DataShare Development

The DataShare module allows an application to manage its own data and share data with other applications. Currently, data can be shared only between applications on the same device.

Available APIs

Table 1 APIs of the data provider

For details about the data provider APIs, see DataShareExtensionAbility.

Table 2 APIs of the data consumer

For more information, see DataShareHelper.

When to Use

There are two roles in DataShare:

• Data provider: adds, deletes, modifies, and queries data, opens files, and shares data.
• Data consumer: accesses the data provided by the provider using DataShareHelper.

Data Provider Application Development (Only for System Applications)

DataShareExtensionAbility provides the following APIs. You can override these APIs as required.

• onCreate

Called by the server to initialize service logic when the DataShare client connects to the DataShareExtensionAbility server.

• insert

Inserts data. This API is called when the client requests to insert data.

• update

Updates data. This API is called when the client requests to update data.

• delete

Deletes data. This API is called when the client requests to delete data.

• query

Queries data. This API is called when the client requests to query data.

• batchInsert

Batch inserts data. This API is called when the client requests to batch insert data.

• normalizeUri

Converts the URI provided by the client to the URI used by the server. This API can be overridden as required.

• denormalizeUri

Converts the URI used by the server to the initial URI passed by the client. This API can be overridden as required.

Before implementing a DataShare service, create a DataShareExtensionAbility object in the DevEco Studio project as follows:

1. In the ets directory of the Module project, right-click and choose New > Directory to create a directory named DataShareAbility.

2. Right-click the DataShareAbility directory, and choose New > TypeScript File to create a file named DataShareAbility.ts.

3. In the DataShareAbility.ts file, import the DataShareExtensionAbility and other dependencies.

   import Extension from '@ohos.application.DataShareExtensionAbility';
   import rdb from '@ohos.data.relationalStore';
   import fileIo from '@ohos.fileio';
   import dataSharePredicates from '@ohos.data.dataSharePredicates';

1. Override DataShareExtensionAbility APIs based on actual requirements. For example, if the data provider provides only data query, override only query().

2. Implement the data provider services. For example, implement data storage of the data provider by using a database, reading and writing files, or accessing the network.

   const DB_NAME = "DB00.db";
   const TBL_NAME = "TBL00";
   const DDL_TBL_CREATE = "CREATE TABLE IF NOT EXISTS "
   + TBL_NAME
   + " (id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT, age INTEGER, isStudent BOOLEAN, Binary BINARY)";

   let rdbStore;
   let result;

   export default class DataShareExtAbility extends Extension {
       private rdbStore_;

   	// Override onCreate().
       onCreate(want, callback) {
           result = this.context.cacheDir + '/datashare.txt';
           // Create an RDB store.
            rdb.getRdbStore(this.context, {
                name: DB_NAME,
                securityLevel: rdb.SecurityLevel.S1
            }, function (err, data) {
                rdbStore = data;
                rdbStore.executeSql(DDL_TBL_CREATE, [], function (err) {
                    console.log('DataShareExtAbility onCreate, executeSql done err:' + JSON.stringify(err));
               });
               if (callbakc) {
                    callback();
               }
           });
       }

   	// Override query().
       query(uri, predicates, columns, callback) {
           if (predicates == null||predicates == undefined) {
               console.info('invalid predicates');
           }
           try {
               rdbStore.query(TBL_NAME, predicates, columns, function (err, resultSet) {
                   if (resultSet != undefined) {
                       console.info('resultSet.rowCount: ' + resultSet.rowCount);
                   }
                   if (callback != undefined) {
                       callback(err, resultSet);
                   }
               });
           } catch (err) {
               console.error('error' + err);
           }
       }
       // Override other APIs as required.
       // ...
   };

1. Define DataShareExtensionAbility in module.json5.

|Field|Description | |————|————————————————————| |“name” |Ability name, corresponding to the ExtensionAbility class name derived from Ability. | |“type” |Ability type. The value is dataShare, indicating the development is based on the datashare template.| |“uri” |URI used for communication. It is the unique identifier for the data consumer to connect to the provider. | |“visible” |Whether it is visible to other applications. Data sharing is allowed only when the value is true.|

module.json5 example

   "extensionAbilities": [
     {
       "srcEntrance": "./ets/DataShareExtAbility/DataShareExtAbility.ts",
       "name": "DataShareExtAbility",
       "icon": "$media:icon",
       "description": "$string:description_datashareextability",
       "type": "dataShare",
       "uri": "datashare://com.samples.datasharetest.DataShare",
       "visible": true
     }
   ]

Data Consumer Application Development

1. Import dependencies.

   import UIAbility from '@ohos.app.ability.UIAbility';
   import dataShare from '@ohos.data.dataShare';
   import dataSharePredicates from '@ohos.data.dataSharePredicates';

1. Define the URI string for communicating with the data provider.

   // Different from the URI defined in the module.json5 file, the URI passed in the parameter has an extra slash (/), because there is a DeviceID parameter between the second and the third slash (/).
   let dseUri = ("datashare:///com.samples.datasharetest.DataShare");

1. Create a DataShareHelper instance.

   let dsHelper;
   let abilityContext;

   export default class EntryAbility extends UIAbility {
   	onWindowStageCreate(windowStage) {
   		abilityContext = this.context;
   		dataShare.createDataShareHelper(abilityContext, dseUri, (err, data)=>{
   			dsHelper = data;
   		});
   	}
   }

1. Use the APIs provided by DataShareHelper to access the services provided by the provider, for example, adding, deleting, modifying, and querying data.

   // Construct a piece of data.
   let valuesBucket = { "name": "ZhangSan", "age": 21, "isStudent": false, "Binary": new Uint8Array([1, 2, 3]) };
   let updateBucket = { "name": "LiSi", "age": 18, "isStudent": true, "Binary": new Uint8Array([1, 2, 3]) };
   let predicates = new dataSharePredicates.DataSharePredicates();
   let valArray = ['*'];
   // Insert a piece of data.
   dsHelper.insert(dseUri, valuesBucket, (err, data) => {
     console.log("dsHelper insert result: " + data);
   });
   // Update data.
   dsHelper.update(dseUri, predicates, updateBucket, (err, data) => {
     console.log("dsHelper update result: " + data);
   });
   // Query data.
   dsHelper.query(dseUri, predicates, valArray, (err, data) => {
     console.log("dsHelper query result: " + data);
   });
   // Delete data.
   dsHelper.delete(dseUri, predicates, (err, data) => {
     console.log("dsHelper delete result: " + data);
   });

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