1.setAnimation和startAnimation区别

设置一个动画播放这一观点。若是你想当即播放的动画，使用startAnimation这种方法提供了容许细粒度控制的起始时间和失效，

但你必须确保：1）动画开始时间 2）动画应该开始时的观点，将被视为无效。

    /**
     * Sets the next animation to play for this view.
     * If you want the animation to play immediately, use
     * startAnimation. This method provides allows fine-grained
     * control over the start time and invalidation, but you
     * must make sure that 1) the animation has a start time set, and
     * 2) the view will be invalidated when the animation is supposed to
     * start.
     *
     * @param animation The next animation, or null.
     */
    public void setAnimation(Animation animation) {
        mCurrentAnimation = animation;
        if (animation != null) {
            animation.reset();
        }
    }

如今开始指定的动画。

/**
     * Start the specified animation now.
     *
     * @param animation the animation to start now
     */
    public void startAnimation(Animation animation) {
        animation.setStartTime(Animation.START_ON_FIRST_FRAME);
        setAnimation(animation);
        invalidateParentCaches();
        invalidate(true);
    }

建议使用

startAnimation来启动动画，setAnimation启动动画是须要条件的