Skip to content

D
Docs

Coping0606 / Docs
与 Fork 源项目一致

Fork自 OpenHarmony / Docs

通知 1
Star 1
Fork 0
D
Docs

体验新版 GitCode，发现更多精彩内容 >>

未验证 提交 9d98721b 编写于 作者: O openharmony_ci 提交者： Gitee
浏览文件
操作

!5351 回流英文纯净markdown修改：无需翻译 

Merge pull request !5351 from 葛亚芳/OpenHarmony-3.1-Release
上级 227e14d6 3980ba64
隐藏空白更改
内联 并排
Showing with 53 addition and 216 deletion
en/application-dev/database/database-storage-guidelines.md
浏览文件 @ 9d98721b
# Lightweight Data Store Development<a name="EN-US_TOPIC_0000001230830543"></a>
# Lightweight Data Store Development
## When to Use<a name="section13841104521714"></a>
## When to Use
The lightweight data store is ideal for storing lightweight and frequently used data, but not for storing a large amount of data or data with frequent changes. The application data is persistently stored on a device in the form of files. Note that the instance accessed by an application contains all data of the file. The data is always loaded to the memory of the device until the application removes it from the memory. The application can perform data operations using the **Storage** APIs.
## Available APIs<a name="section15173156141712"></a>
## Available APIs
The lightweight data store provides applications with data processing capability and allows applications to perform lightweight data storage and query. Data is stored in key-value pairs. Keys are of the string type, and values can be of the number, string, or Boolean type.
......@@ -14,24 +14,9 @@ Create a **Storage** instance for data operations. A **Storage** instance is
**Table 1** API for creating a **Storage** instance
<a name="table17310132152415"></a>
<table><thead align="left"><tr id="row93118212413"><th class="cellrowborder" valign="top" width="17.69%" id="mcps1.2.4.1.1"><p id="p031118214242"><a name="p031118214242"></a><a name="p031118214242"></a>Package Name</p>
</th>
<th class="cellrowborder" valign="top" width="28.249999999999996%" id="mcps1.2.4.1.2"><p id="p19311326245"><a name="p19311326245"></a><a name="p19311326245"></a>Method</p>
</th>
<th class="cellrowborder" valign="top" width="54.059999999999995%" id="mcps1.2.4.1.3"><p id="p1131118252418"><a name="p1131118252418"></a><a name="p1131118252418"></a>Description</p>
</th>
</tr>
</thead>
<tbody><tr id="row38631245202910"><td class="cellrowborder" valign="top" width="17.69%" headers="mcps1.2.4.1.1 "><p id="p8365103153013"><a name="p8365103153013"></a><a name="p8365103153013"></a>ohos.data.storage</p>
</td>
<td class="cellrowborder" valign="top" width="28.249999999999996%" headers="mcps1.2.4.1.2 "><p id="p1937481213019"><a name="p1937481213019"></a><a name="p1937481213019"></a>getStorage(path: string): Promise&lt;Storage&gt;;</p>
</td>
<td class="cellrowborder" valign="top" width="54.059999999999995%" headers="mcps1.2.4.1.3 "><p id="p4311132162417"><a name="p4311132162417"></a><a name="p4311132162417"></a>Obtains the <strong id="b193911821194211"><a name="b193911821194211"></a><a name="b193911821194211"></a>Storage</strong> singleton corresponding to a file for data operations.</p>
</td>
</tr>
</tbody>
</table>
| Package Name | Method | Description |
| ----------------- | ------------------------------------------- | ------------------------------------------------------------ |
| ohos.data.storage | getStorage(path: string): Promise\<Storage> | Obtains the **Storage** singleton corresponding to a file for data operations. |
**Writing Data**
......@@ -39,24 +24,9 @@ Call the **put\(\)** method to add or modify data in a **Storage** instance.
