1.主Activity,用于启动另一个Activity（）
public class MainActivity extends Activity {    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        System.out.println("onCreate");

        findViewById(R.id.btnStartBAct).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent=new Intent(MainActivity.this,BActivity.class);
                intent.putExtra("data","Hello Henry");                                  //进行参数传递
                //startActivity(new Intent(MainActivity.this,BActivity.class));
                startActivity(intent);
            }
        });
    }

    @Override
    protected void onStart()
    {
        super.onStart();
        System.out.println("onStrart");
    }
    @Override
    protected void onRestart()
    {
        super.onRestart();
        System.out.println("onRestart");
    }
    @Override
    protected void onStop()
    {
        super.onStart();
        System.out.println("onStop");
    }
    @Override
    protected void onResume()
    {
        super.onResume();
        System.out.println("onResume");
    }
    @Override
    protected void onPause()
    {
        super.onPause();
        System.out.println("onPause");
    }
    @Override
    protected void onDestroy()
    {
        super.onDestroy();
        System.out.println("onDestroy");
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}
2.从Activity 被MainActivity启动

public class BActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_b);
        System.out.println("B onCreate");

        Intent intent=getIntent();              //获取MainActivity传递过来的Intent

        TextView tv= (TextView) findViewById(R.id.tv);   
        tv.setText(intent.getStringExtra("data"));           //调用Intent的getStringExtra("data")方法取出数据

    }

    @Override
    protected void onStart()
    {
        super.onStart();
        System.out.println("B onStrart");
    }
    @Override
    protected void onRestart()
    {
        super.onRestart();
        System.out.println("B onRestart");
    }
    @Override
    protected void onStop()
    {
        super.onStart();
        System.out.println("B onStop");
    }
    @Override
    protected void onResume()
    {
        super.onResume();
        System.out.println("B onResume");
    }
    @Override
    protected void onPause()
    {
        super.onPause();
        System.out.println("B onPause");
    }
    @Override
    protected void onDestroy()
    {
        super.onDestroy();
        System.out.println("B onDestroy");
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_b, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}
3.传递数据包Bundle
3.1 MainActivity中的

findViewById(R.id.btnStartBAct).setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View view) {
            Intent intent=new Intent(MainActivity.this,BActivity.class);
            //intent.putExtra("data","Hello Henry");

            //传递数据包
            Bundle bundle=new Bundle();
            bundle.putString("name","henry");       //往数据包中添加数据
            bundle.putInt("age",24);
            intent.putExtras(bundle);               //将数据包添加到Intent中

            //startActivity(new Intent(MainActivity.this,BActivity.class));
            startActivity(intent);
        }
    });
}
3.2  BActivity中的

Intent intent=getIntent();
Bundle bundle=intent.getExtras();        //接收数据包

TextView tv= (TextView) findViewById(R.id.tv);
//tv.setText(intent.getStringExtra("data"));
tv.setText(String.format("name=%s,age=%d",bundle.getString("name"),(int)bundle.get("age")));    //调用Bundle的getXXX（）函数获取数据

4.传递引用
4.1使用序列化的方式传递引用类
自定义类：

public class User implements Serializable {        //使用java提供的序列化的方式   
    private String name;
    private int age;

    public void setName(String name) {
        this.name = name;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }
    public User(String name,int age)
    {
        this.name=name;
        this.age=age;
    }
}
主Activity：

public class MainActivity extends Activity {

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

        findViewById(R.id.btnStartBAct).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent=new Intent(MainActivity.this,BActivity.class);    

                intent.putExtra("user", (Serializable) new User("henryQL",24));      //添加自定义的引用类的对象
                startActivity(intent);
            }
        });
    }   

}
被调用的Activity：

public class BActivity extends Activity {

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

        Intent intent=getIntent();       
        User user= (User) intent.getSerializableExtra("user");    //获取序列化的数据

        TextView tv= (TextView) findViewById(R.id.tv);       
        tv.setText(String.format("nmae=%s,age=%d",user.getName(),user.getAge()));
    }
}
4.2 使用Android提供的Parcelable接口

public class User implements Parcelable {
    private String name;
    private int age;

    public void setName(String name) {
        this.name = name;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }
    public User(String name,int age)
    {
        this.name=name;
        this.age=age;
    }

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

    @Override
    public void writeToParcel(Parcel parcel, int i) {
        parcel.writeString(getName());
        parcel.writeInt(getAge());
    }

    public static final Parcelable.Creator<User> CREATOR=new Parcelable.Creator<User>()    //必须命名为CREATOR
    {

        @Override
        public User createFromParcel(Parcel parcel) {
            return new User(parcel.readString(),parcel.readInt());
        }

        @Override
        public User[] newArray(int i) {
            return new User[i];
        }
    };
}

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        System.out.println("onCreate");

        findViewById(R.id.btnStartBAct).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent=new Intent(MainActivity.this,BActivity.class);               

                intent.putExtra("user",new User("Qianlong",24));

                //startActivity(new Intent(MainActivity.this,BActivity.class));
                startActivity(intent);
            }
        });
    }
}

public class BActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_b);
        System.out.println("B onCreate");

        Intent intent=getIntent();     
        User user=intent.getParcelableExtra("user");      //获取Parcelable对象

        TextView tv= (TextView) findViewById(R.id.tv);
        //tv.setText(intent.getStringExtra("data"));
        //tv.setText(String.format("name=%s,age=%d",bundle.getString("name"),(int)bundle.get("age")));
        tv.setText(String.format("nmae=%s,age=%d",user.getName(),user.getAge()));
    }
}
5.Activity传递返回参数
若想打开一个新的Activity的时候能够获取其返回的参数，必须使用startActivityForResult，而不能是之前的startActivity函数了；
此外必须在该类中重写函数onActivityResult，在该函数中用来响应返回的数据。在新的Activity中使用setRequest来发送要返回的数据，并使用finish函数来结束当前的Activity。

public class MainActivity extends Activity {

    private TextView rtnTextView;

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

        rtnTextView= (TextView) findViewById(R.id.rtnTextView);

        findViewById(R.id.newActivityBtn).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //发送数据，并且能够获取另一activity的返回数据
                Intent intent=new Intent(MainActivity.this,MainActivity2Activity.class);
                intent.putExtra("name","henry");
                intent.putExtra("age",24);
                startActivityForResult(intent,1);   //第二个参数是请求码，设置请求码和要发送的intent数据
            }
        });

    }

    //响应MainActivity2Activity的返回数据
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        rtnTextView.setText(data.getStringExtra("data"));   //获取返回的数据
    }
}

public class MainActivity2Activity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main_activity2);

        TextView tv=(TextView)findViewById(R.id.displayTextView);
        Intent intent=getIntent();
        tv.setText(String.format("name=%s,age=%d",intent.getStringExtra("name"),intent.getIntExtra("age",0)));

        //传递返回值
        final EditText editText=(EditText)findViewById(R.id.editText);
        findViewById(R.id.returnBtn).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent1=new Intent();
                intent1.putExtra("data",editText.getText().toString());
                setResult(1,intent1);   //设置返回码，和要返回的Intent
                finish();                
            }
        });
    }
}