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update docs 

Signed-off-by: NAnnie_wang <annie.wangli@huawei.com>
上级 b1f9843a
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Showing with 142 addition and 97 deletion
en/application-dev/database/database-datashare-guidelines.md
浏览文件 @ e7bcc151
......@@ -13,7 +13,7 @@ The **DataShare** module allows an application to manage its own data and share
|query?(uri: string, predicates: DataSharePredicates, columns: Array&lt;string&gt;, callback: AsyncCallback&lt;Object&gt;): void|Queries data from the database.|
|delete?(uri: string, predicates: DataSharePredicates, callback: AsyncCallback&lt;number&gt;): void|Deletes data from the database.|
For details about the data provider APIs, see [DataShareExtensionAbility](../reference/apis/js-apis-application-DataShareExtensionAbility.md).
For details about the data provider APIs, see [DataShareExtensionAbility](../reference/apis/js-apis-application-dataShareExtensionAbility.md).
**Table 2** APIs of the data consumer
......@@ -34,11 +34,52 @@ 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**.
Examples are given below.
### Data Provider Application Development (Only for System Applications)
1. Import dependencies.
[DataShareExtensionAbility](../reference/apis/js-apis-application-dataShareExtensionAbility.md) 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. This method can be overridden as required.
- **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.
- **denormalizeUri**
Converts the URI used by the server to the initial URI passed by the client.
Before implementing a **DataShare** service, you need to 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** dependency package. You can override the service implementation as required. For example, if the data provider provides only the services for inserting, deleting, and querying data, you can override **insert()**, **delete()**, and **query()** only.
4. Import dependencies.
```ts
import Extension from '@ohos.application.DataShareExtensionAbility';
......@@ -47,9 +88,9 @@ Examples are given below.
import dataSharePredicates from '@ohos.data.dataSharePredicates';
```
2. Override **DataShareExtensionAbility** APIs based on actual requirements. For example, if the data provider provides only data query, override only **query()**.
5. Override **DataShareExtensionAbility** APIs based on actual requirements. For example, if the data provider provides only data query, override only **query()**.
3. 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.
6. 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.
```ts
const DB_NAME = "DB00.db";
......@@ -57,29 +98,31 @@ Examples are given below.
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'
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));
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));
});
callback();
if (callback) {
callback();
}
});
}
// Override query().
query(uri, predicates, columns, callback) {
if (predicates == null || predicates == undefined) {
......@@ -103,7 +146,7 @@ Examples are given below.
};
```
4. Define **DataShareExtensionAbility** in **module.json5**.
7. Define **DataShareExtensionAbility** in **module.json5**.
| Field| Description |
| ------------ | ------------------------------------------------------------ |
......@@ -133,25 +176,25 @@ Examples are given below.
1. Import dependencies.
```ts
import Ability from '@ohos.application.Ability';
import UIAbility from '@ohos.app.ability.UIAbility';
import dataShare from '@ohos.data.dataShare';
import dataSharePredicates from '@ohos.data.dataSharePredicates';
```
2. Define the URI string for communicating with the data provider.
```ts
// 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");
```
3. Create a **DataShareHelper** instance.
```ts
let dsHelper;
let abilityContext;
export default class MainAbility extends Ability {
export default class EntryAbility extends UIAbility {
onWindowStageCreate(windowStage) {
abilityContext = this.context;
dataShare.createDataShareHelper(abilityContext, dseUri, (err, data)=>{
......@@ -160,7 +203,7 @@ Examples are given below.
}
}
```
4. Use the APIs provided by **DataShareHelper** to access the services provided by the provider, for example, adding, deleting, modifying, and querying data.
```ts
......@@ -168,7 +211,7 @@ Examples are given below.
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 = new Array("*");
let valArray = ['*'];
// Insert a piece of data.
dsHelper.insert(dseUri, valuesBucket, (err, data) => {
console.log("dsHelper insert result: " + data);
......@@ -183,7 +226,6 @@ Examples are given below.
