java – 如何在Android中修复NetworkonMainThreadException？

参见英文答案 > How do I fix android.os.NetworkOnMainThreadException?                                    53个
我正在创建一个分配项目,我是Android的新手,我想从非常常见的URL http://api.androidhive.info/contacts/访问json,

问题：我正在尝试读取url并获取并解析此url返回的json,

我已经在我的AndroidManifest.xml中添加了以下行

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

首选项：和我的Android首选项是

<uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="18" />

> Api等级18
> Android 4.3

这就是我试图读取网址的方式

static InputStream is = null;

DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);

HttpResponse httpResponse = httpClient.execute(httpPost);
httpentity httpentity = httpResponse.getEntity();
is = httpentity.getContent();

错误消息

11-02 05:23:47.843: E/AndroidRuntime(2207): FATAL EXCEPTION: main
11-02 05:23:47.843: E/AndroidRuntime(2207): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.me.countrypedia/com.me.countrypedia.MainActivity}: android.os.networkonmainthreadException
11-02 05:23:47.843: E/AndroidRuntime(2207):     at android.app.ActivityThread.performlaunchActivity(ActivityThread.java:2211)
11-02 05:23:47.843: E/AndroidRuntime(2207):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
11-02 05:23:47.843: E/AndroidRuntime(2207):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
11-02 05:23:47.843: E/AndroidRuntime(2207):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)

另外,我正在关注ListView示例的本教程
http://www.androidhive.info/2011/11/android-xml-parsing-tutorial/

解决方法:

你的异常实际上告诉你你做错了什么.您没有使用其他线程来执行NetworkOperations.相反,您在UI-Thread上执行网络操作,这不能(不)在Android上运行.

连接到url的代码应该在UI-Thread之外的AsyncTasks doInBackground()方法中执行.

看看有关如何使用AsyncTask：How to use AsyncTask的这个问题