Android 代码判断是否有网络

    public void okGo() {

        ConnectivityManager connectivityManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
        if (networkInfo != null && networkInfo.isAvailable()) {
             Toast.makeText(RadarActivity.this, "当前网络可用", Toast.LENGTH_SHORT).show();

        } else {
             Toast.makeText(RadarActivity.this, "当前网络不可用", Toast.LENGTH_SHORT).show();
        }

    }