如何使用 Intent 将对象从一个 Android Activity 发送到另一个?

问题描述：

如何从一个 Activity传递自定义类型的对象> 到另一个使用类的 putExtra() 方法意图?

How can I pass an object of a custom type from one Activity to another using the putExtra() method of the class Intent?

答

如果你只是传递对象，那么 Parcelable 就是为此而设计的.与使用 Java 的本机序列化相比，它需要更多的努力来使用，但速度更快(我的意思是，WAY 更快).

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).

从文档中，如何实现的一个简单示例是:

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();
    }
}

请注意，如果您有多个字段要从给定的 Parcel 中检索，您必须按照放入它们的相同顺序(即采用 FIFO 方法)执行此操作.

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).

一旦您的对象实现了 Parcelable，只需将它们放入您的 Intents 带有 putExtra():

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);

然后你可以用 getParcelableExtra():

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

如果您的对象类实现了 Parcelable 和 Serializable，那么请确保您强制转换为以下之一:

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);

如何使用 Intent 将对象从一个 Android Activity 发送到另一个?

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