与WIFI扫描类似，WIFI的连接同样是一个耗时的过程，所以需要放到线程中执行，通过回调来通知调用者连接结果。该回调接口的定义如下：
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public
interface
WifiConnectListener {
public
void
OnWifiConnectCompleted(
boolean
isConnected );
}
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从Android的WIFI Setting可以看出，一般添加一个新的WIFI连接，需要给出三个信息，一个是WIFI的SSID，一个是WIFI的密码，另一个是WIFI的加密类型，不同的加密方式，连接时程序中的配置是不同的，这里定义一个枚举，给出四种常见的加密类型：
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public
enum
SecurityMode {
OPEN, WEP, WPA, WPA2
}
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Android的WIFI连接过程，总体上分为三步，第一步，添加网络配置，第二步，根据网络配置连接WIFI，第三步，监听系统的WIFI连接状态消息。下面就直接给出示例代码，关键的地方都在代码中注释了。
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package
com.example.testwifi;
import
java.util.List;
import
java.util.concurrent.TimeUnit;
import
java.util.concurrent.locks.Condition;
import
java.util.concurrent.locks.Lock;
import
java.util.concurrent.locks.ReentrantLock;
import
android.content.BroadcastReceiver;
import
android.content.Context;
import
android.content.Intent;
import
android.content.IntentFilter;
import
android.net.wifi.SupplicantState;
import
android.net.wifi.WifiConfiguration;
import
android.net.wifi.WifiInfo;
import
android.net.wifi.WifiManager;
public
class
WifiConnector {
private
static
final
int
WIFI_CONNECT_TIMEOUT =
20
;
//连接WIFI的超时时间
private
Context mContext;
private
WifiManager mWifiManager;
private
Lock mLock;
private
Condition mCondition;
private
WiFiConncetReceiver mWifiConnectReceiver;
private
WifiConnectListener mWifiConnectListener;
private
boolean
mIsConnnected =
false
;
private
int
mNetworkID = -
1
;
//网络加密模式
public
enum
SecurityMode {
OPEN, WEP, WPA, WPA2
}
//通知连接结果的监听接口
public
interface
WifiConnectListener {
public
void
OnWifiConnectCompleted(
boolean
isConnected );
}
public
WifiConnector( Context context , WifiConnectListener listener ) {
mContext = context;
mLock =
new
ReentrantLock();
mCondition = mLock.newCondition();
mWifiManager=(WifiManager)mContext.getSystemService(Context.WIFI_SERVICE);
mWifiConnectReceiver =
new
WiFiConncetReceiver();
mWifiConnectListener = listener;
}
public
void
connect(
final
String ssid,
final
String password,
final
SecurityMode mode ) {
new
Thread(
new
Runnable() {
@Override
public
void
run() {
//如果WIFI没有打开，则打开WIFI
if
( !mWifiManager.isWifiEnabled() ) {
mWifiManager.setWifiEnabled(
true
);
}
//注册连接结果监听对象
mContext.registerReceiver(mWifiConnectReceiver,
new
IntentFilter(WifiManager.SUPPLICANT_STATE_CHANGED_ACTION));
//连接指定SSID
if
( !onConnect(ssid,password,mode) ) {
mWifiConnectListener.OnWifiConnectCompleted(
false
);
}
else
{
mWifiConnectListener.OnWifiConnectCompleted(
true
);
}
//删除注册的监听类对象
mContext.unregisterReceiver(mWifiConnectReceiver);
}
}).start();
}
protected
boolean
onConnect( String ssid, String password, SecurityMode mode ) {
//添加新的网络配置
WifiConfiguration cfg =
new
WifiConfiguration();
cfg.SSID =
"\""
+ ssid +
"\""
;
if
( password !=
null
&& !
""
.equals(password) ) {
//这里比较关键，如果是WEP加密方式的网络，密码需要放到cfg.wepKeys[0]里面
if
( mode == SecurityMode.WEP ) {
cfg.wepKeys[
0
] =
"\""
+ password +
"\""
;
cfg.wepTxKeyIndex =
0
;
}
else
{
cfg.preSharedKey =
"\""
+ password +
"\""
;
}
}
cfg.status = WifiConfiguration.Status.ENABLED;
//添加网络配置
mNetworkID = mWifiManager.addNetwork(cfg);
mLock.lock();
mIsConnnected =
false
;
//连接该网络
if
( !mWifiManager.enableNetwork(mNetworkID ,
true
) ) {
mLock.unlock();
return
false
;
}
try
{
//等待连接结果
mCondition.await(WIFI_CONNECT_TIMEOUT, TimeUnit.SECONDS);
}
catch
(InterruptedException e) {
e.printStackTrace();
}
mLock.unlock();
return
mIsConnnected;
}
//监听系统的WIFI连接消息
protected
class
WiFiConncetReceiver
extends
BroadcastReceiver {
@Override
public
void
onReceive(Context context, Intent intent) {
if
(!WifiManager.SUPPLICANT_STATE_CHANGED_ACTION.equals(intent.getAction())) {
return
;
}
mLock.lock();
WifiInfo info = mWifiManager.getConnectionInfo();
if
( info.getNetworkId()==mNetworkID && info.getSupplicantState() == SupplicantState.COMPLETED ) {
mIsConnnected =
true
;
mCondition.signalAll();
}
mLock.unlock();
}
}
}
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与WIFI扫描的封装代码类似，这里也用到了Lock和Condition，就是为了阻塞地等待WIFI连接的结果，保证正确的registerReceiver和unregisterReceiver网络连接状态监听对象，同时，设置了WIFI连接超时，防止由于WIFI模块的问题导致界面收不到回调而长时间“卡死”。
另外，AndroidManifest.xml文件中记得添加权限支持哦：
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<uses-permission android:name=
"android.permission.CHANGE_WIFI_STATE"
></uses-permission>
<uses-permission android:name=
"android.permission.ACCESS_WIFI_STATE"
></uses-permission>
<uses-permission android:name=
"android.permission.ACCESS_NETWORK_STATE"
></uses-permission>
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本文转自 Jhuster 51CTO博客，原文链接：http://blog.51cto.com/ticktick/1410080，如需转载请自行联系原作者
