Ability之间或者进程间数据传递之对象（Sequenceable序列化）
鸿蒙入门指南，小白速来！0基础学习路线分享，高效学习方法，重点答疑解惑--->【课程入口】
这两天51cto上的一个粉丝朋友问了我一个问题，Ability之间使用Sequenceable序列化传递数据，如何传递Uri类型数据？网上确实也没有介绍这个使用的demo，为了帮他解决问题，自己帮他写了一个demo，顺手发布一篇博客和源代码。
seralizable是在java api中的类，用它也可以实现序列化，而在android中也有一个类使对象序列化，那就是parcelable，而在HarmonyOS中用Sequenceable来进行序列化。
那么它们之间有什么区别呢？
seralizable:序列化到本地，是一个持久化的操作，效率慢一点
parcelable:只存在于内存，程序结束，序列化后的对象就不存在了。效率快一点
Sequenceable：等同parcelable在Android中的作用。
下面我编写两个AbilitySlice之间互相跳转来传递数据
MainAbilitySlice对应的布局文件代码如下：
<?xml version="1.0" encoding="utf-8"?>
<DirectionalLayout
xmlns:ohos="http://schemas.huawei.com/res/ohos"
ohos:height="match_parent"
ohos:width="match_parent"
ohos:orientation="vertical">
<Text
ohos:id="$+id:text_helloworld"
ohos:height="match_content"
ohos:width="match_content"
ohos:background_element="$graphic:background_ability_main"
ohos:layout_alignment="horizontal_center"
ohos:text="Hello World"
ohos:text_size="50"
/>
</DirectionalLayout>就是系统自动生成的helloworld，我偷懒就没修改了，核心不在这里。
再创建一个TestSlice，布局代码如下：
<?xml version="1.0" encoding="utf-8"?>
<DirectionalLayout
xmlns:ohos="http://schemas.huawei.com/res/ohos"
ohos:height="match_parent"
ohos:width="match_parent"
ohos:orientation="vertical">
<Text
ohos:id="$+id:text_helloworld"
ohos:height="match_content"
ohos:width="match_content"
ohos:background_element="$graphic:background_ability_main"
ohos:layout_alignment="horizontal_center"
ohos:text="TEST"
ohos:text_size="50"
/>
</DirectionalLayout>为了要在两个Slice中间传递一个序列化对象数据，需要先创建一个实体类，并且实现Sequenceable接口，这里才是整个的核心代码，如下：
package com.xdw.sequencedemo;
import ohos.utils.Parcel;
import ohos.utils.Sequenceable;
import ohos.utils.net.Uri;
/**
* Created by 夏德旺 on 2021/2/26 10:39
*/
public class Student implements Sequenceable {
private int number;
private String name;
private Uri uri;
public Student() {
}
public Student(int number, String name, Uri uri) {
this.number = number;
this.name = name;
this.uri = uri;
}
public int getNumber() {
return number;
}
public void setNumber(int number) {
this.number = number;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Uri getUri() {
return uri;
}
public void setUri(Uri uri) {
this.uri = uri;
}
//上面是传统的实体类的构造函数和getter、setter
//下面是序列化的核心
//向包裹中写入数据，包裹可以理解为一块内存区
public boolean marshalling(Parcel out) {
out.writeSequenceable(uri); //注意Uri类型的写法和普通数据类型有所不同
return out.writeInt(number) && out.writeString(name);
}
//从包裹中读取数据
public boolean unmarshalling(Parcel in) {
this.number = in.readInt();
this.name = in.readString();
return in.readSequenceable(uri); //注意Uri类型的写法和普通数据类型有所不同
}
//序列化对象的内部构造器，必须实现
public static final Sequenceable.Producer
PRODUCER = new Sequenceable.Producer
() {
public Student createFromParcel(Parcel in) { //从包裹中获取数据构造对象
// Initialize an instance first, then do customized unmarshlling.
Student instance = new Student();
instance.unmarshalling(in);
return instance;
} //必须实现Producer
};
}
下面编写MainAbilitySlice的代码，给Text控件添加一个点击事件来跳转页面并且传递一个student参数
package com.xdw.sequencedemo.slice; import com.xdw.sequencedemo.ResourceTable; import com.xdw.sequencedemo.Student; import ohos.aafwk.ability.AbilitySlice; import ohos.aafwk.content.Intent; import ohos.agp.components.Component; import ohos.agp.components.Text; import ohos.agp.window.dialog.ToastDialog; import ohos.utils.net.Uri; public class MainAbilitySlice extends AbilitySlice { private Text text; @Override public void onStart(Intent intent) { super.onStart(intent); super.setUIContent(ResourceTable.Layout_ability_main); text = (Text)findComponentById(ResourceTable.Id_text_helloworld); text.setClickedListener(new Component.ClickedListener() { @Override public void onClick(Component component) { Intent intent1 = new Intent(); Student student = new Student(); student.setNumber(1); student.setName("夏德旺"); Uri uri = Uri.parse("http://www.xiadewang.com:8080/login?username=xdw&password=123"); String scheme = uri.getScheme(); //new ToastDialog(getContext()).setText("scheme="+scheme).show(); student.setUri(uri); intent1.setParam("student",student); present(new TestSlice(),intent1); } }); } @Override public void onActive() { super.onActive(); } @Override public void onForeground(Intent intent) { super.onForeground(intent); } }
编写TestSlice的代码接收传递过来的student参数，并且通过toast展示
package com.xdw.sequencedemo.slice;
import com.xdw.sequencedemo.ResourceTable;
import com.xdw.sequencedemo.Student;
import ohos.aafwk.ability.AbilitySlice;
import ohos.aafwk.content.Intent;
import ohos.agp.window.dialog.ToastDialog;
import ohos.utils.net.Uri;
/**
* Created by 夏德旺 on 2021/2/26 10:39
*/
public class TestSlice extends AbilitySlice {
@Override
protected void onStart(Intent intent) {
super.onStart(intent);
super.setUIContent(ResourceTable.Layout_slice_test);
if(intent!=null){
Student student = intent.getSequenceableParam("student");
String name = student.getName();
Uri uri = student.getUri();
//new ToastDialog(getContext()).setText("name="+name).show();
new ToastDialog(getContext()).setText("scheme="+uri.getScheme()).show();
}
}
@Override
protected void onActive() {
super.onActive();
}
@Override
protected void onForeground(Intent intent) {
super.onForeground(intent);
}
}
到此，代码编写完成，下面是运行测试图
这里也顺便完美解决了之前51cto上的粉丝朋友问我的Sequenceable对象无法读取Uri数据的问题。
作者：软通夏德旺
想了解更多内容，请访问51CTO和华为合作共建的鸿蒙社区：https://harmonyos.51cto.com
