iOS键盘弹出遮挡输入框的解决方法

self.phoneinput = [uitextfield new];
  self.phoneinput.placeholder = @"请输入...";
  [self.view addsubview:self.phoneinput];


///键盘弹出 处理遮挡问题
- (void)viewwillappear:(bool)animated
{
  [super viewwillappear:animated];
  
  [[nsnotificationcenter defaultcenter] addobserver:self
                       selector:@selector(keyboardwillshow:)
                         name:uikeyboardwillshownotification
                        object:nil];
  [[nsnotificationcenter defaultcenter] addobserver:self
                       selector:@selector(keyboardwillhide:)
                         name:uikeyboardwillhidenotification
                        object:nil];
}
- (void)keyboardwillshow:(nsnotification *)notification
{
 //获取处于焦点中的view
 nsarray *textfields = @[self.phoneinput];
 uiview *focusview = nil;
 for (uitextfield *view in textfields) {
  if ([view isfirstresponder]) {
   focusview = view;
   break;
  }
 }
 if (focusview) {
   //获取键盘弹出的时间
   double duration = [notification.userinfo[uikeyboardanimationdurationuserinfokey] doublevalue];
   //获取键盘上端y坐标
   cgfloat keyboardy = [notification.userinfo[uikeyboardframeenduserinfokey] cgrectvalue].origin.y;
   //获取输入框下端相对于window的y坐标
   cgrect rect = [focusview convertrect:focusview.bounds toview:[[[uiapplication sharedapplication] delegate] window]];
   cgpoint tmp = rect.origin;
   cgfloat inputboxy = tmp.y + focusview.frame.size.height;
   //计算二者差值
   cgfloat ty = keyboardy- inputboxy;
   nslog(@"position keyboard: %f, inputbox: %f, ty: %f", keyboardy, inputboxy, ty);
   //差值小于0，做平移变换
   [uiview animatewithduration:duration animations:^{
    if (ty < 0) {
     self.view.transform = cgaffinetransformmaketranslation(0, ty);
    }
   }];
  }
}

- (void)keyboardwillhide:(nsnotification *)notification
{
 //获取键盘弹出的时间
 double duration = [notification.userinfo[uikeyboardanimationdurationuserinfokey] doublevalue];
 //还原
 [uiview animatewithduration:duration animations:^{
   self.view.transform = cgaffinetransformmaketranslation(0, 0);
 }];
}
///<uitextfielddelegate>
///uitextfielddelegate编辑完成，视图恢复原状
-(void)textfielddidendediting:(uitextfield *)textfield
{
   self.view.frame =cgrectmake(0, 0, [[uiscreen mainscreen] bounds].size.width,[[uiscreen mainscreen] bounds].size.height);
}