Intent intent = new Intent(this,SecondActivity.class);
intent.putExtra("info", "I am fine");
startActivity(intent);

package com.example.testapplication;
import java.io.Serializable;
/**
 * 对象序列化
 * @author yy
 *
 */
public class Emp implements Serializable {
  private String name;
  private int age;
  public String getName() {
    return name;
  }
  public void setName(String name) {
    this.name = name;
  }
  public int getAge() {
    return age;
  }
  public void setAge(int age) {
    this.age = age;
  }
}

Intent intent = new Intent(this,SecondActivity.class);
intent.putExtra("obj", new Emp());
startActivity(intent);

package com.example.testapplication;
import android.os.Parcel;
import android.os.Parcelable;
/**
 * Parcelable方式
 * @author yy
 *
 */
public class Emp2 implements Parcelable{
  private String name;
  private int age;
  public String getName() {
    return name;
  }
  public void setName(String name) {
    this.name = name;
  }
  public int getAge() {
    return age;
  }
  public void setAge(int age) {
    this.age = age;
  }
  @Override
  public int describeContents() {
    return 0;
  }
  @Override
  public void writeToParcel(Parcel dest, int flag) {
    //写出name
    dest.writeString(name);
    //写出age
    dest.writeInt(age);
  }
  public static final Parcelable.Creator<Emp2> creator = new Creator<Emp2>() {
    @Override
    public Emp2[] newArray(int size) {
      return new Emp2[size];
    }
    @Override
    public Emp2 createFromParcel(Parcel source) {
      Emp2 emp2 = new Emp2();
      //读取的顺序要和上面写出的顺序一致
      //读取name
      emp2.name = source.readString();
      emp2.age = source.readInt();
      return emp2;
    }
  };
}

Intent intent = new Intent(this,SecondActivity.class);
intent.putExtra("obj", new Emp2());
startActivity(intent);