最近写了一个项目，遇到需要处理键盘弹出/收起时，避免键盘遮挡输入框的问题。
所以当时我写了一个BaseViewController框架（可以用来当做所有ViewController的基类），在BaseViewController设置属性判断是否需要处理键盘，并且处理了当键盘第一次弹出时会出现中文键盘高度不对的问题。
github地址：https://github.com/WalkingToTheDistant/KeyboardHandle/tree/master，如果觉得我写的代码对你有帮助的话，给我一个星呗^ _ ^
使用方法
设置基类BaseViewController或者其子类的属性isNeedHandleKeyboard为YES（默认NO），这个变量必须在BaseViewController的ViewDidLoad执行之前设置，因 为在BaseViewController的ViewDidLoad里面会执行检索代码，给所有输入框添加键盘关闭栏。
/** 是否需要处理键盘弹出/收起的事件，默认NO */
@property(nonatomic, assign) BOOL isNeedHandleKeyboard;
代码解析
首先是添加监听，这里的逻辑，就是用_isNeedHandleKeyboard来判断这个ViewController是否需要处理键盘
@interface BaseViewController ()
/** 是否需要处理键盘弹出/收起的事件，默认NO */
@property(nonatomic, assign) BOOL isNeedHandleKeyboard;
/** 键盘弹出时，需要移动的高度值 */
@property(nonatomic, assign) int moveValueForKeyboard;
@end
- (void) viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
if(_isNeedHandleKeyboard == YES){ // 添加键盘监听
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleKeyboardShow:) name:UIKeyboardWillShowNotification object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleKeyboardHide:) name:UIKeyboardWillHideNotification object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleKeyboardFrameChange:) name:UIKeyboardWillChangeFrameNotification object:nil]; // 监听键盘尺寸的变化
}
}
- (void) viewWillDisappear:(BOOL)animated
{
[super viewWillDisappear:animated];
if(_isNeedHandleKeyboard == YES){ // 消除键盘监听
[[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillShowNotification object:nil];
[[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillHideNotification object:nil];
[[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillChangeFrameNotification object:nil];
}
}
接下来处理键盘弹出/收起的事件
// ****************************************************************************************************
// ****************************************************************************************************
#pragma mark - 键盘处理
- (void) handleKeyboardShow:(NSNotification*) notification
{
if(_moveValueForKeyboard > 0){ // 键盘已经处理过，避免在键盘输入的时候再点击了其他的输入框
return;
}
CGRect keyboardFrame = [[[notification userInfo] valueForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
const float duration = [[[notification userInfo] valueForKey:UIKeyboardAnimationDurationUserInfoKey] floatValue];
const UIViewAnimationOptions options = [[[notification userInfo] valueForKey:UIKeyboardAnimationCurveUserInfoKey] integerValue];
UIView *viewFirst = [[self class] getFirstResponder:self.view];
if(viewFirst != nil){
CGPoint pointView = [viewFirst convertPoint:self.view.bounds.origin toView:self.view];
pointView.y += CGRectGetHeight(viewFirst.frame);
_keyboardHeight = CGRectGetHeight(keyboardFrame);
int originYForKeyboard = CGRectGetMaxY(self.view.frame) - _keyboardHeight;
if(pointView.y >= originYForKeyboard){
// 输入框被键盘遮挡
_moveValueForKeyboard = pointView.y - originYForKeyboard;
__block CGRect frame = self.view.frame;
frame.origin.y -= _moveValueForKeyboard;
[UIView animateWithDuration:duration delay:0 options:options animations:^{
self.view.frame = frame;
} completion:nil];
} else {
_moveValueForKeyboard = 0;
}
}
}
- (void) handleKeyboardHide:(NSNotification*)notification
{
if(_moveValueForKeyboard > 0){
const float duration = [[[notification userInfo] valueForKey:UIKeyboardAnimationDurationUserInfoKey] floatValue];
const UIViewAnimationOptions options = [[[notification userInfo] valueForKey:UIKeyboardAnimationCurveUserInfoKey] integerValue];
__block CGRect frame = self.view.frame;
frame.origin.y += _moveValueForKeyboard;