**Table 2** API for writing data
<a name="table52021841142013"></a>
<table><thead align="left"><tr id="row2202741122013"><th class="cellrowborder" valign="top" width="19.79%" id="mcps1.2.4.1.1"><p id="p12161443377"><a name="p12161443377"></a><a name="p12161443377"></a>Class</p>
</th>
<th class="cellrowborder" valign="top" width="37%" id="mcps1.2.4.1.2"><p id="p172028414205"><a name="p172028414205"></a><a name="p172028414205"></a>Method</p>
</th>
<th class="cellrowborder" valign="top" width="43.21%" id="mcps1.2.4.1.3"><p id="p162020415205"><a name="p162020415205"></a><a name="p162020415205"></a>Description</p>
</th>
</tr>
</thead>
<tbody><tr id="row8203194115202"><td class="cellrowborder" valign="top" width="19.79%" headers="mcps1.2.4.1.1 "><p id="p31644311712"><a name="p31644311712"></a><a name="p31644311712"></a>Storage</p>
</td>
<td class="cellrowborder" valign="top" width="37%" headers="mcps1.2.4.1.2 "><p id="p105961650131617"><a name="p105961650131617"></a><a name="p105961650131617"></a>put(key: string, value: ValueType): Promise&lt;void&gt;;</p>
</td>
<td class="cellrowborder" valign="top" width="43.21%" headers="mcps1.2.4.1.3 "><p id="p127261044489"><a name="p127261044489"></a><a name="p127261044489"></a>Writes data of the number, string, and Boolean types.</p>
</td>
</tr>
</tbody>
</table>
| Class | Method | Description |
| ------- | -------------------------------------------------- | ----------------------------------------------------- |
| Storage | put(key: string, value: ValueType): Promise\<void> | Writes data of the number, string, and Boolean types. |
**Reading Data**
......@@ -64,24 +34,9 @@ Call the **get\(\)** method to read data from a **Storage** instance.
**Table 3** API for reading data
<a name="table182143189350"></a>
<table><thead align="left"><tr id="row173241118123511"><th class="cellrowborder" valign="top" width="18.04%" id="mcps1.2.4.1.1"><p id="p94819229584"><a name="p94819229584"></a><a name="p94819229584"></a>Class</p>
</th>
<th class="cellrowborder" valign="top" width="37.830000000000005%" id="mcps1.2.4.1.2"><p id="p18324181853514"><a name="p18324181853514"></a><a name="p18324181853514"></a>Method</p>
</th>
<th class="cellrowborder" valign="top" width="44.13%" id="mcps1.2.4.1.3"><p id="p11324131814355"><a name="p11324131814355"></a><a name="p11324131814355"></a>Description</p>
</th>
</tr>
</thead>
<tbody><tr id="row18325141813350"><td class="cellrowborder" valign="top" width="18.04%" headers="mcps1.2.4.1.1 "><p id="p1448113223583"><a name="p1448113223583"></a><a name="p1448113223583"></a>Storage</p>
</td>
<td class="cellrowborder" valign="top" width="37.830000000000005%" headers="mcps1.2.4.1.2 "><p id="p1335031410172"><a name="p1335031410172"></a><a name="p1335031410172"></a>get(key: string, defValue: ValueType): Promise&lt;ValueType&gt;;</p>
</td>
<td class="cellrowborder" valign="top" width="44.13%" headers="mcps1.2.4.1.3 "><p id="p11862123993920"><a name="p11862123993920"></a><a name="p11862123993920"></a>Reads data of the number, string, and Boolean types.</p>
</td>
</tr>
</tbody>
</table>
| Class | Method | Description |
| ------- | ---------------------------------------------------------- | ---------------------------------------------------- |
| Storage | get(key: string, defValue: ValueType): Promise\<ValueType> | Reads data of the number, string, and Boolean types. |
**Storing Data Persistently**
......@@ -89,24 +44,9 @@ Call the **flush\(\)** method to write the cached data back to its text file f
**Table 4** API for data persistence
<a name="table1290414100219"></a>
<table><thead align="left"><tr id="row690412101627"><th class="cellrowborder" valign="top" width="18.04%" id="mcps1.2.4.1.1"><p id="p1390414101929"><a name="p1390414101929"></a><a name="p1390414101929"></a>Class</p>
</th>
<th class="cellrowborder" valign="top" width="37.830000000000005%" id="mcps1.2.4.1.2"><p id="p59045104215"><a name="p59045104215"></a><a name="p59045104215"></a>Method</p>