});
// Delete data.
dsHelper.delete(dseUri, predicates, (err, data) => {
console.log("dsHelper delete result: " + data);
console.log("dsHelper delete result: " + data);
});
```
en/application-dev/database/database-mdds-guidelines.md
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......@@ -68,16 +68,16 @@ The following uses a single KV store as an example to describe the development p
grantPermission();
// Stage model
import AbilityStage from '@ohos.application.Ability';
import UIAbility from '@ohos.app.ability.UIAbility';
let context = null;
class MainAbility extends AbilityStage {
class EntryAbility extends UIAbility {
onWindowStageCreate(windowStage) {
let context = this.context;
}
}
function grantPermission() {
let permissions = ['ohos.permission.DISTRIBUTED_DATASYNC'];
context.requestPermissionsFromUser(permissions).then((data) => {
......@@ -86,7 +86,7 @@ The following uses a single KV store as an example to describe the development p
console.error('failed: ${error}');
});
}
grantPermission();
```
......@@ -103,9 +103,9 @@ The following uses a single KV store as an example to describe the development p
let context = featureAbility.getContext();
// Obtain the context of the stage model.
import AbilityStage from '@ohos.application.Ability';
import UIAbility from '@ohos.app.ability.UIAbility';
let context = null;
class MainAbility extends AbilityStage{
class EntryAbility extends UIAbility {
onWindowStageCreate(windowStage){
context = this.context;
}
......@@ -119,7 +119,7 @@ The following uses a single KV store as an example to describe the development p
}
distributedKVStore.createKVManager(kvManagerConfig, function (err, manager) {
if (err) {
console.error(`Failed to create KVManager. code is ${err.code},message is ${err.message}`);
console.error(`Failed to createKVManager.code is ${err.code},message is ${err.message}`);
return;
}
console.log('Created KVManager successfully');
......
en/application-dev/database/database-preference-guidelines.md
浏览文件 @ e7bcc151
......@@ -113,10 +113,10 @@ You can use the following APIs to delete a **Preferences** instance or data file
```ts
// Obtain the context.
import Ability from '@ohos.application.Ability'
import UIAbility from '@ohos.app.ability.UIAbility'
let context = null;
let preferences = null;
export default class MainAbility extends Ability {
export default class EntryAbility extends UIAbility {
onWindowStageCreate(windowStage){
context = this.context;
}
......@@ -159,7 +159,7 @@ You can use the following APIs to delete a **Preferences** instance or data file
5. Store data persistently.
Use **flush()** to flush data from the **Preferences** instance to its file.
Use **preferences.flush()** to flush data from the **Preferences** instance to its file.
```js
preferences.flush();
......@@ -186,7 +186,7 @@ You can use the following APIs to delete a **Preferences** instance or data file
console.info("Failed to flush data. Cause: " + err);
return;
}
console.info("Flushed data successfully."); // The observer will be called.
console.info("Flushed data successfully."); // The observer will be called.
})
})
```
......@@ -200,6 +200,6 @@ You can use the following APIs to delete a **Preferences** instance or data file
proDelete.then(() => {
console.info("Deleted data successfully.");
}).catch((err) => {
console.info("Failed to delete data. Cause: " + err);
console.info("Failed to delete. Cause: " + err);
})
```
en/application-dev/reference/apis/js-apis-data-dataShare.md
浏览文件 @ e7bcc151
......@@ -175,7 +175,7 @@ Unsubscribes from the changes of the specified data. This API uses an asynchrono
| -------- | -------------------- | ---- | ------------------------ |
| type | string | Yes | Event type to unsubscribe from. The value is **dataChange**, which indicates data change events.|
| uri | string | Yes | URI of the data.|
| callback | AsyncCallback&lt;void&gt; | No | Callback used to return the result. If the operation is successful, **err** is **undefined**. Otherwise, **err** is an error object.|
| callback | AsyncCallback&lt;void&gt; | No | Callback invoked to return the result. If the operation is successful, **err** is **undefined**. Otherwise, **err** is an error object.|
**Example**
......
en/application-dev/reference/apis/js-apis-data-distributedobject.md
浏览文件 @ e7bcc151
......@@ -53,10 +53,10 @@ Stage model:
```ts
// Import the module.
import distributedObject from '@ohos.data.distributedDataObject';
import Ability from '@ohos.application.Ability';
import UIAbility from '@ohos.app.ability.UIAbility';
// Obtain the context.
let context;
class MainAbility extends Ability{
class EntryAbility extends UIAbility {
onWindowStageCreate(windowStage){
context = this.context
}
......@@ -110,7 +110,7 @@ Called when the **revokeSave()** API is successfully called.
