Pass matlab javaArray('java.lang.Integer',Length) as "java method input: int[]" to be filled in the method failed

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raym 2020-8-5

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https://ww2.mathworks.cn/matlabcentral/answers/575653-pass-matlab-javaarray-java-lang-integer-length-as-java-method-input-int-to-be-filled-in-the

回答： raym 2020-8-6

In java/C#/C++ method, there is a way to input a empty array as one argument in, and the method can fill this array, which could be used then.

Here I have a try in java-Matlab to see if this is feasible using a demo: read a jpg pixel value array using java command from Matlab environment:

filepath = 'C:\.....jpg';
aBufferedImage = javax.imageio.ImageIO.read(java.io.File(filepath));
aContainerJavaArr = javaArray('java.lang.Integer',aWidth*aHeight); % the aWidth and aHeight is the known width and height of the jpg file.
% then use empty aContainerJavaArr as input to the method getRGB, to let it be filled with true pixel RGB color values
aBufferedImage.getRGB(0,0,aWidth,aHeight,aContainerJavaArr,0,aWidth);
No method 'getRGB' with matching signature found for class 'java.awt.image.BufferedImage'.

The argin list is :int,int,int,int,int[],int,int. So I convert all the argument to java.lang.Integer(), but the error is still same.

aBufferedImage.getRGB(java.lang.Integer(0),java.lang.Integer(0),...
    java.lang.Integer(aWidth),java.lang.Integer(aHeight),aContainerJavaArr,java.lang.Integer(0),java.lang.Integer(aWidth));

Why the javaArray('java.lang.Integer',...) cannot be used in this manner?

Thanks.