Make a ProgressBar update smoothly

Question

I'm using a progress bar (in bar form). I wish to make the bar increase and decrease smoothly using an interpolator, but It's not working. This is what I have at the moment:

pb.setInterpolator(main.this, android.R.anim.bounce_interpolator);              pb.setProgress(pb.getProgress()+10); 

Am I doing something really wrong?

Answer 1

The Interpolator has to be attached to an animation and this will work only on Honeycomb or higher:

if(android.os.Build.VERSION.SDK_INT >= 11){     // will update the "progress" propriety of seekbar until it reaches progress     ObjectAnimator animation = ObjectAnimator.ofInt(seekbar, "progress", progress);      animation.setDuration(500); // 0.5 second     animation.setInterpolator(new DecelerateInterpolator());     animation.start(); } else      seekbar.setProgress(progress); // no animation on Gingerbread or lower 

If your minimum SDK is Gingerbread or lower, add:

@TargetApi(Build.VERSION_CODES.HONEYCOMB)  // or  @SuppressLint("NewApi")  

to your function/class.

I used a DecelerateInterpolator, but this is optional and there are others possibilities.

Answer 2

Here is a self-contained drop in solution:

import android.animation.ValueAnimator; import android.animation.ValueAnimator.AnimatorUpdateListener; import android.content.Context; import android.util.AttributeSet; import android.view.animation.AccelerateDecelerateInterpolator; import android.view.animation.Interpolator; import android.widget.ProgressBar;  public class AnimatingProgressBar extends ProgressBar {      private static final Interpolator DEFAULT_INTERPOLATER = new AccelerateDecelerateInterpolator();      private ValueAnimator animator;     private ValueAnimator animatorSecondary;     private boolean animate = true;      public AnimatingProgressBar(Context context, AttributeSet attrs, int defStyle) {         super(context, attrs, defStyle);     }      public AnimatingProgressBar(Context context, AttributeSet attrs) {         super(context, attrs);     }      public AnimatingProgressBar(Context context) {         super(context);     }      public boolean isAnimate() {         return animate;     }      public void setAnimate(boolean animate) {         this.animate = animate;     }      @Override     public synchronized void setProgress(int progress) {         if (!animate) {             super.setProgress(progress);             return;         }         if (animator != null)             animator.cancel();         if (animator == null) {             animator = ValueAnimator.ofInt(getProgress(), progress);             animator.setInterpolator(DEFAULT_INTERPOLATER);             animator.addUpdateListener(new AnimatorUpdateListener() {                  @Override                 public void onAnimationUpdate(ValueAnimator animation) {                     AnimatingProgressBar.super.setProgress((Integer) animation.getAnimatedValue());                 }             });         } else             animator.setIntValues(getProgress(), progress);         animator.start();      }      @Override     public synchronized void setSecondaryProgress(int secondaryProgress) {         if (!animate) {             super.setSecondaryProgress(secondaryProgress);             return;         }         if (animatorSecondary != null)             animatorSecondary.cancel();         if (animatorSecondary == null) {             animatorSecondary = ValueAnimator.ofInt(getProgress(), secondaryProgress);             animatorSecondary.setInterpolator(DEFAULT_INTERPOLATER);             animatorSecondary.addUpdateListener(new AnimatorUpdateListener() {                  @Override                 public void onAnimationUpdate(ValueAnimator animation) {                     AnimatingProgressBar.super.setSecondaryProgress((Integer) animation                             .getAnimatedValue());                 }             });         } else             animatorSecondary.setIntValues(getProgress(), secondaryProgress);         animatorSecondary.start();     }      @Override     protected void onDetachedFromWindow() {         super.onDetachedFromWindow();         if (animator != null)             animator.cancel();         if (animatorSecondary != null)             animatorSecondary.cancel();     }  } 

replace ProgressBar with AnimatingProgressBar in your layout

You many also change the type to AnimatingProgressBar to utilize setAnimate() to disable animation (could be useful when restoring activity state)