## DistributedObjectV9
Provides APIs for managing a distributed data object.
Represents a distributed data object.
### setSessionId<sup>9+</sup>
......@@ -156,10 +156,10 @@ Stage model:
```ts
import distributedObject from '@ohos.data.distributedDataObject';
import Ability from '@ohos.application.Ability';
import UIAbility from '@ohos.app.ability.UIAbility';
// Obtain the context.
let context;
class MainAbility extends Ability{
class EntryAbility extends UIAbility {
onWindowStageCreate(windowStage){
context = this.context
}
......@@ -218,10 +218,10 @@ Stage model:
```ts
import distributedObject from '@ohos.data.distributedDataObject';
import Ability from '@ohos.application.Ability';
import UIAbility from '@ohos.app.ability.UIAbility';
// Obtain the context.
let context;
class MainAbility extends Ability{
class EntryAbility extends UIAbility {
onWindowStageCreate(windowStage){
context = this.context
}
......@@ -257,7 +257,7 @@ Sets a session ID for synchronization. Automatic synchronization is performed fo
| Type| Description|
| -------- | -------- |
| Promise&lt;void&gt; | Promise used to|
| Promise&lt;void&gt; | Promise that returns no value.|
**Error codes**
......@@ -294,10 +294,10 @@ Stage model:
```ts
import distributedObject from '@ohos.data.distributedDataObject';
import Ability from '@ohos.application.Ability';
import UIAbility from '@ohos.app.ability.UIAbility';
// Obtain the context.
let context;
class MainAbility extends Ability{
class EntryAbility extends UIAbility {
onWindowStageCreate(windowStage){
context = this.context
}
......@@ -321,7 +321,7 @@ g_object.setSessionId().then (()=>{
on(type: 'change', callback: Callback<{ sessionId: string, fields: Array&lt;string&gt; }>): void
Subscribes to data changes of this distributed data object.
Subscribes to the data change of this distributed data object.
**System capability**: SystemCapability.DistributedDataManager.DataObject.DistributedObject
......@@ -357,10 +357,10 @@ Stage model:
```ts
import distributedObject from '@ohos.data.distributedDataObject';
import Ability from '@ohos.application.Ability';
import UIAbility from '@ohos.app.ability.UIAbility';
// Obtain the context.
let context;
class MainAbility extends Ability{
class EntryAbility extends UIAbility {
onWindowStageCreate(windowStage){
context = this.context
}
......@@ -381,7 +381,7 @@ g_object.on("change", globalThis.changeCallback);
off(type: 'change', callback?: Callback<{ sessionId: string, fields: Array&lt;string&gt; }>): void
Unsubscribes from the data changes of this distributed data object.
Unsubscribes from the data change of this distributed data object.
**System capability**: SystemCapability.DistributedDataManager.DataObject.DistributedObject
......@@ -413,10 +413,10 @@ Stage model:
```ts
import distributedObject from '@ohos.data.distributedDataObject';
import Ability from '@ohos.application.Ability';
import UIAbility from '@ohos.app.ability.UIAbility';
// Obtain the context.
let context;
class MainAbility extends Ability{
class EntryAbility extends UIAbility {
onWindowStageCreate(windowStage){
context = this.context
}
......@@ -432,7 +432,7 @@ g_object.off("change");
on(type: 'status', callback: Callback<{ sessionId: string, networkId: string, status: 'online' | 'offline' }>): void
Subscribes to statue changes of this distributed data object.
Subscribes to the status change of this distributed data object.
**System capability**: SystemCapability.DistributedDataManager.DataObject.DistributedObject
......@@ -463,10 +463,10 @@ Stage model:
```ts
import distributedObject from '@ohos.data.distributedDataObject';
import Ability from '@ohos.application.Ability';
import UIAbility from '@ohos.app.ability.UIAbility';
// Obtain the context.
let context;
class MainAbility extends Ability{
class EntryAbility extends UIAbility {
onWindowStageCreate(windowStage){
context = this.context
}
......@@ -507,7 +507,7 @@ let g_object = distributedObject.create(context, {name:"Amy", age:18, isVis:fals
globalThis.statusCallback = (sessionId, networkId, status) => {
globalThis.response += "status changed " + sessionId + " " + status + " " + networkId;
}
// Unregister the specified status change callback.
