When an application calls a service, the service will check the permissions of the application, and the service cannot be used if there is no corresponding permission.
If a developer wants to develop a file background download function, there needs to be a Page Ability to provide U pages, and a Service Ability to provide the background file download function. If you want to perform some operations after connecting to the Service Ability in the Page Ability, you need to implement the onAbilityConnectDone() method in the Page Ability.
Components can neither be displayed nor interact with when they are not added to a layout, so a user interface contains at least one layout.
HAR (HarmonyOS Ability Resources) is different from HAP (HarmonyOS Ability Package) in that HAR cannot be installed and run on devices independently, and can only be referenced as dependencies of application modules.
When a time-consuming operation needs to be performed in a HarmonyOS application, it is preferable to create subthreads in FA instead of creating subthreads in Service.
The atomic service consists of one or more HAP packets, andone HAP packet corresponds to one FA or one PA. Each FA or PA can be operated independently to perform 1 specific function.
With the help of HarmonyOS's Al capability, it can detect and recognize the text of image sources such as document remakes and street view reproductions, and can also be integrated into other applications to provide text detection and recognition functions, and provide translation, search and other related services based on therecognition results. This is by taking advantage of the super-resolution of text and images in AI.
The object relational mapping database mainly provides light-grade Key-Value exploration, which supports local applications to store less data, and the data is stored in local files and also loaded in memory, so the access speed is faster and more efficient.
Intent is a carrier for transmitting information between objects.
The global search portal provided on HarmonyOS has a desktop drop-down search box or a negative screen search box.
When using EventHandler to implement inter-thread communication, if EventRunner takes out the InnerEvent event, EventRunner will directly process the event on the new thread.
The user application package of HarmonyOS may not contain a HAP package of the feature type.
When MainAbility and MainAbiitySlice are bound together, the lifecycles of the two are synchronized, including the callback method for transitioning between states.
HarmonyOS's distributed soft bus enables distributed management of application data and user data.
In JavaScript UI development, for wearable projects and TV projects, the name of the home page can be not index, and the first page in the pages configuration list is the home page; for the litewearable project, the name of the home page must be index.
