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Added in API level 12

Summary: Methods | Inherited Methods | [Expand All]

UsbDeviceConnection

public class UsbDeviceConnection
extends Object

java.lang.Object
↳	android.hardware.usb.UsbDeviceConnection

该类用于向USB设备发送和接收数据和控制消息。这个类的实例由openDevice(UsbDevice)创建。

Summary

Public methods
`int`	`bulkTransfer(UsbEndpoint endpoint, byte[] buffer, int offset, int length, int timeout)` 在给定端点上执行批量事务。
`int`	`bulkTransfer(UsbEndpoint endpoint, byte[] buffer, int length, int timeout)` 在给定端点上执行批量事务。
`boolean`	`claimInterface(UsbInterface intf, boolean force)` 声明独家访问 `UsbInterface` 。
`void`	`close()` 释放与设备相关的所有系统资源。
`int`	`controlTransfer(int requestType, int request, int value, int index, byte[] buffer, int offset, int length, int timeout)` 对此设备执行端点零控制事务。
`int`	`controlTransfer(int requestType, int request, int value, int index, byte[] buffer, int length, int timeout)` 对此设备执行端点零控制事务。
`int`	`getFileDescriptor()` 返回设备的本机文件描述符，如果设备未打开，则返回-1。
`byte[]`	`getRawDescriptors()` 返回设备的原始USB描述符。
`String`	`getSerial()` 返回设备的序列号。
`boolean`	`releaseInterface(UsbInterface intf)` 发布独家访问权限 `UsbInterface` 。
`UsbRequest`	`requestWait()` 等待 `queue(ByteBuffer, int)`操作的结果请注意，这可能会返回排队在多个 `UsbEndpoint`的请求。
`boolean`	`setConfiguration(UsbConfiguration configuration)` 设置设备当前的 `UsbConfiguration` 。
`boolean`	`setInterface(UsbInterface intf)` 设置当前 `UsbInterface` 。

Inherited methods

From class java.lang.Object

Public methods

bulkTransfer

Added in API level 18

int bulkTransfer (UsbEndpoint endpoint, 
                byte[] buffer, 
                int offset, 
                int length, 
                int timeout)

在给定端点上执行批量事务。传输的方向取决于端点的方向。

Parameters
`endpoint`	`UsbEndpoint`: the endpoint for this transaction
`buffer`	`byte`: buffer for data to send or receive
`offset`	`int`: the index of the first byte in the buffer to send or receive
`length`	`int`: the length of the data to send or receive
`timeout`	`int`: in milliseconds

Returns
`int`	length of data transferred (or zero) for success, or negative value for failure

bulkTransfer

Added in API level 12

int bulkTransfer (UsbEndpoint endpoint, 
                byte[] buffer, 
                int length, 
                int timeout)

在给定端点上执行批量事务。传输的方向取决于端点的方向。

该方法从缓冲区中的索引0开始传输数据。要指定不同的偏移量，请使用bulkTransfer(UsbEndpoint, byte[], int, int, int) 。

Parameters
`endpoint`	`UsbEndpoint`: the endpoint for this transaction
`buffer`	`byte`: buffer for data to send or receive
`length`	`int`: the length of the data to send or receive
`timeout`	`int`: in milliseconds

Returns
`int`	length of data transferred (or zero) for success, or negative value for failure

claimInterface

Added in API level 12

boolean claimInterface (UsbInterface intf, 
                boolean force)

声明独家访问UsbInterface 。这必须在发送或接收属于接口的任何UsbEndpoint的数据之前完成。

Parameters
`intf`	`UsbInterface`: the interface to claim
`force`	`boolean`: true to disconnect kernel driver if necessary

Returns
`boolean`	true if the interface was successfully claimed

close

Added in API level 12

void close ()

释放与设备相关的所有系统资源。一旦物体关闭，它不能再次使用。客户端必须再次调用openDevice(UsbDevice)以检索新实例以重新建立与设备的通信。

controlTransfer

Added in API level 18

int controlTransfer (int requestType, 
                int request, 
                int value, 
                int index, 
                byte[] buffer, 
                int offset, 
                int length, 
                int timeout)

对此设备执行端点零控制事务。传输方向由请求类型决定。如果requestType＆ USB_ENDPOINT_DIR_MASK是USB_DIR_OUT ，则传输是写入，如果是USB_DIR_IN ，则传输是读取。

Parameters
`requestType`	`int`: request type for this transaction
`request`	`int`: request ID for this transaction
`value`	`int`: value field for this transaction
`index`	`int`: index field for this transaction
`buffer`	`byte`: buffer for data portion of transaction, or null if no data needs to be sent or received
`offset`	`int`: the index of the first byte in the buffer to send or receive
`length`	`int`: the length of the data to send or receive
`timeout`	`int`: in milliseconds

Returns
`int`	length of data transferred (or zero) for success, or negative value for failure

controlTransfer

Added in API level 12

int controlTransfer (int requestType, 
                int request, 
                int value, 
                int index, 
                byte[] buffer, 
                int length, 
                int timeout)

该方法从缓冲区中的索引0开始传输数据。要指定不同的偏移量，请使用controlTransfer(int, int, int, int, byte[], int, int, int) 。

Parameters
`requestType`	`int`: request type for this transaction
`request`	`int`: request ID for this transaction
`value`	`int`: value field for this transaction
`index`	`int`: index field for this transaction
`buffer`	`byte`: buffer for data portion of transaction, or null if no data needs to be sent or received
`length`	`int`: the length of the data to send or receive
`timeout`	`int`: in milliseconds

Returns
`int`	length of data transferred (or zero) for success, or negative value for failure

getFileDescriptor

Added in API level 12

int getFileDescriptor ()

返回设备的本机文件描述符，如果设备未打开，则返回-1。这是为了传递给本机代码来访问设备。

Returns
`int`	the native file descriptor

getRawDescriptors

Added in API level 13

byte[] getRawDescriptors ()

返回设备的原始USB描述符。这可以用来访问不通过更高级别的API直接支持的描述符。

Returns
`byte[]`	raw USB descriptors

getSerial

Added in API level 12

String getSerial ()

返回设备的序列号。如果设备尚未打开，这将返回null。

Returns
`String`	the device serial number

releaseInterface

Added in API level 12

boolean releaseInterface (UsbInterface intf)

发布对 UsbInterface独家访问权限。

Parameters
`intf`	`UsbInterface`

Returns
`boolean`	true if the interface was successfully released

requestWait

Added in API level 12

UsbRequest requestWait ()

等待queue(ByteBuffer, int)操作的结果请注意，这可能会返回排队在多个UsbEndpoint的请求。当使用多个端点时， getEndpoint()和getClientData()可用于确定如何处理此功能的结果。

Returns
`UsbRequest`	a completed USB request, or null if an error occurred

setConfiguration

Added in API level 21

boolean setConfiguration (UsbConfiguration configuration)

设置设备当前的 UsbConfiguration 。

Parameters
`configuration`	`UsbConfiguration`

Returns
`boolean`	true if the configuration was successfully set

setInterface

Added in API level 21

boolean setInterface (UsbInterface intf)

设置当前UsbInterface 。用于在具有相同ID但不同备用设置的两个接口之间进行选择。

Parameters
`intf`	`UsbInterface`

Returns
`boolean`	true if the interface was successfully selected