標籤:註冊 selector 通過 events uitext tar obj change state
第一步:
_rightBtn = [UIButton buttonWithType:UIButtonTypeCustom]; _rightBtn.frame = CGRectMake(kWidth - 50-5, 7, kWidth - _tf.frame.size.width-10, 45); [_rightBtn setBackgroundImage:[UIImage imageNamed:@"send_un"] forState:UIControlStateNormal]; [_rightBtn addTarget:self action:@selector(btnClick:) forControlEvents:UIControlEventTouchUpInside]; [_inputView addSubview:_rightBtn];
第二步:
//監聽textfield的輸入狀態 [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textFieldDidChangeValue:) name:UITextFieldTextDidChangeNotification object:_tf];
第三步:
//這裡可以通過發送object訊息擷取註冊時指定的UITextField對象- (void)textFieldDidChangeValue:(NSNotification *)notification{ UITextField *sender = (UITextField *)[notification object]; if(sender.text.length != 0) { [_rightBtn setBackgroundImage:[UIImage imageNamed:@"send"] forState:UIControlStateNormal]; }else { [_rightBtn setBackgroundImage:[UIImage imageNamed:@"send_un"] forState:UIControlStateNormal]; }}
和簡單,僅做記錄!
ios開發之--通過通知監聽textfield的輸入狀態,判斷按鈕的狀態