Just adding two small points to A.S. answer:
- When you program doesn't do what you want, but doesn't crash
Explain what works
"I want to display an image in the top left corner but it doesn't work."
--> Does the image appear or not? If it doesn't, what to you see? If it does, where is it compared to what you expect?
I really often see some posts where there is a really nice description of what should be achieved, and some code posted, but no explanation about what the code currently does.
This make it more difficult to help. In this example, knowing that the image is displayed but not at the right place is a helpful information
- When people give you an answer or a hint that doesn't work
Try to use that hint to find some more solution or information.
Example, in your question's comment, someone wrote:
"According to your log, you have a NullPointerExeption at line 150"
--> Don't come back instantly on Stack Overflow saying "here is line 150, what should I do?". Try to solve it from the hint first