</th>
<th class="cellrowborder" valign="top" width="44.13%" id="mcps1.2.4.1.3"><p id="p1190416106210"><a name="p1190416106210"></a><a name="p1190416106210"></a>Description</p>
</th>
</tr>
</thead>
<tbody><tr id="row99041710923"><td class="cellrowborder" valign="top" width="18.04%" headers="mcps1.2.4.1.1 "><p id="p7904101018217"><a name="p7904101018217"></a><a name="p7904101018217"></a>Storage</p>
</td>
<td class="cellrowborder" valign="top" width="37.830000000000005%" headers="mcps1.2.4.1.2 "><p id="p1290418101218"><a name="p1290418101218"></a><a name="p1290418101218"></a>flush(): Promise&lt;void&gt;;</p>
</td>
<td class="cellrowborder" valign="top" width="44.13%" headers="mcps1.2.4.1.3 "><p id="p1234935810316"><a name="p1234935810316"></a><a name="p1234935810316"></a>Writes data in the <strong id="b263252724411"><a name="b263252724411"></a><a name="b263252724411"></a>Storage</strong> instance back to its file through an asynchronous thread.</p>
</td>
</tr>
</tbody>
</table>
| Class | Method | Description |
| ------- | ----------------------- | ------------------------------------------------------------ |
| Storage | flush(): Promise\<void> | Writes data in the **Storage** instance back to its file through an asynchronous thread. |
**Observing Data Changes**
......@@ -114,31 +54,10 @@ Specify **StorageObserver** as the callback to subscribe to data changes. When
**Table 5** APIs for subscribing to data changes
<a name="table6483954112110"></a>
<table><thead align="left"><tr id="row124847540217"><th class="cellrowborder" valign="top" width="17.849999999999998%" id="mcps1.2.4.1.1"><p id="p1210134212816"><a name="p1210134212816"></a><a name="p1210134212816"></a>Class</p>
</th>
<th class="cellrowborder" valign="top" width="42.34%" id="mcps1.2.4.1.2"><p id="p1848445472111"><a name="p1848445472111"></a><a name="p1848445472111"></a>Method</p>
</th>
<th class="cellrowborder" valign="top" width="39.81%" id="mcps1.2.4.1.3"><p id="p1848475414213"><a name="p1848475414213"></a><a name="p1848475414213"></a>Description</p>
</th>
</tr>
</thead>
<tbody><tr id="row2048513546212"><td class="cellrowborder" valign="top" width="17.849999999999998%" headers="mcps1.2.4.1.1 "><p id="p17210342586"><a name="p17210342586"></a><a name="p17210342586"></a>Storage</p>
</td>
<td class="cellrowborder" valign="top" width="42.34%" headers="mcps1.2.4.1.2 "><p id="p124859540219"><a name="p124859540219"></a><a name="p124859540219"></a>on(type: 'change', callback: Callback&lt;StorageObserver&gt;): void;</p>
</td>
<td class="cellrowborder" valign="top" width="39.81%" headers="mcps1.2.4.1.3 "><p id="p1148505452114"><a name="p1148505452114"></a><a name="p1148505452114"></a>Subscribes to data changes.</p>
</td>
</tr>
<tr id="row24851554182111"><td class="cellrowborder" valign="top" width="17.849999999999998%" headers="mcps1.2.4.1.1 "><p id="p914241031014"><a name="p914241031014"></a><a name="p914241031014"></a>Storage</p>
</td>
<td class="cellrowborder" valign="top" width="42.34%" headers="mcps1.2.4.1.2 "><p id="p9929202151011"><a name="p9929202151011"></a><a name="p9929202151011"></a>off(type: 'change', callback: Callback&lt;StorageObserver&gt;): void;</p>
</td>
<td class="cellrowborder" valign="top" width="39.81%" headers="mcps1.2.4.1.3 "><p id="p54853548219"><a name="p54853548219"></a><a name="p54853548219"></a>Unsubscribes from data changes.</p>
</td>
</tr>
</tbody>
</table>
| Class | Method | Description |
| ------- | ------------------------------------------------------------ | ------------------------------- |
| Storage | on(type: 'change', callback: Callback\<StorageObserver>): void | Subscribes to data changes. |
| Storage | off(type: 'change', callback: Callback\<StorageObserver>): void | Unsubscribes from data changes. |
**Deleting Data**
......@@ -146,33 +65,13 @@ Use the following APIs to delete a **Storage** instance or data file.
