1 Bundle介绍

Bundle主要用于传递数据；它保存的数据，是以key-value(键值对)的形式存在的。

我们经常使用Bundle在Activity之间传递数据，传递的数据可以是boolean、byte、int、long、float、double、string等基本类型或它们对应的数组，也可以是对象或对象数组。当Bundle传递的是对象或对象数组时，必须实现Serializable 或Parcelable接口。下面分别介绍Activity之间如何传递基本类型、传递对象。

2传递基本类型

Bundle提供了各种常用类型的putXxx()/getXxx()方法，用于读写基本类型的数据。Bundle操作基本数据类型的API表格如下所示：

写数据的方法如下：

// "com.test" is the package name of the destination class
// "com.test.Activity02" is the full class path of the destination class
Intent intent = new Intent().setClassName("com.bundletest", "com.bundletest.Bundle02");

Bundle bundle = new Bundle();
bundle.putString("name", "skywang");
bundle.putInt("height", 175);
intent.putExtras(bundle);

startActivity(intent);

// end current class
finish();

对应的读数据的方法如下：

Bundle bundle = this.getIntent().getExtras();  
  
String name = bundle.getString("name");  
int height = bundle.getInt("height");

3传递Parcelable类型的对象

3.1 Parcelable说明

Parcelable是Android自定义的一个接口，它包括了将数据写入Parcel和从Parcel中读出的API。一个实体（用类来表示），如果需要封装到bundle消息中去，可以通过实现Parcelable接口来实现。

Parcelable和Serializable的API如下表：

3.2 Parcelable接口说明

public interface Parcelable {
    //内容描述接口，基本不用管
    public int describeContents();
    //写入接口函数，打包
    public void writeToParcel(Parcel dest, int flags);
    //读取接口，目的是要从Parcel中构造一个实现了Parcelable的类的实例处理。因为实现类在这里还是不可知的，所以需要用到模板的方式，继承类名通过模板参数传入。
    //为了能够实现模板参数的传入，这里定义Creator嵌入接口,内含两个接口函数分别返回单个和多个继承类实例。
    public interface Creator<T> {
        public T createFromParcel(Parcel source);
        public T[] newArray(int size);
 }
}

3.3 Parcelable接口的实现方法

从parcelable接口定义中，我们可以看到，实现parcelable接口，需要我们实现下面几个方法：
(01)describeContents方法。内容接口描述，默认返回0就可以;
(02)writeToParcel 方法。该方法将类的数据写入外部提供的Parcel中.即打包需要传递的数据到Parcel容器保存，以便从parcel容器获取数据，该方法声明如下：
writeToParcel(Parcel dest, int flags) 具体参数含义见doc文档
(3.)静态的Parcelable.Creator接口，本接口有两个方法：
createFromParcel(Parcelin) 从Parcel容器中读取传递数据值，封装成Parcelable对象返回逻辑层。
newArray(int size) 创建一个类型为T，长度为size的数组，仅一句话（returnnew T[size])即可。方法是供外部类反序列化本类数组使用。

4传递Serializable类型的对象

4.1 Serializable说明

Serializable是一个对象序列化的接口。一个类只有实现了Serializable接口，它的对象才是可序列化的。因此如果要序列化某些类的对象，这些类就必须实现Serializable接口。而实际上，Serializable是一个空接口，没有什么具体内容，它的目的只是简单的标识一个类的对象可以被序列化。

4.2 Serializable接口的实现方法

很简单，只要implements Serializable接口就可以了

5 demo演示程序

下面是对实现上述三种数据传递方式的BundleTest(demo程序)进行简要介绍

5.1 demo概要

BundleTest共包含了4个java文件和2个layout文件(main.xml和main2.xml)

Bundle01.java —— 默认的主Activity窗口。

Bundle02.java —— 主Activity用于跳转的目的窗口。

Book.java —— 实现Parcelable接口的类

Person.java —— 实现Serializable接口的类

main.xml —— Bundle01.java的layout文件

main2.xml —— Bundle02.java的layout文件

工程文件结构如下所示：

5.2代码

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.bundletest"
      android:versionCode="1"
      android:versionName="1.0">
	
