How can I make my custom objects Parcelable?

You can find some examples of this here, here (code is taken here), and here.

You can create a POJO class for this, but you need to add some extra code to make it Parcelable. Have a look at the implementation.

public class Student implements Parcelable{
        private String id;
        private String name;
        private String grade;

        // Constructor
        public Student(String id, String name, String grade){
            this.id = id;
            this.name = name;
            this.grade = grade;
       }
       // Getter and setter methods
       .........
       .........

       // Parcelling part
       public Student(Parcel in){
           String[] data = new String[3];

           in.readStringArray(data);
           // the order needs to be the same as in writeToParcel() method
           this.id = data[0];
           this.name = data[1];
           this.grade = data[2];
       }

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

       @Override
       public void writeToParcel(Parcel dest, int flags) {
           dest.writeStringArray(new String[] {this.id,
                                               this.name,
                                               this.grade});
       }
       public static final Parcelable.Creator CREATOR = new Parcelable.Creator() {
           public Student createFromParcel(Parcel in) {
               return new Student(in); 
           }

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

Once you have created this class, you can easily pass objects of this class through the Intent like this, and recover this object in the target activity.

intent.putExtra("student", new Student("1","Mike","6"));

Here, the student is the key which you would require to unparcel the data from the bundle.

Bundle data = getIntent().getExtras();
Student student = (Student) data.getParcelable("student");

This example shows only String types. But, you can parcel any kind of data you want. Try it out.

EDIT: Another example, suggested by Rukmal Dias.

Here is a website to create a Parcelable Class from your created class:

http://www.parcelabler.com/

IntelliJ IDEA and Android Studio have plugins for this:

• ★ Android Parcelable code generator (Apache License 2.0)
• Auto Parcel (The MIT License)
• SerializableParcelable Generator (The MIT License)
• Parcelable Code Generator (for Kotlin) (Apache License 2.0)

These plugins generate Android Parcelable boilerplate code based on fields in the class.