General: Screenshot protection (closes #216)

Signal/src/AppDelegate.m

@@ -87,8 +87,6 @@
     
     [self performUpdateCheck];
 
-    [self prepareScreenshotProtection];
-    
     self.notificationTracker = [NotificationTracker notificationTracker];
     
     CategorizingLogger* logger = [CategorizingLogger categorizingLogger];
@@ -120,6 +118,8 @@
     
     [self.window makeKeyAndVisible];
     
+    [self prepareScreenshotProtection];
+    
     [Environment.phoneManager.currentCallObservable watchLatestValue:^(CallState* latestCall) {
         if (latestCall == nil){
             return;
@@ -245,6 +245,10 @@
     }
 }
 
+- (void)applicationWillResignActive:(UIApplication *)application{
+    [self protectScreen];
+}
+
 - (void)application:(UIApplication *)application handleActionWithIdentifier:(NSString *)identifier forRemoteNotification:(NSDictionary *)userInfo completionHandler:(void (^)())completionHandler{
     if ([identifier isEqualToString:Signal_Call_Accept_Identifier]) {
         [self.callPickUpFuture trySetResult:@YES];
@@ -276,12 +280,9 @@
 - (void)protectScreen{
     if (Environment.preferences.screenSecurityIsEnabled) {
         self.blankWindow.rootViewController = [UIViewController new];
+
         UIImageView *imageView = [[UIImageView alloc] initWithFrame:self.blankWindow.bounds];
-        if (self.blankWindow.bounds.size.height == 568) {
+        imageView.backgroundColor = [UIColor whiteColor];
-            imageView.image = [UIImage imageNamed:@"Default-568h"];
-        } else {
-            imageView.image = [UIImage imageNamed:@"Default"];
-        }
         imageView.opaque = YES;
         [self.blankWindow.rootViewController.view addSubview:imageView];
         self.blankWindow.hidden = NO;

Signal/src/Storyboard/Storyboard.storyboard

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
-<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="6254" systemVersion="14B25" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" initialViewController="kts-vO-ui1">
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="6250" systemVersion="14C68k" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" initialViewController="kts-vO-ui1">
     <dependencies>
-        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="6247"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="6244"/>
         <capability name="Alignment constraints with different attributes" minToolsVersion="5.1"/>
         <capability name="Constraints to layout margins" minToolsVersion="6.0"/>
     </dependencies>
@@ -2393,7 +2393,7 @@ Licensed under the GPLv3</string>
                             </tableViewSection>
                             <tableViewSection id="JqD-8c-dMF">
                                 <cells>
-                                    <tableViewCell contentMode="scaleToFill" selectionStyle="none" indentationWidth="10" rowHeight="60" id="quP-Cu-8LE" customClass="SettingsTableViewCell">
+                                    <tableViewCell contentMode="scaleToFill" selectionStyle="none" indentationWidth="10" reuseIdentifier="enableScreenSecurity" rowHeight="60" id="quP-Cu-8LE" customClass="SettingsTableViewCell">
                                         <autoresizingMask key="autoresizingMask"/>
                                         <tableViewCellContentView key="contentView" opaque="NO" clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="center" tableViewCell="quP-Cu-8LE" id="i03-Ww-QZz">
                                             <autoresizingMask key="autoresizingMask"/>

Signal/src/view controllers/SettingsTableViewCell.m

@@ -8,11 +8,14 @@
 
 #import "SettingsTableViewCell.h"
 
+#import "Environment.h"
+#import "PreferencesUtil.h"
+
 @implementation SettingsTableViewCell
 
 - (void)awakeFromNib {
     // Initialization code
-    
+    [self.toggle setOn:[Environment.preferences screenSecurityIsEnabled]];
     [self.toggle addTarget:self action:@selector(toggleSetting:) forControlEvents:UIControlEventValueChanged];
 
 }
@@ -27,9 +30,10 @@
 
 -(void)toggleSetting:(id)sender
 {
-    if ([self.reuseIdentifier isEqualToString:@"hideContactImages"])
+    if ([self.reuseIdentifier isEqualToString:@"enableScreenSecurity"])
     {
         self.state.text = self.toggle.isOn ? @"Yes" : @"No";
+        [Environment.preferences setScreenSecurity:self.toggle.isOn];
     }
 }