一、需要权限：

    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />  
       <uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" />  
       <uses-permission android:name="android.permission.MODIFY_PHONE_STATE" />  

二、下面代码实现功能、如果gprs已经打开则先关闭再打开、否则直接打开、

    package com.example.gprstoggle;  
      
    import java.lang.reflect.Method;  
      
    import android.app.Activity;  
    import android.content.Context;  
    import android.net.ConnectivityManager;  
    import android.os.Bundle;  
      
    public class MainActivity extends Activity {  
      
        private ConnectivityManager mCM;   
        @Override  
        protected void onCreate(Bundle savedInstanceState) {  
            super.onCreate(savedInstanceState);  
            setContentView(R.layout.activity_main);  
            init();  
        }  
      
        private void init() {  
            mCM = (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);    
            gprsSetter();  
            finish();  
      
      
        }  
        //打开或关闭GPRS  
        private boolean gprsEnabled(boolean bEnable)    
        {    
            Object[] argObjects = null;    
                        
            boolean isOpen = this.gprsIsOpenMethod("getMobileDataEnabled");    
            if(isOpen == !bEnable)    
            {    
                setGprsEnabled("setMobileDataEnabled", bEnable);    
            }   
                
            return isOpen;      
        }    
        //打开或关闭GPRS  
            private boolean gprsSetter()    
            {    
                Object[] argObjects = null;    
                            
                boolean isOpen = this.gprsIsOpenMethod("getMobileDataEnabled");    
                if(isOpen)    
                {    
                    setGprsEnabled("setMobileDataEnabled", false);   
                    System.out.println("关闭");  
                    try {  
                        Thread.sleep(2000);  
                    } catch (InterruptedException e) {  
                        e.printStackTrace();  
                    }  
                    setGprsEnabled("setMobileDataEnabled", true);  
                    System.out.println("开启");  
                }else{  
                    setGprsEnabled("setMobileDataEnabled", true);  
                    System.out.println("开启");  
                }  
                    
                return isOpen;      
            }   
        //检测GPRS是否打开     
        private boolean gprsIsOpenMethod(String methodName)    
        {    
            Class cmClass       = mCM.getClass();    
            Class[] argClasses  = null;    
            Object[] argObject  = null;    
                
            Boolean isOpen = false;    
            try    
            {    
                Method method = cmClass.getMethod(methodName, argClasses);    
        
                isOpen = (Boolean) method.invoke(mCM, argObject);    
            } catch (Exception e)    
            {    
                e.printStackTrace();    
            }    
        
            return isOpen;    
        }    
      
        //开启/关闭GPRS     
        private void setGprsEnabled(String methodName, boolean isEnable)    
        {    
            Class cmClass       = mCM.getClass();    
            Class[] argClasses  = new Class[1];    
            argClasses[0]       = boolean.class;    
                
            try    
            {    
                Method method = cmClass.getMethod(methodName, argClasses);    
                method.invoke(mCM, isEnable);    
            } catch (Exception e)    
            {    
                e.printStackTrace();    
            }    
        }    
      
    }