when using `repeatable { }` is there any way to h...

# compose

[Arpan Sarkar]

when using repeatable { } is there any way to have a callback when the animation is repeated?

[Doris Liu]

Not at the moment. Out of curiosity, what you would need to do when the animation is repeated?

[Arpan Sarkar]

I have this Progressbar Drawable implementation , so i was just wondering if i can do same kind of implementation in compose

[Arpan Sarkar]

package com.bloodybadboycreation.customview.drawable;

import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.animation.ObjectAnimator;
import android.animation.ValueAnimator;
import android.graphics.Canvas;
import android.graphics.ColorFilter;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.drawable.Animatable;
import android.graphics.drawable.Drawable;
import android.support.annotation.NonNull;
import android.util.Property;
import android.view.animation.DecelerateInterpolator;
import android.view.animation.Interpolator;
import android.view.animation.LinearInterpolator;

/**
 * Created by bloodybadboycreation on 18/9/16.
 */

public class CircularProgressDrawable extends Drawable implements Animatable {

    private static final Interpolator ANGLE_INTERPOLATOR = new LinearInterpolator();
    private static final Interpolator SWEEP_INTERPOLATOR = new DecelerateInterpolator();
    private static final int ANGLE_ANIMATOR_DURATION = 10000;
    private static final int SWEEP_ANIMATOR_DURATION = 5000;
    private static final int MIN_SWEEP_ANGLE = 30;
    private final RectF fBounds = new RectF();

    private ObjectAnimator mObjectAnimatorSweep;
    private ObjectAnimator mObjectAnimatorAngle;
    private boolean mModeAppearing;
    private Paint mPaint;
    private float mCurrentGlobalAngleOffset;
    private float mCurrentGlobalAngle;
    private float mCurrentSweepAngle;
    private float mBorderWidth;
    private boolean mRunning;
    private Property<CircularProgressDrawable, Float> mAngleProperty
            = new Property<CircularProgressDrawable, Float>(Float.class, "angle") {
        @Override
        public Float get(CircularProgressDrawable view) {
            return view.getCurrentGlobalAngle();
        }

        @Override
        public void set(CircularProgressDrawable object, Float value) {
            object.setCurrentGlobalAngle(value);
        }
    };
    private Property<CircularProgressDrawable, Float> mSweepProperty
            = new Property<CircularProgressDrawable, Float>(Float.class, "arc") {
        @Override
        public Float get(CircularProgressDrawable object) {
            return object.getCurrentSweepAngle();
        }

        @Override
        public void set(CircularProgressDrawable object, Float value) {
            object.setCurrentSweepAngle(value);
        }
    };

    public CircularProgressDrawable(int color, float borderWidth) {
        mBorderWidth = borderWidth;

        mPaint = new Paint();
        mPaint.setAntiAlias(true);
        mPaint.setStyle(Paint.Style.STROKE);
        mPaint.setStrokeWidth(borderWidth);
        mPaint.setColor(color);

        setupAnimations();
    }

    @Override
    public void draw(@NonNull Canvas canvas) {
        float startAngle = mCurrentGlobalAngle - mCurrentGlobalAngleOffset;
        float sweepAngle = mCurrentSweepAngle;
        if (!mModeAppearing) {
            startAngle = startAngle + sweepAngle;
            sweepAngle = 360 - sweepAngle - MIN_SWEEP_ANGLE;
        } else {
            sweepAngle += MIN_SWEEP_ANGLE;
        }
        canvas.drawArc(fBounds, startAngle, sweepAngle, false, mPaint);
    }

    @Override
    public void setAlpha(int alpha) {
        mPaint.setAlpha(alpha);
    }

    @Override
    public void setColorFilter(ColorFilter cf) {
        mPaint.setColorFilter(cf);
    }

    @Override
    public int getOpacity() {
        return PixelFormat.TRANSPARENT;
    }


    private void toggleAppearingMode() {
        mModeAppearing = !mModeAppearing;
        if (mModeAppearing) {
            mCurrentGlobalAngleOffset = (mCurrentGlobalAngleOffset + MIN_SWEEP_ANGLE * 2) % 360;
        }
    }

    @Override
    protected void onBoundsChange(Rect bounds) {
        super.onBoundsChange(bounds);
        fBounds.left = bounds.left + mBorderWidth / 2f + .5f;
        fBounds.right = bounds.right - mBorderWidth / 2f - .5f;
        <http://fBounds.top|fBounds.top> = <http://bounds.top|bounds.top> + mBorderWidth / 2f + .5f;
        fBounds.bottom = bounds.bottom - mBorderWidth / 2f - .5f;
    }

    private void setupAnimations() {
        mObjectAnimatorAngle = ObjectAnimator.ofFloat(this, mAngleProperty, 360f);
        mObjectAnimatorAngle.setInterpolator(ANGLE_INTERPOLATOR);
        mObjectAnimatorAngle.setDuration(ANGLE_ANIMATOR_DURATION);
        mObjectAnimatorAngle.setRepeatMode(ValueAnimator.RESTART);
        mObjectAnimatorAngle.setRepeatCount(ValueAnimator.INFINITE);

        mObjectAnimatorSweep = ObjectAnimator.ofFloat(this, mSweepProperty, 360f - MIN_SWEEP_ANGLE * 2);
        mObjectAnimatorSweep.setInterpolator(SWEEP_INTERPOLATOR);
        mObjectAnimatorSweep.setDuration(SWEEP_ANIMATOR_DURATION);
        mObjectAnimatorSweep.setRepeatMode(ValueAnimator.RESTART);
        mObjectAnimatorSweep.setRepeatCount(ValueAnimator.INFINITE);
        mObjectAnimatorSweep.addListener(new AnimatorListenerAdapter() {
            @Override
            public void onAnimationRepeat(Animator animation) {
                toggleAppearingMode();
            }
        });
    }

    @Override
    public void start() {
        if (isRunning()) {
            return;
        }
        mRunning = true;
        mObjectAnimatorAngle.start();
        mObjectAnimatorSweep.start();
        invalidateSelf();
    }

    @Override
    public void stop() {
        if (!isRunning()) {
            return;
        }
        mRunning = false;
        mObjectAnimatorAngle.cancel();
        mObjectAnimatorSweep.cancel();
        invalidateSelf();
    }

    @Override
    public boolean isRunning() {
        return mRunning;
    }

    public float getCurrentGlobalAngle() {
        return mCurrentGlobalAngle;
    }

    public void   setCurrentGlobalAngle(float currentGlobalAngle) {
        mCurrentGlobalAngle = currentGlobalAngle;
        invalidateSelf();
    }

    public float getCurrentSweepAngle() {
        return mCurrentSweepAngle;
    }

    public void setCurrentSweepAngle(float currentSweepAngle) {
        mCurrentSweepAngle = currentSweepAngle;
        invalidateSelf();
    }
}

[Doris Liu]

It looks doable with repeatable keyframes . Here's an example for keyframes: https://developer.android.com/reference/kotlin/androidx/compose/animation/core/package-summary#keyframes. It should be sufficient to handle different appearing mode related logic.