【安卓笔记】仿猎豹清理大师波浪效果

package com.example.wavedemo1;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.os.Handler;
import android.util.AttributeSet;
import android.view.View;
/**
 * @author Rowandjj
 *
 *仿猎豹清理大师波浪效果
 */
public class WaterWaveView extends View
{
	private Handler mHandler;
	private long c = 0L;
	private boolean mStarted = false;
	private final float f = 0.033F;
	private int mAlpha = 70;//透明度
	private int mColor = Color.BLUE;
	private float mAmplitude = 6.0F; // 振幅
	private final Paint mPaint = new Paint();
	private float mWateLevel = 0.5F;//水高(0~1)
	private Path mPath;
	public WaterWaveView(Context paramContext)
	{
		super(paramContext);
		init(paramContext);
	}
	public WaterWaveView(Context paramContext, AttributeSet paramAttributeSet)
	{
		super(paramContext, paramAttributeSet);
		init(paramContext);
	}
	/**
	 * 开始波动
	 */
	public void startWave()
	{
		if (!mStarted)
		{
			this.c = 0L;
			mStarted = true;
			this.mHandler.sendEmptyMessage(0);
		}
	}
	private void init(Context context)
	{
		mPaint.setStrokeWidth(1.0F);
		mPaint.setColor(mColor);
		mPaint.setAlpha(mAlpha);
		mPath = new Path();
		mHandler = new Handler()
		{
			@Override
			public void handleMessage(android.os.Message msg)
			{
				if (msg.what == 0)
				{
					invalidate();
					if (mStarted)
					{
						//不断发消息给自己，使自己不断被重绘
						mHandler.sendEmptyMessageDelayed(0, 60L);
					}
				}
			}
		};
	}
	@Override
	protected void onDraw(Canvas canvas)
	{
		canvas.save();
                mPaint.setAlpha(mAlpha);
		mPaint.setColor(mColor);
		// 得到控件的宽高
		int width = getWidth();
		int height = getHeight();
		// 如果未开始（未调用startWave方法）,绘制一个矩形
		if ((!mStarted) || (width == 0) || (height == 0))
		{
			canvas.drawRect(0.0F, height / 2, width, height, mPaint);
			return;
		}
		if (this.c >= 8388607L)
		{
			this.c = 0L;
		}
		//每次onDraw时c都会自增
		this.c = (1L + this.c);
		float f1 = height * (1.0F - mWateLevel);
		int top = (int) (f1 + mAmplitude);
		mPath.reset();
		// 绘制矩形,即水面静止时的高度
		canvas.drawRect(0.0F, top, width, height, mPaint);
		int startX = 0;
		//波浪效果
		while (startX < width)
		{
			int startY = (int) (f1 - mAmplitude* Math.sin(Math.PI* (2.0F * (startX + this.c * width * this.f))/ width));
			canvas.drawLine(startX, startY, startX, top, mPaint);
			startX++;
		}
		canvas.restore();
	}
	/**
	 * 设置振幅
	 * @param amplitued
	 */
	public void setAmplitude(float amplitued)
	{
		mAmplitude = amplitued;
	}
	/**
	 * 设置透明度
	 * @param alpha
	 */
	public void setWaterAlpha(float alpha)
	{
		this.mAlpha = ((int) (255.0F * alpha));
		mPaint.setAlpha(this.mAlpha);
	}
	/**
	 * 设置颜色
	 * @param color
	 */
	public void setColor(int color)
	{
		this.mColor = color;
	}
	
	/**
	 * 设置水面高度
	 * @param paramFloat
	 */
	public void setWaterLevel(float paramFloat)
	{
		mWateLevel = paramFloat;
	}
	
	@Override
	protected void onAttachedToWindow()
	{
		super.onAttachedToWindow();
		// 关闭硬件加速，防止异常unsupported operation exception
		this.setLayerType(View.LAYER_TYPE_SOFTWARE, null);
	}
}