Android Intent 使用 Parcel 反序列化出错.

来源：互联网发布：大文豪曼因斯坦知乎编辑：程序博客网时间：2024/05/16 12:08

Android Parcel 可以序列化反序列化数据 .但上层的(Intent)却反序列化失败.

结论:

查看Android源代码, Intent 的Parcel 接口代码,也未能找出问题所在.

如下是我的测试代码 :

非持久化测试代码:

        final Intent intent = new Intent("cn.eben.bookshelf.VIEW");

       intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
//

序列化前 Intent 内存

Intent { act=cn.eben.bookshelf.VIEW flg=0x10000000 }

       Parcel parcel = Parcel.obtain();
       intent.writeToParcel(parcel, 0);

       byte[] data = parcel.marshall();


       Parcel readParcel = Parcel.obtain();
       readParcel.unmarshall(data, 0, data.length);
       Intent readIntent = Intent.CREATOR.createFromParcel(readParcel);

// readIntent 内存状态, Intent 反序列化失败.
Intent { (has extras) }
null
null
null
null
null
Bundle[mParcelledData.dataSize=0]
0
null
null
null
null

context.startActivity(readIntent);// Activite 无法启动, Intent 无效

// 持久化测试代码与内存状态

调试中,查看内存状态:

        final Intent intent = new Intent("cn.eben.bookshelf.VIEW");

       intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

查看内存:

序列化前 Intent 内存

Intent { act=cn.eben.bookshelf.VIEW flg=0x10000000 }

       Parcel parcel = Parcel.obtain();
       intent.writeToParcel(parcel, 0);

       byte[] data = parcel.marshall();

// 查看Data内存如下:

[22, 0, 0, 0, 99, 0, 110, 0, 46, 0, 101, 0, 98, 0, 101, 0, 110, 0, 46, 0, 98, 0, 111, 0, 111, 0, 107, 0, 115, 0, 104, 0, 101, 0, 108, 0, 102, 0, 46, 0, 86, 0, 73, 0, 69, 0, 87, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, -1, -1, -1, 0, 0, 0, 16, -1, -1, -1, -1, -1, -1, -1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, -1, -1, -1]

cv.put("intent", data); //将parcel对持久化.

///读取

byte[] data = cursor.getBlob(cursor.getColumnIndex("intent"));

//查看读取到的 Data内存如下: 与写入的相同.

       if (null != data && 1 < data.length) {
           Intent intent = null;
           Parcel parcel = Parcel.obtain();

// 进行反序列化:
parcel.unmarshall(data, 0, data.length);

intent = Intent.CREATOR.createFromParcel(parcel);
// intent 内存状态, Intent 反序列化失败.

Intent { (has extras) }
null
null
null
null
null
Bundle[mParcelledData.dataSize=0]
0
null
null
null
null
}

查看Android Intnet 源代码:

看不出来有什么异常

    public void writeToParcel(Parcel out, int flags) {        out.writeString(mAction);        Uri.writeToParcel(out, mData);        out.writeString(mType);        out.writeInt(mFlags);        out.writeString(mPackage);        ComponentName.writeToParcel(mComponent, out);        if (mSourceBounds != null) {            out.writeInt(1);            mSourceBounds.writeToParcel(out, flags);        } else {            out.writeInt(0);        }        if (mCategories != null) {            out.writeInt(mCategories.size());            for (String category : mCategories) {                out.writeString(category);            }        } else {            out.writeInt(0);        }        if (mSelector != null) {            out.writeInt(1);            mSelector.writeToParcel(out, flags);        } else {            out.writeInt(0);        }        if (mClipData != null) {            out.writeInt(1);            mClipData.writeToParcel(out, flags);        } else {            out.writeInt(0);        }        out.writeBundle(mExtras);    }    public static final Parcelable.Creator<Intent> CREATOR            = new Parcelable.Creator<Intent>() {        public Intent createFromParcel(Parcel in) {            return new Intent(in);        }        public Intent[] newArray(int size) {            return new Intent[size];        }    };    /** @hide */    protected Intent(Parcel in) {        readFromParcel(in);    }    public void readFromParcel(Parcel in) {        setAction(in.readString());        mData = Uri.CREATOR.createFromParcel(in);        mType = in.readString();        mFlags = in.readInt();        mPackage = in.readString();        mComponent = ComponentName.readFromParcel(in);        if (in.readInt() != 0) {            mSourceBounds = Rect.CREATOR.createFromParcel(in);        }        int N = in.readInt();        if (N > 0) {            mCategories = new HashSet<String>();            int i;            for (i=0; i<N; i++) {                mCategories.add(in.readString().intern());            }        } else {            mCategories = null;        }        if (in.readInt() != 0) {            mSelector = new Intent(in);        }        if (in.readInt() != 0) {            mClipData = new ClipData(in);        }        mExtras = in.readBundle();    }

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