Restore the input toolbar's placeholder text.

// FREEBIE

Signal/src/ViewControllers/ConversationView/ConversationInputTextView.h

@@ -18,10 +18,22 @@ NS_ASSUME_NONNULL_BEGIN
 
 #pragma mark -
 
+@protocol ConversationTextViewToolbarDelegate <NSObject>
+
+- (void)textViewDidChange;
+
+- (void)textViewReturnPressed;
+
+@end
+
+#pragma mark -
+
 @interface ConversationInputTextView : UITextView
 
 @property (weak, nonatomic) id<ConversationInputTextViewDelegate> inputTextViewDelegate;
 
+@property (weak, nonatomic) id<ConversationTextViewToolbarDelegate> textViewToolbarDelegate;
+
 - (NSString *)trimmedText;
 
 @end

Signal/src/ViewControllers/ConversationView/ConversationInputTextView.m

@@ -8,6 +8,16 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
+@interface ConversationInputTextView () <UITextViewDelegate>
+
+@property (nonatomic) UILabel *placeholderView;
+@property (nonatomic) NSArray<NSLayoutConstraint *> *placeholderConstraints;
+@property (nonatomic) BOOL isEditing;
+
+@end
+
+#pragma mark -
+
 @implementation ConversationInputTextView
 
 - (instancetype)init
@@ -16,9 +26,10 @@ NS_ASSUME_NONNULL_BEGIN
     if (self) {
         [self setTranslatesAutoresizingMaskIntoConstraints:NO];
 
+        self.delegate = self;
+
         CGFloat cornerRadius = 6.0f;
 
-        self.font = [UIFont ows_dynamicTypeBodyFont];
         self.backgroundColor = [UIColor whiteColor];
         self.layer.borderColor = [UIColor lightGrayColor].CGColor;
         self.layer.borderWidth = 0.5f;
@@ -26,9 +37,6 @@ NS_ASSUME_NONNULL_BEGIN
 
         self.scrollIndicatorInsets = UIEdgeInsetsMake(cornerRadius, 0.0f, cornerRadius, 0.0f);
 
-        self.textContainerInset = UIEdgeInsetsMake(4.0f, 2.0f, 4.0f, 2.0f);
-        self.contentInset = UIEdgeInsetsMake(1.0f, 0.0f, 1.0f, 0.0f);
-
         self.scrollEnabled = YES;
         self.scrollsToTop = NO;
         self.userInteractionEnabled = YES;
@@ -45,13 +53,89 @@ NS_ASSUME_NONNULL_BEGIN
 
         self.text = nil;
 
-        //        _placeHolder = nil;
-        //        _placeHolderTextColor = [UIColor lightGrayColor];
+        self.placeholderView = [UILabel new];
+        self.placeholderView.text = NSLocalizedString(@"new_message", @"");
+        self.placeholderView.textColor = [UIColor lightGrayColor];
+        self.placeholderView.textAlignment = NSTextAlignmentLeft;
+        [self addSubview:self.placeholderView];
+
+        // We need to do these steps _after_ placeholderView is configured.
+        self.font = [UIFont ows_dynamicTypeBodyFont];
+        self.textContainerInset = UIEdgeInsetsMake(4.0f, 2.0f, 4.0f, 2.0f);
+        self.contentInset = UIEdgeInsetsMake(1.0f, 0.0f, 1.0f, 0.0f);
+
+        [self ensurePlaceholderConstraints];
+        [self updatePlaceholderVisibility];
     }
 
