constraints

问题 I have given an aspect ratio constraint of 1:2 for an imageView in my xib. I have created an IBOutlet for the constraint. Now I need to change the aspect ratio to 1:1 for certain criteria. I want to know whether there is any way to change the constraint's multiplier value other than removing the old constraint and putting in a new one?? 回答1: I think its not possible other than the 'remove and replace constraint' method. 回答2: The multiplier is a get only property. So you can change only

问题 I have given an aspect ratio constraint of 1:2 for an imageView in my xib. I have created an IBOutlet for the constraint. Now I need to change the aspect ratio to 1:1 for certain criteria. I want to know whether there is any way to change the constraint's multiplier value other than removing the old constraint and putting in a new one?? 回答1: I think its not possible other than the 'remove and replace constraint' method. 回答2: The multiplier is a get only property. So you can change only

问题 There is a constraint violation handling "On conflict" statement, working fine if i want to check 1 (!) constraint For example : INSERT INTO my_table (co1,col2..colN) VALUES (...) ON CONFLICT (col1, col2) DO NOTHING --or update But if i have 2 constaints unique(col1,col2) and unique(col5,col6,col7) , the query below is not working : INSERT INTO my_table (co1,col2..colN) VALUES (...) ON CONFLICT (col1, col2) DO NOTHING --or update ON CONFLICT (col5, col6, col7) DO NOTHING --or update This

问题 There is a constraint violation handling "On conflict" statement, working fine if i want to check 1 (!) constraint For example : INSERT INTO my_table (co1,col2..colN) VALUES (...) ON CONFLICT (col1, col2) DO NOTHING --or update But if i have 2 constaints unique(col1,col2) and unique(col5,col6,col7) , the query below is not working : INSERT INTO my_table (co1,col2..colN) VALUES (...) ON CONFLICT (col1, col2) DO NOTHING --or update ON CONFLICT (col5, col6, col7) DO NOTHING --or update This

问题 Find the shortest path from source to destination in a directed graph with positive and negative edges, such that at no point in the path the sum of edges coming before it is negative. If no such path exists report that too. I tried to use modified Bellman Ford, but could not find the correct solution. I would like to clarify a few points : yes there can be negative weight cycles. n is the number of edges. Assume that a O(n) length path exists if the problem has a solution. +1/-1 edge weights

问题 In this playground I would like to create a map containing at most a single action of each type in the Action union. Each of the unioned types is differentiated by having a different string literal property 'type'. I have a definition for this map which compiles but is too loose... const lastAction:{ [A in Action["type"]]?:Action } = {} The constraint on keys within the lastAction map enforces that... the key is a "type" property from some Action type the value must be some Action type ...it

问题 I have two custom UIViews on the screen. UIViewOne occupies 75% of the screen, and UIViewTwo 25%. I need to click on UIViewTwo, resize it to make the second bigger and smaller first. I also know that this needs to be done using constraints, but I don't know how. Please tell me how to solve this problem. 回答1: One approach is to add two Height constraints to view1 and change their Priority , add a Height constraint at 75% ( multiplier = 0.75 ) set its Priority to 999 add a Height constraint at

问题 So I have a constraint layout with height wrap_content and width match_parent . I would like to know How to align a button to the centre of a recycler view if they are rendered horizontally. How to align a button to the centre of a LinearLayout (which will be populated later).. if they are rendered horizontally. I tried constraint.Guideline but it seems not working because of constraint layout wrap_content height. any suggestions? 回答1: Maybe for other people this answer can be useful. We can

问题 I need change center of some views programmatically. 10 or more. I don't want to adding each bottom constraint as outlet, so could I search them from code like as: for(NSLayoutConstraint *constraint in view.constraints) Which attributes should I check? I need constraint for bottom space of superview. 回答1: Have you heard about IBOutletCollection ? When you link any object from IB to VC code, in popup window you can select IBOutletCollection Option. After link all constraints you want, only

问题 I am having trouble getting constraints to work on my UITableViewCell . The cell currently has 2 text fields and a button with an image. iPhone X Storyboard Currently without constraints the cell content doesn't change position no matter which device I test it on. For instance on an iPad it looks like this iPad storyboard When I add constraints it looks like it is going to work, but then when I run the app the content is all screwed up. Here are screenshots of what it looks like with