**Table 6** APIs for deleting data
<a name="table2445155152418"></a>
<table><thead align="left"><tr id="row164451856244"><th class="cellrowborder" valign="top" width="17.72%" id="mcps1.2.4.1.1"><p id="p8182648181513"><a name="p8182648181513"></a><a name="p8182648181513"></a>Package Name</p>
</th>
<th class="cellrowborder" valign="top" width="43.980000000000004%" id="mcps1.2.4.1.2"><p id="p184461952245"><a name="p184461952245"></a><a name="p184461952245"></a>Method</p>
</th>
<th class="cellrowborder" valign="top" width="38.3%" id="mcps1.2.4.1.3"><p id="p11446652246"><a name="p11446652246"></a><a name="p11446652246"></a>Description</p>
</th>
</tr>
</thead>
<tbody><tr id="row1644616517249"><td class="cellrowborder" valign="top" width="17.72%" headers="mcps1.2.4.1.1 "><p id="p318244815153"><a name="p318244815153"></a><a name="p318244815153"></a>ohos.data.storage</p>
</td>
<td class="cellrowborder" valign="top" width="43.980000000000004%" headers="mcps1.2.4.1.2 "><p id="p194461457246"><a name="p194461457246"></a><a name="p194461457246"></a>deleteStorage(path: string): Promise&lt;void&gt;;</p>
</td>
<td class="cellrowborder" valign="top" width="38.3%" headers="mcps1.2.4.1.3 "><p id="p19291149141220"><a name="p19291149141220"></a><a name="p19291149141220"></a>Deletes a <strong id="b16577722115210"><a name="b16577722115210"></a><a name="b16577722115210"></a>Storage</strong> instance from the cache and deletes its file from the device.</p>
</td>
</tr>
<tr id="row64461551242"><td class="cellrowborder" valign="top" width="17.72%" headers="mcps1.2.4.1.1 "><p id="p1918314488153"><a name="p1918314488153"></a><a name="p1918314488153"></a>ohos.data.storage</p>
</td>
<td class="cellrowborder" valign="top" width="43.980000000000004%" headers="mcps1.2.4.1.2 "><p id="p134467513248"><a name="p134467513248"></a><a name="p134467513248"></a>removeStorageFromCache(path: string): Promise&lt;void&gt;;</p>
</td>
<td class="cellrowborder" valign="top" width="38.3%" headers="mcps1.2.4.1.3 "><p id="p164461159247"><a name="p164461159247"></a><a name="p164461159247"></a>Deletes a <strong id="b12971117115417"><a name="b12971117115417"></a><a name="b12971117115417"></a>Storage</strong> instance from the cache to release memory.</p>
</td>
</tr>
</tbody>
</table>
## How to Develop<a name="section146940394256"></a>
| Package Name | Method | Description |
| ----------------- | ---------------------------------------------------- | ------------------------------------------------------------ |
| ohos.data.storage | deleteStorage(path: string): Promise\<void> | Deletes a **Storage** instance from the cache and deletes its file from the device. |
| ohos.data.storage | removeStorageFromCache(path: string): Promise\<void> | Deletes a **Storage** instance from the cache to release memory. |
## How to Develop
1. Import **@ohos.data.storage** and related modules to the development environment.
......@@ -192,7 +91,7 @@ Use the following APIs to delete a **Storage** instance or data file.
```
1. Write data.
3. Write data.
Use the **put\(\)** method of the **Storage** class to write data to the cached **Storage** instance.
......@@ -210,7 +109,7 @@ Use the following APIs to delete a **Storage** instance or data file.
```
1. Read data.
4. Read data.
Use the **get\(\)** method of the **Storage** class to read data.
......@@ -228,7 +127,7 @@ Use the following APIs to delete a **Storage** instance or data file.
```
1. Store data persistently.
5. Store data persistently.
Use the **flush** or **flushSync** method to flush data in the **Storage** instance to its file.
