如何通过对象到一个新的活动？ （如何注入） [英] How to pass object to a new Activity? (how to inject)

问题描述

我想传递一个对象（不是数据！）来实现一些接口（例如IConnect的）到一个新的活动。 活动将调用这个对象的一些方法来获取数据。

如何做到这一点？ （序列化和Parcelable是对象/数据/结构我想，不为对象/界面，做的东西）。

我应该传递一个类名的意图演员？然后活动将创建所需的对象？ 如何注入对象（几个不同的类，它实现的IConnect）到一个新的活动？

解决方案

MyParcelable.java

 公共类MyParcelable实现Parcelable {

    私人字符串MVAL;

    公共MyParcelable（字符串VAL）{
        MVAL = VAL;
    }

    公共静态最终Parcelable.Creator＆LT; MyParcelable＆GT; CREATOR =
        新Parcelable.Creator＆LT; MyParcelable＆GT;（）{
        公共MyParcelable createFromParcel（包裹中）{
            字符串s = in.readString（）;
            返回新MyParcelable（S）;
        }

        公共MyParcelable [] newArray（INT尺寸）{
            返回新MyParcelable【尺寸】;
        }
    };

    公共字符串的getValue（）{
        返回MVAL;
    }

    公共无效writeToParcel（地块P）{
        p.writeString（MVAL）;
    }

    公共字符串的toString（）{
        返回MyParcelable [VAL =+ MVAL +];
    }

}
 

---

SendParcelable.java

 公共类SendParcelable延伸活动{
    @覆盖
    公共无效的onCreate（包冰柱）{
        super.onCreate（冰柱）;
        意向意图=新的意图（这一点，ReceiveParcelable.class）;
        Parcelable P =新MyParcelable（测试）;
        intent.putExtra（myparcelable，p）的;
        Log.i（ParcelDemo，发送Parcelable）;
        startActivity（意向）;
    }
}
 

---

ReceiveParcelable.java

 公共类ReceiveParcelable延伸活动{
    @覆盖
    公共无效的onCreate（包冰柱）{
      super.onCreate（冰柱）;
      意向意图= getIntent（）;
       Parcelable p值= intent.getParcelableExtra（myparcelable）;
        Log.i（ParcelDemo，得到Parcelable+ P）;
        如果（P = NULL和放大器;！＆放，P的instanceof MyParcelable和放大器;＆安培;
            （（MyParcelable）P）.getValue（）。等于（测试））{
            Log.i（ParcelDemo，成功！）;
        } 其他 {
            Log.i（ParcelDemo，失败！）;
        }
    }
}
 

---

希望这有助于！

I want to pass an object (not data!) that implements some interface (ex. IConnect ) to a new Activity. Activity will call some methods from this object to acquire data.

How to do that? (Serializable and Parcelable are for objects/data/structures i guess, not for objects/interfaces that 'DO' something).

Should I pass a class name in Intent extras? and then Activity will create desired object? How to inject an object (a few different classes that implements IConnect) to a new Activity ?

解决方案

MyParcelable.java

public class MyParcelable implements Parcelable { 

    private String mVal; 

    public MyParcelable(String val) { 
        mVal = val; 
    } 

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

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

    public String getValue() { 
        return mVal; 
    } 

    public void writeToParcel(Parcel p) { 
        p.writeString(mVal); 
    } 

    public String toString() { 
        return "MyParcelable[val=" + mVal + "]"; 
    } 

} 

---

SendParcelable.java

public class SendParcelable extends Activity { 
    @Override 
    public void onCreate(Bundle icicle) { 
        super.onCreate(icicle); 
        Intent intent = new Intent(this, ReceiveParcelable.class); 
        Parcelable p = new MyParcelable("test"); 
        intent.putExtra("myparcelable", p); 
        Log.i("ParcelDemo", "Sending Parcelable"); 
        startActivity(intent); 
    } 
} 

---

ReceiveParcelable.java

public class ReceiveParcelable extends Activity { 
    @Override 
    public void onCreate(Bundle icicle) { 
      super.onCreate(icicle); 
      Intent intent = getIntent(); 
       Parcelable p = intent.getParcelableExtra("myparcelable"); 
        Log.i("ParcelDemo", "Got Parcelable " + p); 
        if (p != null && p instanceof MyParcelable && 
            ((MyParcelable) p).getValue().equals("test")) { 
            Log.i("ParcelDemo", "Success!"); 
        } else { 
            Log.i("ParcelDemo", "Failure!"); 
        } 
    } 
} 

---

Hope this helps!

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