data() {
            return {
                fileSizeString: "", // 缓存总数
            }
        },
                 
// 计算缓存
            formatSize() {
                console.log(123)
                let that = this;
                plus.cache.calculate(function(size) {
                    let sizeCache = parseInt(size);
                    if (sizeCache == 0) {
                        that.fileSizeString = "0B";
                    } else if (sizeCache < 1024) {
                        that.fileSizeString = sizeCache + "B";
                    } else if (sizeCache < 1048576) {
                        that.fileSizeString = (sizeCache / 1024).toFixed(2) + "KB";
                    } else if (sizeCache < 1073741824) {
                        that.fileSizeString = (sizeCache / 1048576).toFixed(2) + "MB";
                    } else {
                        that.fileSizeString = (sizeCache / 1073741824).toFixed(2) + "GB";
                    }
                });
            },
            // 清理缓存
            clearCache() {
                let that = this;
                let os = plus.os.name;
                if (os == 'Android') {
                    let main = plus.android.runtimeMainActivity();
                    let sdRoot = main.getCacheDir();
                    let files = plus.android.invoke(sdRoot, "listFiles");
                    let len = files.length;
                    for (let i = 0; i < len; i++) {
                        let filePath = '' + files[i]; // 没有找到合适的方法获取路径，这样写可以转成文件路径 
                        plus.io.resolveLocalFileSystemURL(filePath, function(entry) {
                            if (entry.isDirectory) {
                                entry.removeRecursively(function(entry) { //递归删除其下的所有文件及子目录 
                                    uni.showToast({
                                        title: '缓存清理完成',
                                        duration: 2000
                                    });
                                    that.formatSize(); // 重新计算缓存 
                                }, function(e) {
                                    console.log(e.message)
                                });
                            } else {
                                entry.remove();
                            }
                        }, function(e) {
                            console.log('文件路径读取失败')
                        });
                    }
                } else { // ios 
                    plus.cache.clear(function() {
                        uni.showToast({
                            title: '缓存清理完成',
                            duration: 2000
                        });
                        that.formatSize();
                    });
                }
            },