Harmonyos practice - Introduction to development, analysis of atomized services

HarmonyOS operating system

   Before introducing Hongmeng system , It is necessary for us to understand the background of the times when xiahongmeng system came into being . In recent years , In the field of electronic information technology, China has increasingly found the need for “ Independent ”, Lack of resources , The scarcity of talents is the top priority .

   I still remember that some time ago, there were such comments on the Internet ： Huawei's terminal equipment poses a threat to communication security , Terminal system exists  ” backstage ” , In this case , We need to prove ourselves with strength . therefore ,2021 year 6 month 2 Japan , Huawei officially announced its independently developed operating system —HarmonyOS, That is Hongmeng .

   conference , What impresses me most is HarmonyOS All things connected 、 The powerful features of distributed and its application Feature Ability（ Meta service ） User interface presentation form , This makes its interaction with users smoother 、 concise 、 convenient . Let's take a closer look HarmonyOS Of  “ Service card ”  function .

Atomic Services

   Before that , We have to learn about  “ Service card ”  Closely related atomic Services . Atomized services are provided by HarmonyOS  A future oriented service delivery method , It has independence 、 Non drive 、 Light （ No installation required ） Other characteristics , It aims to provide users with an efficient service mode .

   It has everywhere 、 Cross device 、 Direct service and other features ：

（1） Service discovery ： Atomic services can be found and used in the Service Center .（2） Intelligent recommendation ： Atomic services can be actively recommended to users based on appropriate scenarios ; Users can find the services recommended by the system in the service center and small art suggestions .（3） Service card ： Users can obtain the display and dynamic change of important information in the service without opening the atomic service , Like the weather 、 Key business notes 、 Hot news list .（4） Support cross device sharing ： For example, after accessing Huawei to share , Users can share atomic services to friends , After friends confirm, open the shared service .（5） Support multi terminal collaboration ： For example, mobile phones use composition files to turn pages and annotate , Cooperate with smart screen display to complete distributed office ; The mobile phone acts as a handle , Play games with smart screen .

Service card

   I believe many friends heard it for the first time  “ Service card ”  This word , Will be thinking ： That's what's on my phone screen  “ Small components ”  Do you ？ Ah ！ You don't have to say , There are really differences between them , But there are similarities .   First of all , You can recall our daily operation habits of using electronic products , When we use widgets ： For example, add a new... On the home screen  “ Photo ”  Components of , The small parts can be replaced automatically from time to time 、 Topic filtering 、 Character classification and so on . So if you happen to see a very interesting picture , Want to see it , Do you need to click the photo to view the details ？ I believe we all know this way of interaction very well . But have you ever thought about , It can be more  “ Hommization ”, more  ” Understand you “  Well ？

   you 're right , This is it. HarmonyOS, It did . In Hongmeng's design , The introduction of service cards is different from the past EMUI The biggest difference , On the screen, we just need to find... Below the icon  “ Little horizontal line ”  Of app, Of course , These are the same people who support HarmonyOS Of app. We just need to be at the icon position , Gently stroke up , You can call out the corresponding application card , These cards can also be customized in size  、 Fixed on the home screen and other functions .

   Compared with closed IOS system , Personally, I think it is to 3DTouch Functions become unnecessary  ”3D“  了 , No force required , Just swipe .  It's more like the parent class of a widget , Undertake the other . This design method is particularly flexible in use , You don't need to be in a specific location to use . You can say that , As long as you can fit the screen , Use whatever you like .

   Developers can provide these service cards  ” cut the dress according to one 's figure “, Customize unique features , Improve daily use efficiency . Under the blessing of submenu ability , Like a treasure payment we use everyday , There is no need to enter... To open the subway card app, as long as  “ hop ”  A small card can realize the function . This is what we have to marvel at ： How fast this is 、 Efficient interactive experience ！

   There are three parties involved in the development of service cards , Card providers 、 Card users and card management services , They interact with each other , Jointly maintain the realization of convenient functions .

HarmonyOS Developer We can understand the division of labor among the three ：

·  Provider module

   Provide the content of the card display HarmonyOS Application or atomized service , Control the display of the card 、 Control layout and control click events .

Card service ：

   Implemented by the card provider developer , Developer implementation onCreateForm、onUpdateForm and onDeleteForm Process and create cards 、 Requests for updating cards and deleting cards , Provide corresponding card services .

Communication adaptation layer ：

   from HarmonyOS SDK Provide , Responsible for communication with card management service , It is used to actively push the card update data to the card management service .

Card provider instance management ：

   Implemented by the card provider developer , Responsible for persistent management of card instances allocated by the card management service .

·  User module

   Host application that displays the contents of the card , Control where the card is displayed in the host .

·  Management service module

   Resident agent service for managing cards added in the system , Including the management and use of card objects , And periodic refresh of cards . The card user and provider need to add / Delete / When requesting to update the card , The card management service will pull up the card provider to get the card information .

Communication adaptation layer ：

   Be responsible for communicating with card users and providers RPC signal communication .

Periodically refresh ：

   After the card is added , Start the scheduled task according to the card refresh policy and trigger the card refresh periodically .

Card cache management ：

   After the card is added to the card management service , Cache the view information of the card , So that the cache data can be returned directly the next time the card is obtained , Reduce delay .

Card lifecycle management ：

   When the card is switched to the background or blocked , Pause card refresh ; And card upgrades / Update and clean up card data in the unloading scenario .

Card user object management ：

   Of the card user RPC Object management , It is used for verification requested by the user and callback processing after card update .

Environment building

   of JDK Environment configuration of , Please refer to the blogger's recent

article

. Once installed , We went to Huawei's official website to download

DevEco Studio

（ official IDE）, No need to change , Select the default configuration . Since there is no specific project development , No more source code here , It will be updated in the follow-up study , Please pay more attention to , The following implements Huawei wearable devices — Smart watch  Hello World  Output .

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Click Run to display  Hello World

Simple Hongmeng version  Hello World  It's done here , Don't try it soon  ^ _^