android開發步步為營之48：通過WifiManager自動連上某個wifi熱點

最近參加了個某個創業公司的面試，他們做了個應用，就是用戶打開他們的應用就可以提供免費上網的功能，然後面試的過程中，那哥們說，你對wifi這些協議你懂嗎？需要用到比較底層的東西哦，我勒個去，就這麼一個上網功能就需要很底層嗎？搞得很高深的樣子，真是底層是涉及到修改android的框架了，修改手機ROM了，你們做到這一步了嗎？沒有吧，只是在android框架提供api基礎上實現的，為此，我今天特意實驗了一把。也就10幾分鐘就搞定的事情，我被你們懵到了，額。。。

開發過程中主要用到WifiManager這個系統自帶的服務，它有如下幾個狀態

WifiManager.WIFI_STATE_DISABLED: //wifi不可用

WifiManager.WIFI_STATE_DISABLING://wifi 正在關閉或者斷開

WifiManager.WIFI_STATE_ENABLED://wifi已經打開可用

WifiManager.WIFI_STATE_ENABLING://wifi正在打開或者連接

WifiManager.WIFI_STATE_UNKNOWN://未知消息

好，開始我們的實驗：

第一步：AndroidManifest.xml添加相關權限

第二步：新建測試頁面/study/res/layout/activity_wifi.xml

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"
tools:context=".MainActivity" >

android:id="@+id/btnWifi"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="47dp"
android:text="自動連上wifi" />

第三步：實現Activity，WifiManagerTestActivity.java

/**
* 自動選擇連上某個wifi信號
*/
package com.figo.study;

import java.util.List;

import android.app.Activity;
import android.content.Context;
import android.net.wifi.WifiConfiguration;
import android.net.wifi.WifiConfiguration.AuthAlgorithm;
import android.net.wifi.WifiConfiguration.KeyMgmt;
import android.net.wifi.WifiManager;
import android.os.Bundle;
import android.text.TextUtils;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

/**
* @author zhuzhifei
*/
public class WifiManagerTestActivity extends Activity {
private Button btnWifi;
WifiManager wifiManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_wifi);
//獲取wifi管理服務
wifiManager = (WifiManager) this.getSystemService(Context.WIFI_SERVICE);

btnWifi = (Button) findViewById(R.id.btnWifi);
btnWifi.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
// connect("newhome","newhome123",WifiCipherType.WIFICIPHER_WEP);
//啟動wifi
connect("newhome","newhome123",WifiCipherType.WIFICIPHER_WPA);
}
});

}

private static final String TAG = WifiManagerTestActivity.class
.getSimpleName();

// 定義幾種加密方式，一種是WEP，一種是WPA，還有沒有密碼的情況
public enum WifiCipherType {
WIFICIPHER_WEP, WIFICIPHER_WPA, WIFICIPHER_NOPASS, WIFICIPHER_INVALID
}

// 提供一個外部接口，傳入要連接的無線網ssid，password，
public void connect(String ssid, String password, WifiCipherType type) {
Thread thread = new Thread(new ConnectRunnable(ssid, password, type));
thread.start();
}

// 查看以前是否也配置過這個網絡
private WifiConfiguration isExsits(String SSID) {
List existingConfigs = wifiManager
.getConfiguredNetworks();
for (WifiConfiguration existingConfig : existingConfigs) {
if (existingConfig.SSID.equals("\"" + SSID + "\"")) {
return existingConfig;
}
}
return null;
}

private WifiConfiguration createWifiInfo(String SSID, String Password,
WifiCipherType Type) {
WifiConfiguration config = new WifiConfiguration();
config.allowedAuthAlgorithms.clear();
config.allowedGroupCiphers.clear();
config.allowedKeyManagement.clear();
config.allowedPairwiseCiphers.clear();
config.allowedProtocols.clear();
config.SSID = "\"" + SSID + "\"";
// nopass
if (Type == WifiCipherType.WIFICIPHER_NOPASS) {
config.wepKeys[0] = "";
config.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.NONE);
config.wepTxKeyIndex = 0;
}
// wep
if (Type == WifiCipherType.WIFICIPHER_WEP) {
if (!TextUtils.isEmpty(Password)) {
if (isHexWepKey(Password)) {
config.wepKeys[0] = Password;
} else {
config.wepKeys[0] = "\"" + Password + "\"";
}
}
config.allowedAuthAlgorithms.set(AuthAlgorithm.OPEN);
config.allowedAuthAlgorithms.set(AuthAlgorithm.SHARED);
config.allowedKeyManagement.set(KeyMgmt.NONE);
config.wepTxKeyIndex = 0;
}
// wpa
if (Type == WifiCipherType.WIFICIPHER_WPA) {
config.preSharedKey = "\"" + Password + "\"";
config.hiddenSSID = true;
config.allowedAuthAlgorithms
.set(WifiConfiguration.AuthAlgorithm.OPEN);
config.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.TKIP);
config.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.WPA_PSK);
config.allowedPairwiseCiphers
.set(WifiConfiguration.PairwiseCipher.TKIP);
// 此處需要修改否則不能自動重聯
// config.allowedProtocols.set(WifiConfiguration.Protocol.WPA);
config.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.CCMP);
config.allowedPairwiseCiphers
.set(WifiConfiguration.PairwiseCipher.CCMP);
config.status = WifiConfiguration.Status.ENABLED;
}
return config;
}

// 打開wifi功能
private boolean openWifi() {
boolean bRet = true;
if (!wifiManager.isWifiEnabled()) {
bRet = wifiManager.setWifiEnabled(true);
}
return bRet;
}
//啟動一個新線程打開wifi
class ConnectRunnable implements Runnable {
private String ssid;

private String password;

private WifiCipherType type;

public ConnectRunnable(String ssid, String password, WifiCipherType type) {
this.ssid = ssid;
this.password = password;
this.type = type;
}

@Override
public void run() {
// 打開wifi
openWifi();
// 開啟wifi功能需要一段時間(我在手機上測試一般需要1-3秒左右)，所以要等到wifi
// 狀態變成WIFI_STATE_ENABLED的時候才能執行下面的語句
while (wifiManager.getWifiState() == WifiManager.WIFI_STATE_ENABLING) {
try {
// 為了避免程序一直while循環，讓它睡個100毫秒檢測……
Thread.sleep(100);
} catch (InterruptedException ie) {
}
}

WifiConfiguration wifiConfig = createWifiInfo(ssid, password, type);
//
if (wifiConfig == null) {
Log.d(TAG, "wifiConfig is null!");
return;
}

WifiConfiguration tempConfig = isExsits(ssid);

if (tempConfig != null) {
wifiManager.removeNetwork(tempConfig.networkId);
}

int netID = wifiManager.addNetwork(wifiConfig);
boolean enabled = wifiManager.enableNetwork(netID, true);
Log.d(TAG, "enableNetwork status enable=" + enabled);
boolean connected = wifiManager.reconnect();
Log.d(TAG, "enableNetwork connected=" + connected);
}
}

private static boolean isHexWepKey(String wepKey) {
final int len = wepKey.length();

// WEP-40, WEP-104, and some vendors using 256-bit WEP (WEP-232?)
if (len != 10 && len != 26 && len != 58) {
return false;
}

return isHex(wepKey);
}

private static boolean isHex(String key) {
for (int i = key.length() - 1; i >= 0; i--) {
final char c = key.charAt(i);
if (!(c >= '0' && c <= '9' || c >= 'A' && c <= 'F' || c >= 'a'
&& c <= 'f')) {
return false;
}
}

return true;
}

}