简单的在Activity间传数据，我们一般有两种方式：

1.直接用Intent的putExtra(), getStringExtra();

2.先new一个Bundle对象，用Bundle的putExtra().

那么这两种方式有什么不一样呢？

我们先看一下Intent对象相应函数的源代码：

public Intent putExtra(String name, String value) {
        if (mExtras == null) {
            mExtras = new Bundle();
        }
        mExtras.putString(name, value);
        return this;
    }

public String getStringExtra(String name) {
        return mExtras == null ? null : mExtras.getString(name);
    }

 可以知道，Intent的相关操作的实现是基于Bundle的，Bundle操作数据相对于Intent有哪些优势呢？

举个例子，如果我要从A界面跳转到B界面和C界面，那么我要写写两个Intent，如果传的数据相同，我两个Intent都要添加，但是如果我用Bundle，直接一次性包装就可以了。

再有，如果A界面要传值给B界面，再从B界面传值到C界面，你可以想象用Intent是多么的麻烦了，但是用Bundle就很简洁，而且还可以在B界面中添加新的信息。

其实在Android代码中这样的情况蛮多的，比如Intent的setClass和ComponentName这两种方式又有什么区别呢？请看setClass源代码：

public Intent(Context packageContext, Class<?> cls) {
        mComponent = new ComponentName(packageContext, cls);
    }

public Intent setClass(Context packageContext, Class<?> cls) {
        mComponent = new ComponentName(packageContext, cls);
        return this;
    }

当然如果传的数据非常之多而且很复杂，用这两种方式显然是不适合的，这时候我们可以使用可序列化的结构类，实例代码如下：

Parcelable类。最主要的类，也就是我们要传送的对象的类，需要实现Parcelable接口。

package com.zeph.android.Parcelable;

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

public class BenParcelable implements Parcelable {

	public String name;

	public int age;

	public String profession;

	public BenParcelable(String name, int age, String profession) {
		this.name = name;
		this.age = age;
		this.profession = profession;
	}

	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;
	}

	public String getprofession() {
		return profession;
	}

	public void setprofession(String profession) {
		this.profession = profession;
	}

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

	@Override
	public void writeToParcel(Parcel parcel, int flag) {
		parcel.writeString(name);
		parcel.writeInt(age);
		parcel.writeString(profession);
	}

	public static final Creator<BenParcelable> CREATOR = new Creator<BenParcelable>() {
		public BenParcelable createFromParcel(Parcel in) {
			return new BenParcelable(in);
		}

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

	private BenParcelable(Parcel in) {
		name = in.readString();
		age = in.readInt();
		profession = in.readString();
	}
}

ParcelableActivity类，传递对象的Activity类。

package com.zeph.android.Parcelable;

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

public class ParcelableActivity extends Activity {

	private Button myButton;

	@Override
	public void onCreate(Bundle savedInstanceState) {

		super.onCreate(savedInstanceState);

		setContentView(R.layout.main);

		myButton = (Button) findViewById(R.id.myButton);

		myButton.setOnClickListener(new OnClickListener() {

			@Override
			public void onClick(View arg0) {

				BenParcelable benParcelable = new BenParcelable("BenZeph", 23,
						"Java/Android Engineer");

				Intent intent = new Intent();

				intent.setClass(getApplicationContext(),
						GetParcelableActivity.class);

				Bundle bundle = new Bundle();

				bundle.putParcelable("Ben", benParcelable);

				intent.putExtras(bundle);

				startActivity(intent);

			}
		});
	}
}

GetParcelableActivity类，接收序列化对象的Activity类。

package com.zeph.android.Parcelable;

import android.app.Activity;
import android.os.Bundle;

public class GetParcelableActivity extends Activity {
	@Override
	protected void onCreate(Bundle savedInstanceState) {

		super.onCreate(savedInstanceState);

		setContentView(R.layout.main);

		BenParcelable parcelable = getIntent().getParcelableExtra("Ben");

		System.out.println(parcelable.getName());

		System.out.println(parcelable.getAge());
		
