The circular area progress bar and progress circular progress bar of the similar thunder download progress

The circular area progress bar and progress circular progress bar of the similar thunder download progress

Old rules: first:

Briefly describe the implementation principle:
1. Custom view, inheriting View
2. Draw a circle in onDraw and fill it
3. If the total area of the circular area is known, the blue area can be calculated based on the Progress ratio (assuming the maximum progress value is 100 ).
4. The height of the blue part along the vertical diameter can be solved through the geometric relationships such as circle, triangle, slice area, and angle (For details, refer)
5. Draw related geometric figures and fill in appropriate colors

As a control, it is still only a basic function, and some details are not perfect. We will continue to improve and expand it later. The Source Code address is RoundAreaProgressBar.