......@@ -236,7 +135,7 @@ Use the following APIs to delete a **Storage** instance or data file.
storage.flush();
```
2. Observe data changes.
6. Observe data changes.
Specify **StorageObserver** as the callback to subscribe to data changes for an application. When the value of the subscribed key is changed and the **flush\(\)** method is executed, **StorageObserver** will be invoked. Unregister the **StorageObserver** when it is no longer required.
......@@ -256,7 +155,7 @@ Use the following APIs to delete a **Storage** instance or data file.
```
1. Delete the specified file.
7. Delete the specified file.
Use the **deleteStorage** method to delete the **Storage** singleton of the specified file from the memory, and delete the specified file, its backup file, and damaged files. After the specified files are deleted, the application cannot use that instance to perform any data operation. Otherwise, data inconsistency will occur. The deleted data and files cannot be restored.
......@@ -269,4 +168,3 @@ Use the following APIs to delete a **Storage** instance or data file.
})
```
en/application-dev/device/usb-guidelines.md
浏览文件 @ 9d98721b
# USB Service Development<a name="EN-US_TOPIC_0000001177435986"></a>
# USB Service Development
## When to Use<a name="section312612461984"></a>
## When to Use
In Host mode, you can obtain the list of connected devices, enable or disable the devices, manage device access permissions, and perform data transfer or control transfer.
## APIs<a name="section912mcpsimp"></a>
## APIs
The USB service provides the following functions: query of USB device list, bulk data transfer, control transfer, and access permission management.
The following table lists the USB APIs currently available. For details, see the _API Reference_.
The following table lists the USB APIs currently available. For details, see the [API Reference](../reference/apis/js-apis-usb.md).
**Table 1** Open USB APIs
<a name="table948mcpsimp"></a>
<table><thead align="left"><tr id="row954mcpsimp"><th class="cellrowborder" valign="top" width="58.589999999999996%" id="mcps1.2.3.1.1"><p id="p956mcpsimp"><a name="p956mcpsimp"></a><a name="p956mcpsimp"></a>API</p>
</th>
<th class="cellrowborder" valign="top" width="41.410000000000004%" id="mcps1.2.3.1.2"><p id="p958mcpsimp"><a name="p958mcpsimp"></a><a name="p958mcpsimp"></a>Description</p>
</th>
</tr>
</thead>
<tbody><tr id="row960mcpsimp"><td class="cellrowborder" valign="top" width="58.589999999999996%" headers="mcps1.2.3.1.1 "><p id="p763891054416"><a name="p763891054416"></a><a name="p763891054416"></a>hasRight(deviceName: string): boolean</p>
</td>
<td class="cellrowborder" valign="top" width="41.410000000000004%" headers="mcps1.2.3.1.2 "><p id="p8666818458"><a name="p8666818458"></a><a name="p8666818458"></a>Checks whether the user, for example, the application or system, has the device access permissions. The value <strong id="b106930333555"><a name="b106930333555"></a><a name="b106930333555"></a>true</strong> is returned if the user has the device access permissions; the value <strong id="b72426431937"><a name="b72426431937"></a><a name="b72426431937"></a>false</strong> is returned otherwise.</p>
</td>
</tr>
<tr id="row965mcpsimp"><td class="cellrowborder" valign="top" width="58.589999999999996%" headers="mcps1.2.3.1.1 "><p id="p1063810103448"><a name="p1063810103448"></a><a name="p1063810103448"></a>requestRight(deviceName: string): Promise&lt;boolean&gt;</p>
</td>
<td class="cellrowborder" valign="top" width="41.410000000000004%" headers="mcps1.2.3.1.2 "><p id="p18677811454"><a name="p18677811454"></a><a name="p18677811454"></a>Requests the temporary permission for a given application to access the USB device.</p>
</td>
</tr>