     return self;
 }
 
+- (void)setFont:(UIFont *_Nullable)font
+{
+    [super setFont:font];
+
+    self.placeholderView.font = font;
+}
+
+- (void)setContentInset:(UIEdgeInsets)contentInset
+{
+    [super setContentInset:contentInset];
+
+    [self ensurePlaceholderConstraints];
+}
+
+- (void)setTextContainerInset:(UIEdgeInsets)textContainerInset
+{
+    [super setTextContainerInset:textContainerInset];
+
+    [self ensurePlaceholderConstraints];
+}
+
+- (void)ensurePlaceholderConstraints
+{
+    OWSAssert(self.placeholderView);
+
+    if (self.placeholderConstraints) {
+        [NSLayoutConstraint deactivateConstraints:self.placeholderConstraints];
+    }
+
+    // We align the location of our placeholder with the text content of
+    // this view.  The only safe way to do that is by measuring the
+    // beginning position.
+    UITextRange *beginningTextRange =
+        [self textRangeFromPosition:self.beginningOfDocument toPosition:self.beginningOfDocument];
+    CGRect beginningTextRect = [self firstRectForRange:beginningTextRange];
+
+    CGFloat hInset = beginningTextRect.origin.x;
+    CGFloat topInset = beginningTextRect.origin.y;
+
+    self.placeholderConstraints = @[
+        [self.placeholderView autoPinEdgeToSuperviewEdge:ALEdgeLeft withInset:hInset],
+        [self.placeholderView autoPinEdgeToSuperviewEdge:ALEdgeRight withInset:hInset],
+        [self.placeholderView autoPinEdgeToSuperviewEdge:ALEdgeTop withInset:topInset],
+    ];
+}
+
+- (void)updatePlaceholderVisibility
+{
+    self.placeholderView.hidden = self.text.length > 0 || self.isEditing;
+}
+
+- (void)setText:(NSString *_Nullable)text
+{
+    [super setText:text];
+
+    [self updatePlaceholderVisibility];
+}
+
+- (void)setIsEditing:(BOOL)isEditing
+{
+    _isEditing = isEditing;
+
+    [self updatePlaceholderVisibility];
+}
+
 - (BOOL)canBecomeFirstResponder
 {
     return YES;
@@ -246,6 +330,47 @@ NS_ASSUME_NONNULL_BEGIN
 //}
 //@end
 
+#pragma mark - UITextViewDelegate
+
+- (void)textViewDidBeginEditing:(UITextView *)textView
+{
+    // TODO: Is this necessary?
+
+    [textView becomeFirstResponder];
+
+    self.isEditing = YES;
+}
+
+- (void)textViewDidChange:(UITextView *)textView
+{
+    OWSAssert(self.textViewToolbarDelegate);
+
+    [self updatePlaceholderVisibility];
+
+    [self.textViewToolbarDelegate textViewDidChange];
+}
+
+- (void)textViewDidEndEditing:(UITextView *)textView
+{
+    [textView resignFirstResponder];
+
+    self.isEditing = NO;
+}
+
+- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text
+{
+    OWSAssert(self.textViewToolbarDelegate);
+
+    if (range.length > 0) {
+        return YES;
+    }
+    if ([text isEqualToString:@"\n"]) {
+        [self.textViewToolbarDelegate textViewReturnPressed];
+        return NO;
+    }
+    return YES;
+}
+
 @end
 
 NS_ASSUME_NONNULL_END

Signal/src/ViewControllers/ConversationView/ConversationInputToolbar.h

@@ -20,9 +20,6 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (void)textViewDidChange;
 
-// TODO: Is this necessary.
-//- (void)textViewDidBeginEditing;
-
 @end
 
 #pragma mark -

Signal/src/ViewControllers/ConversationView/ConversationInputToolbar.m

@@ -14,25 +14,26 @@ NS_ASSUME_NONNULL_BEGIN
 
 static void *kConversationInputTextViewObservingContext = &kConversationInputTextViewObservingContext;
 
-@interface ConversationInputToolbar () <UIGestureRecognizerDelegate, UITextViewDelegate>
+@interface ConversationInputToolbar () <UIGestureRecognizerDelegate, ConversationTextViewToolbarDelegate>
+
+@property (nonatomic, readonly) ConversationInputTextView *inputTextView;
+@property (nonatomic, readonly) UIButton *attachmentButton;
+@property (nonatomic, readonly) UIButton *sendButton;
+@property (nonatomic, readonly) UIButton *voiceMemoButton;
+@property (nonatomic, readonly) UIView *leftButtonWrapper;
+@property (nonatomic, readonly) UIView *rightButtonWrapper;
 
-@property (nonatomic) ConversationInputTextView *inputTextView;
-@property (nonatomic) UIButton *attachmentButton;
-@property (nonatomic) UIButton *sendButton;
 @property (nonatomic) BOOL shouldShowVoiceMemoButton;
-@property (nonatomic) UIButton *voiceMemoButton;
-@property (nonatomic) UIView *leftButtonWrapper;
-@property (nonatomic) UIView *rightButtonWrapper;
 
 @property (nonatomic) NSArray<NSLayoutConstraint *> *contentContraints;
 
