Component Startup Rules (Stage Model)

Component startup refers to the behavior of starting or connecting to an application component.

  • Start the UIAbility, ServiceExtensionAbility, and DataShareExtensionAbility components. For example, you can use startAbility(), startServiceExtensionAbility(), and startAbilityByCall().

  • Connect to the ServiceExtensionAbility and DataShareExtensionAbility components. For example, you can use connectServiceExtensionAbility() and createDataShareHelper().

To deliver a better user experience, OpenHarmony restricts the following behavior:

  • A background application randomly displays a dialog box, such as an ads pop-up.

  • Background applications wake up each other. This type of behavior occupies system resources and increases power consumption, or even causes system frozen.

  • A foreground application randomly redirects to another application, for example, redirecting to the payment page of another application. This type of behavior poses security risks.

In view of this, OpenHarmony formulates a set of component startup rules, as follows:

  • Before starting a component of another application, verify the visible field of the target component.

    • If the visible field of the target component is false, verify the ohos.permission.START_INVISIBLE_ABILITY permission.
    • For details, see Component Visible Configuration.

  • Before starting a component of a background application, verify the BACKGROUND permission.

    • An application is considered as a foreground application only when the application process gains focus or its UIAbility component is running in the foreground.
    • Verify the ohos.permission.START_ABILITIES_FROM_BACKGROUND permission.

  • When the startAbilityByCall() method is used, verify the call permission. For details, see Using Call to Implement UIAbility Interaction and Using Cross-Device Call.

    • Verify the ohos.permission.ABILITY_BACKGROUND_COMMUNICATION permission.

NOTE

  • Component startup control has been implemented since OpenHarmony v3.2 Release.

  • The new component startup rules are more strict than the original ones. You must be familiar with the new startup rules to prevent service exceptions.

Intra-Device Component Startup Rules

The rules for starting components on the same device vary in the following scenarios:

  • Starting or connecting to the UIAbility, ServiceExtensionAbility, and DataShareExtensionAbility components

  • Using startAbilityByCall() to start the UIAbility component

startup-rule

Inter-Device Component Startup Rules

The rules for starting components on a different device vary in the following scenarios:

  • Starting or connecting to the UIAbility, ServiceExtensionAbility, and DataShareExtensionAbility components

  • Using startAbilityByCall() to start the UIAbility component

component-startup-rules