Implement circle progress indicator view on android.

ProgressCircle.java

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.view.View;

public class ProgressCircle extends View {

    public static final String TAG = ProgressCircle.class.getSimpleName();

    private static final int ALPHA_TRANSPARENT = 0;
    private static final int ALPHA_OPAQUE = 255;

    private static final boolean DEFAULT_INDETERMINATE_STATE = true;
    private static final int DEFAULT_PROGRESS_WIDTH = 5;
    private static final int DEFAULT_PROGRESS_BACKGROUND_COLOR = Color.TRANSPARENT;
    private static final int DEFAULT_PROGRESS_COLOR = Color.WHITE;
    private static final int DEFAULT_INDETERMINATE_PROGRESS_COLOR = Color.WHITE;
    private static final int DEFAULT_INDETERMINATE_PROGRESS_PERIOD = 2000;
    private static final float DEFAULT_INDETERMINATE_ARC_SIZE = 0.2f;

    private boolean mIndeterminate;
    private int mProgressWidth;
    private int mProgressBackgroundColor;
    private int mProgressColor;
    private int mIndeterminateProgressColor;
    private int mIndeterminatePeriod;
    private float mIndeterminateArcSize;

    private int mWidth;
    private int mHeight;

    private RectF mProgressArcRect;
    private Paint mPaintProgressBackground;
    private Paint mPaintProgress;
    private Paint mPaintIndeterminateProgress;

    private float mProgress;
    private long mLastProgressUpdate;

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

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

        TypedArray a = context.getTheme().obtainStyledAttributes(
                attrs,
                R.styleable.ProgressCircle,
                0, 0);

        try {
            mIndeterminate = a.getBoolean(R.styleable.ProgressCircle_indeterminate, DEFAULT_INDETERMINATE_STATE);
            mProgressWidth = a.getDimensionPixelSize(R.styleable.ProgressCircle_progressStrokeWidth, DEFAULT_PROGRESS_WIDTH);
            mProgressBackgroundColor = a.getColor(R.styleable.ProgressCircle_progressBackgroundColor, DEFAULT_PROGRESS_BACKGROUND_COLOR);
            mProgressColor = a.getColor(R.styleable.ProgressCircle_progressAccentColor, DEFAULT_PROGRESS_COLOR);
            mIndeterminateProgressColor = a.getColor(R.styleable.ProgressCircle_indeterminateProgressAccentColor, DEFAULT_INDETERMINATE_PROGRESS_COLOR);
            mIndeterminatePeriod = a.getInteger(R.styleable.ProgressCircle_indeterminatePeriod, DEFAULT_INDETERMINATE_PROGRESS_PERIOD);
            mIndeterminateArcSize = a.getFloat(R.styleable.ProgressCircle_indeterminateArcSize, DEFAULT_INDETERMINATE_ARC_SIZE);
        } finally {
            a.recycle();
        }

        mPaintProgressBackground = new Paint() {{
            this.setColor(mProgressBackgroundColor);
            this.setStrokeWidth(mProgressWidth);
            this.setStyle(Style.STROKE);
        }};

        mPaintProgress = new Paint() {{
            this.setColor(mProgressColor);
            this.setStrokeWidth(mProgressWidth);
            this.setStyle(Style.STROKE);
        }};

        mPaintIndeterminateProgress = new Paint() {{
            this.setColor(mIndeterminateProgressColor);
            this.setStrokeWidth(mProgressWidth);
            this.setStyle(Style.STROKE);
        }};

    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        mWidth = w;
        mHeight = h;
        mProgressArcRect = new RectF(mProgressWidth, mProgressWidth, mWidth - mProgressWidth, mHeight - mProgressWidth);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        long now = System.currentTimeMillis();

        // draw background circle
        drawCircle(canvas, mPaintProgressBackground);

        if (mIndeterminate) {
            long duration = now - mLastProgressUpdate;
            if (duration > mIndeterminatePeriod) {
                mLastProgressUpdate = now;
                duration = 0;
            }
            drawCircle(canvas, (float) duration / mIndeterminatePeriod, mIndeterminateArcSize, mPaintIndeterminateProgress);
            invalidate(); // animation loop
        } else {
            drawCircle(canvas, 0.0f, mProgress, mPaintProgress);
        }
    }

    protected void drawCircle(Canvas canvas, Paint paint) {
        drawCircle(canvas, 0.0f, 1.0f, paint);
    }

    protected void drawCircle(Canvas canvas, float start, float size, Paint paint) {
        canvas.drawArc(mProgressArcRect, -90.0f + 360.0f * start, 360.0f * size, false, paint);
    }

    public void setIndeterminate(boolean yes) {
        if (mIndeterminate != yes) {
            mIndeterminate = yes;
            invalidate();
        }
    }

    public void setProgress(float progress) {
        mProgress = progress;
        invalidate();
    }

}

styleable_attrs.xml

<declare-styleable name="ProgressCircle">
    <attr name="indeterminate" format="boolean" />
    <attr name="progressStrokeWidth" format="dimension" />
    <attr name="progressBackgroundColor" format="color" />
    <attr name="progressAccentColor" format="color" />
    <attr name="indeterminateProgressAccentColor" format="color" />
    <attr name="indeterminatePeriod" format="integer" />
    <attr name="indeterminateArcSize" format="float" />
</declare-styleable>