		System.out.println(parcelable.getprofession());

	}

}

1.使用ZBar项目。下载地址是： http://zbar.sourceforge.net/iphone/index.html

2.新建一个项目。

3.导入 ZBar的sdk。把ZBar SDK的目录拉入项目，然后选中copy选项

4.在项目文件的target中加入 以下framework

 

5.在appDelegate文件中加入 标记部分的代码

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
    // Override point for customization after application launch.
    self.viewController = [[[ViewController alloc] initWithNibName:@"ViewController" bundle:nil] autorelease];
    self.window.rootViewController = self.viewController;
    [self.window makeKeyAndVisible];
    
    
    // force view class to load so it may be referenced directly from NIB
    [ZBarReaderView class];
    
    
    return YES;
}

 6.在.h文件中加入   ZBarReaderViewDelegate的实现，代码如下:

//
//  ViewController.h
//  FootSafety
//
//  Created by 泽宇 徐 on 12-6-12.
//  Copyright (c) 2012年 __MyCompanyName__. All rights reserved.
//

#import <UIKit/UIKit.h>
#import "ZBarSDK.h"

@interface ViewController : UIViewController<ZBarReaderViewDelegate>
{
    IBOutlet UILabel  * label ;
    ZBarReaderView *readerView;
    ZBarCameraSimulator *cameraSim;
}

@property(nonatomic,retain) UILabel * label ;
@property (nonatomic, retain) IBOutlet ZBarReaderView *readerView;


@end

 7.在.m文件中要实现的主要方法是：

- (void) readerView: (ZBarReaderView*) view
     didReadSymbols: (ZBarSymbolSet*) syms
          fromImage: (UIImage*) img
{
    // do something useful with results
    for(ZBarSymbol *sym in syms) {
        self.label.text = sym.data;
        break;
    }
}

 这里是功能是读取照片信息，把条码放如label显示

-(void) viewDidAppear:(BOOL)animated
{
    // run the reader when the view is visible
    [readerView start];
}

 这个是在显示视图的时候，启动摄像头，开始扫描

- (void)viewDidLoad
{
    [super viewDidLoad];
	// Do any additional setup after loading the view, typically from a nib.
    
    // the delegate receives decode results
    readerView.readerDelegate = self;
    
    // you can use this to support the simulator
    if(TARGET_IPHONE_SIMULATOR) {
        cameraSim = [[ZBarCameraSimulator alloc]
                     initWithViewController: self];
        cameraSim.readerView = readerView;
    }

}

 在初始化的时候，设置托管。

.m文件所有内容是：

//
//  ViewController.m
//  FootSafety
//
//  Created by 泽宇 徐 on 12-6-12.
//  Copyright (c) 2012年 __MyCompanyName__. All rights reserved.
//

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController
@synthesize label;
@synthesize readerView;

- (void)viewDidLoad
{
    [super viewDidLoad];
	// Do any additional setup after loading the view, typically from a nib.
    
    // the delegate receives decode results
    readerView.readerDelegate = self;
    
    // you can use this to support the simulator
    if(TARGET_IPHONE_SIMULATOR) {
        cameraSim = [[ZBarCameraSimulator alloc]
                     initWithViewController: self];
        cameraSim.readerView = readerView;
    }

}

-(void) viewDidAppear:(BOOL)animated
{
    // run the reader when the view is visible
    [readerView start];
}


- (void) readerView: (ZBarReaderView*) view
     didReadSymbols: (ZBarSymbolSet*) syms
          fromImage: (UIImage*) img
{
    // do something useful with results
    for(ZBarSymbol *sym in syms) {
        self.label.text = sym.data;
        break;
    }
}



- (void)viewDidUnload
{
    [super viewDidUnload];
    // Release any retained subviews of the main view.
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);
}

-(void) dealloc
{
    [self.readerView release];
    [self.label release];
    [super dealloc];
}

@end

 在ViewController.xib文件中 增加一个view，并且修改view的类是ZBarReaderView ，并且指向 .h文件中定义的 

ZBarReaderView *readerView;