关于UITextField和UITextView的placeholder

1. 大家都知道UITextField支持设置placeholder, 并且可以改变placeholder字体大小和颜色, 参照代码:

/* 设置placeholder*/[textField setPlaceholder:@"placeholder in textField"];/* 改变placeholder的颜色 */[textField setValue:[UIColor redColor] forKeyPath:@"_placeholderLabel.textColor"];/* 改变placeholder的字体大小 */[textField setValue:[UIFont systemFontOfSize:20.f] forKeyPath:@"_placeholderLabel.font"];2. UITextView是不支持placeholder, 不过没事, 我们可以手动添加一个label, 设置字体大小颜色就只需要操作label即可:

/* 添加UITextView */UITextView *textView = [[UITextView alloc] initWithFrame:CGRectMake(0, 0, 320.f, 47.f)];textView.delegate = self;// textView.backgroundColor = [UIColor clearColor];[self addSubView:textView];/* 添加placeholder Label */UILabel *placeHolderLabel = [[UILabel alloc] initWithFrame:CGRectZero];placeHolderLabel.textColor = [UIColor lightGrayColor];placeHolderLabel.text = @"placeholder in textView";[placeHolderLabel sizeToFit];placeHolderLabel.frame = CGRectMake(0, 5.f, placeHolderLabel.frame.size.width, placeHolderLabel.frame.size.height);[self addSubView:placeHolderLabel];/* 监听textView发生变化, 无内容则显示placeholder */- (void)textViewDidChange:(UITextView *)textView{    if ([[textView.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] isEqualToString:@""]) {        placeHolderLabel.text = @"placeholder in textView";    }else{        placeHolderLabel.text = @"";    }}

，别人失去了信心，他却下决心实现自己的目标。