ver1.00.00

update

lib/tool/cacheImage.dart

@@ -0,0 +1,194 @@
+import 'dart:io';
+import 'dart:convert';
+import 'package:flutter/foundation.dart';
+import 'package:flutter/material.dart';
+import 'package:dio/dio.dart';
+import 'package:path_provider/path_provider.dart';
+import 'package:crypto/crypto.dart';
+import 'package:path/path.dart' as p;
+
+/// 一个支持自动 Dio 缓存的 Image 组件
+/// 用法完全对齐 Image.network(url)
+class CacheImage extends StatefulWidget {
+  final String url;
+  final double? width;
+  final double? height;
+  final BoxFit? fit;
+  final double scale;
+  final AlignmentGeometry alignment;
+  final ImageRepeat repeat;
+  final FilterQuality filterQuality;
+  final Color? color;
+  final BlendMode? colorBlendMode;
+  final ImageLoadingBuilder? loadingBuilder;
+  final ImageErrorWidgetBuilder? errorBuilder;
+  final bool matchTextDirection;
+
+  // 使用位置参数接收 url，其余为可选命名参数
+  const CacheImage.network(
+      this.url, {
+        Key? key,
+        this.width,
+        this.height,
+        this.fit,
+        this.scale = 1.0,
+        this.alignment = Alignment.center,
+        this.repeat = ImageRepeat.noRepeat,
+        this.filterQuality = FilterQuality.low,
+        this.color,
+        this.colorBlendMode,
+        this.loadingBuilder,
+        this.errorBuilder,
+        this.matchTextDirection = false,
+      }) : super(key: key);
+
+  @override
+  State<CacheImage> createState() => _CacheImageState();
+}
+
+class _CacheImageState extends State<CacheImage> {
+  File? _localFile;
+  bool _isInit = false;
+
+  /// 统一日志工具（支持发布/调试环境）
+  void _log(String message, {bool isError = false}) {
+    // 发布环境只打印错误日志，调试环境全部打印
+    if (kReleaseMode) {
+      if (isError) {
+        print('[CacheImage-ERROR] $message');
+      }
+    } else {
+      final tag = isError ? '[CacheImage-ERROR]' : '[CacheImage-INFO]';
+      print('$tag $message');
+    }
+  }
+
+  @override
+  void initState() {
+    super.initState();
+    _log('图片组件初始化，URL: ${widget.url}');
+    _handleCache();
+  }
+
+  // 当外部传入的 url 发生变化时，重新触发缓存逻辑
+  @override
+  void didUpdateWidget(CacheImage oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    if (oldWidget.url != widget.url) {
+      _log('URL 发生变化，重新加载缓存\n旧URL: ${oldWidget.url}\n新URL: ${widget.url}');
+      _handleCache();
+    }
+  }
+
+  Future<void> _handleCache() async {
+    try {
+      _log('开始处理图片缓存逻辑，URL: ${widget.url}');
+
+      // 1. 生成唯一文件名 (MD5)
+      final String fileName = md5.convert(utf8.encode(widget.url)).toString();
+      _log('生成文件MD5: $fileName');
+
+      // 获取临时目录 (建议缓存放在临时目录，由系统根据空间决定是否清理)
+      final Directory cacheDir = await getTemporaryDirectory();
+      final File file = File(p.join(cacheDir.path, 'image_cache', fileName));
+      _log('本地缓存路径: ${file.path}');
+
+      // 2. 检查本地是否存在
+      if (await file.exists()) {
+        _log('✅ 本地缓存已存在，直接加载本地文件');
+        if (mounted) {
+          setState(() {
+            _localFile = file;
+            _isInit = true;
+          });
+        }
+        return;
+      }
+
+      // 3. 本地不存在，使用 Dio 下载
+      _log('ℹ️ 本地无缓存，开始从网络下载图片');
+      final dio = Dio();
+      final response = await dio.get(
+        widget.url,
+        options: Options(responseType: ResponseType.bytes),
+      );
+      _log('✅ 图片下载完成，数据大小: ${response.data.length} bytes');
+
+      // 4. 尝试保存到本地 (Quiet Mode: 失败仅打印，不抛出异常)
+      try {
+        await file.parent.create(recursive: true);
+        await file.writeAsBytes(response.data);
+        _log('✅ 图片成功保存到本地缓存');
+        if (mounted) {
+          setState(() {
+            _localFile = file;
+          });
+        }
+      } catch (e) {
+        _log('❌ 本地保存失败 (不影响显示): $e', isError: true);
+      }
+    } catch (e) {
+      _log('❌ 下载或逻辑处理失败: $e', isError: true);
+    } finally {
+      if (mounted) {
+        setState(() => _isInit = true);
+      }
+      _log('🏁 图片缓存逻辑执行完成');
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    // 如果本地文件已就绪，直接加载本地文件
+    if (_localFile != null) {
+      _log('使用本地缓存图片渲染');
+      return Image.file(
+        _localFile!,
+        key: widget.key,
+        width: widget.width,
+        height: widget.height,
+        fit: widget.fit,
+        alignment: widget.alignment,
+        repeat: widget.repeat,
+        filterQuality: widget.filterQuality,
+        color: widget.color,
+        colorBlendMode: widget.colorBlendMode,
+        matchTextDirection: widget.matchTextDirection,
+        // 如果文件读取过程中出错，尝试回退到网络或报错组件
+        errorBuilder: widget.errorBuilder ?? (context, error, stack) {
+          _log('❌ 本地图片加载失败，回退到网络加载', isError: true);
+          return _buildNetworkImage();
+        },
+      );
+    }
+
+    // 默认或下载中，渲染网络图片
+    _log('使用网络图片渲染（加载中/无缓存）');
+    return _buildNetworkImage();
+  }
+
+  Widget _buildNetworkImage() {
+    return Image.network(
+      widget.url,
+      key: widget.key,
+      width: widget.width,
+      height: widget.height,
+      fit: widget.fit,
+      scale: widget.scale,
+      alignment: widget.alignment,
+      repeat: widget.repeat,
+      filterQuality: widget.filterQuality,
+      color: widget.color,
+      colorBlendMode: widget.colorBlendMode,
+      matchTextDirection: widget.matchTextDirection,
+      loadingBuilder: widget.loadingBuilder,
+      errorBuilder: (context, error, stack) {
+        _log('❌ 网络图片加载失败: $error', isError: true);
+        if (widget.errorBuilder != null) {
+          return widget.errorBuilder!(context, error, stack);
+        }
+        return const SizedBox();
+      },
+    );
+  }
+}