android - 按主页按钮时出现 NotSerializableException

Question

我有一个 Activity，其中有一个私有(private)类数据。在 onSaveInstanceState 方法中，我尝试将此保存为 Data 的一个实例。这是我的整个 Activity :

public class TestActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    }

    @Override
    public void onSaveInstanceState(Bundle outState){
        outState.putSerializable("TEST", new Data());
    }

    private class Data implements Serializable {

        private static final long serialVersionUID = -4312723541994925110L;

    }
}

现在，当我更改设备的方向时，Data 对象会按应有的方式保存和读取。但是，当我按下主页按钮时，应用程序崩溃并在 logcat 中显示以下内容:

05-10 20:05:51.895: E/AndroidRuntime(30317): FATAL EXCEPTION: main 05-10 20:05:51.895: E/AndroidRuntime(30317): java.lang.RuntimeException: Parcelable encountered IOException writing serializable object (name = com.rigidbits.test.TestActivity$Data) 05-10 20:05:51.895: E/AndroidRuntime(30317): at android.os.Parcel.writeSerializable(Parcel.java:1176) 05-10 20:05:51.895: E/AndroidRuntime(30317): at android.os.Parcel.writeValue(Parcel.java:1130) 05-10 20:05:51.895: E/AndroidRuntime(30317): at android.os.Parcel.writeMapInternal(Parcel.java:488) 05-10 20:05:51.895: E/AndroidRuntime(30317): at android.os.Bundle.writeToParcel(Bundle.java:1552) 05-10 20:05:51.895: E/AndroidRuntime(30317): at android.os.Parcel.writeBundle(Parcel.java:502) 05-10 20:05:51.895: E/AndroidRuntime(30317): at android.app.ActivityManagerProxy.activityPaused(ActivityManagerNative.java:1615) 05-10 20:05:51.895: E/AndroidRuntime(30317): at android.app.ActivityThread.handlePauseActivity(ActivityThread.java:2298) 05-10 20:05:51.895: E/AndroidRuntime(30317): at android.app.ActivityThread.access$1700(ActivityThread.java:117) 05-10 20:05:51.895: E/AndroidRuntime(30317): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:938) 05-10 20:05:51.895: E/AndroidRuntime(30317): at android.os.Handler.dispatchMessage(Handler.java:99) 05-10 20:05:51.895: E/AndroidRuntime(30317): at android.os.Looper.loop(Looper.java:130) 05-10 20:05:51.895: E/AndroidRuntime(30317): at android.app.ActivityThread.main(ActivityThread.java:3683) 05-10 20:05:51.895: E/AndroidRuntime(30317): at java.lang.reflect.Method.invokeNative(Native Method) 05-10 20:05:51.895: E/AndroidRuntime(30317): at java.lang.reflect.Method.invoke(Method.java:507) 05-10 20:05:51.895: E/AndroidRuntime(30317): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:862) 05-10 20:05:51.895: E/AndroidRuntime(30317): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:620) 05-10 20:05:51.895: E/AndroidRuntime(30317): at dalvik.system.NativeStart.main(Native Method) 05-10 20:05:51.895: E/AndroidRuntime(30317): Caused by: java.io.NotSerializableException: com.rigidbits.test.TestActivity 05-10 20:05:51.895: E/AndroidRuntime(30317): at java.io.ObjectOutputStream.writeNewObject(ObjectOutputStream.java:1535) 05-10 20:05:51.895: E/AndroidRuntime(30317): at java.io.ObjectOutputStream.writeObjectInternal(ObjectOutputStream.java:1847) 05-10 20:05:51.895: E/AndroidRuntime(30317): at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1689) 05-10 20:05:51.895: E/AndroidRuntime(30317): at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1653) 05-10 20:05:51.895: E/AndroidRuntime(30317): at java.io.ObjectOutputStream.writeFieldValues(ObjectOutputStream.java:1143) 05-10 20:05:51.895: E/AndroidRuntime(30317): at java.io.ObjectOutputStream.defaultWriteObject(ObjectOutputStream.java:413) 05-10 20:05:51.895: E/AndroidRuntime(30317): at java.io.ObjectOutputStream.writeHierarchy(ObjectOutputStream.java:1241) 05-10 20:05:51.895: E/AndroidRuntime(30317): at java.io.ObjectOutputStream.writeNewObject(ObjectOutputStream.java:1575) 05-10 20:05:51.895: E/AndroidRuntime(30317): at java.io.ObjectOutputStream.writeObjectInternal(ObjectOutputStream.java:1847) 05-10 20:05:51.895: E/AndroidRuntime(30317): at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1689) 05-10 20:05:51.895: E/AndroidRuntime(30317): at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1653) 05-10 20:05:51.895: E/AndroidRuntime(30317): at android.os.Parcel.writeSerializable(Parcel.java:1171) 05-10 20:05:51.895: E/AndroidRuntime(30317): ... 16 more

当我在 onSaveInstanceState 方法中注释该行时，Data 对象未保存，应用程序正确消失。

有什么帮助吗？

Answer 1

好的，我认为问题在于您使用的是私有(private)内部类。

因此它可以访问您的外部类的方法和字段，即您的 Activity 。

因为您的 Activity 不可序列化(因此不应该)，您得到了异常。

An instance of InnerClass can exist only within an instance of OuterClass and has direct access to the methods and fields of its enclosing instance.

有两种解决方案。

• 让你的内部类静态化

• 将您的内部类移动为它自己的类并将其声明为公共(public)类

这些解决方案都使您的 Data 类成为一个独立的类，然后它不需要您的 Activity 实例存在

引用:http://docs.oracle.com/javase/tutorial/java/javaOO/nested.html