手機必須root

public static void setSettingsWifi() {
    ShellUtil.runRootCmd("svc wifi enable");
}

package com.watch.in.uitlis.data;
/**
 * Created by Administrator on 2017/6/21.
 */
import android.util.Log;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
 
public class ShellUtil
{
    private static String TAG = ShellUtil.class.getName();
    public static String runCommand(String command)
    {
        Process process = null;
String result = "false";
        try
{
            process = Runtime.getRuntime().exec(command);
process.waitFor();
result = inputStreamToString
 
(process.getInputStream());
Log.e(TAG, result);
} catch (Exception e)
        {
            return result;
} finally
{
            try
{
                process.destroy();
} catch (Exception e)
            {
            }
        }
        return result;
}

    //http://blog.csdn.net/alexander_xfl/article/details/9150971
 
    //command can be some cmd, use ; to split
public static String runRootCmd(String command)
    {
        return runRootCmd(command,  ";");
}

    public static String runRootCmd(String command, String split)
    {
        Process process = null;
DataOutputStream os = null;
String result = "false";
        try
{
            process = Runtime.getRuntime().exec("su");
OutputStream outstream = process.getOutputStream();
DataOutputStream dataOutputStream = new DataOutputStream(outstream);
String temp = "";
String[] cmds = command.split(split);
            for(int i = 0; i < cmds.length; i++)
                temp += cmds[i] + "\n";
dataOutputStream.writeBytes(temp);
dataOutputStream.flush();
dataOutputStream.writeBytes("exit\n");
dataOutputStream.flush();
process.waitFor();
result = inputStreamToString(process.getInputStream());
Log.i(TAG, temp);
} catch (Exception e)
        {
            Log.e(TAG, e.getMessage());
            return result;
} finally
{
            Log.i(TAG, result);
            try
{
                if (os != null)
                {
                    os.close();
}
                process.destroy();
} catch (Exception e)
            {
                Log.e(TAG, e.getMessage());
}
        }
        return result;
}

    private static String inputStreamToString(InputStream in) throws IOException
    {
        StringBuffer out = new StringBuffer();
        byte[] b = new byte[1024];
        for (int n; (n = in.read(b)) != -1;)
        {
            out.append(new String(b, 0, n));
}
        return out.toString();
}
}

<!-- wifi設定模組相關許可權條 -->
<!-- 以下是使用wifi訪問網路所需的許可權 -->
<uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" />
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="android.permission.UPDATE_DEVICE_STATS" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
<uses-permission android:name="android.permission.MODIFY_PHONE_STATE" />
<uses-permission android:name="android.permission.WRITE_SETTINGS" />

許可權挑有用的就行