harmony 鸿蒙ArkUI Subsystem Changelog

2025-06-12
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ArkUI Subsystem Changelog

cl.arkui.1 Validation Changes for the @Require Decorator on Regular Variables and @State or @Provide Decorated Variables

Access Level

Public API

Reason for Change

Enhancements to the @Require decorator are made to include value assignment verification for regular variables and \@State or \@Provide decorated variables.

Change Impact

Before change: @Require only supports the verification for @Prop and @BuilderParam decorators.

After change: @Require supports the verification for regular variables and @Prop, @BuilderParam, @State, or @Provide decorated variables.

The following is an example of incorrect code:

@Entry
@Component
struct Index {
  @State message: string = 'Hello World';

  @Builder buildTest() {
    Row() {
      Text('Hello, world')
        .fontSize(30)
    }
  }

  build() {
    Row() {
      Child()
    }
  }
}

@Component
struct Child {
  @Builder buildFuction() {
    Column() {
      Text('initBuilderParam')
        .fontSize(30)
    }
  }
  // As @Require is used here, parameters must be passed in to the constructor.
  @Require regular_value: string = 'Hello';
  @Require @State state_value: string = "Hello";
  @Require @Provide provide_value: string = "Hello";
  @Require @BuilderParam initbuildTest: () => void = this.buildFuction;
  @Require @Prop initMessage: string = 'Hello';

  build() {
    Column() {
      Text(this.initMessage)
        .fontSize(30)
      this.initbuildTest();
    }
  }
}

Below is an example of correct usage:

@Entry
@Component
struct Index {
  @State message: string = 'Hello World';

  @Builder buildTest() {
    Row() {
      Text('Hello, world')
        .fontSize(30)
    }
  }

  build() {
    Row() {
      Child({ regular_value: this.message, state_value: this.message, provide_value: this.message, initMessage: this.message, message: this.message,
        buildTest: this.buildTest, initbuildTest: this.buildTest })
    }
  }
}

@Component
struct Child {
  @Builder buildFuction() {
    Column() {
      Text('initBuilderParam')
        .fontSize(30)
    }
  }
  @Require regular_value: string = 'Hello';
  @Require @State state_value: string = "Hello";
  @Require @Provide provide_value: string = "Hello";
  @Require @BuilderParam buildTest: () => void;
  @Require @BuilderParam initbuildTest: () => void = this.buildFuction;
  @Require @Prop initMessage: string = 'Hello';
  @Require @Prop message: string;

  build() {
    Column() {
      Text(this.initMessage)
        .fontSize(30)
      Text(this.message)
        .fontSize(30)
      this.initbuildTest();
      this.buildTest();
    }
    .width('100%')
    .height('100%')
  }
}

Start API Level

Change Since

OpenHarmony SDK 5.0.0.12

Adaptation Guide

Adjust the @Require variable values based on the provided error messages.

Reference

\@Require Decorator: Validating Constructor Input Parameters

cl.arkui.2 Restrictions on Using Access Qualifiers for Custom Component Member Properties

Access Level

Public API

Reason for Change

To enforce proper use of access qualifiers (private, public, and protected) in accordance with specifications, compilation verification is required.

Change Impact

The console outputs warning logs when incorrect usage is detected.

The following is an example of incorrect usage:

When a member variable is decorated by both the private access qualifier and the @State, @Prop, @Provide, or @BuilderParam decorator, the parent component AccessRestrictions uses the custom component ComponentsChild to construct and assign values. However, ComponentsChild’s private attributes do not support external construction and assignment. Therefore, ArkTS generates a warning log.

@Entry
@Component
struct AccessRestrictions {
  @Builder buildTest() {
    Text("Parent builder")
  }
  build() {
    Column() {
      ComponentsChild({state_value: "Hello", prop_value: "Hello", provide_value: "Hello", builder_value: this.buildTest, regular_value: "Hello"})
    }
    .width('100%')
  }
}

@Component
struct ComponentsChild {
  @State private state_value: string = "Hello";
  @Prop private prop_value: string = "Hello";
  @Provide private provide_value: string = "Hello";
  @BuilderParam private builder_value: () => void = this.buildTest;
  private regular_value: string = "Hello";
  @Builder buildTest() {
    Text("Child builder")
  }
  build() {
    Column() {
      Text("Hello")
        .fontSize(50)
        .fontWeight(FontWeight.Bold)
    }
  }
}

Member variables decorated by @StorageLink, @StorageProp, @LocalStorageLink, or @Consume can only be modified by private members. Therefore, when they are decorated by the private access qualifier, ArkTS generates a warning log.

@Entry
@Component
struct AccessRestrictions {
  build() {
    Column() {
      ComponentChild()
    }
    .width('100%')
  }
}

@Component
struct ComponentChild {
  @LocalStorageProp("sessionLocalProp") public local_prop_value: string = "Hello";
  @LocalStorageLink("sessionLocalLink") public local_link_value: string = "Hello";
  @StorageProp("sessionProp") public storage_prop_value: string = "Hello";
  @StorageLink("sessionLink") public storage_link_value: string = "Hello";
  @Consume public consume_value: string;
  build() {
    Column() {
      Text("Hello")
        .fontSize(50)
        .fontWeight(FontWeight.Bold)
    }
  }
}

The @Link or @ObjectLink decorated variables can only be initialized from the parent components. Therefore, when they are decorated by the private access qualifier, ArkTS generates a warning log.

@Entry
@Component
struct AccessRestrictions {
  build() {
    Column() {
      ComponentChild({link_value: "Hello", objectLink_value: new ComponentObj()})
    }
    .width('100%')
  }
}

@Observed
class ComponentObj {
  count: number = 0;
}
@Component
struct ComponentChild {
  @Link private link_value: string;
  @ObjectLink private objectLink_value: ComponentObj;
  build() {
    Column() {
      Text("Hello")
        .fontSize(50)
        .fontWeight(FontWeight.Bold)
    }
  }
}

Custom components do not support inheritance. Therefore, when they are decorated by the protected access qualifier, ArkTS generates a warning log.

@Entry
@Component
struct AccessRestrictions {
  build() {
    Column() {
      ComponentChild({regular_value: "Hello"})
    }
    .width('100%')
  }
}

@Component
struct ComponentChild {
  protected regular_value: string = "Hello";
  build() {
    Column() {
      Text("Hello")
        .fontSize(50)
        .fontWeight(FontWeight.Bold)
    }
  }
}

The @Require decorator requires external construction and assignment, which is not supported for private members. Therefore, when a member variable is decorated by the private access qualifier, the @Require decorator, and the @State, @Prop, @Provide, or @BuilderParam decorator, ArkTS generates a warning log.

@Entry
@Component
struct AccessRestrictions {
  build() {
    Column() {
      ComponentChild({prop_value: "Hello"})
    }
    .width('100%')
  }
}
@Component
struct ComponentChild {
  @Require @Prop private prop_value: string = "Hello";
  build() {
    Column() {
      Text("Hello")
        .fontSize(50)
        .fontWeight(FontWeight.Bold)
    }
  }
}

API Level

Change Since

OpenHarmony SDK 5.0.0.12

Adaptation Guide

Adjust the use of access qualifiers based on the provided error messages.

Reference

Constraints on Access Modifiers of Custom Component Member Variables