如何从电晕sdk中的SD卡加载图像

Question

如何使用电晕sdk从SD卡或手机存储器显示图像？`

Answer 1

可以使用Android上的LFS和IO API在SD卡上读取和写入文件.

要访问内置内存中的手机,请添加android权限"android.permission.WRITE_EXTERNAL_STORAGE"并将路径设置为"/".从那里你可以访问记忆卡.

例:

local lfs = require("lfs")
local path = "/"
local pathType = ""

-- Check to see if path exists
if path and lfs.attributes( path ) then
    pathType = lfs.attributes( path ).mode
end

-- Check if path is a directory
if pathType == "directory" then
   for file in lfs.dir( path ) do
       if "." ~= file and ".." ~= file then
          -- Get the file attributes.
          local fileAtr = lfs.attributes( path .. "/" .. file )
          -- Print path, name and type of file (Directory or file)
          print(path,file,fileAtr.mode)
       end
    end
end

这将在终端窗口中打印文件的路径,文件名和类型.(仅在Mac和Android设备上测试过.)

我找到了一种在Android和模拟器上的沙箱外显示图像的方法.(未经过PC测试)

例:

local lfs = require("lfs")
    --------------------------- Change this path ---------------------------
local path = "path/to/the/image.jpg"                                    -- Change this path to the path of an image on your computer
------------------------------------------------------------------------


local tmpPath = system.pathForFile("tmp.jpg",system.TemporaryDirectory) -- Destination path to the temporary image

--------------------------- Read ----------------------------
local file, reason = io.open( path, "r" )                               -- Open the image in read mode
local contents
if file then
    contents = file:read( "*a" )                                        -- Read contents
    io.close( file )                                                    -- Close the file (Important!)
else
    print("Invalid path")
    return
end

--------------------------- Write ----------------------------

local file = io.open( tmpPath, "w" )                                    -- Open the destination path in write mode
if file then
    file:write(contents)                                                -- Writes the contents to a file
    io.close(file)                                                      -- Close the file (Important!)
else
    print("Error")
    return
end

---------------------- Open and remove -----------------------
local img = display.newImage("tmp.jpg",system.TemporaryDirectory)       -- Display the image from the temporary directory
os.remove(tmpPath)                                                      -- Removes the image, so that we can load another image.