Question

我正在尝试将URL中的文本文件读取到Android中的String。我尝试了多个代码，我目前正在使用这个代码：

BufferedReader in = new BufferedReader(new InputStreamReader(new URL("https://wordpress.org/plugins/about/readme.txt").openStream()));

每一段代码都在这一行中给了我一个IllegalStateException。我有以下权限：

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

我希望有人可以解释一下为什么会这样。这是完整的错误：

FATAL EXCEPTION: main
Process: com.example.MyApp, PID: 15407
java.lang.IllegalStateException: Could not execute method of the activity
    at android.view.View$1.onClick(View.java:3996)
    at android.view.View.performClick(View.java:4710)
    at android.view.View$PerformClick.run(View.java:19510)
    at android.os.Handler.handleCallback(Handler.java:733)
    at android.os.Handler.dispatchMessage(Handler.java:95)
    at android.os.Looper.loop(Looper.java:146)
    at android.app.ActivityThread.main(ActivityThread.java:5679)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:515)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1291)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1107)
    at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.reflect.InvocationTargetException
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:515)
    at android.view.View$1.onClick(View.java:3991)
    ... 11 more
Caused by: android.os.NetworkOnMainThreadException
    at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1166)
    at java.net.InetAddress.lookupHostByName(InetAddress.java:385)
    at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236)
    at java.net.InetAddress.getAllByName(InetAddress.java:214)
    at com.android.okhttp.internal.Dns$1.getAllByName(Dns.java:28)
    at com.android.okhttp.internal.http.RouteSelector.resetNextInetSocketAddress(RouteSelector.java:216)
    at com.android.okhttp.internal.http.RouteSelector.next(RouteSelector.java:122)
    at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:409)
    at com.android.okhttp.internal.http.HttpEngine.sendSocketRequest(HttpEngine.java:362)
    at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:308)
    at com.android.okhttp.internal.http.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:345)
    at com.android.okhttp.internal.http.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:296)
    at com.android.okhttp.internal.http.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:179)
    at com.android.okhttp.internal.http.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:246)
    at java.net.URL.openStream(URL.java:470)
    at com.example.MyApp.MainActivity.search(MainActivity.java:60)
    ... 14 more

Answer 1

问题正是异常状态

Caused by: android.os.NetworkOnMainThreadException
    at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1166)

我认为从Android Honeycomb版本开始，您无法在主UI线程上执行网络操作。请考虑使用AsyncTask之类的内容代替网络操作（Docs）。

您也可以关闭Strict mode作为解决方法，但不建议这样做。

StrictMode.ThreadPolicy newPolicy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(newPolicy );

从url读取文本文件会产生IllegalStateException

1 个答案: