用函数参数替换重复的代码

我有以下代码，其中包含很多重复..

override fun onOptionsItemSelected(item: MenuItem?): Boolean { when (item?.itemId) { R.id.action_crop -> { val bitmap = capturedReceiptImageView.bitmap val bitmapCropped = BitmapHelper.cropBitmap(bitmap, capturedReceiptImageView.getDimensions()) capturedReceiptImageView.setImageBitmap(bitmapCropped) capturedReceiptImageView.invalidate() bitmap.recycle() } R.id.action_rotate_left -> { val bitmap = capturedReceiptImageView.bitmap val bitmapRotated = BitmapHelper.rotateBitmap(bitmap, -90.0f) capturedReceiptImageView.setImageBitmap(bitmapRotated) capturedReceiptImageView.invalidate() bitmap.recycle() } R.id.action_rotate_right -> { val bitmap = capturedReceiptImageView.bitmap val bitmapRotated = BitmapHelper.rotateBitmap(bitmap, 90.0f) capturedReceiptImageView.setImageBitmap(bitmapRotated) capturedReceiptImageView.invalidate() bitmap.recycle() } R.id.action_increase_contrast -> { val bitmap = capturedReceiptImageView.bitmap val bitmapChangedContrast = BitmapHelper.changeBitmapContrast(bitmap, 1.10f) capturedReceiptImageView.setImageBitmap(bitmapChangedContrast) capturedReceiptImageView.invalidate() bitmap.recycle() } R.id.action_decrease_contrast -> { val bitmap = capturedReceiptImageView.bitmap val bitmapChangedContrast = BitmapHelper.changeBitmapContrast(bitmap, 0.90f) capturedReceiptImageView.setImageBitmap(bitmapChangedContrast) capturedReceiptImageView.invalidate() bitmap.recycle() } R.id.action_save -> { val bitmap = capturedReceiptImageView.bitmap BitmapHelper.saveBitmap(bitmap, capturedReceiptUri) } else -> { return false } } return true } 

我想要一个函数，这需要另一个函数通过函数rotateBitmap changeBitmapContrast等这应该在BitmapHelper中调用这个函数的重复，并返回位图

我怎样才能改变我的代码来完成呢？

Answer 1

 fun applyBitmapOperation(imageView: ImageView): ((Bitmap) -> Bitmap) -> Unit { val bitmap = imageView.bitmap return { function -> val resultBitmap = function(bitmap) capturedReceiptImageView.setImageBitmap(resultBitmap) capturedReceiptImageView.invalidate() bitmap.recycle() } } override fun onOptionsItemSelected(item: MenuItem?): Boolean { val apply = applyBitmapOperation(capturedReceiptImageView) when (item?.itemId) { R.id.action_crop -> { apply { bitmap -> BitmapHelper.cropBitmap(bitmap, capturedReceiptImageView.getDimensions()) } } R.id.action_rotate_left -> { apply { bitmap -> BitmapHelper.rotateBitmap(bitmap, -90.0f) } } R.id.action_rotate_right -> { apply { bitmap -> BitmapHelper.rotateBitmap(bitmap, 90.0f) } } R.id.action_increase_contrast -> { apply { bitmap -> BitmapHelper.changeBitmapContrast(bitmap, 1.10f) } } R.id.action_decrease_contrast -> { apply { bitmap -> BitmapHelper.changeBitmapContrast(bitmap, 0.90f) } } R.id.action_save -> { val bitmap = capturedReceiptImageView.bitmap BitmapHelper.saveBitmap(bitmap, capturedReceiptUri) } else -> { return false } } return true } 

Answer 2

我能够得到这个与以下工作..

  private fun applyBitmapOperation(predicate: KFunction2<@ParameterName(name = "bitmap") Bitmap, @ParameterName(name = "changeAmount") Float, Bitmap>, changeAmount: Float) { val bitmap = capturedReceiptImageView.bitmap val bitmapChanged = predicate.invoke(bitmap, changeAmount) capturedReceiptImageView.setImageBitmap(bitmapChanged) capturedReceiptImageView.invalidate() bitmap.recycle() } 

像这样称呼

 applyBitmapOperation(::changeBitmapContrast, 1.10f)