    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".Bundle01"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
		<activity android:name=".Bundle02"> </activity>
    </application>
    <uses-sdk android:minSdkVersion="11" />
</manifest>

main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
	<TextView  
		android:layout_width="fill_parent" 
		android:layout_height="wrap_content" 
		android:text="@string/app_01"
		/>

	<Button  
		android:id="@+id/btnBasic" 
		android:layout_width="fill_parent" 
		android:layout_height="wrap_content" 
		android:text="@string/text_basic"
		/>

	<Button  
		android:id="@+id/btnPar" 
		android:layout_width="fill_parent" 
		android:layout_height="wrap_content" 
		android:text="@string/text_par"
		/>

	<Button  
		android:id="@+id/btnSer" 
		android:layout_width="fill_parent" 
		android:layout_height="wrap_content" 
		android:text="@string/text_ser"
		/>



</LinearLayout>

main2.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
	<TextView  
		android:layout_width="fill_parent" 
		android:layout_height="wrap_content" 
		android:text="@string/app_02"
		/>

	<Button  
		android:id="@+id/btnBack" 
		android:layout_width="fill_parent" 
		android:layout_height="wrap_content" 
		android:text="@string/text_jump_back"
		/>
    
</LinearLayout>

strings.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string name="hello">Hello MyBundleTest!</string>
    <string name="app_name">MyBundleTest</string>
    <string name="app_01">Bundle_01</string>
    <string name="app_02">Bundle_02</string>
    <string name="text_basic">Bundle Basic Data</string>
    <string name="text_par">Bundle Parcelable Data</string>
    <string name="text_ser">Bundle Seriable Data</string>
    <string name="text_jump_back">Jump Back to Bundler01</string>
</resources>

Bundle01.java

package com.bundletest;

import android.app.Activity;
import android.os.Bundle;  
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.content.Intent;
import android.util.Log;

public class Bundle01 extends Activity implements View.OnClickListener{

	private static final String TAG = "skywang-->Bundle01";

	private Button mBtnBasic = null;
	private Button mBtnPar = null;
	private Button mBtnSer = null;

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);

		mBtnBasic = (Button) findViewById(R.id.btnBasic);
		mBtnBasic.setOnClickListener(this);

		mBtnPar = (Button) findViewById(R.id.btnPar);
		mBtnPar.setOnClickListener(this);

		mBtnSer = (Button) findViewById(R.id.btnSer);
		mBtnSer.setOnClickListener(this);
	}


	@Override
	public void onClick(View view) {
		switch (view.getId()) {
			case R.id.btnBasic:
				sendBasicDataThroughBundle();
				break;
			case R.id.btnPar:
				sendParcelableDataThroughBundle();
				break;
			case R.id.btnSer:
				sendSeriableDataThroughBundle();
				break;
			default:
				break;

		}
	}

	// sent basic data, such as int, strin, etc...  through bundle
    private void sendBasicDataThroughBundle(){  
		// "com.test" is the package name of the destination class
		// "com.test.Activity02" is the full class path of the destination class
		Intent intent = new Intent().setClassName("com.bundletest", "com.bundletest.Bundle02");
		
		Bundle bundle = new Bundle();
		bundle.putString("name", "skywang");
		bundle.putInt("height", 175);
		intent.putExtras(bundle);
		
		startActivity(intent);

		// end current class
		finish();
	}

	// sent object through Pacelable
    private void sendParcelableDataThroughBundle(){  
		Intent intent = new Intent().setClassName("com.bundletest", "com.bundletest.Bundle02");

        Book mBook = new Book();
        mBook.setBookName("Android");
        mBook.setAuthor("skywang");
        mBook.setPublishTime(2013);

