scale_fill_manual is not working in geom_bar
<p>I'm trying to change the color in a barplot in ggplot2 using scale_fill_manual, but for some reason only works if i use the fill option inside aesthetics.
I made an example:</p>

<pre><code>library(ggplot2)
library(dplyr) 
iris %&gt;% ggplot(aes(x=Sepal.Width,y=Sepal.Length))+
geom_bar(stat="identity") + scale_fill_manual(values='lightblue')
</code></pre>

<p>Here is the result, no changing in the color:
<a href="https://i.stack.imgur.com/Ik81h.png" rel="noreferrer"><img src="https://i.stack.imgur.com/Ik81h.png" alt="enter image description here"></a></p>

<p>Now, using the fill option inside aesthetics, it works:</p>

<pre><code>iris %&gt;% ggplot(aes(x=Sepal.Width,y=Sepal.Length, fill=factor(2) ))+
geom_bar(stat="identity")+scale_fill_manual(values='lightblue')
</code></pre>

<p><a href="https://i.stack.imgur.com/YHRW2.png" rel="noreferrer"><img src="https://i.stack.imgur.com/YHRW2.png" alt="enter image description here"></a></p>

<p>There is some way to change the bar colour without using the fill option, only using scale_fill_manual?</p>