CODEWITHSUNDEEP
androiddesign-patterns
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Reputation: 8425

Better way to pass data between Activities in Android

In my application I am fetching data from JavaScript, as it is not possible to return the data as an array or object, I am returning it as a String.

Now to organize the data I am creating a class which contains ArrayLists and other string variables and further I am creating array of my class objects variable to store multiple records.

public class Data {

    ArrayList<String> m_empArrayList = new ArrayList();
    ArrayList<String> m_depArrayList = new ArrayList();
    String m_time;
    String m_duration;

}

Data d = new Data();

What would be a good approach to pass the data between Activities? As Intents and ShredPrefrences are used to pass small units of data I am not considering it here.

Upvotes: 2

Views: 3420

Answers (2)

Octavian Helm
Octavian Helm

Reputation: 39604

Implement the Parcelable interface in your custom object and transmit it via an Intent.

Here is an example of a Parcelable object.

public class MyObject implements Parcelable {

    private String someString = null;
    private int someInteger = 0;

    public MyObject() {
        // perform initialization if necessary
    }

    private MyObject(Parcel in) {
        someString = in.readString();
        someInteger = in.readInt();
    }

    public static final Parcelable.Creator<MyObject> CREATOR =
            new Parcelable.Creator<MyObject>() {

        @Override
        public MyObject createFromParcel(Parcel source) {
            return new MyObject(source);
        }

        @Override
        public MyObject[] newArray(int size) {
            return new MyObject[size];
        }

    };

    // Getters and setters

    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeString(someString);
        dest.writeInt(someInteger);
    }

}

Here is what happens. If you implement the Parcelable interface you have to create a private constructor which takes a Parcel as a parameter. That Parcel holds all the serialized values.

You must implement the nested class Parcelable.Creator with the name CREATOR as this is going to be called by Android when recreating your object.

The method describeContents() is only of use in special cases. You can leave it as it is with a return value of 0.

The interesting action happens in writeToParcel() where you, as the name tells, write your data to a Parcel object.

Now you can just add your custom object directly to an Intent like in this example.

MyObject myObject = new MyObject();
Intent i = new Intent();
i.setExtra("MY_OBJECT", myObject);
// implicit or explicit destination declaration
startActivity(i);

Upvotes: 6

Sujit
Sujit

Reputation: 10622

you can use Application class present in Android to pass data between activities.

here is a good link..http://www.helloandroid.com/tutorials/maintaining-global-application-state

Upvotes: 3

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