<tr id="row970mcpsimp"><td class="cellrowborder" valign="top" width="58.589999999999996%" headers="mcps1.2.3.1.1 "><p id="p196381710194415"><a name="p196381710194415"></a><a name="p196381710194415"></a>connectDevice(device: USBDevice): Readonly&lt;USBDevicePipe&gt;</p>
</td>
<td class="cellrowborder" valign="top" width="41.410000000000004%" headers="mcps1.2.3.1.2 "><p id="p467178204510"><a name="p467178204510"></a><a name="p467178204510"></a>Connects to the USB device based on the device information returned by <strong id="b191413527412"><a name="b191413527412"></a><a name="b191413527412"></a>getDevices()</strong>.</p>
</td>
</tr>
<tr id="row975mcpsimp"><td class="cellrowborder" valign="top" width="58.589999999999996%" headers="mcps1.2.3.1.1 "><p id="p8638171010441"><a name="p8638171010441"></a><a name="p8638171010441"></a>getDevices(): Array&lt;Readonly&lt;USBDevice&gt;&gt;</p>
</td>
<td class="cellrowborder" valign="top" width="41.410000000000004%" headers="mcps1.2.3.1.2 "><p id="p176715864514"><a name="p176715864514"></a><a name="p176715864514"></a>Obtains the USB device list.</p>
</td>
</tr>
<tr id="row1551153313610"><td class="cellrowborder" valign="top" width="58.589999999999996%" headers="mcps1.2.3.1.1 "><p id="p156381410184417"><a name="p156381410184417"></a><a name="p156381410184417"></a>setConfiguration(pipe: USBDevicePipe, config: USBConfig): number</p>
</td>
<td class="cellrowborder" valign="top" width="41.410000000000004%" headers="mcps1.2.3.1.2 "><p id="p126812817456"><a name="p126812817456"></a><a name="p126812817456"></a>Sets the USB device configuration.</p>
</td>
</tr>
<tr id="row1393711361263"><td class="cellrowborder" valign="top" width="58.589999999999996%" headers="mcps1.2.3.1.1 "><p id="p1563812109442"><a name="p1563812109442"></a><a name="p1563812109442"></a>setInterface(pipe: USBDevicePipe, iface: USBInterface): number</p>
</td>
<td class="cellrowborder" valign="top" width="41.410000000000004%" headers="mcps1.2.3.1.2 "><p id="p136868164513"><a name="p136868164513"></a><a name="p136868164513"></a>Sets a USB interface.</p>
</td>
</tr>
<tr id="row149651544154717"><td class="cellrowborder" valign="top" width="58.589999999999996%" headers="mcps1.2.3.1.1 "><p id="p991359174910"><a name="p991359174910"></a><a name="p991359174910"></a>claimInterface(pipe: USBDevicePipe, iface: USBInterface, force?: boolean): number</p>
</td>
<td class="cellrowborder" valign="top" width="41.410000000000004%" headers="mcps1.2.3.1.2 "><p id="p20859028134917"><a name="p20859028134917"></a><a name="p20859028134917"></a>Claims a USB interface</p>
</td>
</tr>
<tr id="row115717481477"><td class="cellrowborder" valign="top" width="58.589999999999996%" headers="mcps1.2.3.1.1 "><p id="p17913393493"><a name="p17913393493"></a><a name="p17913393493"></a>function bulkTransfer(pipe: USBDevicePipe, endpoint: USBEndpoint, buffer: Uint8Array, timeout?: number): Promise&lt;number&gt;</p>
</td>
<td class="cellrowborder" valign="top" width="41.410000000000004%" headers="mcps1.2.3.1.2 "><p id="p1786016281498"><a name="p1786016281498"></a><a name="p1786016281498"></a>Performs bulk transfer.</p>
</td>
</tr>
<tr id="row1042013527474"><td class="cellrowborder" valign="top" width="58.589999999999996%" headers="mcps1.2.3.1.1 "><p id="p19913596492"><a name="p19913596492"></a><a name="p19913596492"></a>closePipe(pipe: USBDevicePipe): number</p>
</td>
<td class="cellrowborder" valign="top" width="41.410000000000004%" headers="mcps1.2.3.1.2 "><p id="p686013285492"><a name="p686013285492"></a><a name="p686013285492"></a>Closes a USB device pipe.</p>
</td>
</tr>
<tr id="row954011574471"><td class="cellrowborder" valign="top" width="58.589999999999996%" headers="mcps1.2.3.1.1 "><p id="p491315910499"><a name="p491315910499"></a><a name="p491315910499"></a>releaseInterface(pipe: USBDevicePipe, iface: USBInterface): number</p>
</td>