 #pragma mark - Voice Memo Recording UI
 
 @property (nonatomic, nullable) UIView *voiceMemoUI;
-@property (nonatomic) UIView *voiceMemoContentView;
+@property (nonatomic, nullable) UIView *voiceMemoContentView;
 @property (nonatomic) NSDate *voiceMemoStartTime;
 @property (nonatomic, nullable) NSTimer *voiceMemoUpdateTimer;
-@property (nonatomic) UILabel *recordingLabel;
+@property (nonatomic, nullable) UILabel *recordingLabel;
 @property (nonatomic) BOOL isRecordingVoiceMemo;
 @property (nonatomic) CGPoint voiceMemoGestureStartLocation;
 
@@ -69,7 +70,7 @@ static void *kConversationInputTextViewObservingContext = &kConversationInputTex
     [backgroundView autoPinEdgesToSuperviewEdges];
 
     _inputTextView = [ConversationInputTextView new];
-    self.inputTextView.delegate = self;
+    self.inputTextView.textViewToolbarDelegate = self;
     [self addSubview:self.inputTextView];
 
     // We want to be permissive about taps on the send and attachment buttons,
@@ -111,7 +112,7 @@ static void *kConversationInputTextViewObservingContext = &kConversationInputTex
 
     UIImage *voiceMemoIcon = [UIImage imageNamed:@"voice-memo-button"];
     OWSAssert(voiceMemoIcon);
-    self.voiceMemoButton = [UIButton buttonWithType:UIButtonTypeCustom];
+    _voiceMemoButton = [UIButton buttonWithType:UIButtonTypeCustom];
     [self.voiceMemoButton setImage:[voiceMemoIcon imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate]
                           forState:UIControlStateNormal];
     self.voiceMemoButton.imageView.tintColor = [UIColor ows_materialBlueColor];
@@ -157,7 +158,7 @@ static void *kConversationInputTextViewObservingContext = &kConversationInputTex
 
     [self ensureShouldShowVoiceMemoButton];
     // TODO: Remove this when we remove the delegate method.
-    [self textViewDidChange:self.inputTextView];
+    [self textViewDidChange];
 }
 
 - (void)clearTextMessage
@@ -495,6 +496,8 @@ static void *kConversationInputTextViewObservingContext = &kConversationInputTex
 
     UIView *oldVoiceMemoUI = self.voiceMemoUI;
     self.voiceMemoUI = nil;
+    self.voiceMemoContentView = nil;
+    self.recordingLabel = nil;
     NSTimer *voiceMemoUpdateTimer = self.voiceMemoUpdateTimer;
     self.voiceMemoUpdateTimer = nil;
 
@@ -572,41 +575,19 @@ static void *kConversationInputTextViewObservingContext = &kConversationInputTex
     [self.inputToolbarDelegate attachmentButtonPressed];
 }
 
-#pragma mark - UITextViewDelegate
+#pragma mark - ConversationTextViewToolbarDelegate
 
-- (void)textViewDidBeginEditing:(UITextView *)textView
-{
-    OWSAssert(textView == self.inputTextView);
-
-    [textView becomeFirstResponder];
-}
-
-- (void)textViewDidChange:(UITextView *)textView
+- (void)textViewDidChange
 {
     OWSAssert(self.inputToolbarDelegate);
-    OWSAssert(textView == self.inputTextView);
 
     [self ensureShouldShowVoiceMemoButton];
     [self.inputToolbarDelegate textViewDidChange];
 }
 
-- (void)textViewDidEndEditing:(UITextView *)textView
+- (void)textViewReturnPressed
 {
-    OWSAssert(textView == self.inputTextView);
-
-    [textView resignFirstResponder];
-}
-
-- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text
-{
-    if (range.length > 0) {
-        return YES;
-    }
-    if ([text isEqualToString:@"\n"]) {
-        [self sendButtonPressed];
-        return NO;
-    }
-    return YES;
+    [self sendButtonPressed];
 }
 
 #pragma mark - Text Input Sizing

Signal/src/ViewControllers/ConversationView/ConversationViewController.m

@@ -3491,6 +3491,8 @@ typedef NS_ENUM(NSInteger, MessagesRangeSizeMode) {
                           message:errorMessage];
 }
 
+// TODO: Is this necessary? It seems redundant with observing changes to
+// the collection view's layout.
 - (void)textViewDidChangeLayout
 {
     OWSAssert([NSThread isMainThread]);