Huawei H14-231_V1.0 - HCIP-HarmonyOS Application Developer V1.0

Sampling refers to the process of sampling a digital signal in a continuous time domain at certain time intervals to obtain a discrete signal in the discrete time domain.

When MainAbility and MainAbiitySlice are bound together, the lifecycles of the two are synchronized, including the callback method for transitioning between states.

The data generated by a developer's use of Data Ability can be shared between different applications on the same device, but cannot be shared across devices.

In HarmonyOS, both relational databases and object-relational mapping databases can use SQL statements to manipulate databases.

In order to avoid affecting the startup speed, developers need to postpone the execution of non-essential time-consuming tasks until the time of use, instead of performing all initializations in the onStart() method.

A developer needs to read the resource files in the rawfile folder, and the following code can be used to read them successfully.

Image

image(Image)findComponentByld(ResourceTable.Id_cormponent_image);

Image.setPixelMap (ResourceTable.Media hawei);

HarmonyOS's relational database and object relational mapping database are both based on SQLite.

Suppose that multiple AbilitySlice are associated in MainAbility, and multiple AbilitySlice are switched in the same page, the lifecycle of MainAbility and all AbilitySlice is synchronized.

In HarmonyOS's "1+8+N" strategy, mobile phones belong to one of the "8" devices.

HarmonyOS maintains a stack of AbilitySlice instances for each Page, and each AbilityS1ice instance that enters the foreground will be added to the stack.

Developers can create user interfaces directly on AbilitySlice or on Ability.

If the third-party library used by the developer involves permission management, the permission needs to be declared one by one in the config.json file of the application.

In the process of developing an application based on HarmonyOS, in order to avoid applying for permissions that are unrelated to the user's required functions, a developer uses the UUID generated by the application instead of the device ID to reduce the permission application. The developer's actions exemplify the principle of applying for permissions in the vicinity.

The lightweight preference database is a non-relational database, which mainly provides lightweight key-value operations and supports local applications to store a large amount of data. If a HarmonyOS developer uses a lightweight preference database to save data, the data will be stored in a local file and will not be loaded into memory.

The Service Ability created by a developer does not have a user interface. Can be launched by other apps. When the user switches to another application, the Service will be killed in the background.