Iphone 无法将图像添加到UITextField ios7的左视图

我在Xcode 5.1中的一个视图中添加了一个UITextField，我试图使用下面的代码将图像添加到其左视图，但是当我运行all时，我看不到图像，不明白原因，请帮助

UIImageView *imgView = [[UIImageView alloc] init];
imgView.image = [UIImage imageNamed:@"Key.png"];

[txtCode setLeftViewMode:UITextFieldViewModeAlways];
[txtCode setLeftView:imgView];

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设置图像视图的边框：

yourTextField.borderStyle = UITextBorderStyleNone;

UIImageView *imgView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 5, 20)];
imgView.image = [UIImage imageNamed:@"Key.png"];

[yourTextField setLeftViewMode:UITextFieldViewModeAlways];
[yourTextField setLeftView:imgView];

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希望这将帮助你…添加图像在paddingView如果你想

UIView *paddingView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 5, 20)];
self.textFiled.leftView = paddingView;
self.textFiled.leftViewMode = UITextFieldViewModeAlways;

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是否尝试为imageview设置帧？

[UIImage ImageName:@“Key.png”]

是否返回对象？还是返回零？