• Ability之间或者进程间数据传递之对象(Sequenceable序列化)


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    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

    Ability之间或者进程间数据传递之对象(Sequenceable序列化)

    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。

    下载demo源代码

    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

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  • 原文地址:https://www.cnblogs.com/HarmonyOS/p/14452742.html
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