HttpURLConnection无法openConnection

Question

@Override
protected Void doInBackground(String... params) {
    String type = params[0];
    String url= "http://10.0.2.2/login.php" ;
    if(type.equals("Singin"))  {
        try {
            URL Singin_url = new URL(url);
            //Cannot not resolve method 'openConnection()'
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        } catch (MalformedURLException e) {
            e.printStackTrace();
        }
    }
    return null;
}

为什么不让它让OpenConnection？ 我不能前进，因为它说'连接＆＃39;没有初始化

Answer 1

您需要在openConnection()对象URL上调用Singin_url方法。您在String对象上调用它。

@Override
protected Void doInBackground(String... params)
{
    String type = params[0];
    String url= "http://10.0.2.2/login.php" ;
    if(type.equals("Singin"))
    {
        try {
            URL Singin_url = new URL(url);
            HttpURLConnection connection = (HttpURLConnection)Singin_url.openConnection();    
        } catch (MalformedURLException e) {
            e.printStackTrace();
        }    
    }
    return null;
}

此外，您的变量名称第一个字符应为小写，例如signInUrl。