实现Parcelable

Activity之间通过intent传递object时，该object的class需要实现Parcelable。

 

Interface for classes whose instances can be written to and restored from a Parcel. Classes implementing the Parcelable interface must also have a non-null static field called CREATOR of a type that implements the Parcelable.Creator interface.

A typical implementation of Parcelable is:

public class MyParcelable implements Parcelable {
    private int mData;

    public int describeContents() {
        //一般返回0即可
        return 0;
    }

    public void writeToParcel(Parcel out, int flags) {
        out.writeInt(mData);
    }

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

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

    private MyParcelable(Parcel in) {
        mData = in.readInt();
    }
}

 http://developer.android.com/reference/android/os/Parcelable.html

 

最核心的地方是

private MyParcelable(Parcel in)

和

writeToParcel(Parcel out, int flags)

读写顺序要一致。

 

public class Bill implements Parcelable {
    Integer fee;
    String title;
    Boolean result;

    public int describeContents() {
        return 0;
    }

    public void writeToParcel(Parcel out, int flags) {
        out.writeInt(fee);
        out.writeString(title);
        out.writeByte((byte) (result!=null && result ? 1 : 0));
    }

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

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

    private Bill(Parcel in) {
        fee = in.readInt();
        title = in.readString();
        result = (in.readByte()==1);
    }
}