[IOS] Create UIView through center point

1. Just create a view arbitrarily, and then change the center value of the view, the view will be shifted to the center point

UIButton* btn = [[UIButton alloc]initWithFrame:CGRectMake(0, 0, 70, 70)];
btn.center = CGPointMake(self.view.frame.size.width/2, self.view.frame.size.height/2);

 

2. Some supplements about the center point

    1. The center point of the page: self.view.center

    2. Get the coordinates of the center point of a view: CGRectGetMidX and CGRectGetMidY

 

3. Sometimes it occurs that direct assignment through center cannot appear in the expected position:

For example, btn.center = view.center, you will find the shift

At this point, the center point of the view should be obtained manually, as follows:

wifiBtn.center = CGPointMake(CGRectGetMidX(_wifi_view.bounds), CGRectGetMidY(_wifi_view.bounds));

 

refer to:

1.https://stackoverflow.com/questions/18189572/cgrect-positioning-according-to-center-point

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