Expected method to read dictionary element not found on object of type 'id

Question

I am trying to upgrade my app to Xcode 9.3.1 from 8 and have these errors:

Expected method to read dictionary element not found on object of type 'id<NSCopying>'

My code is:

// Normalize the blending mode to use for the key.
// *** Error on next three lines ***
id src = (options[CCBlendFuncSrcColor] ?: @(GL_ONE));
id dst = (options[CCBlendFuncDstColor] ?: @(GL_ZERO));
id equation = (options[CCBlendEquationColor] ?: @(GL_FUNC_ADD));

NSDictionary *normalized = @{
    CCBlendFuncSrcColor: src,
    CCBlendFuncDstColor: dst,
    CCBlendEquationColor: equation,

    // Assume they meant non-separate blending if they didn't fill in the keys.
    // *** Error on next line ***
    CCBlendFuncSrcAlpha: (options[CCBlendFuncSrcAlpha] ?: src),
    CCBlendFuncDstAlpha: (options[CCBlendFuncDstAlpha] ?: dst),
    CCBlendEquationAlpha: (options[CCBlendEquationAlpha] ?: equation),
};

Can anyone point me in the right direction? I have bolded the errors in the code.

What is `options`? Why was this Objective-C code tagged with Swift? — rmaddy, May 12 '18 at 02:29

score 1 · Answer 1 · answered May 12 '18 at 05:15

1

The compiler thinks that options is of type id<NSCopying>, not an NSDictionary *, which is required to use the dictionary[key] syntax. Your code snippet does not include where that is declared, which is where the error would be.

answered May 12 '18 at 05:15

Carl Lindberg

2,902
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score 0 · Answer 2 · answered May 22 '18 at 20:45

You must cast your object options

    // Normalize the blending mode to use for the key.
id src = (((NSDictionary *)options)[CCBlendFuncSrcColor] ?: @(GL_ONE));
id dst = (((NSDictionary *)options)[CCBlendFuncDstColor] ?: @(GL_ZERO));
id equation = (((NSDictionary *)options)[CCBlendEquationColor] ?: @(GL_FUNC_ADD));

NSDictionary *normalized = @{
    CCBlendFuncSrcColor: src,
    CCBlendFuncDstColor: dst,
    CCBlendEquationColor: equation,

    // Assume they meant non-separate blending if they didn't fill in the keys.
    CCBlendFuncSrcAlpha: (((NSDictionary *)options)[CCBlendFuncSrcAlpha] ?: src),
    CCBlendFuncDstAlpha: (((NSDictionary *)options)[CCBlendFuncDstAlpha] ?: dst),
    CCBlendEquationAlpha: (((NSDictionary *)options)[CCBlendEquationAlpha] ?: equation),
};

Expected method to read dictionary element not found on object of type 'id

2 Answers2