// Unsubscribe from the specified status change callback for the distributed data object.
g_object.off("status",globalThis.statusCallback);
// Unregister all status change callbacks.
g_object.off("status");
......@@ -517,10 +517,10 @@ Stage model:
```ts
import distributedObject from '@ohos.data.distributedDataObject';
import Ability from '@ohos.application.Ability';
import UIAbility from '@ohos.app.ability.UIAbility';
// Obtain the context.
let context;
class MainAbility extends Ability{
class EntryAbility extends UIAbility {
onWindowStageCreate(windowStage){
context = this.context
}
......@@ -529,7 +529,7 @@ let g_object = distributedObject.create(context, {name:"Amy", age:18, isVis:fals
globalThis.statusCallback = (sessionId, networkId, status) => {
globalThis.response += "status changed " + sessionId + " " + status + " " + networkId;
}
// Unregister the specified status change callback.
// Unsubscribe from all status change callbacks for the distributed data object.
g_object.off("status",globalThis.statusCallback);
// Unregister all status change callbacks.
g_object.off("status");
......@@ -579,10 +579,10 @@ g_object.save("local", (result) => {
Stage model:
```ts
import distributedObject from '@ohos.data.distributedDataObject';
import Ability from '@ohos.application.Ability';
import UIAbility from '@ohos.app.ability.UIAbility';
// Obtain the context.
let context;
class MainAbility extends Ability{
class EntryAbility extends UIAbility {
onWindowStageCreate(windowStage){
context = this.context
}
......@@ -627,6 +627,8 @@ The saved data will be released in the following cases:
**Example**
FA model:
```js
import distributedObject from '@ohos.data.distributedDataObject';
import featureAbility from '@ohos.ability.featureAbility';
......@@ -643,13 +645,14 @@ g_object.save("local").then((result) => {
console.error("save failed");
});
```
Stage model:
```js
import distributedObject from '@ohos.data.distributedDataObject';
import Ability from '@ohos.application.Ability';
import UIAbility from '@ohos.app.ability.UIAbility';
// Obtain the context.
let context;
class MainAbility extends Ability{
class EntryAbility extends UIAbility {
onWindowStageCreate(windowStage){
context = this.context
}
......@@ -712,10 +715,10 @@ Stage model:
```ts
import distributedObject from '@ohos.data.distributedDataObject';
import Ability from '@ohos.application.Ability';
import UIAbility from '@ohos.app.ability.UIAbility';
// Obtain the context.
let context;
class MainAbility extends Ability {
class EntryAbility extends UIAbility {
onWindowStageCreate(windowStage) {
context = this.context
}
......@@ -786,10 +789,10 @@ Stage model:
```ts
import distributedObject from '@ohos.data.distributedDataObject';
import Ability from '@ohos.application.Ability';
import UIAbility from '@ohos.app.ability.UIAbility';
// Obtain the context.
let context;
class MainAbility extends Ability {
class EntryAbility extends UIAbility {
onWindowStageCreate(windowStage) {
context = this.context
}
......@@ -1000,7 +1003,7 @@ Unsubscribes from the status change of this distributed data object.
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| type | string | Yes| Event type to unsubscribe from. The value is **status**, which indicates the status change (online or offline) of the distributed data object.|
| type | string | Yes| Event type to unsubscribe from. The value is **status**, which indicates the status change (online or offline) of the distributed data object. |
| callback | Callback<{ sessionId: string, deviceId: string, status: 'online' \| 'offline' }> | No| Callback for status changes. If this parameter is not specified, all status change callbacks of this distributed data object will be unsubscribed from.<br>**sessionId** indicates the session ID of the distributed data object.<br>**deviceId** indicates the device ID of the distributed data object.<br>**status** indicates the object status, which can be online or offline.|
......
