水波浪效果

WaterWaveView.java

package com.example.glowbuttontest;

import java.lang.ref.WeakReference;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.os.Handler;
import android.os.Message;
import android.util.AttributeSet;
import android.view.View;

public class WaterWaveView extends View {
	/** 水的画笔 */
	private Paint mPaintWater = null;
	/** 产生波浪效果的因子 */
	private long mWaveFactor = 0L;
	/** 正在执行波浪动画 */
	private boolean isWaving = false;
	/** 振幅 */
	private float mAmplitude = 20.0F;
	/** 波浪的速度 */
	private float mWaveSpeed = 0.020F;
	/** 水的高度占容器总高度的百分比 */
	private float mWaterLevel = 0.5F;
	/** 水的透明度 */
	private int mWaterAlpha = 255;
	/** 水的颜色 */
	private int mWaterColor = 0x4bbdfe;

	private MyHandler mHandler = null;

	private static class MyHandler extends Handler {
		private WeakReference<WaterWaveView> mWeakRef = null;

		private int refreshPeriod = 100;

		public MyHandler(WaterWaveView host) {
			mWeakRef = new WeakReference<WaterWaveView>(host);
		}

		@Override
		public void handleMessage(Message msg) {
			super.handleMessage(msg);
			if (mWeakRef.get() != null) {
				mWeakRef.get().invalidate();
				sendEmptyMessageDelayed(0, refreshPeriod);
			}
		}
	}

	public WaterWaveView(Context paramContext) {
		super(paramContext);
		init(paramContext);
	}

	public WaterWaveView(Context context, AttributeSet attributeSet) {
		super(context, attributeSet);
		init(context);
	}

	private void init(Context paramContext) {
		setBackgroundColor(0x804bbdfe);
		mPaintWater = new Paint();
		mPaintWater.setStrokeWidth(1.0F);
		mPaintWater.setColor(mWaterColor);
		mPaintWater.setAlpha(mWaterAlpha);
		mHandler = new MyHandler(this);
	}

	public void animateWave() {
		if (!isWaving) {
			mWaveFactor = 0L;
			isWaving = true;
			mHandler.sendEmptyMessage(0);
		}
	}

	protected void onDraw(Canvas canvas) {
		super.onDraw(canvas);
		// 获取整个View（容器）的宽、高
		int width = getWidth();
		int height = getHeight();

		// 如果没有执行波浪动画，或者也没有指定容器宽高，就画个简单的矩形
		if (!isWaving || (width == 0) || (height == 0)) {
			canvas.drawRect(0.0F, height / 2, width, height, mPaintWater);
			return;
		}

		// 重新生成波浪的形状
		mWaveFactor++;
		if (mWaveFactor >= Integer.MAX_VALUE) {
			mWaveFactor = 0L;
		}

		// 计算出水的高度
		float waterHeight = height * mWaterLevel;
		// 先把水静止的部分画出来
		int staticHeight = (int) (waterHeight + mAmplitude);
		canvas.drawRect(0.0F, staticHeight, width, height, mPaintWater);

		// 待绘制的波浪线的x坐标
		int xToBeDrawed = 0;
		// 波浪线高度
		int waveHeight = (int) (waterHeight - mAmplitude
				* Math.sin(Math.PI
						* (2.0F * (xToBeDrawed + (mWaveFactor * width)
								* mWaveSpeed)) / width));
		// 波浪线新的高度
		int newWaveHeight = waveHeight;
		while (true) {
			if (xToBeDrawed >= width) {
				break;
			}
			// 根据当前x值计算波浪线新的高度
			newWaveHeight = (int) (waterHeight - mAmplitude
					* Math.sin(Math.PI
							* (2.0F * (xToBeDrawed + (mWaveFactor * width)
									* mWaveSpeed)) / width));

			// 先画出梯形的顶边
			canvas.drawLine(xToBeDrawed, waveHeight, xToBeDrawed + 1,
					newWaveHeight, mPaintWater);

			// 画出动态变化的柱子部分
			canvas.drawLine(xToBeDrawed, newWaveHeight, xToBeDrawed,
					staticHeight, mPaintWater);
			xToBeDrawed++;
			waveHeight = newWaveHeight;
		}
	}

	/**
	 * 设置波浪的振幅
	 */
	public void setAmplitude(float amplitude) {
		mAmplitude = amplitude;
	}

	/**
	 * 设置水的透明度
	 * 
	 * @param alpha
	 *            透明的百分比，值为0到1之间的小数，越接近0越透明
	 */
	public void setWaterAlpha(float alpha) {
		mWaterAlpha = (int) (255.0F * alpha);
		mPaintWater.setAlpha(mWaterAlpha);
	}

	/** 设置水的颜色 */
	public void setWaterColor(int color) {
		mWaterColor = color;
	}

	/**
	 * 设置水在容器里的百分比
	 */
	public void setWaterLevel(float level) {
		mWaterLevel = level;
	}

	/**
	 * 设置波浪速度
	 */
	public void setWaveSpeed(float speed) {
		mWaveSpeed = speed;
	}
}