exception in UsbManager.openDevice
时间: 2024-03-26 22:41:20 浏览: 18
这个异常通常是由于没有正确的USB权限导致的。在AndroidManifest.xml文件中添加以下行:
```xml
<uses-permission android:name="android.permission.USB_PERMISSION" />
```
然后在Java代码中,你需要请求USB权限:
```java
UsbManager usbManager = (UsbManager) getSystemService(Context.USB_SERVICE);
PendingIntent permissionIntent = PendingIntent.getBroadcast(this, 0, new Intent("com.android.example.USB_PERMISSION"), 0);
usbManager.requestPermission(device, permissionIntent);
```
请确保在请求USB权限之前,你已经获取了对USB设备的访问权限。这可以通过以下代码来实现:
```java
UsbDevice device = (UsbDevice) intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
if (usbManager.hasPermission(device)) {
// 已经有权限了,可以直接访问USB设备
} else {
// 没有权限,需要请求权限
}
```
相关问题
java中usbmanager_【已解决】android程序运行出错:UsbManager(4294): exception in UsbManager.openDevice,java.lang.Se...
这个错误通常是由于没有正确的USB权限导致的。在AndroidManifest.xml文件中添加以下行:
```xml
<uses-permission android:name="android.permission.USB_PERMISSION" />
```
然后在Java代码中,你需要请求USB权限:
```java
UsbManager usbManager = (UsbManager) getSystemService(Context.USB_SERVICE);
PendingIntent permissionIntent = PendingIntent.getBroadcast(this, 0, new Intent("com.android.example.USB_PERMISSION"), 0);
usbManager.requestPermission(device, permissionIntent);
```
请确保在请求USB权限之前,你已经获取了对USB设备的访问权限。这可以通过以下代码来实现:
```java
UsbDevice device = (UsbDevice) intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
if (usbManager.hasPermission(device)) {
// 已经有权限了,可以直接访问USB设备
} else {
// 没有权限,需要请求权限
}
```
nested exception is org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.
nested exception is org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.exceptions.PersistenceException:
Error querying database. Cause: org.apache.ibatis.executor.ExecutorException: A query was run and no Result Maps were found for the Mapped Statement 'com.example.mapper.UserMapper.getUserById'. It's likely that neither a Result Type nor a Result Map was specified.
Cause: org.apache.ibatis.executor.ExecutorException: A query was run and no Result Maps were found for the Mapped Statement 'com.example.mapper.UserMapper.getUserById'. It's likely that neither a Result Type nor a Result Map was specified.
This exception is thrown when there is an issue with executing a query using MyBatis framework. In this case, the nested exception is org.apache.ibatis.exceptions.PersistenceException, which indicates that there was an error querying the database.
The specific error message states that no Result Maps were found for the Mapped Statement 'com.example.mapper.UserMapper.getUserById'. This means that either a Result Type or a Result Map was not specified for the query.
To resolve this issue, you need to make sure that the appropriate Result Type or Result Map is specified for the query in the MyBatis mapping file (XML) or in the annotation-based configuration.
相关推荐
![pdf](https://img-home.csdnimg.cn/images/20210720083512.png)
![zip](https://img-home.csdnimg.cn/images/20210720083736.png)
![zip](https://img-home.csdnimg.cn/images/20210720083736.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)