android 4.0.x上AnimatorSet.setDuration上的坑

標籤：

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<span style="font-size:18px;">  最近在用<a target=_blank href="https://github.com/skyfishjy/android-ripple-background">https://github.com/skyfishjy/android-ripple-background</a>開原始檔控制的時候，在Android4.0.x上遇到一個問題，本來優雅的動畫變得很快。</span>

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<span style="font-size:18px;">  剛開始以為是硬體加速的問題，但是查資料後，發現google在4.0的時候就預設的把硬體加速開啟了，所以之上的版本都應該一樣的。後來和同事一起研究的時候發現，好像是animatorSet.setDuration()方法沒有效果，又查了源碼發現下面的區別：</span>

API 15

/**     * Sets the length of each of the current child animations of this AnimatorSet. By default,     * each child animation will use its own duration. If the duration is set on the AnimatorSet,     * then each child animation inherits this duration.     *     * @param duration The length of the animation, in milliseconds, of each of the child     * animations of this AnimatorSet.     */    @Override    public AnimatorSet setDuration(long duration) {        if (duration < 0) {            throw new IllegalArgumentException("duration must be a value of zero or greater");        }        // Just record the value for now - it will be used later when the AnimatorSet starts        mDuration = duration;        return this;    }

API 19

    /**     * Sets the length of each of the current child animations of this AnimatorSet. By default,     * each child animation will use its own duration. If the duration is set on the AnimatorSet,     * then each child animation inherits this duration.     *     * @param duration The length of the animation, in milliseconds, of each of the child     * animations of this AnimatorSet.     */    @Override    public AnimatorSet setDuration(long duration) {        if (duration < 0) {            throw new IllegalArgumentException("duration must be a value of zero or greater");        }        for (Node node : mNodes) {            // TODO: don't set the duration of the timing-only nodes created by AnimatorSet to            // insert "play-after" delays            node.animation.setDuration(duration);        }        mDuration = duration;        return this;    }

原來是在API15上AnimatorSet.setDuration()方法並沒有給它的子objectAnimator設定，解決方案當然是給每個add到animatorSet中的ObjectAnimator都設定自己的duration。

這是最典型的Android版本相容問題，踩過坑了就不要再犯。

android 4.0.x上AnimatorSet.setDuration上的坑