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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;
-
}
-
-
}
5.3输出图片
Bundle01.java对应的界面如下:
点击“Bundle Basic Data”、“Bundle Parcelable Data”、“Bundle Seriable Data”均跳转到如下界面,但它们对应的logcat信息不同。
点击“Bundle Basic Data”的logcat如下:
点击“Bundle Parcelable Data”的logcat如下:
点击“Bundle Seriable Data”的logcat如下:
转自:http://www.cnblogs.com/skywang12345/archive/2013/03/06/3165555.html