登陆

1.登陆 UITextView

1.1 UITextView实现placeholder，可多行编辑

-(void)setPassword{
    UILabel *password = [[UILabel alloc]initWithFrame:CGRectMake(20, 200, 80, 50)];
    password.text = @"密  码";
    [self.view addSubview:password];
    UITextView * passwordText = [[UITextView alloc]initWithFrame:CGRectMake(100, 210, 200, 30)];
    passwordText.text = @"请输入密码...";
    passwordText.autoresizingMask = UIViewAutoresizingFlexibleHeight| UIViewAutoresizingFlexibleWidth;
    passwordText.font = [UIFont systemFontOfSize:16];
    passwordText.backgroundColor = [UIColor whiteColor];
    passwordText.hidden = NO;
    passwordText.delegate = self;
    self.passwordText = passwordText;
    [self.view addSubview:self.passwordText];
}
-(void)setUser{
    UILabel *user = [[UILabel alloc]initWithFrame:CGRectMake(20, 100, 80, 50)];
    user.text = @"用户名";
    [self.view addSubview:user];
    UITextView * userText = [[UITextView alloc]initWithFrame:CGRectMake(100, 110, 200, 30)];
    userText.text = @"请输入用户名...";
    userText.autoresizingMask = UIViewAutoresizingFlexibleHeight| UIViewAutoresizingFlexibleWidth;
    userText.font = [UIFont systemFontOfSize:16];
    userText.backgroundColor = [UIColor whiteColor];
    userText.hidden = NO;
    userText.delegate = self;
    self.userText = userText;
    [self.view addSubview:self.userText];
}

开始和结束编辑时进行判断

-(void)textViewDidBeginEditing:(UITextView *)textView{
    if ([textView.text isEqualToString:@"请输入密码..."]) {
        self.passwordText.text = @"";
    }
    if ([textView.text isEqualToString:@"请输入用户名..."]) {
        self.userText.text = @"";
    }
}
-(void)textViewDidEndEditing:(UITextView *)textView{
    if (textView.text.length == 0) {
        if (self.userText.text.length == 0) {
            self.userText.text = @"请输入用户名...";
        }
        if (self.passwordText.text.length == 0) {
            self.passwordText.text = @"请输入密码...";
        }
    }
   
}

1.2判断表层TextView的内容来实现底层TextView的显示于隐藏

//经过判断表层TextView的内容来实现底层TextView的显示于隐藏
-(BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text{
    if(![text isEqualToString:@""])
    {
        [_backgroundTextView setHidden:YES];
    }
    if([text isEqualToString:@""]&&range.length==1&&range.location==0){
        [_backgroundTextView setHidden:NO];
    }
    if ([text isEqualToString:@"\n"]) {
        [textView resignFirstResponder];
        return NO;
    }
    return YES;
}

2.  登陆 直接使用 UITextField 的 placeholder  属性

-(void)setPassword{
    UILabel *password = [[UILabel alloc]initWithFrame:CGRectMake(20, 200, 80, 50)];
    password.text = @"密  码";
    [self.view addSubview:password];
    UITextField * passwordText = [[UITextField alloc]initWithFrame:CGRectMake(100, 210, 200, 30)];
    passwordText.placeholder = @"请输入密码...";//默认显示的字
    passwordText.secureTextEntry = YES; //是否以密码形式显示
    passwordText.autoresizingMask = UIViewAutoresizingFlexibleHeight| UIViewAutoresizingFlexibleWidth;//自适应高度
    passwordText.font = [UIFont systemFontOfSize:16];
    [passwordText setBorderStyle:UITextBorderStyleRoundedRect]; //外框类型
    passwordText.returnKeyType = UIReturnKeyDone;  //键盘返回类型
    passwordText.clearButtonMode = UITextFieldViewModeWhileEditing; //编辑时会出现个修改X
    passwordText.hidden = NO;
    passwordText.delegate = self;
    self.passwordText = passwordText;
    [self.view addSubview:self.passwordText];
}
-(void)setUser{
    UILabel *user = [[UILabel alloc]initWithFrame:CGRectMake(20, 100, 80, 50)];
    user.text = @"用户名";
    [self.view addSubview:user];
    UITextField * userText = [[UITextField alloc]initWithFrame:CGRectMake(100, 110, 200, 30)];
    userText.placeholder = @"请输入用户名...";//默认显示的字
    userText.autoresizingMask = UIViewAutoresizingFlexibleHeight| UIViewAutoresizingFlexibleWidth;
    userText.font = [UIFont systemFontOfSize:16];
    [userText setBorderStyle:UITextBorderStyleRoundedRect]; //外框类型
    userText.clearButtonMode = UITextFieldViewModeWhileEditing; //编辑时会出现个修改X
    userText.hidden = NO;
    userText.delegate = self;
    self.userText = userText;
    [self.view addSubview:self.userText];
}

按下Done按钮的调用方法，咱们让键盘消失  <UITextFieldDelegate>

//按下Done按钮的调用方法，咱们让键盘消失
-(BOOL)textFieldShouldReturn:(UITextField *)textField{
    [textField resignFirstResponder];
    return YES;
}