Question

如果我调试我的应用程序。应用程序在这行代码中崩溃，我收到此警告：

警告：

Local declaration of 'imgView' hides instance variable

代码行：

[brightnessFilter forceProcessingAtSize:imgView.sizeInPixels];

代码块：

- (IBAction)sliderBrightness:(id)sender {

    UIImage *inputImage = imgView.image;

    sourcePicture = [[GPUImagePicture alloc] initWithImage:inputImage smoothlyScaleOutput:YES];
    brightnessFilter = [[GPUImageBrightnessFilter alloc] init];

    GPUImageView *imgView = (GPUImageView *)self.view;
    [brightnessFilter forceProcessingAtSize:imgView.sizeInPixels]; 

    [sourcePicture addTarget:brightnessFilter];
    [brightnessFilter addTarget:imgView];

    [sourcePicture processImage];
}

有人可以帮我解决问题吗？

Answer 1

安德烈给了你基础知识。非常具体。

这是您当前的代码：

- (IBAction)sliderBrightness:(id)sender {

    UIImage *inputImage = imgView.image; // <--- This line refers to an instance var

    sourcePicture = [[GPUImagePicture alloc] initWithImage:inputImage smoothlyScaleOutput:YES];
    brightnessFilter = [[GPUImageBrightnessFilter alloc] init];

    GPUImageView *imgView = (GPUImageView *)self.view; <--- This line defines a local
    [brightnessFilter forceProcessingAtSize:imgView.sizeInPixels]; 

    [sourcePicture addTarget:brightnessFilter];
    [brightnessFilter addTarget:imgView];

    [sourcePicture processImage];
}

查看我添加的评论，以“＆lt; --- This line”开头。第一个标记您对实例变量imgView的引用。

第二个注释标记了一个用同一名称定义不同的局部变量imgView的地方。

如果您打算使用其他本地变量，请将该名称更改为其他名称，例如

    GPUImageView *theGPUimgView = (GPUImageView *)self.view;

如果您打算更改实例变量，那么将其作为赋值，并删除变量声明：

   imgView = (GPUImageView *)self.view;

我猜你想要第二种情况，你改变实例变量的内容，但我不确定。这是你的代码。

Answer 2

替换此代码：

GPUImageView *imgView = (GPUImageView *)self.view;
[brightnessFilter forceProcessingAtSize:imgView.sizeInPixels]; 

[sourcePicture addTarget:brightnessFilter];
[brightnessFilter addTarget:imgView];

使用此代码：

GPUImageView *imgView2 = (GPUImageView *)self.view;
[brightnessFilter forceProcessingAtSize:imgView2.sizeInPixels]; 

[sourcePicture addTarget:brightnessFilter];
[brightnessFilter addTarget:imgView2];

您有两个名为imgView的变量，它会向您发出警告，但没有理由导致崩溃。崩溃是因为您提供的代码之外的其他原因。

Answer 3

你已经声明了两个名为imgView的变量（Local和Instance）。将imgView的GPUImageView的局部变量实例改为其他名称，例如gpuimgView

- (IBAction)sliderBrightness:(id)sender {

    UIImage *inputImage = imgView.image;

    sourcePicture = [[GPUImagePicture alloc] initWithImage:inputImage smoothlyScaleOutput:YES];
    brightnessFilter = [[GPUImageBrightnessFilter alloc] init];

    GPUImageView *gpuimgView = (GPUImageView *)self.view;//changed to gpuimgView
    [brightnessFilter forceProcessingAtSize:gpuimgView.sizeInPixels]; 

    [sourcePicture addTarget:brightnessFilter];
    [brightnessFilter addTarget:gpuimgView];

    [sourcePicture processImage];
}

希望它会帮助你......

本地声明＆＃39; imgView＆＃39;隐藏实例变量（app崩溃）

3 个答案: