uni-app java.lang.NoClassDefFoundError: Failed resolution of: Ljava/nio/file/Paths;

对, 我可以自己实现 wgt的解压缩, 我只是想问文档上既然支持到 andorid 21, 那sdk里写的时候, 要么判断一下android版本号, 要么就干脆用 1.7的api去写, 难道这个不算bug么, 如果不fix, 那请你们更新文档, 说支持android O+呀

Java11应该是向下兼容Java8的，后台看依然有报错。

The error java.lang.NoClassDefFoundError: Failed resolution of: Ljava/nio/file/Paths; typically occurs in a Java or Android environment when the specified class (java.nio.file.Paths) cannot be found or loaded at runtime. This issue can arise for several reasons, especially in the context of uni-app or Android development.

Possible Causes and Solutions:

1. Java Version Compatibility:

   • The java.nio.file.Paths class is part of the Java NIO (New I/O) package, which was introduced in Java 7. If you’re using an older version of Java (e.g., Java 6 or earlier), this class will not be available.
   • Solution: Ensure that your project is using Java 7 or later. In Android Studio, you can configure the Java version in your build.gradle file:

     android {
         compileOptions {
             sourceCompatibility JavaVersion.VERSION_1_8
             targetCompatibility JavaVersion.VERSION_1_8
         }
     }
     

2. Android API Level:

   • The java.nio.file package is not fully supported on older Android devices. The Paths class is part of the java.nio.file package, which was introduced in Android API level 26 (Android 8.0).
   • Solution: If you’re targeting older Android versions (below API 26), you cannot use java.nio.file.Paths. Instead, use alternative methods for file handling, such as java.io.File.

3. ProGuard/R8 Configuration:

   • If you’re using ProGuard or R8 for code shrinking and obfuscation, it might be removing or obfuscating the java.nio.file.Paths class.
   • Solution: Add a rule to your proguard-rules.pro file to keep the java.nio.file.Paths class:

     -keep class java.nio.file.Paths { *; }
     

4. Missing Dependencies:

   • Ensure that all necessary dependencies are included in your project. If you’re using a library that relies on java.nio.file.Paths, make sure it’s properly added to your build.gradle file.
   • Solution: Verify and add any missing dependencies.

5. Uni-App Specific Issues:

   • Uni-app is a cross-platform framework, and if you’re encountering this issue in a uni-app project, it might be related to the native Android code or plugins you’re using.
   • Solution: Check if any native Android plugins or modules in your uni-app project are using java.nio.file.Paths. If so, ensure they are compatible with your target Android API level.

Example of Alternative Implementation:

If you cannot use java.nio.file.Paths due to compatibility issues, you can use java.io.File for basic file operations. For example:

import java.io.File;

public class FileExample {
    public static void main(String[] args) {
        File file = new File("path/to/your/file.txt");
        if (file.exists()) {
            System.out.println("File exists!");
        } else {
            System.out.println("File does not exist.");
        }
    }
}