<1>什麼是Wi-Fi?
Wi-Fi是一種可以將個人電腦、手持設備(如PDA、手機)等終端以無線方式互相連接的技術。Wi-Fi是一個無線網路通信技術的品牌,由Wi-Fi聯盟(Wi-FiAlliance)所持有。
Wi-Fi 原先是無線保真的縮寫,Wi-Fi 的英文全稱為wireless fidelity,在無線局域網的范疇是指“無線相容性認證”,實質上是一種商業認證,同時也是一種無線聯網的技術,以前通過網線連接電腦,而現在則是通過無線電波來連網;常見的就是一個無線路由器,那麼在這個無線路由器的電波覆蓋的有效范圍都可以采用WIFI連接方式進行聯網,如果無線路由器連接瞭一條ADSL線路或者別的上網線路,則又被稱為“熱點”。
<2>獲取WI-FI網卡的狀態(常量)
public static final int WIFI_STATE_DISABLED
Wi-Fi is disabled. WI-FI網卡不可用
Constant Value(常量值): 1 (0x00000001)
public static final int WIFI_STATE_DISABLING
Wi-Fi is currently being disabled. WI-FI網卡正在關閉
The state will change to WIFI_STATE_DISABLED if it finishes successfully.
最終狀態會變成WI-FI網卡不可用
Constant Value(常量值): 0 (0x00000000)
public static final int WIFI_STATE_ENABLED
Wi-Fi is enabled. WI-FI網卡可用
Constant Value(常量值): 3 (0x00000003)
public static final int WIFI_STATE_ENABLING
Wi-Fi is currently being enabled. WI-FI網卡正在打開
The state will change to WIFI_STATE_ENABLED if it finishes successfully.
最終狀態會變成WI-FI網卡可用
Constant Value(常量值): 2 (0x00000002)
public static final int WIFI_STATE_UNKNOWN
Wi-Fi is in an unknown state. 未知 網卡狀態
This state will occur when an error happens while enabling or disabling.
Constant Value(常量值): 4 (0x00000004)
<3>操作WI-FI的所需的權限
可以在幫助文檔裡找到詳細的權限,這裡隻列出一部分。
Manifest.permission(權限)
public static final String CHANGE_WIFI_MULTICAST_STATE
Allows applications to enter Wi-Fi Multicast mode
Constant Value: "android.permission.CHANGE_WIFI_MULTICAST_STATE"
public static final String CHANGE_WIFI_STATE
Allows applications to change Wi-Fi connectivity state
Constant Value: "android.permission.CHANGE_WIFI_STATE"
public static final String CHANGE_NETWORK_STATE
Allows applications to change network connectivity state
Constant Value: "android.permission.CHANGE_NETWORK_STATE
<4>改變WI-FI網卡的狀態
對WI-FI網卡進行操作需要通過WifiManager對象進行
WifiManager wifiManager = (WifiManager) this.getSystemService(Context.WIFI_SERVICE);
打開WI-FI網卡
wifiManager.setWifiEnabled(true);
關閉WI-FI網卡
wifiManager.setWifiEnabled(false);
獲取網卡當前狀態
wifiManager..getWifiState()
package mars.wifi;
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 WifiActivity extends Activity {
/** Called when the activity is first created. */
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.startWifi);
stopButton = (Button)findViewById(R.id.stopWifi);
checkButton = (Button)findViewById(R.id.checkWifi);
startButton.setOnClickListener(new StartWifiListener());
stopButton.setOnClickListener(new StopWifiListener());
checkButton.setOnClickListener(new CheckWifiListener());
}
class StartWifiListener implements OnClickListener{
public void onClick(View v) {
wifiManager = (WifiManager)WifiActivity.this.getSystemService(Context.WIFI_SERVICE);
wifiManager.setWifiEnabled(true);
System.out.println("wifi state —>" + wifiManager.getWifiState());
Toast.makeText(WifiActivity.this, "當前Wifi網卡狀態為" + wifiManager.getWifiState(), Toast.LENGTH_SHORT).show();
}
}
class StopWifiListener implements OnClickListener{
public void onClick(View arg0) {
// TODO Auto-generated method stub
wifiManager = (WifiManager)WifiActivity.this.getSystemService(Context.WIFI_SERVICE);
wifiManager.setWifiEnabled(false);
switch (wifiManager.getWifiState())
{
case WifiManager.WIFI_STATE_DISABLED:
System.out.println("wifi state —>" + "WIFI已關閉");
break;
case WifiManager.WIFI_STATE_DISABLING:
System.out.println("wifi state —>" + "WIFI正在關閉中");
break;
case WifiManager.WIFI_STATE_ENABLED:
System.out.println("wifi state —>" + "WIFI已啟用");
break;
case WifiManager.WIFI_STATE_ENABLING:
System.out.println("wifi state —>" + "WIFI正在啟動中");
break;
case WifiManager.WIFI_STATE_UNKNOWN:
System.out.println("wifi state —>" + "未知WIFI狀態");
break;
}
Toast.makeText(WifiActivity.this, "當前Wifi網卡狀態為" + wifiManager.getWifiState(), Toast.LENGTH_SHORT).show();
}
}
class CheckWifiListener implements OnClickListener{
public void onClick(View v) {
wifiManager = (WifiManager)WifiActivity.this.getSystemService(Context.WIFI_SERVICE);
System.out.println("wifi state —>" + wifiManager.getWifiState());
Toast.makeText(WifiActivity.this, "當前Wifi網卡狀態為" + wifiManager.getWifiState(), Toast.LENGTH_SHORT).show();
}
}
}
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="https://schemas.android.com/apk/res/android"
package="mars.wifi" android:versionCode="1" android:versionName="1.0">
<application android:icon="@drawable/icon" android:label="@string/app_name">
<activity android:name=".WifiActivity" android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
<uses-sdk android:minSdkVersion="4" />
<!– 以下是使用wifi訪問網絡所需要的權限 www.aiwalls.com –>
<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>
</manifest>