Errore durante il passaggio di un oggetto da un attività ad un altro (Usando Parcelable)

Question

ho cercato di passare una classe di oggetti da un'attività ad un altro utilizzando Parcelable

ho creare una classe e il nome degli studenti

package com.example.test08_passobjectoverintent; 

import android.os.Parcel; 
import android.os.Parcelable; 

public class Student implements Parcelable 
{ 

    private String st_AcadimicNumber ; 
    private String st_Name ; 
    private String st_Class ; 
    public String getSt_AcadimicNumber() { 
     return st_AcadimicNumber; 
    } 
    public void setSt_AcadimicNumber(String st_AcadimicNumber) { 
     this.st_AcadimicNumber = st_AcadimicNumber; 
    } 
    public String getSt_Name() { 
     return st_Name; 
    } 
    public void setSt_Name(String st_Name) { 
     this.st_Name = st_Name; 
    } 
    public String getSt_Class() { 
     return st_Class; 
    } 
    public void setSt_Class(String st_Class) { 
     this.st_Class = st_Class; 
    } 

    public Student(String st_AcadimicNumber, String st_Name, String st_Class) { 
     super(); 
     this.st_AcadimicNumber = st_AcadimicNumber; 
     this.st_Name = st_Name; 
     this.st_Class = st_Class; 
    } 
public Student() { 
    super(); 
} 
    @Override 
    public int describeContents() { 
     // TODO Auto-generated method stub 
     return 0; 
    } 

    @Override 
    public void writeToParcel(Parcel dest, int flags) { 
     // TODO Auto-generated method stub 

    } 

} 

nell'attività principale ho utilizzare questo codice per passare l'Obejct ...

   Student st = new Student("aaa","bbb","ccc"); 
       Intent intent = new Intent(MainActivity.this,Main2Activity.class); 
       intent.putExtra("stu", st); 
       startActivity(intent); 

nella seconda attività (Recupera One)

ho utilizzare questo codice (errore è QUI)

Student model = (Student)getIntent().getParcelableExtra("stu"); 

LogCat errore

12-09 15:50:06.068: E/Trace(30655): error opening trace file: No such file or directory (2) 
12-09 15:50:06.188: D/libEGL(30655): loaded /system/lib/egl/libEGL_mali.so 
12-09 15:50:06.188: D/libEGL(30655): loaded /system/lib/egl/libGLESv1_CM_mali.so 
12-09 15:50:06.193: D/libEGL(30655): loaded /system/lib/egl/libGLESv2_mali.so 
12-09 15:50:06.193: D/(30655): Device driver API match 
12-09 15:50:06.193: D/(30655): Device driver API version: 10 
12-09 15:50:06.193: D/(30655): User space API version: 10 
12-09 15:50:06.193: D/(30655): mali: REVISION=Linux-r2p4-02rel0 BUILD_DATE=Wed Sep 12 17:53:53 KST 2012 
12-09 15:50:06.218: D/OpenGLRenderer(30655): Enabling debug mode 0 
12-09 15:50:08.033: D/GestureDetector(30655): [Surface Touch Event] mSweepDown False, mLRSDCnt : -1 mTouchCnt : 4 mFalseSizeCnt:0 
12-09 15:50:08.123: D/AndroidRuntime(30655): Shutting down VM 
12-09 15:50:08.123: W/dalvikvm(30655): threadid=1: thread exiting with uncaught exception (group=0x40e372a0) 
12-09 15:50:08.128: E/AndroidRuntime(30655): FATAL EXCEPTION: main 
12-09 15:50:08.128: E/AndroidRuntime(30655): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.test08_passobjectoverintent/com.example.test08_passobjectoverintent.Main2Activity}: android.os.BadParcelableException: Parcelable protocol requires a Parcelable.Creator object called CREATOR on class com.example.test08_passobjectoverintent.Student 
12-09 15:50:08.128: E/AndroidRuntime(30655): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2100) 
12-09 15:50:08.128: E/AndroidRuntime(30655): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2125) 
12-09 15:50:08.128: E/AndroidRuntime(30655): at android.app.ActivityThread.access$600(ActivityThread.java:140) 
12-09 15:50:08.128: E/AndroidRuntime(30655): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1227) 
12-09 15:50:08.128: E/AndroidRuntime(30655): at android.os.Handler.dispatchMessage(Handler.java:99) 
12-09 15:50:08.128: E/AndroidRuntime(30655): at android.os.Looper.loop(Looper.java:137) 
12-09 15:50:08.128: E/AndroidRuntime(30655): at android.app.ActivityThread.main(ActivityThread.java:4898) 
12-09 15:50:08.128: E/AndroidRuntime(30655): at java.lang.reflect.Method.invokeNative(Native Method) 
12-09 15:50:08.128: E/AndroidRuntime(30655): at java.lang.reflect.Method.invoke(Method.java:511) 
12-09 15:50:08.128: E/AndroidRuntime(30655): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1008) 
12-09 15:50:08.128: E/AndroidRuntime(30655): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:775) 
12-09 15:50:08.128: E/AndroidRuntime(30655): at dalvik.system.NativeStart.main(Native Method) 
12-09 15:50:08.128: E/AndroidRuntime(30655): Caused by: android.os.BadParcelableException: Parcelable protocol requires a Parcelable.Creator object called CREATOR on class com.example.test08_passobjectoverintent.Student 
12-09 15:50:08.128: E/AndroidRuntime(30655): at android.os.Parcel.readParcelable(Parcel.java:2086) 
12-09 15:50:08.128: E/AndroidRuntime(30655): at android.os.Parcel.readValue(Parcel.java:1965) 
12-09 15:50:08.128: E/AndroidRuntime(30655): at android.os.Parcel.readMapInternal(Parcel.java:2226) 
12-09 15:50:08.128: E/AndroidRuntime(30655): at android.os.Bundle.unparcel(Bundle.java:223) 
12-09 15:50:08.128: E/AndroidRuntime(30655): at android.os.Bundle.getParcelable(Bundle.java:1165) 
12-09 15:50:08.128: E/AndroidRuntime(30655): at android.content.Intent.getParcelableExtra(Intent.java:4451) 
12-09 15:50:08.128: E/AndroidRuntime(30655): at com.example.test08_passobjectoverintent.Main2Activity.onCreate(Main2Activity.java:22) 
12-09 15:50:08.128: E/AndroidRuntime(30655): at android.app.Activity.performCreate(Activity.java:5191) 
12-09 15:50:08.128: E/AndroidRuntime(30655): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094) 
12-09 15:50:08.128: E/AndroidRuntime(30655): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2064) 
12-09 15:50:08.128: E/AndroidRuntime(30655): ... 11 more 

Answer 1

è necessario implementare il codice per scrivere e leggere i vostri campi di classe da pacco.

In writeToParcel:

@Override 
public void writeToParcel(Parcel dest, int flags) { 
     dest.writeString(st_AcadimicNumber); 
     dest.writeString(st_Name); 
     dest.writeString(st_Class); 
} 

il pacco CREATORE:

public static final Parcelable.Creator<Track> CREATOR 
= new Parcelable.Creator<Track>() { 
    public Student createFromParcel(Parcel in) { 
     return new Track(in); 
    } 

    public Student[] newArray(int size) { 
     return new Track[size]; 
    } 
}; 

e il costruttore:

public Student (Parcel source){ 
     /* 
     * Reconstruct from the Parcel. Keep same order as in writeToParcel() 
     */ 
     st_AcadimicNumber = source.readString(); 
     st_Name = source.readString(); 
     st_Class = source.readString(); 
} 

E il gioco è fatto.

saluti