Animations--动画基础

基础动画

//1.在0.5s内，将_field.alpha 的数值变为1.0
[UIView animateWithDuration:0.5 animations:^{
   _field.alpha = 1.0;
}];

//2. 较1，在动画完成后，输出log:animation finished!
[UIView animateWithDuration:0.5 animations:^{
   _field.alpha = 1.0;
} completion:^(BOOL finished) {
    NSLog(@"animation finished!");
}];

//3. 较2，动画在该行代码执行后，延迟0.5s执行
//   options: 动画时间曲线项，常用如下：
//       UIViewAnimationOptionCurveEaseInOut            = 0 << 16, // default
//       UIViewAnimationOptionCurveEaseIn               = 1 << 16,
//       UIViewAnimationOptionCurveEaseOut              = 2 << 16,
//       UIViewAnimationOptionCurveLinear               = 3 << 16,
//       UIViewAnimationOptionAllowUserInteraction      = 1 <<  1, // turn on user interaction while animating
//       UIViewAnimationOptionBeginFromCurrentState     = 1 <<  2, // start all views from current value, not initial value
//       UIViewAnimationOptionRepeat                    = 1 <<  3, // repeat animation indefinitely
//       UIViewAnimationOptionAutoreverse               = 1 <<  4, // if repeat, run animation back and forth
[UIView animateWithDuration:0.5 delay:0.5 options:UIViewAnimationOptionCurveLinear animations:^{
   _field.alpha = 1.0;
} completion:^(BOOL finished){
    NSLog(@"animation finished!");
}];

//4. 较3，动画附带一定的弹簧效果，IOS7+;
//   usingSpringWithDamping: 阻尼率，0.0~1.0，越小振荡效果越明显
//   initialSpringVelocity: 用于改变动画的初始速率，比如：_field.在X轴上 会以200pt/s 变化，而你想要的效果为100pt/s, 则可设置其值为0.5； 一般情况下，设置为0（即不做处理）较合适
//   推荐使用该动画方法
[UIView animateWithDuration:0.5 delay:0.5 usingSpringWithDamping:0.5 initialSpringVelocity:0.5 options:UIViewAnimationOptionCurveLinear animations:^{

} completion:^(BOOL finished){
    NSLog(@"animation finished!");
}];

关键帧动画

//较基础动画，可在一个动画中控制UIView的属性值发生多段变化。
//   options: 动画时间曲线项，常用如下：
//        UIViewKeyframeAnimationOptionCalculationModeLinear     = 0 << 10, // default
//        UIViewKeyframeAnimationOptionCalculationModeDiscrete   = 1 << 10,
//        UIViewKeyframeAnimationOptionCalculationModePaced      = 2 << 10,
//        UIViewKeyframeAnimationOptionCalculationModeCubic      = 3 << 10,
//        UIViewKeyframeAnimationOptionCalculationModeCubicPaced = 4 << 10,
//        UIViewKeyframeAnimationOptionAllowUserInteraction      = UIViewAnimationOptionAllowUserInteraction, // turn on user interaction while animating
//        UIViewKeyframeAnimationOptionBeginFromCurrentState     = UIViewAnimationOptionBeginFromCurrentState, // start all views from current value, not initial value
//        UIViewKeyframeAnimationOptionRepeat                    = UIViewAnimationOptionRepeat, // repeat animation indefinitely
//        UIViewKeyframeAnimationOptionAutoreverse               = UIViewAnimationOptionAutoreverse, // if repeat, run animation back and forth
[UIView animateKeyframesWithDuration:0.5 delay:0.5 options:UIViewKeyframeAnimationOptionCalculationModeDiscrete animations:^{
   //关键帧1
   // addKeyframeWithRelativeStartTime: 相对起始时间
   // relativeDuration: 相对执行时间
   [UIView addKeyframeWithRelativeStartTime:0 relativeDuration:0.8 animations:^{
       _field.alpha = 1.0;
   }];
   //关键帧2
   [UIView addKeyframeWithRelativeStartTime:0.8 relativeDuration:0.2 animations:^{
       _field.alpha = 0.5;
   }];

} completion:^(BOOL finished){
   NSLog(@"animation finished!");
}];