SwiftUI Series 12｜The relationship between SwiftUI, Combine and Observation
What really needs to be distinguished is how status changes are observed, propagated and closed.
When I first learned about SwiftUI state management, I would be confused by these words at some stage:
ObservableObject@Published-Combine -Observation
The question is usually:
- They are all related to “state changes will drive interface updates”
- But not on the same floor
So what really needs to be clarified is:
- Who owns the status
- How changes are observed
- How to pass the observation to the interface
1. Combine and Observation do not really answer questions at the same level.
A common situation is to compare them directly as substitute relationships. But a more practical understanding is:
- Combine is more like a set of universal reactive streaming tools
- Observation is more like a mechanism for state observation in the SwiftUI era
In other words, Combine has a broader problem awareness, and Observation is closer to “how the interface state is tracked and refreshed.”
2. What many teams really need is not to mess up the status propagation chain first.
The most common problems in real projects are:
- Status owner is unknown
- It’s unclear where the changes come from
- It is not clear which layer is observing and which layer is converting.
At this time, no matter what name is used for the bottom layer, the page will be easily messed up.
3. A practical judgment: What is needed now is “the state is observed by the interface” or “the event stream is combined and processed”
If your main concern is:
- Page status changes
- ViewModel update
- UI refreshes with status
The Observation style is usually more natural.
If you are more concerned about:
- Merge multiple asynchronous event sources
- Streaming event processing
- More versatile event chain combinations
That Combine’s awareness of issues is still valuable.
4. Conclusion: First straighten out the state boundaries, and then talk about the specific observation mechanism
To put it in shorter form, I would say:
In SwiftUI, the real key to the relationship between Combine and Observation is whether the state owners, change sources and interface observation boundaries are first straightened out.
When the boundaries are clear, technology selection will be much clearer; When the boundaries are unclear, changing any mechanism will just change the name and continue the chaos.
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