遵循ASyncTask示例时强制关闭

Question

I'm getting a force close error when attempting to follow this tutorial:

http://www.bango29.com/go/blog/2011/android-asynctask-is-a-beauty-part-2

Any suggestions? I'm really not sure where I went wrong in this.

MY SOURCE:

public class HttpGetAndroidExample {

    // The url of the website. This is just an example

    private static final String webSiteURL = "http://www.supercars.net/gallery/119513/2841/5.html";

    // The path of the folder that you want to save the images to

    private static final String folderPath = "<FOLDER PATH>";

    public static void main(String[] args) {

        try {

            // Connect to the website and get the html

            Document doc = Jsoup.connect(webSiteURL).get();

            // Get all elements with img tag ,

            Elements img = doc.getElementsByTag("img");

            for (Element el : img) {

                // for each element get the srs url
                String src = el.absUrl("src");

                System.out.println("Image Found!");

                System.out.println("src attribute is : " + src);

                getImages(src);

            }

        } catch (IOException ex) {

            System.err.println("There was an error");

            Logger.getLogger(HttpGetAndroidExample.class.getName()).log(Level.SEVERE,
                    null, ex);

        }

    }

    private static void getImages(String src) throws IOException {

        String folder = null;

        // Exctract the name of the image from the src attribute
        int indexname = src.lastIndexOf("/");

        if (indexname == src.length()) {

            src = src.substring(1, indexname);

        }

        indexname = src.lastIndexOf("/");

        String name = src.substring(indexname, src.length());

        System.out.println(name);

        // Open a URL Stream

        URL url = new URL(src);

        InputStream in = url.openStream();

        OutputStream out = new BufferedOutputStream(new FileOutputStream(
                folderPath + name));

        for (int b; (b = in.read()) != -1;) {

            out.write(b);

        }

        out.close();

        in.close();

    }

}

Logcat:

07-18 17:22:06.449: D/ActivityThread(11404): setTargetHeapUtilization:0.25
07-18 17:22:06.449: D/ActivityThread(11404): setTargetHeapIdealFree:8388608
07-18 17:22:06.449: D/ActivityThread(11404): setTargetHeapConcurrentStart:2097152
07-18 17:22:06.469: W/dalvikvm(11404): threadid=1: thread exiting with uncaught exception (group=0x41e1f438)
07-18 17:22:06.469: E/AndroidRuntime(11404): FATAL EXCEPTION: main
07-18 17:22:06.469: E/AndroidRuntime(11404): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.httpgetandroidexample/com.example.httpgetandroidexample.HttpGetAndroidExample}: java.lang.ClassCastException: com.example.httpgetandroidexample.HttpGetAndroidExample cannot be cast to android.app.Activity
07-18 17:22:06.469: E/AndroidRuntime(11404):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2012)
07-18 17:22:06.469: E/AndroidRuntime(11404):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2113)
07-18 17:22:06.469: E/AndroidRuntime(11404):    at android.app.ActivityThread.access$700(ActivityThread.java:139)
07-18 17:22:06.469: E/AndroidRuntime(11404):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1224)
07-18 17:22:06.469: E/AndroidRuntime(11404):    at android.os.Handler.dispatchMessage(Handler.java:99)
07-18 17:22:06.469: E/AndroidRuntime(11404):    at android.os.Looper.loop(Looper.java:137)
07-18 17:22:06.469: E/AndroidRuntime(11404):    at android.app.ActivityThread.main(ActivityThread.java:4918)
07-18 17:22:06.469: E/AndroidRuntime(11404):    at java.lang.reflect.Method.invokeNative(Native Method)
07-18 17:22:06.469: E/AndroidRuntime(11404):    at java.lang.reflect.Method.invoke(Method.java:511)
07-18 17:22:06.469: E/AndroidRuntime(11404):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1004)
07-18 17:22:06.469: E/AndroidRuntime(11404):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:771)
07-18 17:22:06.469: E/AndroidRuntime(11404):    at dalvik.system.NativeStart.main(Native Method)
07-18 17:22:06.469: E/AndroidRuntime(11404): Caused by: java.lang.ClassCastException: com.example.httpgetandroidexample.HttpGetAndroidExample cannot be cast to android.app.Activity
07-18 17:22:06.469: E/AndroidRuntime(11404):    at android.app.Instrumentation.newActivity(Instrumentation.java:1068)
07-18 17:22:06.469: E/AndroidRuntime(11404):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2003)
07-18 17:22:06.469: E/AndroidRuntime(11404):    ... 11 more

MANIFEST:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.httpgetandroidexample"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="17" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.httpgetandroidexample.HttpGetAndroidExample"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

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

</manifest>

Answer 1

There are two issues:

In manifest, you've declared the HttpGetAndroidExample class as an activity. Contradictory to that, the HttpGetAndroidExample class does not extend the Activiy class. So, its not an activity. That's why the exception HttpGetAndroidExample cannot be cast to android.app.Activity . Either extend it to be an Activity and create the required functions or remove it from the manifest if its not an activity.

Also, there is no where on the tutorial link I could see this class.