网络

public class NetStateUtil {

    /*
 * 判断网络连接是否已开
 * true 已打开  false 未打开
 * */
    public static boolean isConn(Context context){
        boolean bisConnFlag=false;
        ConnectivityManager conManager = (ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo network = conManager.getActiveNetworkInfo();
        if(network!=null){
            bisConnFlag=conManager.getActiveNetworkInfo().isAvailable();
        }
        return bisConnFlag;
    }

    /**
     * 当判断当前手机没有网络时选择是否打开网络设置
     * @param context
     */
    public static void showNoNetWorkDlg(final Context context) {
        AlertDialog.Builder builder = new AlertDialog.Builder(context);
        builder.setIcon(R.mipmap.ic_launcher)         //
                .setTitle(R.string.app_name)            //
                .setMessage("当前无网络").setPositiveButton("设置", new DialogInterface.OnClickListener() {

            @Override
            public void onClick(DialogInterface dialog, int which) {
                // 跳转到系统的网络设置界面
                Intent intent = null;
                // 先判断当前系统版本
                if(android.os.Build.VERSION.SDK_INT > 10){  // 3.0以上
                    intent = new Intent(android.provider.Settings.ACTION_WIRELESS_SETTINGS);
                }else{
                    intent = new Intent();
                    intent.setClassName("com.android.settings", "com.android.settings.WirelessSettings");
                }
                context.startActivity(intent);

            }
        }).setNegativeButton("知道了", null).show();

    }

判断

  if (wangluo.isConn(this))
     {
         tu tu = new tu();
         tu.execute("http://api.tianapi.com/meinv/?key=8ec324bf03d34f7706fb4c35a4355d7e&num=10");
     }else
         {
             wangluo.showNoNetWorkDlg(this);
         }
}