ios - Changing Size Classes in Code (Swift) -


i’ve been trying , running building adaptive layouts in pure code (no storyboards used). use layout anchors set constraints , utilize traitcollectiondidchange method vary between various sets of constraints , other interface changes. use switch statement call corresponding method corresponding set of constraints. 

override func traitcollectiondidchange(_ previoustraitcollection: uitraitcollection?) {     super.traitcollectiondidchange(previoustraitcollection)      switch (traitcollection.horizontalsizeclass, traitcollection.verticalsizeclass) {     case (.regular, .regular):         setupregularregular()      case (.compact, .compact):         setupcompactcompact()      case (.regular, .compact):         setupregularcompact()      case (.compact, .regular):         setupcompactregular()      default: break     }  }

for sake of testing, changed 1 constraint, centeryanchor.constraint. in portrait constant -150, in landscape want changed 50. ipad, set constant 0.

biglabel.centeryanchor.constraint(equalto: view.centeryanchor, constant: -150).isactive = true

it works fine when switching between iphone , ipad. however, if start rotating iphone portrait landscape, layout system fails, saying:

[layoutconstraints] unable simultaneously satisfy constraints. @ least 1 of constraints in following list 1 don't want.  try this:      (1) @ each constraint , try figure out don't expect;      (2) find code added unwanted constraint or constraints , fix it.  ( "<nslayoutconstraint:0x600000097890 uilabel:0x7fac02c08aa0'main label'.centery == uiview:0x7fac02e0a950.centery - 150   (active)>", "<nslayoutconstraint:0x604000097840 uilabel:0x7fac02c08aa0'main label'.centery == uiview:0x7fac02e0a950.centery + 50   (active)>" )  attempt recover breaking constraint  <nslayoutconstraint:0x604000097840 uilabel:0x7fac02c08aa0'main label'.centery == uiview:0x7fac02e0a950.centery + 50   (active)>

i tried overriding various methods , setting isactive property of constraint false , true, didn’t help. searched web couple of days. no solution far. question is, how switch between size classes right way when rotating device? necessary override other method or something? there better solution adaptive layout in pure code? there best practices when comes adaptive layouts / size classes / layout anchors , constraints in code (without using storyboard)? help!

p.s. methods setting constraints are:

func setupcompactregular() {      biglabel.centeryanchor.constraint(equalto: view.centeryanchor, constant: -150).isactive = true  }  func setupregularcompact() {      biglabel.centeryanchor.constraint(equalto: view.centeryanchor, constant: 50).isactive = true  }

the issue creating new constraints.. try holding reference constraint , change methods update them

func setupcompactregular() {      self.biglabelcenteryanchor.constant = -150  }  func setupregularcompact() {      self.biglabelcenteryanchor.constant = 50  }

call layoutifneeded() right after if doesnt update automatically


Comments

Post a Comment

Popular posts from this blog

python Tkinter Capturing keyboard events save as one single string -

is possible store keyboard events 1 string? code below stores 1 char , prints it. card reader or bar code reader, contains collection of character/ string not 1 character @ time. goal save char pressed text variable. from tkinter import * root = tk() def key(event): text= event.char text+= event.char print ("pressed", text) def callback(event): frame.focus_set() print ("clicked at", event.x, event.y) frame = frame(root, width=100, height=100) frame.bind("<key>", key) frame.bind("<button-1>", callback) frame.pack() root.mainloop() currently, creating text variable , everytime key() function gets called, , text stores last character typed. you can define text module level variable , , use module level text inside key function - text = '' def key(event): global text text+= event.char print("pressed", text)
Read more

android - InAppBilling registering BroadcastReceiver in AndroidManifest -

i'm implementing inapp billing in android app. works well, however, i'm trying decouple broadcast receiver activity manifest. suggestion in android's trivialdrive sample: // important: dynamically register broadcast messages updated purchases. // register receiver here instead of <receiver> in manifest // because call getpurchases() @ startup, therefore can ignore // broadcasts sent while app isn't running. // note: registering listener in activity bad idea, done here // because sample. regardless, receiver must registered after // iabhelper setup, before first call getpurchases(). currently there's class extends broadcastreceiver : public class iabbroadcastreceiver extends broadcastreceiver { /** * intent action receiver should filter for. */ public static final string action = "com.android.vending.billing.purchases_updated"; private final iabbroadcastlistener mlistener; public iabbroadcastreceiver(iabbroadcastlistener listener) { m
Read more

javascript - Z-index in d3.js -

i have map , when hover effect on region of map below yellow line , circle, last ones disappear. how can solve problem? http://jsfiddle.net/ot21n9qx/ var arc = g.append("path") .style("fill", "none") .style("stroke", "yellow") .style("stroke-width", 2) .attr("d", "m" + pathorigin[0] + "," + pathorigin[1] + " q" + svgpoint[0] + "," + pathorigin[1] + " " + svgpoint[0] + "," + svgpoint[1]); var circlesize = d3.scale.linear() .domain([0, 0.5, 1]) .range([4, 10, 4]); svg not have z order draws objects in order created. need create path , circle after create highlight regions. here forked fiddle: http://jsfiddle.net/o00fzgaf/1/
Read more