CircularProgressDrawable.java

package com.company.components;

import android.animation.Animator;
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.util.Property;
import android.view.animation.DecelerateInterpolator;
import android.view.animation.Interpolator;
import android.view.animation.LinearInterpolator;

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 = 2000;
    private static final int          SWEEP_ANIMATOR_DURATION = 600;
    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;

    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(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;
    }

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

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

    public float getCurrentGlobalAngle() {
        return mCurrentGlobalAngle;
    }

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

    public float getCurrentSweepAngle() {
        return mCurrentSweepAngle;
    }
    
    private void toggleAppearingMode() {
        mModeAppearing = !mModeAppearing;
        if (mModeAppearing) {
            mCurrentGlobalAngleOffset = (mCurrentGlobalAngleOffset + MIN_SWEEP_ANGLE * 2) % 360;
        }
    }

    //////////////////////////////////////////////////////////////////////////////
    ////////////////            Animation

    private Property<CircularProgressDrawable, Float> mAngleProperty
            = new Property<CircularProgressDrawable, Float>(Float.class, "angle") {
        @Override
        public Float get(CircularProgressDrawable object) {
            return object.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);
        }
    };

    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 Animator.AnimatorListener() {
            @Override
            public void onAnimationStart(Animator animation) {

            }

            @Override
            public void onAnimationEnd(Animator animation) {

            }

            @Override
            public void onAnimationCancel(Animator animation) {

            }

            @Override
            public void onAnimationRepeat(Animator animation) {
                toggleAppearingMode();
            }
        });
    }
}

MaterialProgressBar.java

package com.company.components;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.view.View;

public class MaterialProgressBar extends View {

    private CircularProgressDrawable mDrawable;

    public MaterialProgressBar(Context context) {
        this(context, null);
    }

    public MaterialProgressBar(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public MaterialProgressBar(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);

        mDrawable = new CircularProgressDrawable(Color.parseColor("#1E88E5"), 3);
        mDrawable.setCallback(this);
        if (getVisibility() == VISIBLE) {
            mDrawable.start();
        }
    }
    
    @Override
    public void draw(Canvas canvas) {
        super.draw(canvas);
        mDrawable.draw(canvas);
    }

    @Override
    protected void onVisibilityChanged(View changedView, int visibility) {
        super.onVisibilityChanged(changedView, visibility);
        if (mDrawable != null) {
            if (visibility == VISIBLE) {
                mDrawable.start();
            } else {
                mDrawable.stop();
            }
        }
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        mDrawable.setBounds(0, 0, w, h);
    }

    @Override
    protected boolean verifyDrawable(Drawable who) {
        return who == mDrawable || super.verifyDrawable(who);
    }
}