OutlineContainer.java

package com.keju.maomao.view.azzviewpager;

import android.content.Context;
import android.content.res.Resources;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.graphics.Rect;
import android.graphics.drawable.Animatable;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.view.animation.AnimationUtils;
import android.view.animation.Interpolator;
import android.widget.FrameLayout;

import com.keju.maomao.R;

public class OutlineContainer extends FrameLayout implements Animatable {

	private Paint mOutlinePaint;

	private boolean mIsRunning = false;
	private long mStartTime;
	private float mAlpha = 1.0f;
	private static final long ANIMATION_DURATION = 500;
	private static final long FRAME_DURATION = 1000 / 60;
	private final Interpolator mInterpolator = new Interpolator() {
		public float getInterpolation(float t) {
			t -= 1.0f;
			return t * t * t + 1.0f;
		}
	};

	public OutlineContainer(Context context) {
		super(context);
		init();
	}

	public OutlineContainer(Context context, AttributeSet attrs) {
		super(context, attrs);
		init();
	}

	public OutlineContainer(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
		init();
	}

	private void init() {
		mOutlinePaint = new Paint();
		mOutlinePaint.setAntiAlias(true);
		mOutlinePaint.setStrokeWidth(dpToPx(getResources(), 2));
		mOutlinePaint.setColor(getResources().getColor(R.color.blue));
		mOutlinePaint.setStyle(Style.STROKE);

		int padding = dpToPx(getResources(), 10);
		setPadding(padding, padding, padding, padding);
	}

	@Override
	protected void dispatchDraw(Canvas canvas) {
		super.dispatchDraw(canvas);
		int offset = dpToPx(getResources(), 5);
		if (mOutlinePaint.getColor() != JazzyViewPager.sOutlineColor) {
			mOutlinePaint.setColor(JazzyViewPager.sOutlineColor);
		}
		mOutlinePaint.setAlpha((int) (mAlpha * 255));
		Rect rect = new Rect(offset, offset, getMeasuredWidth() - offset,
				getMeasuredHeight() - offset);
		canvas.drawRect(rect, mOutlinePaint);
	}

	public void setOutlineAlpha(float alpha) {
		mAlpha = alpha;
	}

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

	@Override
	public void start() {
		if (mIsRunning)
			return;
		mIsRunning = true;
		mStartTime = AnimationUtils.currentAnimationTimeMillis();
		post(mUpdater);
	}

	@Override
	public void stop() {
		if (!mIsRunning)
			return;
		mIsRunning = false;
	}

	private final Runnable mUpdater = new Runnable() {
		@Override
		public void run() {
			long now = AnimationUtils.currentAnimationTimeMillis();
			long duration = now - mStartTime;
			if (duration >= ANIMATION_DURATION) {
				mAlpha = 0.0f;
				invalidate();
				stop();
				return;
			} else {
				mAlpha = mInterpolator.getInterpolation(1 - duration
						/ (float) ANIMATION_DURATION);
				invalidate();
			}
			postDelayed(mUpdater, FRAME_DURATION);
		}
	};

	private int dpToPx(Resources res, int dp) {
		return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dp,
				res.getDisplayMetrics());
	}
}