        Bundle mBundle = new Bundle();
        mBundle.putParcelable("ParcelableValue", mBook);
        intent.putExtras(mBundle);
          
        startActivity(intent);
		finish();
    }

	// sent object through seriable
    private void sendSeriableDataThroughBundle(){  
		Intent intent = new Intent().setClassName("com.bundletest", "com.bundletest.Bundle02");

		Person mPerson = new Person();
        mPerson.setName("skywang");
        mPerson.setAge(24);

        Bundle mBundle = new Bundle();
        mBundle.putSerializable("SeriableValue",mPerson);
        intent.putExtras(mBundle);
          
        startActivity(intent);
		finish();
    }

}

Bundle02.java

package com.bundletest;

import android.app.Activity;
import android.os.Bundle;  
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.content.Intent;
import android.util.Log;

public class Bundle02 extends Activity implements View.OnClickListener {

	private static final String TAG = "skywang-->Bundle02";

	private Button mBtnBack = null;
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main2);

		mBtnBack = (Button) findViewById(R.id.btnBack);
		mBtnBack.setOnClickListener(this);

		receiveBasicData();
		receiveParcelableData();
		receiveSeriableData();
	}

	private void receiveBasicData() {
        Bundle bundle = this.getIntent().getExtras();  
          
        String name = bundle.getString("name");  
        int height = bundle.getInt("height");
		if (name != null && height != 0)
		Log.d(TAG, "receice basic data -- " +
				   "name="+name+", height="+height);
	}

	private void receiveParcelableData() {
		Book mBook = (Book)getIntent().getParcelableExtra("ParcelableValue");
		if (mBook != null)
			Log.d(TAG, "receice parcel data -- " +
					   "Book name is: " + mBook.getBookName()+", "+
					   "Author is: " + mBook.getAuthor() + ", "+
					   "PublishTime is: " + mBook.getPublishTime());
	}

	private void receiveSeriableData() {
		Person mPerson = (Person)getIntent().getSerializableExtra("SeriableValue");  
		if (mPerson != null)
			Log.d(TAG, "receice serial data -- " +
					   "The name is:" + mPerson.getName() + ", "+
					   "age is:" + mPerson.getAge());  
	}

	@Override
	public void onClick(View view) {
		switch (view.getId()) {
			case R.id.btnBack:
			{
				// "com.test" is the package name of the destination class
				// "com.test.Activity01" is the full class path of the destination class
				Intent intent = new Intent().setClassName("com.bundletest", "com.bundletest.Bundle01");
				startActivity(intent);
				// end current class
				finish();
			}
				break;
			default:
				break;

		}
	}

}

Book.java

package com.bundletest;

import android.os.Parcel;  
import android.os.Parcelable;  

public class Book implements Parcelable {  
    private String bookName;  
    private String author;  
    private int publishTime;  
      
    public String getBookName() {  
        return bookName;  
    }  
    public void setBookName(String bookName) {  
        this.bookName = bookName;  
    }  
    public String getAuthor() {  
        return author;  
    }  
    public void setAuthor(String author) {  
        this.author = author;  
    }  
    public int getPublishTime() {  
        return publishTime;  
    }  
    public void setPublishTime(int publishTime) {  
        this.publishTime = publishTime;  
    }  
      
    public static final Parcelable.Creator<Book> CREATOR = new Creator<Book>() {  
		@Override
        public Book createFromParcel(Parcel source) {  
            Book mBook = new Book();  
            mBook.bookName = source.readString();  
            mBook.author = source.readString();  
            mBook.publishTime = source.readInt();  
            return mBook;  
        }  
		@Override
        public Book[] newArray(int size) {  
            return new Book[size];  
        }  
    };  
      
	@Override
    public int describeContents() {  
        return 0;  
    }  

	@Override
    public void writeToParcel(Parcel parcel, int flags) {  
        parcel.writeString(bookName);  
        parcel.writeString(author);  
        parcel.writeInt(publishTime);  
    }  
}

Person.java

package com.bundletest;

import java.io.Serializable;  

public class Person implements Serializable {  

    private static final long serialVersionUID = 1L; 

    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;  
    }  
      
}