@ohos.connectedTag (Active Tags)

The connectedTag module provides APIs for using active tags. You can use the APIs to initialize the active tag chip and read and write active tags.

NOTE

The initial APIs of this module are supported since API version 8. Newly added APIs will be marked with a superscript to indicate their earliest API version.

Modules to Import

import connectedTag from '@ohos.connectedTag';

connectedTag.init

init(): boolean

Initializes the active tag chip.

Required permissions: ohos.permission.NFC_TAG

System capability: SystemCapability.Communication.ConnectedTag

Return value

connectedTag.initialize⁹⁺

initialize(): void

Initializes the active tag chip.

Required permissions: ohos.permission.NFC_TAG

System capability: SystemCapability.Communication.ConnectedTag

Error codes For details about the error codes, see NFC Error Codes.

connectedTag.uninit

uninit(): boolean

Uninitializes the active tag resources.

Required permissions: ohos.permission.NFC_TAG

System capability: SystemCapability.Communication.ConnectedTag

Return value

connectedTag.uninitialize⁹⁺

uninitialize(): void

Uninitializes the active tag resources.

Required permissions: ohos.permission.NFC_TAG

System capability: SystemCapability.Communication.ConnectedTag

Error codes For details about the error codes, see NFC Error Codes.

connectedTag.readNdefTag

readNdefTag(): Promise<string>

Reads the content of this active tag. This API uses a promise to return the result.

Required permissions: ohos.permission.NFC_TAG

System capability: SystemCapability.Communication.ConnectedTag

Return value

Example

import connectedTag from '@ohos.connectedTag';
import { BusinessError } from '@ohos.base';

connectedTag.readNdefTag().then((data) => {
    console.log("connectedTag readNdefTag Promise data = " + data);
}).catch((err: BusinessError)=> {
    console.log("connectedTag readNdefTag Promise err: " + err);
});

connectedTag.read⁹⁺

read(): Promise<number[]>

Reads the content of this active tag. This API uses a promise to return the result.

Required permissions: ohos.permission.NFC_TAG

System capability: SystemCapability.Communication.ConnectedTag

Return value

Error codes For details about the error codes, see NFC Error Codes.

Example

import connectedTag from '@ohos.connectedTag';
import { BusinessError } from '@ohos.base';

connectedTag.read().then((data) => {
    console.log("connectedTag read Promise data = " + data);
}).catch((err: BusinessError)=> {
    console.log("connectedTag read Promise err: " + err);
});

connectedTag.readNdefTag

readNdefTag(callback: AsyncCallback<string>): void

Reads the content of this active tag. This API uses an asynchronous callback to return the result.

Required permissions: ohos.permission.NFC_TAG

System capability: SystemCapability.Communication.ConnectedTag

Parameters

Example

import connectedTag from '@ohos.connectedTag';

connectedTag.readNdefTag((err, data)=> {
    if (err) {
        console.log("connectedTag readNdefTag AsyncCallback err: " + err);
    } else {
        console.log("connectedTag readNdefTag AsyncCallback data: " + data);
    }
});

connectedTag.read⁹⁺

read(callback: AsyncCallback<number[]>): void

Reads the content of this active tag. This API uses an asynchronous callback to return the result.

Required permissions: ohos.permission.NFC_TAG

System capability: SystemCapability.Communication.ConnectedTag

Parameters

Error codes For details about the error codes, see NFC Error Codes.

Example

import connectedTag from '@ohos.connectedTag';

connectedTag.read((err, data)=> {
    if (err) {
        console.log("connectedTag read AsyncCallback err: " + err);
    } else {
        console.log("connectedTag read AsyncCallback data: " + data);
    }
});

connectedTag.writeNdefTag

writeNdefTag(data: string): Promise<void>

Writes data to this active tag. This API uses a promise to return the result.

Required permissions: ohos.permission.NFC_TAG

System capability: SystemCapability.Communication.ConnectedTag

Parameters

Return value

Example

import connectedTag from '@ohos.connectedTag';
import { BusinessError } from '@ohos.base';

let rawData = "010203"; // change it tobe correct.
connectedTag.writeNdefTag(rawData).then(() => {
    console.log("connectedTag writeNdefTag Promise success.");
}).catch((err: BusinessError)=> {
    console.log("connectedTag writeNdefTag Promise err: " + err);
});

connectedTag.write⁹⁺

write(data: number[]): Promise<void>

Writes data to this active tag. This API uses a promise to return the result.

Required permissions: ohos.permission.NFC_TAG

System capability: SystemCapability.Communication.ConnectedTag

Parameters

Return value

Error codes For details about the error codes, see NFC Error Codes.

Example

import connectedTag from '@ohos.connectedTag';
import { BusinessError } from '@ohos.base';

let rawData = [0x01, 0x02, 0x03]; // change it tobe correct.
connectedTag.write(rawData).then(() => {
    console.log("connectedTag write NdefTag Promise success.");
}).catch((err: BusinessError)=> {
    console.log("connectedTag write NdefTag Promise err: " + err);
});

connectedTag.writeNdefTag

writeNdefTag(data: string, callback: AsyncCallback<void>): void

Writes data to this active tag. This API uses an asynchronous callback to return the result.

Required permissions: ohos.permission.NFC_TAG

System capability: SystemCapability.Communication.ConnectedTag

Parameters

Example

import connectedTag from '@ohos.connectedTag';

let rawData = "010203"; // change it tobe correct.
connectedTag.writeNdefTag(rawData, (err)=> {
    if (err) {
        console.log("connectedTag writeNdefTag AsyncCallback err: " + err);
    } else {
        console.log("connectedTag writeNdefTag AsyncCallback success.");
    }
});

connectedTag.write⁹⁺

write(data: number[], callback: AsyncCallback<void>): void

Writes data to this active tag. This API uses an asynchronous callback to return the result.

Required permissions: ohos.permission.NFC_TAG

System capability: SystemCapability.Communication.ConnectedTag

Parameters

Error codes For details about the error codes, see NFC Error Codes.

Example

import connectedTag from '@ohos.connectedTag';

let rawData = [0x01, 0x02, 0x03]; // change it tobe correct.
connectedTag.write(rawData, (err)=> {
    if (err) {
        console.log("connectedTag write NdefTag AsyncCallback err: " + err);
    } else {
        console.log("connectedTag write NdefTag AsyncCallback success.");
    }
});

connectedTag.on('notify')

on(type: "notify", callback: Callback<number>): void

Registers the NFC field strength state events.

Required permissions: ohos.permission.NFC_TAG

System capability: SystemCapability.Communication.ConnectedTag

Parameters

connectedTag.off('notify')

off(type: "notify", callback?: Callback<number>): void

Unregisters the NFC field strength state events.

Required permissions: ohos.permission.NFC_TAG

System capability: SystemCapability.Communication.ConnectedTag

Parameters

Example

import connectedTag from '@ohos.connectedTag';

// Register the event.
connectedTag.on("notify", (rfState : number)=> {
  console.log("connectedTag on Callback rfState: " + rfState);
});

let initStatus = connectedTag.init();
console.log("connectedTag init status: " + initStatus);

// Add NFC connected tag business operations here.
// connectedTag.writeNdefTag(rawData)
// connectedTag.readNdefTag()

let uninitStatus = connectedTag.uninit();
console.log("connectedTag uninit status: " + uninitStatus);

// Unregister the event.
connectedTag.off("notify", (rfState : number)=> {
  console.log("connectedTag off Callback rfState: " + rfState);
});

NfcRfType

Enumerates the NFC field strength states.

System capability: SystemCapability.Communication.ConnectedTag