我用下面的代码保存一个图像。

val cw = ContextWrapper(applicationContext)
val directory =
        cw.getDir("imageDir", Context.MODE_PRIVATE)
val file = File(directory, Utility().replaceSpaces(categoryName) + ".png")
if (!file.exists()) {
Log.d("path", file.toString())
var fos: FileOutputStream? = null
try {
     fos = FileOutputStream(file)
     bitmap.compress(Bitmap.CompressFormat.PNG, 100, fos)
     fos.flush()
     fos.close()
     } catch (e: IOException) {
         e.printStackTrace()
     }
}

我使用以下代码检索图像。

val uri =
    if (category.isEmpty()) "@drawable/appicon"
    else "@drawable/${Utility().replaceSpaces(category)}"
var image = resources.getIdentifier(uri, null, packageName)

if (image == 0)
    image = resources.getIdentifier("@drawable/appicon", null, packageName)

val imageView = ImageView(this)

检索图像时，图像始终为0