我如何通过一个自定义类型的对象从一个活动到另一个使用类意图的putExtra()方法?


当前回答

你的类应该实现Serializable或Parcelable。

public class MY_CLASS implements Serializable

一旦完成,你可以在putExtra上发送一个对象

intent.putExtra("KEY", MY_CLASS_instance);

startActivity(intent);

要得到额外的,你只需要做

Intent intent = getIntent();
MY_CLASS class = (MY_CLASS) intent.getExtras().getSerializable("KEY");

如果您的类实现了Parcelable,请使用下一个

MY_CLASS class = (MY_CLASS) intent.getExtras().getParcelable("KEY");

我希望它能帮到你

其他回答

在臂膀上

在build.gradle中添加kotlin扩展。

apply plugin: 'kotlin-android-extensions'

android {
    androidExtensions {
        experimental = true
   }
}

然后像这样创建数据类。

@Parcelize
data class Sample(val id: Int, val name: String) : Parcelable

传递带有意图的对象

val sample = Sample(1,"naveen")

val intent = Intent(context, YourActivity::class.java)
    intent.putExtra("id", sample)
    startActivity(intent)

获取带有意图的对象

val sample = intent.getParcelableExtra("id")

最简单的方法是在item是字符串的情况下使用以下代码:

intent.putextra("selected_item",item)

接收:

String name = data.getStringExtra("selected_item");

如果你有一个单例类(fx Service)作为你的模型层的网关,它可以通过在该类中有一个带有getter和setter的变量来解决。

活动一:

Intent intent = new Intent(getApplicationContext(), Activity2.class);
service.setSavedOrder(order);
startActivity(intent);

活动二:

private Service service;
private Order order;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_quality);

    service = Service.getInstance();
    order = service.getSavedOrder();
    service.setSavedOrder(null) //If you don't want to save it for the entire session of the app.
}

在服务:

private static Service instance;

private Service()
{
    //Constructor content
}

public static Service getInstance()
{
    if(instance == null)
    {
        instance = new Service();
    }
    return instance;
}
private Order savedOrder;

public Order getSavedOrder()
{
    return savedOrder;
}

public void setSavedOrder(Order order)
{
    this.savedOrder = order;
}

此解决方案不需要对相关对象进行任何序列化或其他“打包”。但是,只有在使用这种架构时才会有好处。

public class SharedBooking implements Parcelable{

    public int account_id;
    public Double betrag;
    public Double betrag_effected;
    public int taxType;
    public int tax;
    public String postingText;

    public SharedBooking() {
        account_id = 0;
        betrag = 0.0;
        betrag_effected = 0.0;
        taxType = 0;
        tax = 0;
        postingText = "";
    }

    public SharedBooking(Parcel in) {
        account_id = in.readInt();
        betrag = in.readDouble();
        betrag_effected = in.readDouble();
        taxType = in.readInt();
        tax = in.readInt();
        postingText = in.readString();
    }

    public int getAccount_id() {
        return account_id;
    }
    public void setAccount_id(int account_id) {
        this.account_id = account_id;
    }
    public Double getBetrag() {
        return betrag;
    }
    public void setBetrag(Double betrag) {
        this.betrag = betrag;
    }
    public Double getBetrag_effected() {
        return betrag_effected;
    }
    public void setBetrag_effected(Double betrag_effected) {
        this.betrag_effected = betrag_effected;
    }
    public int getTaxType() {
        return taxType;
    }
    public void setTaxType(int taxType) {
        this.taxType = taxType;
    }
    public int getTax() {
        return tax;
    }
    public void setTax(int tax) {
        this.tax = tax;
    }
    public String getPostingText() {
        return postingText;
    }
    public void setPostingText(String postingText) {
        this.postingText = postingText;
    }
    public int describeContents() {
        // TODO Auto-generated method stub
        return 0;
    }
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeInt(account_id);
        dest.writeDouble(betrag);
        dest.writeDouble(betrag_effected);
        dest.writeInt(taxType);
        dest.writeInt(tax);
        dest.writeString(postingText);

    }

    public static final Parcelable.Creator<SharedBooking> CREATOR = new Parcelable.Creator<SharedBooking>()
    {
        public SharedBooking createFromParcel(Parcel in)
        {
            return new SharedBooking(in);
        }
        public SharedBooking[] newArray(int size)
        {
            return new SharedBooking[size];
        }
    };

}

传递数据:

Intent intent = new Intent(getApplicationContext(),YourActivity.class);
Bundle bundle = new Bundle();
i.putParcelableArrayListExtra("data", (ArrayList<? extends Parcelable>) dataList);
intent.putExtras(bundle);
startActivity(intent);

检索数据:

Bundle bundle = getIntent().getExtras();
dataList2 = getIntent().getExtras().getParcelableArrayList("data");

对于你知道要在应用程序中传递数据的情况,使用“全局变量”(比如静态类)

以下是Dianne Hackborn (hackbod -谷歌安卓软件工程师)对此事的看法:

For situations where you know the activities are running in the same process, you can just share data through globals. For example, you could have a global HashMap<String, WeakReference<MyInterpreterState>> and when you make a new MyInterpreterState come up with a unique name for it and put it in the hash map; to send that state to another activity, simply put the unique name into the hash map and when the second activity is started it can retrieve the MyInterpreterState from the hash map with the name it receives.