uni-app 获取和清除缓存

data() {
    return {
      fileSizeString: "", // 缓存总数
    }
  },

 methods: {
      // 计算缓存
    getStorageSize() {
      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) + "K";
        } else if (sizeCache < 1073741824) {
          that.fileSizeString = (sizeCache / 1048576).toFixed(2) + "M";
        } else {
          that.fileSizeString = (sizeCache / 1073741824).toFixed(2) + "G";
        }
      });
    },
    // 清理缓存
    clearStorage() {
      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.getStorageSize(); // 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.getStorageSize();
        });
      }
    },
}