如何在Android上动画化视图的背景颜色变化?

例如:

我有一个红色背景色的视图。视图的背景颜色变为蓝色。我怎样才能在颜色之间平滑过渡呢?

如果视图不能做到这一点,那么另一种选择是受欢迎的。


当前回答

这是我在Base Activity中用来改变背景的方法。我使用在代码中生成的GradientDrawables,但可以适应。

    protected void setPageBackground(View root, int type){
        if (root!=null) {
            Drawable currentBG = root.getBackground();
            //add your own logic here to determine the newBG 
            Drawable newBG = Utils.createGradientDrawable(type); 
            if (currentBG==null) {
                if(Build.VERSION.SDK_INT<Build.VERSION_CODES.JELLY_BEAN){
                    root.setBackgroundDrawable(newBG);
                }else{
                    root.setBackground(newBG);
                }
            }else{
                TransitionDrawable transitionDrawable = new TransitionDrawable(new Drawable[]{currentBG, newBG});
                transitionDrawable.setCrossFadeEnabled(true);
                if(Build.VERSION.SDK_INT<Build.VERSION_CODES.JELLY_BEAN){
                     root.setBackgroundDrawable(transitionDrawable);
                }else{
                    root.setBackground(transitionDrawable);
                }
                transitionDrawable.startTransition(400);
            }
        }
    }

更新:如果有人遇到同样的问题,我发现,出于某种原因,在Android <4.3使用setCrossFadeEnabled(true)导致一个不受欢迎的白色效果,所以我不得不切换到一个纯色<4.3使用@Roman Minenok ValueAnimator方法上面提到。

其他回答

这里有一个很好的函数可以做到这一点:

public static void animateBetweenColors(final @NonNull View viewToAnimateItsBackground, final int colorFrom,
                                        final int colorTo, final int durationInMs) {
    final ColorDrawable colorDrawable = new ColorDrawable(durationInMs > 0 ? colorFrom : colorTo);
    ViewCompat.setBackground(viewToAnimateItsBackground, colorDrawable);
    if (durationInMs > 0) {
        final ValueAnimator colorAnimation = ValueAnimator.ofObject(new ArgbEvaluator(), colorFrom, colorTo);
        colorAnimation.addUpdateListener(animator -> {
            colorDrawable.setColor((Integer) animator.getAnimatedValue());
            ViewCompat.setBackground(viewToAnimateItsBackground, colorDrawable);
        });
        colorAnimation.setDuration(durationInMs);
        colorAnimation.start();
    }
}

在Kotlin中:

@JvmStatic
fun animateBetweenColors(viewToAnimateItsBackground: View, colorFrom: Int, colorTo: Int, durationInMs: Int) {
    val colorDrawable = ColorDrawable(if (durationInMs > 0) colorFrom else colorTo)
    ViewCompat.setBackground(viewToAnimateItsBackground, colorDrawable)
    if (durationInMs > 0) {
        val colorAnimation = ValueAnimator.ofObject(ArgbEvaluator(), colorFrom, colorTo)
        colorAnimation.addUpdateListener { animator: ValueAnimator ->
            colorDrawable.color = (animator.animatedValue as Int)
            ViewCompat.setBackground(viewToAnimateItsBackground, colorDrawable)
        }
        colorAnimation.duration = durationInMs.toLong()
        colorAnimation.start()
    }
}

这是我在Base Activity中用来改变背景的方法。我使用在代码中生成的GradientDrawables,但可以适应。

    protected void setPageBackground(View root, int type){
        if (root!=null) {
            Drawable currentBG = root.getBackground();
            //add your own logic here to determine the newBG 
            Drawable newBG = Utils.createGradientDrawable(type); 
            if (currentBG==null) {
                if(Build.VERSION.SDK_INT<Build.VERSION_CODES.JELLY_BEAN){
                    root.setBackgroundDrawable(newBG);
                }else{
                    root.setBackground(newBG);
                }
            }else{
                TransitionDrawable transitionDrawable = new TransitionDrawable(new Drawable[]{currentBG, newBG});
                transitionDrawable.setCrossFadeEnabled(true);
                if(Build.VERSION.SDK_INT<Build.VERSION_CODES.JELLY_BEAN){
                     root.setBackgroundDrawable(transitionDrawable);
                }else{
                    root.setBackground(transitionDrawable);
                }
                transitionDrawable.startTransition(400);
            }
        }
    }

更新:如果有人遇到同样的问题,我发现,出于某种原因,在Android <4.3使用setCrossFadeEnabled(true)导致一个不受欢迎的白色效果,所以我不得不切换到一个纯色<4.3使用@Roman Minenok ValueAnimator方法上面提到。

在Kotlin中使用以下函数:

private fun animateColorValue(view: View) {
    val colorAnimation =
        ValueAnimator.ofObject(ArgbEvaluator(), Color.GRAY, Color.CYAN)
    colorAnimation.duration = 500L
    colorAnimation.addUpdateListener { animator -> view.setBackgroundColor(animator.animatedValue as Int) }
    colorAnimation.start()
}

传递任何你想改变颜色的视图。

添加一个文件夹动画到res文件夹。(名称必须是animator)。添加一个动画资源文件。例如res/animator/fade.xml

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
    <objectAnimator
        android:propertyName="backgroundColor"
        android:duration="1000"
        android:valueFrom="#000000"
        android:valueTo="#FFFFFF"
        android:startOffset="0"
        android:repeatCount="-1"
        android:repeatMode="reverse" />
</set>

在Activity java文件中,调用这个

View v = getWindow().getDecorView().findViewById(android.R.id.content);
AnimatorSet set = (AnimatorSet) AnimatorInflater.loadAnimator(this, R.animator.fade);
set.setTarget(v);
set.start();

最好的方法是使用ValueAnimator和ColorUtils.blendARGB

 ValueAnimator valueAnimator = ValueAnimator.ofFloat(0.0f, 1.0f);
 valueAnimator.setDuration(325);
 valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
        @Override
        public void onAnimationUpdate(ValueAnimator valueAnimator) {

              float fractionAnim = (float) valueAnimator.getAnimatedValue();

              view.setBackgroundColor(ColorUtils.blendARGB(Color.parseColor("#FFFFFF")
                                    , Color.parseColor("#000000")
                                    , fractionAnim));
        }
});
valueAnimator.start();