目录

Uniform Data Structs (ArkTS)

When to Use

For some common uniform data types defined by UTD, uniform data structs are provided for different data types to facilitate your use. For example, for the system-defined desktop icon type (whose uniform data type identifier is 'openharmony.app-item'), the related description of the data struct is explicitly defined.

In certain scenarios, apps can directly use the UTD uniform data structs that we define, for example, in cross-app drag-and-drop. The drag-out app can write the drag data into the drag event DragEvent according to the uniform data struct, and the drag-in app reads the drag data from the drag event and parses it according to the uniform data struct. This enables data interaction between different apps to follow the same standard definition, effectively reducing the development workload of cross-app data interaction.

Uniform Data Structs

The following table lists the uniform data structs provided by the UDMF.

Data Struct Data Type Description
PlainText 'general.plain-text' Plain text.
Hyperlink 'general.hyperlink' Hyperlink.
HTML 'general.html' Rich text.
OpenHarmonyAppItem 'openharmony.app-item' Icon.
ContentForm 'general.content-form' Content widget.

How to Develop

The following describes how to use the uniform data structs to define a hyperlink and a plain text.

The data provider can call addRecord() provided by the UDMF to add data records and call getRecords() to obtain all data records in the current data object.

  1. Import the required modules.

    // 1. Import the uniformDataStruct, unifiedDataChannel, and uniformTypeDescriptor modules.
import { uniformDataStruct, uniformTypeDescriptor, unifiedDataChannel } from '@kit.ArkData';
import { hilog } from '@kit.PerformanceAnalysisKit';

  2. Create a data record for a hyperlink.

  3. Create a data record for the plain text data type.

  4. Create a unified data object and record.

  5. Add a data record.

  6. Obtain all data records in the current UnifiedData object.

  7. Traverse each record, determine the data type, and convert the data type into a child class object to obtain the original data record.

    // 2. Create a data record for a hyperlink.
let hyperlinkDetails: Record<string, string> = {
  'attr1': 'value1',
  'attr2': 'value2'
}
let hyperlink: uniformDataStruct.Hyperlink = {
  uniformDataType: 'general.hyperlink',
  url: 'www.XXX.com',
  description: 'This is the description of this hyperlink',
  details: hyperlinkDetails
}

// Modify the description of hyperlink.
hyperlink.description = '...';

// Access the object property.
hilog.info(0xFF00, '[Sample_Udmf]', `hyperlink.url = ${hyperlink.url}`);

// 3. Create a plain text data type record.
let plainTextDetails: Record<string, string> = {
  'attr1': 'value1',
  'attr2': 'value2'
}
let plainText: uniformDataStruct.PlainText = {
  uniformDataType: 'general.plain-text',
  textContent: 'This is plainText textContent example',
  abstract: 'this is abstract',
  details: plainTextDetails
}
// 4. Create a unified data object and record.
let unifiedData = new unifiedDataChannel.UnifiedData();
let hyperlinkRecord =
  new unifiedDataChannel.UnifiedRecord(uniformTypeDescriptor.UniformDataType.HYPERLINK, hyperlink);
let plainTextRecord =
  new unifiedDataChannel.UnifiedRecord(uniformTypeDescriptor.UniformDataType.PLAIN_TEXT, plainText);

// 5. Add a data record.
unifiedData.addRecord(hyperlinkRecord);
unifiedData.addRecord(plainTextRecord);

// 6. Obtain all data records in this UnifiedData instance.
let records = unifiedData.getRecords();

// 7. Traverse all records, determine the data type of the record, and convert the record into a child class object to obtain the original data record.
for (let i = 0; i < records.length; i++) {
  let unifiedDataRecord = records[i] as unifiedDataChannel.UnifiedRecord;
  let record = unifiedDataRecord.getValue() as object;
  if (record != undefined) {
    // Obtain the type of each data record.
    let type: string = record['uniformDataType'];
    switch (type) {
      case uniformTypeDescriptor.UniformDataType.HYPERLINK:
        Object.keys(record).forEach(key => {
          hilog.info(0xFF00, '[Sample_Udmf]', `show records: ${key}, value: ${record[key]}`);
        });
        break;
      case uniformTypeDescriptor.UniformDataType.PLAIN_TEXT:
        Object.keys(record).forEach(key => {
          hilog.info(0xFF00, '[Sample_Udmf]', `show records: ${key}, value: ${record[key]}`);
        });
        break;
      default:
        break;
    }
  }
}