不能在我的Andr​​oid应用程序连接到互联网只。每种方法连接互联网返回空 [英] can't connect to internet in ONLY in my android app. Each method to connect internet returns null

问题描述

我使用 HttpURLConnection类的连接方法，但它返回空。
没有其他的消息没有printstack只是空。

I am using HttpURLConnection's connect method but it returns null. no other message no printstack just null.

URL url = new URL("http://whatever");
URLConnection urlConnection = url.openConnection();
InputStream in = new BufferedInputStream(urlConnection.getInputStream());

在上面也返回空

不知道为什么会这样来了。但我无法连接到网络。

Don't know why this comes. But I cant connect to net.

我也试图与HttpURLConnection类和URLConnection都是不同的例子。

i also tried with HttpURLConnection and urlconnection both are different example.

推荐答案

您说您正在使用 HttpURLConnection类但在code你波斯特的URLConnection 。这是你如何作出正确的 HttpURLConnection类：

You said you are using HttpURLConnection but in the code you poste URLConnection. This is how you make a proper HttpURLConnection:

URL url = new URL("http://www.android.com/");
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
try {
  InputStream in = new BufferedInputStream(urlConnection.getInputStream());
  readStream(in);
 finally {
  urlConnection.disconnect();
 }
}

您还必须做在主线程超出这个连接（使用的AsyncTask 或其他方式）或其他应用程序将崩溃。

You also have to do this connection outside the main thread (Using AsyncTask or other method) or otherwise the app will crash.

另外添加正确的权限是：

Also add the right permissions for it:

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

希望它帮助！祝你好运！

Hope it helps! Good Luck!

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