Android 将列表从一个活动传递到另一个活动

Passing a List from one Activity to another

提问by Name is Nilay

How to pass Collections like ArrayList, etc from one Activityto another as we used to pass Strings, intwith help of putExtra method of Intent?

在 Intent 的 putExtra 方法的帮助下，如何像过去一样将诸如ArrayList, etc 之类的集合从一个Activity传递到另一个？Stringsint

Can anyone please help me as i want to pass a List<String>from one Activityto another?

任何人都可以帮助我，因为我想List<String>从一个传递Activity到另一个？

回答by nhaarman

You can pass an ArrayList<E>the same way, if the Etype is Serializable.

你可以传递一个ArrayList<E>同样的方式，如果E类型Serializable。

You would call the putExtra (String name, Serializable value)of Intentto store, and getSerializableExtra (String name)for retrieval.

您可以调用putExtra (String name, Serializable value)ofIntent来存储和getSerializableExtra (String name)检索。

Example:

例子：

ArrayList<String> myList = new ArrayList<String>();
intent.putExtra("mylist", myList);

In the other Activity:

在另一个活动中：

ArrayList<String> myList = (ArrayList<String>) getIntent().getSerializableExtra("mylist");

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Please note that serialization can cause performance issues: it takes time, and a lot of objects will be allocated (and thus, have to be garbage collected).

请注意，序列化可能会导致性能问题：它需要时间，并且将分配大量对象（因此必须进行垃圾回收）。

回答by Shahin ShamS

First you need to create a Parcelable object class, see the example

首先需要创建一个 Parcelable 对象类，看例子

public class Student implements Parcelable {

        int id;
        String name;

        public Student(int id, String name) {
            this.id = id;
            this.name = name;

        }

        public int getId() {
            return id;
        }

        public String getName() {
            return name;
        }


        @Override
        public int describeContents() {
            // TODO Auto-generated method stub
            return 0;
        }

        @Override
        public void writeToParcel(Parcel dest, int arg1) {
            // TODO Auto-generated method stub
            dest.writeInt(id);
            dest.writeString(name);
        }

        public Student(Parcel in) {
            id = in.readInt();
            name = in.readString();
        }

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

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

And the list

还有名单

ArrayList<Student> arraylist = new ArrayList<Student>();

Code from Calling activity

来自呼叫活动的代码

Intent intent = new Intent(this, SecondActivity.class);
Bundle bundle = new Bundle();
bundle.putParcelableArrayList("mylist", arraylist);
intent.putExtras(bundle);       
this.startActivity(intent);

Code on called activity

调用活动的代码

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_second);   

    Bundle bundle = getIntent().getExtras();
    ArrayList<Student> arraylist = bundle.getParcelableArrayList("mylist");
}

回答by niky_d

I tried all the proposed techniques but none of them worked and stopped my app from working and then I finally succedded. Here is how I did it... In main activity I did this:

我尝试了所有建议的技术，但它们都不起作用，并阻止了我的应用程序工作，然后我终于成功了。这是我是如何做到的......在主要活动中，我是这样做的：

            List<String> myList...;
            Intent intent = new Intent...;
            Bundle b=new Bundle();
            b.putStringArrayList("KEY",(ArrayList<String>)myList);            
            intent_deviceList.putExtras(b);
            ....startActivity(intent);

To get the data in the new Activity:

获取新活动中的数据：

    List<String> myList...
    Bundle b = getIntent().getExtras();
    if (b != null) {
        myList = bundle.getStringArrayList("KEY");
    }

I hope this will help someone...

我希望这会帮助某人...

回答by RajaReddy PolamReddy

use putExtrato pass value to an intent. use getSerializableExtramethod to retrieve the data like this

用于putExtra将值传递给意图。使用getSerializableExtra方法来检索这样的数据

Activity A :

活动一：

ArrayList<String> list = new ArrayList<String>();

intent.putExtra("arraylist", list);
startActivity(intent);

Activity B:

活动乙：

ArrayList<String> list = getIntent().getSerializableExtra("arraylist");

回答by AkashG

To pass ArrayList from one activity to another activity, one should include

要将 ArrayList 从一个活动传递到另一个活动，应该包括

intent.putStringArrayListExtra(KEY, list); //where list is ArrayList which you want to pass

before starting the activity.And to get the ArrayList in another activity include

在开始活动之前。并在另一个活动中获取 ArrayList 包括

Bundle bundle = getIntent().getExtras();
        if (bundle != null) {
            temp = bundle.getStringArrayList(KEY); // declare temp as ArrayList
                }

you will be able to pass ArrayList through this.Hope this will be helpful to you.

您将能够通过此传递 ArrayList。希望这对您有所帮助。