UIView "stuck" in UITabBarController view top left corner - objective-c

Question

I'm initializing a loader subview to match the height, width and position of the UITabBar I'm using to wrap my app:
// In UITabBarController implementation
LoaderView *loaderView = [[LoaderView alloc] initWithFrame:[self tabBar].viewForBaselineLayout.frame];
[[self view] addSubview:loaderView];
//
// LoaderView.h
#import <UIKit/UIKit.h>
#interface LoaderView : UIView
#property (nonatomic, strong) UILabel *messageLabel;
#property (nonatomic, strong) NSString *message;
#property (nonatomic) CGRect frame;
- (void)createLabel;
- (void)drawLoader;
- (void)setText:(NSString *)newMessage;
- (void)show:(NSNotification *)notification;
#end
//
// LoaderView.m
#import "LoaderView.h"
#implementation LoaderView
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
[self drawLoader];
}
return self;
}
- (void)drawLoader
{
UIColor *semiOpaqueGray = [[UIColor alloc] initWithRed:0.0f green:0.0f blue:0.0f alpha:0.8f];
[self setBackgroundColor:semiOpaqueGray];
[self createLabel];
}
- (void)createLabel
{
_messageLabel = [[UILabel alloc] initWithFrame: CGRectMake(15,9,([self frame].size.width - 10), 30)];
_messageLabel.textColor = [[UIColor alloc] initWithWhite:1.0 alpha:1];
_messageLabel.backgroundColor = [[UIColor alloc] initWithWhite:1.0 alpha:0.0];
[self addSubview:_messageLabel];
}
#end
The frame struct represents this incoming frame data:
2013-09-16 07:48:35.552 ---[97825:a0b] {{0, 519}, {320, 49}}
// Ostensibly 0,519 origin point and 320,49 w/h
The result is this. The mostly opaque dark box can be spotted in the top left corner. It looks like it's being positioned by its center point of the loader to the top left most point of the screen:
I can make the size of the box change, but I can't seem to move it from that top left position. Further, I set an animation on it, and that animation adjusts the frame (sliding it up an down from the tab bar area). That seems to have no effect either.
Thanks in advance for your help.

Answer 1

You can gently add your loadingView your application window. After set the frame of loaderView.
[loadView setFrame:CGRectMake(0,0,self.frame.size.width.,self.frame.size.height)];
[self.window addSubview:loaderView];
Then after loading finished.
[self.window removeSubview:loaderView];

Answer 2

Your superview is the problem. If you're adding it to your UINavigationController then the y-axis likely won't respond nicely. Try using the primary view of your controller
loaderView.frame = CGRectMake(x, 514, 40, 320); // made up numbers
[self.mapView addSubview:loaderView];
Also you're accessing your tabBar. Try using UIDevice window for getting your width and inherit the height from your labels on the bottom (or nest the labels within your LoaderView)
Also look into actually using UITabBar for handling this.