Question

我无法使用Jsoup获得Google主页的标题。我得到了FATAL EXCEPTION: Thread。

logcat的：

10-19 05:46:44.153: E/AndroidRuntime(597): FATAL EXCEPTION: Thread-75
10-19 05:46:44.153: E/AndroidRuntime(597): android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
10-19 05:46:44.153: E/AndroidRuntime(597):  at android.view.ViewRootImpl.checkThread(ViewRootImpl.java:3939)
10-19 05:46:44.153: E/AndroidRuntime(597):  at android.view.ViewRootImpl.requestLayout(ViewRootImpl.java:701)
10-19 05:46:44.153: E/AndroidRuntime(597):  at android.view.View.requestLayout(View.java:12555)
10-19 05:46:44.153: E/AndroidRuntime(597):  at android.view.View.requestLayout(View.java:12555)
10-19 05:46:44.153: E/AndroidRuntime(597):  at android.view.View.requestLayout(View.java:12555)
10-19 05:46:44.153: E/AndroidRuntime(597):  at android.view.View.requestLayout(View.java:12555)
10-19 05:46:44.153: E/AndroidRuntime(597):  at android.widget.RelativeLayout.requestLayout(RelativeLayout.java:268)
10-19 05:46:44.153: E/AndroidRuntime(597):  at android.view.View.requestLayout(View.java:12555)
10-19 05:46:44.153: E/AndroidRuntime(597):  at android.widget.TextView.checkForRelayout(TextView.java:6716)
10-19 05:46:44.153: E/AndroidRuntime(597):  at android.widget.TextView.setText(TextView.java:3256)
10-19 05:46:44.153: E/AndroidRuntime(597):  at android.widget.TextView.setText(TextView.java:3110)
10-19 05:46:44.153: E/AndroidRuntime(597):  at android.widget.TextView.setText(TextView.java:3085)
10-19 05:46:44.153: E/AndroidRuntime(597):  at com.example.spravochnik05.MainActivity$1.run(MainActivity.java:34)
10-19 05:46:44.153: E/AndroidRuntime(597):  at java.lang.Thread.run(Thread.java:856)

代码：

public class MainActivity extends Activity {

    private TextView textView;
    public Document doc;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        textView = (TextView) findViewById(R.id.textView1);

        Thread thread = new Thread(new Runnable() {

            @Override
            public void run() {
                try {
                    doc = Jsoup.connect("http://google.com").get();
                    textView.setText(doc.title());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        });

