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

你可以创建一个对象动画器。例如,我有一个targetView,我想改变你的背景颜色:

int colorFrom = Color.RED;
int colorTo = Color.GREEN;
int duration = 1000;
ObjectAnimator.ofObject(targetView, "backgroundColor", new ArgbEvaluator(), colorFrom, colorTo)
    .setDuration(duration)
    .start();

其他回答

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。

答案可以从很多方面给出。你也可以使用ValueAnimator的ofArgb(startColor,endColor)。

火灾> 21:

int cyanColorBg = ContextCompat.getColor(this,R.color.cyan_bg);
int purpleColorBg = ContextCompat.getColor(this,R.color.purple_bg);

ValueAnimator valueAnimator = ValueAnimator.ofArgb(cyanColorBg,purpleColorBg);
        valueAnimator.setDuration(500);
        valueAnimator.setInterpolator(new LinearInterpolator());
        valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
              @Override
              public void onAnimationUpdate(ValueAnimator valueAnimator) {
                   relativeLayout.setBackgroundColor((Integer)valueAnimator.getAnimatedValue());
              }
        });
        valueAnimator.start();

你可以像这样使用ValueAnimator:

 fun startColorAnimation(v: View) {
    val colorStart = v.solidColor
    val colorEnd = Color.RED
    val colorAnim: ValueAnimator = ObjectAnimator.ofInt(v, "backgroundColor", colorStart, colorEnd)
    colorAnim.setDuration(1000)
    colorAnim.setEvaluator(ArgbEvaluator())
    colorAnim.repeatCount = 1
    colorAnim.repeatMode = ValueAnimator.REVERSE
    colorAnim.start()
}

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();

基于ademar111190的答案,我创建了这个方法,它将在任意两种颜色之间脉冲视图的背景颜色:

private void animateBackground(View view, int colorFrom, int colorTo, int duration) {


    ObjectAnimator objectAnimator = ObjectAnimator.ofObject(view, "backgroundColor", new ArgbEvaluator(), colorFrom, colorTo);
    objectAnimator.setDuration(duration);
    //objectAnimator.setRepeatCount(Animation.INFINITE);
    objectAnimator.addListener(new Animator.AnimatorListener() {
        @Override
        public void onAnimationStart(Animator animation) {

        }

        @Override
        public void onAnimationEnd(Animator animation) {
            // Call this method again, but with the two colors switched around.
            animateBackground(view, colorTo, colorFrom, duration);
        }

        @Override
        public void onAnimationCancel(Animator animation) {

        }

        @Override
        public void onAnimationRepeat(Animator animation) {

        }
    });
    objectAnimator.start();
}