iOS_开发经验总结：键盘遮挡输入框时的解决方法

今天我来讲一下键盘遮挡输入框时的解决方法。我做的一个界面是这样的

我的输入框是在最下面，如果不做相关的操作的话，当编辑UITextField的时候，弹出键盘就会挡着输入框，那怎么解决这个问题呢，我们可以考虑让输入框随键盘一起向上移动，当关闭键盘时让输入框也一起向下移动回到原来的位置，这样就可以解决键盘挡着输入框的问题啦

下面看具体的代码实现：

在ios5.0之前呢键盘高度固定是216像素高，而ios5.0之后包括ios5.0键盘的高度再不是固定的，当由英文切换在中文输入时，键盘由原来的216变成了252

先说ios5.0之前的解决办法吧，我是通过UITextField的委托方法-(void)textFieldDidBeginEditing:(UITextField *)textField和另一个关掉键盘的方法

- (BOOL)textFieldShouldReturn:(UITextField *)textField来实现的，点击键盘上的Return会关掉键盘的

 1 - (void)textFieldDidBeginEditing:(UITextField *)textField
 2 {
 3     CGRect frame = textField.frame;
 4     int offset = frame.origin.y +422 - (self.view.frame.size.height - 240);//键盘高度216
 5     NSLog(@"offset is %d",offset);
 6     NSTimeInterval animationDuration = 0.30f;
 7     [UIView beginAnimations:@"ResizeForKeyBoard" context:nil];
 8     [UIView setAnimationDuration:animationDuration];
 9     float width = self.view.frame.size.width;
10     float height = self.view.frame.size.height;
11     if(offset > 0)
12     {
13         CGRect rect = CGRectMake(0.0f, -offset,width,height);
14         self.view.frame = rect;
15     }
16     [UIView commitAnimations];
17 }

 1 - (BOOL)textFieldShouldReturn:(UITextField *)textField
 2 {
 3     NSTimeInterval animationDuration = 0.30f;
 4     [UIView beginAnimations:@"ResizeForKeyboard" context:nil];
 5     [UIView setAnimationDuration:animationDuration];
 6     CGRect rect = CGRectMake(0.0f, 0.0f, self.view.frame.size.width, self.view.frame.size.height);
 7     self.view.frame = rect;
 8     [UIView commitAnimations];
 9     [textField resignFirstResponder];
10     return YES;
11 }

对了在添加-(void)textFieldDidBeginEditing:(UITextField *)textField方法前要声明并设置delegate

另一个方法是针对ios5.0之后键盘高度随输入法不同变化时的解决办法，同时也适用于ios5.0之前

在-(void)viewDidLoad方法里面添加通知

1   if(IOS_VERSION<5.0)
2     {
3         [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];
4         [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillHideNotification object:nil];
5     }else{
6         [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];
7     }

至于如何获取IOS系统版本号通过如下可获取

#define IOS_VERSION [[[UIDevice currentDevice] systemVersion] floatValue]

添加一个方法-(void)keyboardWillShow:(NSNotification *)notification具体如下

-(void)keyboardWillShow:(NSNotification *)notification
{

#if __IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_3_2
        if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone) {
#endif
#if __IPHONE_OS_VERSION_MIN_REQUIRED >= __IPHONE_3_2
            NSValue *keyboardBoundsValue = [[notification userInfo] objectForKey:UIKeyboardFrameEndUserInfoKey];
#else
            NSValue *keyboardBoundsValue = [[notification userInfo] objectForKey:UIKeyboardBoundsUserInfoKey];
#endif
            CGRect keyboardBounds;
            [keyboardBoundsValue getValue:&keyboardBounds];
            NSInteger offset =self.view.frame.size.height-keyboardBounds.origin.y+64.0;
            CGRect listFrame = CGRectMake(0, -offset, self.view.frame.size.width,self.view.frame.size.height);
            NSLog(@"offset is %d",offset);
            [UIView beginAnimations:@"anim" context:NULL];
            [UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
            [UIView setAnimationBeginsFromCurrentState:YES];
            [UIView setAnimationDuration:0.3];
            //处理移动事件，将各视图设置最终要达到的状态
    
            self.view.frame=listFrame;
            
            [UIView commitAnimations];
            
        }
}

这个是编辑输入框时的效果

这个是键盘切换成中文输入法时的效果