        thread.start();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
}

新错误logcat：

10-19 06:08:28.302: E/AndroidRuntime(846): FATAL EXCEPTION: main
10-19 06:08:28.302: E/AndroidRuntime(846): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.spravochnik05/com.example.spravochnik05.MainActivity}: android.os.NetworkOnMainThreadException
10-19 06:08:28.302: E/AndroidRuntime(846):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1955)
10-19 06:08:28.302: E/AndroidRuntime(846):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1980)
10-19 06:08:28.302: E/AndroidRuntime(846):  at android.app.ActivityThread.access$600(ActivityThread.java:122)
10-19 06:08:28.302: E/AndroidRuntime(846):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1146)
10-19 06:08:28.302: E/AndroidRuntime(846):  at android.os.Handler.dispatchMessage(Handler.java:99)
10-19 06:08:28.302: E/AndroidRuntime(846):  at android.os.Looper.loop(Looper.java:137)
10-19 06:08:28.302: E/AndroidRuntime(846):  at android.app.ActivityThread.main(ActivityThread.java:4340)
10-19 06:08:28.302: E/AndroidRuntime(846):  at java.lang.reflect.Method.invokeNative(Native Method)
10-19 06:08:28.302: E/AndroidRuntime(846):  at java.lang.reflect.Method.invoke(Method.java:511)
10-19 06:08:28.302: E/AndroidRuntime(846):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
10-19 06:08:28.302: E/AndroidRuntime(846):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
10-19 06:08:28.302: E/AndroidRuntime(846):  at dalvik.system.NativeStart.main(Native Method)
10-19 06:08:28.302: E/AndroidRuntime(846): Caused by: android.os.NetworkOnMainThreadException
10-19 06:08:28.302: E/AndroidRuntime(846):  at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1084)
10-19 06:08:28.302: E/AndroidRuntime(846):  at java.net.InetAddress.lookupHostByName(InetAddress.java:391)
10-19 06:08:28.302: E/AndroidRuntime(846):  at java.net.InetAddress.getAllByNameImpl(InetAddress.java:242)
10-19 06:08:28.302: E/AndroidRuntime(846):  at java.net.InetAddress.getAllByName(InetAddress.java:220)
10-19 06:08:28.302: E/AndroidRuntime(846):  at libcore.net.http.HttpConnection.<init>(HttpConnection.java:71)
10-19 06:08:28.302: E/AndroidRuntime(846):  at libcore.net.http.HttpConnection.<init>(HttpConnection.java:50)
10-19 06:08:28.302: E/AndroidRuntime(846):  at libcore.net.http.HttpConnection$Address.connect(HttpConnection.java:351)
10-19 06:08:28.302: E/AndroidRuntime(846):  at libcore.net.http.HttpConnectionPool.get(HttpConnectionPool.java:86)
10-19 06:08:28.302: E/AndroidRuntime(846):  at libcore.net.http.HttpConnection.connect(HttpConnection.java:128)
10-19 06:08:28.302: E/AndroidRuntime(846):  at libcore.net.http.HttpEngine.openSocketConnection(HttpEngine.java:308)
10-19 06:08:28.302: E/AndroidRuntime(846):  at libcore.net.http.HttpEngine.connect(HttpEngine.java:303)
10-19 06:08:28.302: E/AndroidRuntime(846):  at libcore.net.http.HttpEngine.sendSocketRequest(HttpEngine.java:282)
10-19 06:08:28.302: E/AndroidRuntime(846):  at libcore.net.http.HttpEngine.sendRequest(HttpEngine.java:232)
10-19 06:08:28.302: E/AndroidRuntime(846):  at libcore.net.http.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:80)
10-19 06:08:28.302: E/AndroidRuntime(846):  at org.jsoup.helper.HttpConnection$Response.execute(HttpConnection.java:425)
10-19 06:08:28.302: E/AndroidRuntime(846):  at org.jsoup.helper.HttpConnection$Response.execute(HttpConnection.java:410)
10-19 06:08:28.302: E/AndroidRuntime(846):  at org.jsoup.helper.HttpConnection.execute(HttpConnection.java:164)
10-19 06:08:28.302: E/AndroidRuntime(846):  at org.jsoup.helper.HttpConnection.get(HttpConnection.java:153)
10-19 06:08:28.302: E/AndroidRuntime(846):  at com.example.spravochnik05.MainActivity.onCreate(MainActivity.java:26)
10-19 06:08:28.302: E/AndroidRuntime(846):  at android.app.Activity.performCreate(Activity.java:4465)
10-19 06:08:28.302: E/AndroidRuntime(846):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
10-19 06:08:28.302: E/AndroidRuntime(846):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1919)
10-19 06:08:28.302: E/AndroidRuntime(846):  ... 11 more

我该如何解决这个问题？

Answer 1

textView.setText(doc.title());

删除此行。您无法从线程更新UI。而是使用runOnUIThread()，或使用线程处理程序。

最佳选择是使用Android推荐的AsyncTask。

以下是AsyncTask的使用情况，该{{3}}执行doInBackground() method中的后台操作，并使用onPostExecute方法更新用户界面。

以下是使用AsyncTask：

的示例

在onCreate方法中：

new DownloadFilesTask().execute();

在onCreate结束后添加此类：

 private class DownloadFilesTask extends AsyncTask<Void, Void, Void> {

        @Override
        protected Void doInBackground(Void... arg0) {
            doc = Jsoup.connect("http://google.com").get();
            return null;
        }

        @Override
        protected void onPostExecute(Void result) {
            super.onPostExecute(result);

            if (doc != null) {
                textView.setText(doc.title());
            }
            else {
                textView.setText("Doc not found");
            }
        }
}

Answer 2

在日志中：

CalledFromWrongThreadException：仅创建的原始线程视图层次结构可以触及其视图。

表示您正在尝试从非ui线程更新UI元素，因此请使用AsyncTask或runOnUiThread来获取非ui线程中的更新UI元素。

使用runOnUiThread：

 .....
 try {
         doc = Jsoup.connect("http://google.com").get();
         MainActivity.this.runOnUiThread(new Runnable() {

           @Override
            public void run() {
                 textView.setText(doc.title());
             }
          });           
        } catch (IOException e) {
                    // TODO Auto-generated catch block
          e.printStackTrace();
  }

...

Answer 3

您无法在非UI线程中更改TextView的文本。尝试在非UI线程中的runOnUIThread(Runnable)中使用Activity方法与UI线程进行通信

Answer 4

使用AyncTask代替线程，因为这一行：

textView.setText(doc.title());

现在就会给你一个错误。

Answer 5

从你的线程中获取代码，并将其放在AsyncTask线程中：

class DownloadFile extends AsyncTask<Void, Void, Void> {
    @Override
    protected String doInBackground(String... arg0) {
                your code
    }

}

某些操作（例如发出HTTP请求）不允许在主UI线程上运行。

执行：

new DownloadFile().execute()

致命异常：使用Jsoup时的线程

5 个答案: