fix issues of textfield (cocos2d#20303)

* fix infinite loop

* fix issue that touch event does not match
If click area ouside keyboard, then engine only receive touch begin event witouth touch end or touch cancled event.

cocos/platform/ios/CCEAGLView-ios.h

@@ -116,6 +116,7 @@ Copyright (C) 2008 Apple Inc. All Rights Reserved.
 @property(nonatomic,readonly) EAGLContext *context;
 
 @property(nonatomic,readwrite) BOOL multiSampling;
+@property(nonatomic, readonly) BOOL isKeyboardShown;
 
 
 /** CCEAGLView uses double-buffer. This method swaps the buffers */
@@ -132,5 +133,4 @@ Copyright (C) 2008 Apple Inc. All Rights Reserved.
 
 -(void) showKeyboard;
 -(void) hideKeyboard;
--(BOOL) isKeyboardShown;
 @end

cocos/platform/ios/CCEAGLView-ios.mm

@@ -78,7 +78,7 @@ CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
 
 @interface CCEAGLView ()
 @property (nonatomic) CCInputView* textInputView;
-@property(nonatomic) BOOL isKeyboardShown;
+@property(nonatomic, readwrite, assign) BOOL isKeyboardShown;
 @property(nonatomic, copy) NSNotification* keyboardShowNotification;
 @property(nonatomic, assign) CGRect originalRect;
 @end
@@ -472,11 +472,6 @@ - (void) hideKeyboard
     [self.textInputView removeFromSuperview];
 }
 
--(BOOL) isKeyboardShown
-{
-    return self.isKeyboardShown;
-}
-
 -(void) doAnimationWhenKeyboardMoveWithDuration:(float) duration distance:(float) dis
 {
     [UIView beginAnimations:nil context:nullptr];

cocos/platform/ios/CCInputView-ios.mm

@@ -38,13 +38,12 @@ - (BOOL) canBecomeFirstResponder {
     return YES;
 }
 
-- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event
+- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
 {
     [self resignFirstResponder];
     [self removeFromSuperview];
 }
 
-
 #pragma TextInput protocol
 
 - (id<UITextInputDelegate>)inputDelegate {