判斷網路連結

         需要加入的許可權是：             <uses-permission android:name="android.permission.INTERNET" />              <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />        protected boolean CheckNetwork1() {     // TODO Auto-generated method stub    boolean flag=false;    ConnectivityManager cwjManager=(ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);     if(cwjManager.getActiveNetworkInfo()!=null)    flag=cwjManager.getActiveNetworkInfo().isAvailable();    if(!flag){    Builder b=new AlertDialog.Builder(this).setTitle("沒有可用的網路").setMessage("請開啟GPRS或WIFI網路串連");    b.setPositiveButton("確定",new DialogInterface.OnClickListener() {    public void onClick(DialogInterface dialog, int which) {     // TODO Auto-generated method stub        }    }).setNegativeButton("取消", new DialogInterface.OnClickListener() {    public void onClick(DialogInterface dialog, int which) {    // TODO Auto-generated method stub dialog.cancel();    }    }).create(); b.show();     }     return flag;    }