en/application-dev/reference/apis/js-apis-data-preferences.md
浏览文件 @ e7bcc151
......@@ -38,7 +38,7 @@ Obtains a **Preferences** instance. This API uses an asynchronous callback to re
| Name | Type | Mandatory| Description |
| -------- | ------------------------------------------------ | ---- | ------------------------------------------------------------ |
| context | Context | Yes | Application context.<br>For the application context of the FA model, see [Context](js-apis-inner-app-context.md).<br>For the application context of the stage model, see [Context](js-apis-ability-context.md). |
| context | Context | Yes | Application context.<br>For details about the application context of the FA model, see [Context](js-apis-inner-app-context.md).<br>For details about the application context of the stage model, see [Context](js-apis-ability-context.md). |
| name | string | Yes | Name of the **Preferences** instance.|
| callback | AsyncCallback&lt;[Preferences](#preferences)&gt; | Yes | Callback invoked to return the result. If the operation is successful, **err** is **undefined** and **object** is the **Preferences** instance obtained. Otherwise, **err** is an error code.|
......@@ -69,9 +69,9 @@ Stage model:
```ts
// Obtain the context.
import Ability from '@ohos.application.Ability';
import UIAbility from '@ohos.app.ability.UIAbility';
let context = null;
class MainAbility extends Ability{
class EntryAbility extends UIAbility {
onWindowStageCreate(windowStage){
context = this.context;
}
......@@ -103,7 +103,7 @@ Obtains a **Preferences** instance. This API uses a promise to return the result
| Name | Type | Mandatory| Description |
| ------- | ------------------------------------- | ---- | ----------------------- |
| context | Context | Yes | Application context.<br>For the application context of the FA model, see [Context](js-apis-inner-app-context.md).<br>For the application context of the stage model, see [Context](js-apis-ability-context.md). |
| context | Context | Yes | Application context.<br>For details about the application context of the FA model, see [Context](js-apis-inner-app-context.md).<br>For details about the application context of the stage model, see [Context](js-apis-ability-context.md). |
| name | string | Yes | Name of the **Preferences** instance.|
**Return value**
......@@ -139,9 +139,9 @@ Stage model:
```ts
// Obtain the context.
import Ability from '@ohos.application.Ability';
import UIAbility from '@ohos.app.ability.UIAbility';
let context = null;
class MainAbility extends Ability{
class EntryAbility extends UIAbility {
onWindowStageCreate(windowStage){
context = this.context;
}
......@@ -177,7 +177,7 @@ The deleted **Preferences** instance cannot be used for data operations. Otherwi
| Name | Type | Mandatory| Description |
| -------- | ------------------------------------- | ---- | ---------------------------------------------------- |
| context | Context | Yes | Application context.<br>For the application context of the FA model, see [Context](js-apis-inner-app-context.md).<br>For the application context of the stage model, see [Context](js-apis-ability-context.md). |
| context | Context | Yes | Application context.<br>For details about the application context of the FA model, see [Context](js-apis-inner-app-context.md).<br>For details about the application context of the stage model, see [Context](js-apis-ability-context.md). |
| name | string | Yes | Name of the **Preferences** instance to delete. |
| callback | AsyncCallback&lt;void&gt; | Yes | Callback invoked to return the result. If the operation is successful, **err** is **undefined**. Otherwise, **err** is an error code.|
......@@ -215,9 +215,9 @@ Stage model:
```ts
// Obtain the context.
import Ability from '@ohos.application.Ability';
import UIAbility from '@ohos.app.ability.UIAbility';
let context = null;
class MainAbility extends Ability{
class EntryAbility extends UIAbility {
onWindowStageCreate(windowStage){
context = this.context;
}
......@@ -252,7 +252,7 @@ The deleted **Preferences** instance cannot be used for data operations. Otherwi
| Name | Type | Mandatory| Description |
| ------- | ------------------------------------- | ---- | ----------------------- |
| context | Context | Yes | Application context.<br>For the application context of the FA model, see [Context](js-apis-inner-app-context.md).<br>For the application context of the stage model, see [Context](js-apis-ability-context.md). |
| context | Context | Yes | Application context.<br>For details about the application context of the FA model, see [Context](js-apis-inner-app-context.md).<br>For details about the application context of the stage model, see [Context](js-apis-ability-context.md). |
| name | string | Yes | Name of the **Preferences** instance to delete.|
**Return value**
......@@ -294,9 +294,9 @@ Stage model:
```ts
// Obtain the context.
