[英]Android: ClassNotFoundException when passing serializable object to Activity
I have a few crash report logs from android market similar to this: 我有一些来自Android市场的崩溃报告日志,如下所示:
Exception class: java.lang.ClassNotFoundException
Source method: PathClassLoader.findClass()
java.lang.RuntimeException: Unable to start activity ComponentInfo{my.app.package/my.app.package.MyActivity}: java.lang.RuntimeException: Parcelable encounteredClassNotFoundException reading a Serializable object (name = my.app.package.a.ae)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2833)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2854)
at android.app.ActivityThread.access$2300(ActivityThread.java:136)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2179)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:143)
at android.app.ActivityThread.main(ActivityThread.java:5068)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:521)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.RuntimeException: Parcelable encounteredClassNotFoundException reading a Serializable object (name = my.app.package.a.ae)
at android.os.Parcel.readSerializable(Parcel.java:1951)
at android.os.Parcel.readValue(Parcel.java:1822)
at android.os.Parcel.readMapInternal(Parcel.java:2008)
at android.os.Bundle.unparcel(Bundle.java:208)
at android.os.Bundle.getBundle(Bundle.java:1078)
at android.app.Activity.onRestoreInstanceState(Activity.java:861)
at android.app.Activity.performRestoreInstanceState(Activity.java:835)
at android.app.Instrumentation.callActivityOnRestoreInstanceState(Instrumentation.java:1135)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2811)
... 11 more
Caused by: java.lang.ClassNotFoundException: my.app.package.a.ae
at java.lang.Class.classForName(Native Method)
at java.lang.Class.forName(Class.java:235)
at java.io.ObjectInputStream.resolveClass(ObjectInputStream.java:2590)
at java.io.ObjectInputStream.readNewClassDesc(ObjectInputStream.java:1846)
at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:826)
at java.io.ObjectInputStream.readNewObject(ObjectInputStream.java:2066)
at java.io.ObjectInputStream.readNonPrimitiveContent(ObjectInputStream.java:929)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:2285)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:2240)
at android.os.Parcel.readSerializable(Parcel.java:1945)
... 19 more
Caused by: java.lang.NoClassDefFoundError: my.app.package.a.ae
... 29 more
Caused by: java.lang.ClassNotFoundException: my.app.package.a.ae in loader dalvik.system.PathClassLoader[.]
at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:243)
at java.lang.ClassLoader.loadClass(ClassLoader.java:573)
at java.lang.ClassLoader.loadClass(ClassLoader.java:532)
... 29 more
Please note that I am using proguard -> that's why the "missing" class name is "a.ae". 请注意,我使用的是proguard->这就是为什么“缺少”的类名是“ a.ae”的原因。
Actually, "a.ae" is the name proguard gave to the class "MyObject", which is shown below. 实际上,“ a.ae”是proguard赋予类“ MyObject”的名称,如下所示。
Any ideia on why this happens? 为什么会这样?
I don't think it has to do with proguard, because if it was a problem caused by proguard class renaming, it should happen all times and I would be able to reproduce this issue myself. 我认为这与proguard无关,因为如果这是由proguard类重命名引起的问题,它应该一直存在,并且我可以自己重现此问题。
Does it have to do with passing a serializable object to MyActivity? 它与将可序列化的对象传递给MyActivity有关吗?
In MyActivity I have 在MyActivity中
public void onCreate(Bundle savedInstanceState) {
myObj = (MyObject) getIntent().getSerializableExtra("nameOfMyObject");
//here I am trying to read myObj's properties and app seems to crash here
} }
MyObject is just an entity with several types of class members, ex: MyObject只是具有几种类型的类成员的实体,例如:
public class MyObject implements Serializable { 公共类MyObject实现Serializable {
/** Generated serialVersionUID */
static final long serialVersionUID = -267025879233327409L;
static final String CONSTANT1 = "xpto";
LinkedHashMap<String, Object> components;
ArrayList<String> prop1;
(...)
}
I am starting MyActivity with: 我以以下方式启动MyActivity:
MyObject obj = new MyObj(stuff);
Intent intent;
intent = new Intent(CurrentActivity.this, MyActivity.class);
intent.putExtra("nameOfMyObject", obj);
CurrentActivity.this.startActivity(intent);
Do you think it has to do with the way the object is being passed (as a serializable extra)? 您是否认为它与对象传递的方式有关(作为可序列化的额外内容)?
In the case that I don't find any other solution I think I will "serialize" the object myself to a String and then pass the String extra. 在找不到其他解决方案的情况下,我想我自己将对象“序列化”为字符串,然后额外传递字符串。 What do you think about this? 你怎么看待这件事?
EDIT: I have tried to reproduce this issue, without success, in the emulator and in the following devices: 编辑:我尝试在模拟器和以下设备中重现此问题,但未成功:
-Motorola Milestone 2 Android 2.2 -摩托罗拉Milestone 2 Android 2.2
-Samsung Galaxy Tab Android 2.2 -三星Galaxy Tab Android 2.2
-Vodafone 845 Android 2.1 -沃达丰845 Android 2.1
-HTC Tatoo Android 1.6 -HTC Tatoo Android 1.6
-Xperia X10 Android 1.6 -Xperia X10 Android 1.6
-Nexus One Android 2.2 -Nexus One Android 2.2
-Google G1 Android 1.5 -Google G1 Android 1.5
Any new ideas? 有什么新主意吗?
Finally reached a conclusion on this issue: it was being caused by Proguard, or more specifically, because I didn't have a propper Proguard configuration. 终于在这个问题上得出了一个结论:这是由Proguard引起的,或更具体地说,是因为我没有合适的Proguard配置。
It turns out Proguard was changing my Serializable
's classes names, which makes Class.forName(className)
fail. 事实证明,Proguard更改了我的Serializable
的类名称,这使Class.forName(className)
失败。
I had to reconfigure my proguard.cfg
file adding the following lines: 我必须重新配置我的proguard.cfg
文件,并添加以下几行:
-keep class * implements java.io.Serializable
-keepclassmembers class * implements java.io.Serializable {
static final long serialVersionUID;
private static final java.io.ObjectStreamField[] serialPersistentFields;
!static !transient <fields>;
!private <fields>;
!private <methods>;
private void writeObject(java.io.ObjectOutputStream);
private void readObject(java.io.ObjectInputStream);
java.lang.Object writeReplace();
java.lang.Object readResolve();
}
You should look into implementing Parcelable
. 您应该研究实现Parcelable
。 These two links should get you started: http://developer.android.com/reference/android/os/Parcel.html http://developer.android.com/reference/android/os/Parcelable.html 这两个链接应该可以帮助您入门: http : //developer.android.com/reference/android/os/Parcel.html http://developer.android.com/reference/android/os/Parcelable.html
LinkedHashMap
doesn't implement Serializable
so this may be causing the error. LinkedHashMap
没有实现Serializable
因此这可能会导致错误。 Try either implementing a small test to serialize this class or try removing the LinkedHashMap
and see if the error persists. 尝试实施一个小型测试来序列化此类,或者尝试删除LinkedHashMap
并查看错误是否仍然存在。
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