_moveValueForKeyboard = 0;
[UIView animateWithDuration:duration delay:0 options:options animations:^{
self.view.frame = frame;
} completion:nil];
}
}
- (void) handleKeyboardFrameChange:(NSNotification*)notification
{
/* 在这里处理中文键盘的高度变化问题，在第一次弹出键盘之后，键盘上随后会展现中文的智能检测栏，导致键盘的高度会变高，而在UIKeyboardWillShowNotification得到的高度缺不包含这个监测栏的高度，从而输入框位置会被键盘遮挡。所以需要在这里监听键盘尺寸的变化，然后再计算尺寸变化值并修改输入框的位置。*/
CGRect keyboardFrame = [[[notification userInfo] valueForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
if(_moveValueForKeyboard > 0){ // 需要处理中文键盘的尺寸变化问题
int valueChange = CGRectGetHeight(keyboardFrame) - _keyboardHeight;
if(valueChange != 0){
const float duration = [[[notification userInfo] valueForKey:UIKeyboardAnimationDurationUserInfoKey] floatValue];
const UIViewAnimationOptions options = [[[notification userInfo] valueForKey:UIKeyboardAnimationCurveUserInfoKey] integerValue];
__block CGRect frame = self.view.frame;
frame.origin.y -= valueChange;
_moveValueForKeyboard += valueChange;
_keyboardHeight = CGRectGetHeight(keyboardFrame);
[UIView animateWithDuration:duration delay:0 options:options animations:^{
self.view.frame = frame;
} completion:nil];
}
}
}
这些事件处理需要一个方法辅助，一个是获取当前键盘输入的控件，然后再获取其相对屏幕的坐标，用以判断它是否被键盘给遮挡了
/** 获取当前键盘输入的控件 */
+ (UIView*) getFirstResponder:(UIView*)superView
{
if(superView.isFirstResponder == YES){
return superView;
}
for(UIView *viewChild in superView.subviews){
if([viewChild isFirstResponder] == YES){
return viewChild;
}
}
// 再搜索下一层Subview
for(UIView *viewChild in superView.subviews){
UIView *viewResult = [[self class] getFirstResponder:viewChild];
if(viewResult != nil){
return viewResult;
}
}
return nil;
}
在键盘上方添加关闭栏的通用方法。
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
if(_isNeedHandleKeyboard == YES){
[self addDoneKeyboardViewToInputView:self.view];
}
}
/** 创建键盘关闭的View */
+ (UIView*) getKeyboardHideViewWithTarget:(id)target withSelector:(SEL)selector
{
UIView *viewResult = [[UIView alloc] initWithFrame:CGRectMake(0, 0, CGRectGetWidth(UIScreen.mainScreen.bounds), 40)];
[viewResult setBackgroundColor:RGBColor(250, 250, 250)];
int height = CGRectGetHeight(viewResult.frame);
int width = 80;
int x = CGRectGetMaxX(viewResult.frame) - width;
int y = 0;
UIButton *btnDone = [UIButton buttonWithType:UIButtonTypeSystem];
[btnDone setTitle:@"完成" forState:UIControlStateNormal];
[btnDone.titleLabel setFont:Font_Bold(16.0f)];
[btnDone setFrame:CGRectMake(x, y, width, height)];
[btnDone addTarget:target action:selector forControlEvents:UIControlEventTouchUpInside];
[viewResult addSubview:btnDone];
return viewResult;
}
/** 给所有输入框的键盘都添加关闭 */
- (void) addDoneKeyboardViewToInputView:(UIView*) superView
{
//这个方法可能是有效率问题，因为需要遍历整个ViewController的view，暂时还想不到更好的方法
for(UIView *viewChlid in [superView subviews]){
if([viewChlid isKindOfClass:[UITextField class]] == YES){
if([viewChlid inputAccessoryView] == nil){
UIView *viewDone = [[self class] getKeyboardHideViewWithTarget:self withSelector:@selector(closeKeyboard)];
[((UITextField*)viewChlid) setInputAccessoryView:viewDone];
}
} else if([viewChlid isKindOfClass:[UITextView class]] == YES){
if([viewChlid inputAccessoryView] == nil){
UIView *viewDone = [[self class] getKeyboardHideViewWithTarget:self withSelector:@selector(closeKeyboard)];
[((UITextView*)viewChlid) setInputAccessoryView:viewDone];
}
} else {
[self addDoneKeyboardViewToInputView:viewChlid];
}
}
}
/** 关闭ViewController的键盘 */
- (void) closeKeyboard
{
[self.view endEditing:YES];
}
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