import Ability from '@ohos.application.Ability';
import UIAbility from '@ohos.app.ability.UIAbility';
let context = null;
class MainAbility extends Ability{
class EntryAbility extends UIAbility {
onWindowStageCreate(windowStage){
context = this.context;
}
......@@ -328,7 +328,7 @@ The removed **Preferences** instance cannot be used for data operations. Otherwi
| Name | Type | Mandatory| Description |
| -------- | ------------------------------------- | ---- | ---------------------------------------------------- |
| context | Context | Yes | Application context.<br>For the application context of the FA model, see [Context](js-apis-inner-app-context.md).<br>For the application context of the stage model, see [Context](js-apis-ability-context.md). |
| context | Context | Yes | Application context.<br>For details about the application context of the FA model, see [Context](js-apis-inner-app-context.md).<br>For details about the application context of the stage model, see [Context](js-apis-ability-context.md). |
| name | string | Yes | Name of the **Preferences** instance to remove. |
| callback | AsyncCallback&lt;void&gt; | Yes | Callback invoked to return the result. If the operation is successful, **err** is **undefined**. Otherwise, **err** is an error code.|
......@@ -358,9 +358,9 @@ Stage model:
```ts
// Obtain the context.
import Ability from '@ohos.application.Ability';
import UIAbility from '@ohos.app.ability.UIAbility';
let context = null;
class MainAbility extends Ability{
class EntryAbility extends UIAbility {
onWindowStageCreate(windowStage){
context = this.context;
}
......@@ -394,7 +394,7 @@ The removed **Preferences** instance cannot be used for data operations. Otherwi
| Name | Type | Mandatory| Description |
| ------- | ------------------------------------- | ---- | ----------------------- |
| context | Context | Yes | Application context.<br>For the application context of the FA model, see [Context](js-apis-inner-app-context.md).<br>For the application context of the stage model, see [Context](js-apis-ability-context.md). |
| context | Context | Yes | Application context.<br>For details about the application context of the FA model, see [Context](js-apis-inner-app-context.md).<br>For details about the application context of the stage model, see [Context](js-apis-ability-context.md). |
| name | string | Yes | Name of the **Preferences** instance to remove.|
**Return value**
......@@ -428,9 +428,9 @@ Stage model:
```ts
// Obtain the context.
import Ability from '@ohos.application.Ability';
import UIAbility from '@ohos.app.ability.UIAbility';
let context = null;
class MainAbility extends Ability{
class EntryAbility extends UIAbility {
onWindowStageCreate(windowStage){
context = this.context;
}
......@@ -662,7 +662,7 @@ try {
has(key: string, callback: AsyncCallback&lt;boolean&gt;): void
Checks whether this **Preferences** instance contains a KV pair with the given key. This API uses an asynchronous callback to return the result..
Checks whether this **Preferences** instance contains a KV pair with the given key. This API uses an asynchronous callback to return the result.
**System capability**: SystemCapability.DistributedDataManager.Preferences.Core
......@@ -698,7 +698,7 @@ try {
has(key: string): Promise&lt;boolean&gt;
Checks whether this **Preferences** instance contains a KV pair with the given key. This API uses a promise to return the result..
Checks whether this **Preferences** instance contains a KV pair with the given key. This API uses a promise to return the result.
**System capability**: SystemCapability.DistributedDataManager.Preferences.Core
......@@ -987,7 +987,7 @@ Unsubscribes from data changes.
| Name | Type | Mandatory| Description |
| -------- | -------------------------------- | ---- | ------------------------------------------ |
| type | string | Yes | Event type to unsubscribe from. The value **change** indicates data change events. |
| callback | Callback&lt;{ key : string }&gt; | No | Callback to unregister. If this parameter is left blank, the callbacks used to subscribing to all data changes will be unregistered.|
| callback | Callback&lt;{ key : string }&gt; | No | Callback to unregister. If this parameter is left blank, all callbacks for data changes will be unregistered. |
**Example**
......
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