在路径上找不到类“edu.stanford.cs231m.HelloAndroidActivity”：DexPathList

Question

我正在尝试根据斯坦福移动计算机视觉课程http://web.stanford.edu/class/cs231m/实施“HelloAndroid”。我遇到了“ClassNotFoundException”问题。在Android模拟器上它说“不幸的是，HelloAndroid已经停止了”。 Eclipse中的LogCat显示以下内容：

04-17 22:28:47.180: D/AndroidRuntime(2036): Shutting down VM
04-17 22:28:47.180: D/AndroidRuntime(2036): --------- beginning of crash
04-17 22:28:47.180: E/AndroidRuntime(2036): FATAL EXCEPTION: main
04-17 22:28:47.180: E/AndroidRuntime(2036): Process: edu.stanford.cs231m, PID: 2036
04-17 22:28:47.180: E/AndroidRuntime(2036): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{edu.stanford.cs231m/edu.stanford.cs231m.HelloAndroidActivity}: java.lang.ClassNotFoundException: Didn't find class "edu.stanford.cs231m.HelloAndroidActivity" on path: DexPathList[[zip file "/data/app/edu.stanford.cs231m-1/base.apk"],nativeLibraryDirectories=[/vendor/lib64, /system/lib64]]
04-17 22:28:47.180: E/AndroidRuntime(2036):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2209)
04-17 22:28:47.180: E/AndroidRuntime(2036):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
04-17 22:28:47.180: E/AndroidRuntime(2036):     at android.app.ActivityThread.access$800(ActivityThread.java:144)
04-17 22:28:47.180: E/AndroidRuntime(2036):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
04-17 22:28:47.180: E/AndroidRuntime(2036):     at android.os.Handler.dispatchMessage(Handler.java:102)
04-17 22:28:47.180: E/AndroidRuntime(2036):     at android.os.Looper.loop(Looper.java:135)
04-17 22:28:47.180: E/AndroidRuntime(2036):     at android.app.ActivityThread.main(ActivityThread.java:5221)
04-17 22:28:47.180: E/AndroidRuntime(2036):     at java.lang.reflect.Method.invoke(Native Method)
04-17 22:28:47.180: E/AndroidRuntime(2036):     at java.lang.reflect.Method.invoke(Method.java:372)
04-17 22:28:47.180: E/AndroidRuntime(2036):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
04-17 22:28:47.180: E/AndroidRuntime(2036):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
04-17 22:28:47.180: E/AndroidRuntime(2036): Caused by: java.lang.ClassNotFoundException: Didn't find class "edu.stanford.cs231m.HelloAndroidActivity" on path: DexPathList[[zip file "/data/app/edu.stanford.cs231m-1/base.apk"],nativeLibraryDirectories=[/vendor/lib64, /system/lib64]]
04-17 22:28:47.180: E/AndroidRuntime(2036):     at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
04-17 22:28:47.180: E/AndroidRuntime(2036):     at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
04-17 22:28:47.180: E/AndroidRuntime(2036):     at java.lang.ClassLoader.loadClass(ClassLoader.java:469)
04-17 22:28:47.180: E/AndroidRuntime(2036):     at android.app.Instrumentation.newActivity(Instrumentation.java:1065)
04-17 22:28:47.180: E/AndroidRuntime(2036):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2199)
04-17 22:28:47.180: E/AndroidRuntime(2036):     ... 10 more
04-17 22:28:47.180: E/AndroidRuntime(2036):     Suppressed: java.lang.ClassNotFoundException: edu.stanford.cs231m.HelloAndroidActivity
04-17 22:28:47.180: E/AndroidRuntime(2036):         at java.lang.Class.classForName(Native Method)
04-17 22:28:47.180: E/AndroidRuntime(2036):         at java.lang.BootClassLoader.findClass(ClassLoader.java:781)
04-17 22:28:47.180: E/AndroidRuntime(2036):         at java.lang.BootClassLoader.loadClass(ClassLoader.java:841)
04-17 22:28:47.180: E/AndroidRuntime(2036):         at java.lang.ClassLoader.loadClass(ClassLoader.java:504)
04-17 22:28:47.180: E/AndroidRuntime(2036):         ... 13 more
04-17 22:28:47.180: E/AndroidRuntime(2036):     Caused by: java.lang.NoClassDefFoundError: Class not found using the boot class loader; no stack available

供参考，java代码是

package edu.stanford.cs231m.helloandroid;
import android.widget.TextView;
import android.app.Activity;
import android.os.Bundle;
public class HelloAndroidActivity extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {

        TextView txtView = new TextView(this);
        txtView.setText("Hello czAndroid!");
        setContentView(txtView);

        super.onCreate(savedInstanceState);
    }
}

manifest.xml是

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="edu.stanford.cs231m"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk
    android:minSdkVersion="21"
    android:targetSdkVersion="21" />

<application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >

    <activity 
        android:name="HelloAndroidActivity" 
        android:label="@string/app_name" 
        android:screenOrientation="landscape">
        <intent-filter>
            <category android:name="android.intent.category.LAUNCHER"/>
            <action android:name="android.intent.action.MAIN"/>
        </intent-filter>
    </activity>

</application>

</manifest>

项目窗口就像

如果重要，模拟器的详细信息如下：

java构建路径是

我已经为此工作了将近一天，并尝试了一些方法，例如在“HelloAndroidActivity”中添加一个点，选择java构建路径中的所有项目等，但这些都不起作用。

Answer 1

事实证明，我的manifest.xml包名写错了。我写了

package="edu.stanford.cs231m"

正确的应该是

package="edu.stanford.cs231m.helloandroid"

问题解决了。