android自定义控件之彩虹加载圆圈

import android.animation.Animator;
import android.animation.ObjectAnimator;
import android.animation.ValueAnimator;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.Cap;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.util.Property;
import android.view.View;
import android.view.animation.AccelerateDecelerateInterpolator;
import android.view.animation.Interpolator;
import android.view.animation.LinearInterpolator;

import com.xh.boke.R;

/**
 * 彩虹加载圆圈
 * Created by Administrator on 2015/10/21 0021.
 */
public class CircularProgress extends View {

    private static final Interpolator ANGLE_INTERPOLATOR = new LinearInterpolator();
    private static final Interpolator SWEEP_INTERPOLATOR = new AccelerateDecelerateInterpolator();
    private static final int ANGLE_ANIMATOR_DURATION = 2000;
    private static final int SWEEP_ANIMATOR_DURATION = 900;
    private static final int MIN_SWEEP_ANGLE = 30;
    private static final int DEFAULT_BORDER_WIDTH = 3;
    private final RectF fBounds = new RectF();

    private ObjectAnimator mObjectAnimatorSweep;
    private ObjectAnimator mObjectAnimatorAngle;
    private boolean mModeAppearing = true;
    private Paint mPaint;
    private float mCurrentGlobalAngleOffset;
    private float mCurrentGlobalAngle;
    private float mCurrentSweepAngle;
    private float mBorderWidth;
    private boolean mRunning;
    //彩虹的颜色
    private int[] mColors = {0xFFFF0000,0xFFFF7F00,0xFFFFFF00,0xFF00FF00,0xFF00FFFF,0xFF0000FF,0xFF8B00FF};

    private int mCurrentColorIndex;
    private int mNextColorIndex;

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

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

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

        float density = context.getResources().getDisplayMetrics().density;
        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.CircularProgress, defStyleAttr, 0);
        mBorderWidth = a.getDimension(R.styleable.CircularProgress_borderWidth,
                DEFAULT_BORDER_WIDTH * density);
        a.recycle();

        mCurrentColorIndex = 0;
        mNextColorIndex = 1;

        mPaint = new Paint();
        mPaint.setAntiAlias(true);
        mPaint.setStyle(Paint.Style.STROKE);
        mPaint.setStrokeCap(Cap.ROUND);
        mPaint.setStrokeWidth(mBorderWidth);
        mPaint.setColor(mColors[mCurrentColorIndex]);

        setupAnimations();
    }

    private void start() {
        if (isRunning()) {
            return;
        }
        mRunning = true;
        mObjectAnimatorAngle.start();
        mObjectAnimatorSweep.start();
        invalidate();
    }

    private void stop() {
        if (!isRunning()) {
            return;
        }
        mRunning = false;
        mObjectAnimatorAngle.cancel();
        mObjectAnimatorSweep.cancel();
        invalidate();
    }

    private boolean isRunning() {
        return mRunning;
    }

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

    @Override
    protected void onAttachedToWindow() {
        start();
        super.onAttachedToWindow();
    }

    @Override
    protected void onDetachedFromWindow() {
        stop();
        super.onDetachedFromWindow();
    }
    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        fBounds.left = mBorderWidth / 2f + .5f;
        fBounds.right = w - mBorderWidth / 2f - .5f;
        fBounds.top = mBorderWidth / 2f + .5f;
        fBounds.bottom = h - mBorderWidth / 2f - .5f;
    }

    @Override
    public void draw(Canvas canvas) {
        super.draw(canvas);
        float startAngle = mCurrentGlobalAngle - mCurrentGlobalAngleOffset;
        float sweepAngle = mCurrentSweepAngle;
        if (mModeAppearing) {
            mPaint.setColor(gradient(mColors[mCurrentColorIndex], mColors[mNextColorIndex],
                    mCurrentSweepAngle / (360 - MIN_SWEEP_ANGLE * 2)));
            sweepAngle += MIN_SWEEP_ANGLE;
        } else {
            startAngle = startAngle + sweepAngle;
            sweepAngle = 360 - sweepAngle - MIN_SWEEP_ANGLE;
        }
        canvas.drawArc(fBounds, startAngle, sweepAngle, false, mPaint);
    }

    private static int gradient(int color1, int color2, float p) {
        int r1 = (color1 & 0xff0000) >> 16;
        int g1 = (color1 & 0xff00) >> 8;
        int b1 = color1 & 0xff;
        int r2 = (color2 & 0xff0000) >> 16;
        int g2 = (color2 & 0xff00) >> 8;
        int b2 = color2 & 0xff;
        int newr = (int) (r2 * p + r1 * (1 - p));
        int newg = (int) (g2 * p + g1 * (1 - p));
        int newb = (int) (b2 * p + b1 * (1 - p));
        return Color.argb(255, newr, newg, newb);
    }

    private void toggleAppearingMode() {
        mModeAppearing = !mModeAppearing;
        if (mModeAppearing) {
            mCurrentColorIndex = ++mCurrentColorIndex % mColors.length;
            mNextColorIndex = ++mNextColorIndex % mColors.length;
            mCurrentGlobalAngleOffset = (mCurrentGlobalAngleOffset + MIN_SWEEP_ANGLE * 2) % 360;
        }
    }
    // ////////////////////////////////////////////////////////////////////////////
    // ////////////// Animation

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

        @Override
        public void set(CircularProgress object, Float value) {
            object.setCurrentGlobalAngle(value);
        }
    };

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

        @Override
        public void set(CircularProgress 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();
            }
        });
    }

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

    public float getCurrentGlobalAngle() {
        return mCurrentGlobalAngle;
    }

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

    public float getCurrentSweepAngle() {
        return mCurrentSweepAngle;
    }
}

attrs.xml

<resources>
    <!--progress -->
    <declare-styleable name="CircularProgress">
        <attr name="borderWidth" format="dimension" />
    </declare-styleable>
</resources>

应用(加命名空间xmlns:lmw="http://schemas.android.com/apk/res-auto")

<!-- 最后一行是粗细 -->
<xxx.CircularProgress
　　android:layout_width="40dp"
　　android:layout_height="40dp"
　　lmw:borderWidth="4dp"/>