Cannot resolve symbol 'PAPER_OUT

如果在 Java 代码中出现了 "Cannot resolve symbol 'PAPER_OUT'" 的错误，说明在代码中使用了不存在的常量或类。

在上面的示例代码中，使用了 PrinterStateReason.PAPER_OUT 来表示打印机的缺纸状态。但是，如果没有正确导入 javax.print.attribute.standard 包，就会出现该错误。

请确保在代码中正确导入 javax.print.attribute.standard 包，例如：

import javax.print.*;
import javax.print.attribute.*;
import javax.print.attribute.standard.*;
import java.util.*;

如果还是出现了该错误，请检查是否正确地拼写了常量名和类名。

相关问题

Cannot resolve symbol 'ACTION_USB_STATE'

`ACTION_USB_STATE` is a constant defined in the `android.hardware.usb.UsbManager` class. It is used to broadcast USB state changes. If you are getting the error "Cannot resolve symbol 'ACTION_USB_STATE'", it means that you haven't imported the necessary class or there might be an issue with your Android project configuration.

To resolve this issue, make sure you have the following import statement at the top of your Java file:

import android.hardware.usb.UsbManager;

Also, ensure that you have the necessary permissions declared in your AndroidManifest.xml file:

<uses-permission android:name="android.permission.USB_PERMISSION" />

If you have already done these steps and still encounter the issue, try cleaning and rebuilding your project or restarting your IDE.

Cannot resolve symbol 'WRITE_EXTERNAL_STORAGE'

This error typically occurs when you are trying to use the WRITE_EXTERNAL_STORAGE permission in your Android application but have not declared it in the AndroidManifest.xml file.

To resolve this error, add the following line of code to your AndroidManifest.xml file:

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

This will declare the WRITE_EXTERNAL_STORAGE permission and allow your application to write to external storage.