
scanResult = WifiList.get(i);
stringBuffer = stringBuffer.append(scanResult.SSID).append(" ")
.append(scanResult.BSSID).append(" ")
.append(scanResult.frequency).append(" ")
.append(scanResult.level).append("\n");
textView.setText(stringBuffer.toString());
}
stringBuffer = stringBuffer.append
("-----------------------------------------------").append("\n");
textView.setText(stringBuffer.toString());
stringBuffer = stringBuffer.append("当前Wifi—BSSID").append(":").append(wifiInfo.getBSSID()).append("\n")
.append("当前wifi—HiddenSSID").append(": ").append(wifiInfo.getHiddenSSID()).append("\n")
.append("当前Wifi—IpAddress").append(": ").append(wifiInfo.getIpAddress()).append("\n")
.append("当前Wifi—LinkSpeed").append(": ").append(wifiInfo.getLinkSpeed()).append("\n")
.append("当前Wifi—MacAddress").append(": ").append(wifiInfo.getMacAddress()).append("\n")
.append("当前Wifi—Network ID").append(": ").append(wifiInfo.getNetworkId()).append("\n")
.append("当前Wifi—RSSI").append(": ").append(wifiInfo.getRssi()).append("\n")
.append("当前Wifi—SSID").append(": ").append(wifiInfo.getSSID()).append("\n")
.append("-----------------------------------------------").append("\n")
.append("全部打印出关于本机Wifi信息").append(": ").append
(wifiInfo.toString());
textView.setText(stringBuffer.toString());
}
//stringBuffer=stringBuffer.append("-----------------------------------------------").append("\n");
//textView.setText()
}
}
class check_btListener implements OnClickListener {
public void onClick(View v) {
// TODO Auto-generated method stub
wifiManager = (WifiManager) MainActivity.this
.getSystemService(Context.WIFI_SERVICE);
System.out.println(wifiManager.getWifiState());
Toast.makeText(MainActivity.this,
"当前网卡状态为:" + change(), Toast.LENGTH_SHORT)
.show();
}
}
class close_btListener implements OnClickListener {
public void onClick(View v) {
// TODO Auto-generated method stub
wifiManager = (WifiManager) MainActivity.this
.getSystemService(Context.WIFI_SERVICE);
wifiManager.setWifiEnabled(false);
System.out.println(wifiManager.getWifiState());
Toast.makeText(MainActivity.this,
"当前网卡状态为" + change(), Toast.LENGTH_SHORT)
.show();
}
}
class open_btListener implements OnClickListener {
public void onClick(View v) {
// TODO Auto-generated method stub
wifiManager = (WifiManager) MainActivity.this.getSystemService(Context.WIFI_SERVICE);
wifiManager.setWifiEnabled(true);
System.out.println(wifiManager.getWifiState());
Toast.makeText(MainActivity.this,
"当前网卡状态为" + change(), Toast.LENGTH_SHORT)
.show();
}
}
public String change() {
String temp = null;
switch (wifiManager.getWifiState()) {
case 0:
temp = "wifi正在关闭ING";
break;
case 1:
temp = "wifi已经关闭";
break;
case 2:
temp = "wifi正在打开ING";
break;
case 3:
temp = "wifi已经打开";
break;
default:
break;
}
return temp;
}
}