效果看这里，有动画展示
https://blog.csdn.net/cjh_android/article/details/51508634
AccelerateDecelerateInterpolator
@android:anim/accelerate_decelerate_interpolator
在动画开始与结束的地方速率改变比较慢，在中间的时候加速
AccelerateInterpolator
@android:anim/accelerate_interpolator
在动画开始的地方速率改变比较慢，然后开始加速
AnticipateInterpolator
@android:anim/anticipate_interpolator
开始的时候向后然后向前甩
AnticipateOvershootInterpolator
@android:anim/anticipate_overshoot_interpolator
开始的时候向后然后向前甩一定值后返回最后的值
BounceInterpolator
@android:anim/bounce_interpolator
动画结束的时候弹起
CycleInterpolator
@android:anim/cycle_interpolator
动画循环播放特定的次数，速率改变沿着正弦曲线
DecelerateInterpolator
@android:anim/decelerate_interpolator
在动画开始的地方快然后慢
LinearInterpolator
@android:anim/linear_interpolator
以常量速率改变
OvershootInterpolator
@android:anim/overshoot_interpolator
向前甩一定值后再回到原来位置
各插值器的源码
/**
* Maps a value representing the elapsed fraction of an animation to a value that represents
* the interpolated fraction. This interpolated value is then multiplied by the change in
* value of an animation to derive the animated value at the current elapsed animation time.
*
* @param input A value between 0 and 1.0 indicating our current point
* in the animation where 0 represents the start and 1.0 represents
* the end
* @return The interpolation value. This value can be more than 1.0 for
* interpolators which overshoot their targets, or less than 0 for
* interpolators that undershoot their targets.
*/
float getInterpolation(float input);
AccelerateDecelerateInterpolator
/**
* An interpolator where the rate of change starts and ends slowly but
* accelerates through the middle.
*/
public float getInterpolation(float input) {
return (float)(Math.cos((input + 1) * Math.PI) / 2.0f) + 0.5f;
}
AccelerateInterpolator
/**
* An interpolator where the rate of change starts out slowly and
* and then accelerates.
*/
public AccelerateInterpolator() {
mFactor = 1.0f;
mDoubleFactor = 2.0;
}
public float getInterpolation(float input) {
if (mFactor == 1.0f) {
return input * input;
} else {
return (float)Math.pow(input, mDoubleFactor);
}
}
AnticipateInterpolator
/**
* An interpolator where the change starts backward then flings forward.
*/
public AnticipateInterpolator() {
mTension = 2.0f;
}
public float getInterpolation(float t) {
// a(t) = t * t * ((tension + 1) * t - tension)
return t * t * ((mTension + 1) * t - mTension);
}
AnticipateOvershootInterpolator
/**
* An interpolator where the change starts backward then flings forward and overshoots
* the target value and finally goes back to the final value.
*/
public AnticipateOvershootInterpolator() {
mTension = 2.0f * 1.5f;
}
/**
* @param tension Amount of anticipation/overshoot. When tension equals 0.0f,
* there is no anticipation/overshoot and the interpolator becomes
* a simple acceleration/deceleration interpolator.
*/
public AnticipateOvershootInterpolator(float tension) {
mTension = tension * 1.5f;
}
private static float a(float t, float s) {
return t * t * ((s + 1) * t - s);
}
private static float o(float t, float s) {
return t * t * ((s + 1) * t + s);
}
public float getInterpolation(float t) {
// a(t, s) = t * t * ((s + 1) * t - s)
// o(t, s) = t * t * ((s + 1) * t + s)
// f(t) = 0.5 * a(t * 2, tension * extraTension), when t < 0.5
// f(t) = 0.5 * (o(t * 2 - 2, tension * extraTension) + 2), when t <= 1.0
if (t < 0.5f) return 0.5f * a(t * 2.0f, mTension);
else return 0.5f * (o(t * 2.0f - 2.0f, mTension) + 2.0f);
}
BounceInterpolator
/**
* An interpolator where the change bounces at the end.
*/
private static float bounce(float t) {
return t * t * 8.0f;
}
public float getInterpolation(float t) {
// _b(t) = t * t * 8
// bs(t) = _b(t) for t < 0.3535
// bs(t) = _b(t - 0.54719) + 0.7 for t < 0.7408
// bs(t) = _b(t - 0.8526) + 0.9 for t < 0.9644
// bs(t) = _b(t - 1.0435) + 0.95 for t <= 1.0
// b(t) = bs(t * 1.1226)
t *= 1.1226f;
if (t < 0.3535f) return bounce(t);
else if (t < 0.7408f) return bounce(t - 0.54719f) + 0.7f;
else if (t < 0.9644f) return bounce(t - 0.8526f) + 0.9f;
else return bounce(t - 1.0435f) + 0.95f;
}
CycleInterpolator
/**
* Repeats the animation for a specified number of cycles. The
* rate of change follows a sinusoidal pattern.
*/
public CycleInterpolator(float cycles) {
mCycles = cycles;
}
public float getInterpolation(float input) {
return (float)(Math.sin(2 * mCycles * Math.PI * input));
}
DecelerateInterpolator
/**
* An interpolator where the rate of change starts out quickly and
* and then decelerates.
*/
public DecelerateInterpolator() {
}
/**
* Constructor
*
* @param factor Degree to which the animation should be eased. Setting factor to 1.0f produces
* an upside-down y=x^2 parabola. Increasing factor above 1.0f makes exaggerates the
* ease-out effect (i.e., it starts even faster and ends evens slower)
*/
public DecelerateInterpolator(float factor) {
mFactor = factor;
}
public float getInterpolation(float input) {
float result;
if (mFactor == 1.0f) {
result = (float)(1.0f - (1.0f - input) * (1.0f - input));
} else {
result = (float)(1.0f - Math.pow((1.0f - input), 2 * mFactor));
}
return result;
}
private float mFactor = 1.0f;
OvershootInterpolator
/**
* An interpolator where the change flings forward and overshoots the last value
* then comes back.
*/
private final float mTension;
public OvershootInterpolator() {
mTension = 2.0f;
}
/**
* @param tension Amount of overshoot. When tension equals 0.0f, there is
* no overshoot and the interpolator becomes a simple
* deceleration interpolator.
*/
public OvershootInterpolator(float tension) {
mTension = tension;
}
public float getInterpolation(float t) {
// _o(t) = t * t * ((tension + 1) * t + tension)
// o(t) = _o(t - 1) + 1
t -= 1.0f;
return t * t * ((mTension + 1) * t + mTension) + 1.0f;
}