<td class="cellrowborder" valign="top" width="41.410000000000004%" headers="mcps1.2.3.1.2 "><p id="p14860202813493"><a name="p14860202813493"></a><a name="p14860202813493"></a>Releases a USB interface.</p>
</td>
</tr>
<tr id="row1475577184811"><td class="cellrowborder" valign="top" width="58.589999999999996%" headers="mcps1.2.3.1.1 "><p id="p69131096493"><a name="p69131096493"></a><a name="p69131096493"></a>getFileDescriptor(pipe: USBDevicePipe): number</p>
</td>
<td class="cellrowborder" valign="top" width="41.410000000000004%" headers="mcps1.2.3.1.2 "><p id="p16860202864913"><a name="p16860202864913"></a><a name="p16860202864913"></a>Obtains the file descriptor.</p>
</td>
</tr>
<tr id="row074819259481"><td class="cellrowborder" valign="top" width="58.589999999999996%" headers="mcps1.2.3.1.1 "><p id="p891416916496"><a name="p891416916496"></a><a name="p891416916496"></a>getRawDescriptor(pipe: USBDevicePipe): Uint8Array</p>
</td>
<td class="cellrowborder" valign="top" width="41.410000000000004%" headers="mcps1.2.3.1.2 "><p id="p486042804917"><a name="p486042804917"></a><a name="p486042804917"></a>Obtains the raw USB descriptor.</p>
</td>
</tr>
<tr id="row1557362913482"><td class="cellrowborder" valign="top" width="58.589999999999996%" headers="mcps1.2.3.1.1 "><p id="p129141944919"><a name="p129141944919"></a><a name="p129141944919"></a>controlTransfer(pipe: USBDevicePipe, contrlparam: USBControlParams, timeout?: number): Promise&lt;number&gt;</p>
</td>
<td class="cellrowborder" valign="top" width="41.410000000000004%" headers="mcps1.2.3.1.2 "><p id="p78605286493"><a name="p78605286493"></a><a name="p78605286493"></a>Performs control transfer.</p>
</td>
</tr>
</tbody>
</table>
## How to Develop<a name="section980mcpsimp"></a>
| API | Description |
| ------------------------------------------------------------ | ------------------------------------------------------------ |
| hasRight(deviceName: string): boolean | Checks whether the user, for example, the application or system, has the device access permissions. The value **true** is returned if the user has the device access permissions; the value **false** is returned otherwise. |
| requestRight(deviceName: string): Promise\<boolean> | Requests the temporary permission for a given application to access the USB device. |
| connectDevice(device: USBDevice): Readonly\<USBDevicePipe> | Connects to the USB device based on the device information returned by **getDevices()**. |
| getDevices(): Array<Readonly\<USBDevice>> | Obtains the USB device list. |
| setConfiguration(pipe: USBDevicePipe, config: USBConfig): number | Sets the USB device configuration. |
| setInterface(pipe: USBDevicePipe, iface: USBInterface): number | Sets a USB interface. |
| claimInterface(pipe: USBDevicePipe, iface: USBInterface, force?: boolean): number | Claims a USB interface. |
| function bulkTransfer(pipe: USBDevicePipe, endpoint: USBEndpoint, buffer: Uint8Array, timeout?: number): Promise\<number> | Performs bulk transfer. |
| closePipe(pipe: USBDevicePipe): number | Closes a USB device pipe. |
| releaseInterface(pipe: USBDevicePipe, iface: USBInterface): number | Releases a USB interface. |
| getFileDescriptor(pipe: USBDevicePipe): number | Obtains the file descriptor. |
| getRawDescriptor(pipe: USBDevicePipe): Uint8Array | Obtains the raw USB descriptor. |
| controlTransfer(pipe: USBDevicePipe, contrlparam: USBControlParams, timeout?: number): Promise\<number> | Performs control transfer. |
## How to Develop
You can set a USB device as a host to connect to a device for data transfer. The development procedure is as follows:
......@@ -211,6 +152,4 @@ You can set a USB device as a host to connect to a device for data transfer. The
```js
usb.releaseInterface(pipe, interface);
usb.closePipe(pipe);
```
```
\ No newline at end of file
Markdown is supported
0% 或 .
You are about to add 0 people to the discussion. Proceed with caution.
先完成此消息的编辑！
想要评论请 注册 或