点击按钮改变textField的状态

创建一个TextField

//创建一个按钮,用来textfield切换状态

    UIButton *changePicbutton=[UIButton buttonWithType:UIButtonTypeSystem];

    changePicbutton.frame=CGRectMake(100, 200, 50, 50);

    [changePicbutton setImage:[UIImage imageNamed:@"check.png"] forState:UIControlStateNormal];

    [changePicbutton addTarget:self action:@selector(changePic:) forControlEvents:UIControlEventTouchUpInside];

    self.isClick=NO;

    [self.window addSubview:changePicbutton];

-(void)changePic:(UIButton *)button

{

    if (self.isClick) {

        [button setImage:[UIImage imageNamed:@"check.png"] forState:UIControlStateNormal];

    }else{

        [button setImage:[UIImage imageNamed:@"checked.png"] forState:UIControlStateNormal];

    }

    self.isClick=!self.isClick

    ;

    self.textField.secureTextEntry=!self.textField.secureTextEntry;

}