How to send an object from one Android Activity to another using Intents?

在 Activity 之間傳遞參數的方法:

文章1:
How to send an object from one Android Activity to another using Intents
http://stackoverflow.com/questions/2139134/how-to-send-an-object-from-one-android-activity-to-another-using-intents

文章2:
How to pass an object from one activity to another on Android
http://stackoverflow.com/questions/2736389/how-to-pass-an-object-from-one-activity-to-another-on-android


If you’re just passing objects around then Parcelable was designed for this. It requires a little more effort to use than using Java’s native serialization, but it’s way faster (and I mean way, WAY faster).

From the docs, a simple example for how to implement is:

// simple class that just has one member property as an example
public class MyParcelable implements Parcelable {
    private int mData;

    /* everything below here is for implementing Parcelable */

    // 99.9% of the time you can just ignore this
    @Override
    public int describeContents() {
        return 0;
    }

    // write your object's data to the passed-in Parcel
    @Override
    public void writeToParcel(Parcel out, int flags) {
        out.writeInt(mData);
    }

    // this is used to regenerate your object. All Parcelables must have a CREATOR that implements these two methods
    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];
        }
    };

    // example constructor that takes a Parcel and gives you an object populated with it's values
    private MyParcelable(Parcel in) {
        mData = in.readInt();
    }
}

Observe that in the case you have more than one field to retrieve from a given Parcel, you must do this in the same order you put them in (that is, in a FIFO approach).

Once you have your objects implement Parcelable it’s just a matter of putting them into your Intents with putExtra():

Intent i = new Intent();
i.putExtra("name_of_extra", myParcelableObject);

Then you can pull them back out with getParcelableExtra():

Intent i = getIntent();
MyParcelable myParcelableObject = (MyParcelable) i.getParcelableExtra("name_of_extra");

If your Object Class implements Parcelable and Serializable then make sure you do cast to one of the following:

i.putExtra("parcelable_extra", (Parcelable) myParcelableObject);
i.putExtra("serializable_extra", (Serializable) myParcelableObject);

You can send serializable object through intent

// send where details is object
ClassName details = new ClassName();
Intent i = new Intent(context, EditActivity.class);
i.putExtra("Editing", details);
startActivity(i);


//receive
ClassName model = (ClassName) getIntent().getSerializableExtra("Editing");

And 

Class ClassName implements Serializable {
} 

//To pass:
intent.putExtra("MyClass", obj);

// To retrieve object in second Activity
getIntent().getSerializableExtra("MyClass");

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