WaveView2.java

package yifeiyuan.practice.practicedemos.wave;

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

import java.util.ArrayList;
import java.util.List;
import java.util.Timer;
import java.util.TimerTask;

/**
 *
 * @author chenjing
 * 
 */
public class WaveView2 extends View
{

	private int mViewWidth;
	private int mViewHeight;

	/**
	 * ˮλ��
	 */
	private float mLevelLine;

	/**
	 * ���������
	 */
	private float mWaveHeight = 80;
	/**
	 * ����
	 */
	private float mWaveWidth = 200;
	/**
	 * �����ص�����ߵIJ���
	 */
	private float mLeftSide;

	private float mMoveLen;
	/**
	 * ˮ��ƽ���ٶ�
	 */
	public static final float SPEED = 1.7f;

	private List<Point> mPointsList;
	private Paint mPaint;
	private Paint mTextPaint;
	private Path mWavePath;
	private boolean isMeasured = false;

	private Timer timer;
	private MyTimerTask mTask;
	Handler updateHandler = new Handler()
	{

		@Override
		public void handleMessage(Message msg)
		{
			// ��¼ƽ����λ��
			mMoveLen += SPEED;
			// ˮλ����
			mLevelLine -= 0.1f;
			if (mLevelLine < 0)
				mLevelLine = 0;
			mLeftSide += SPEED;
			// ����ƽ��
			for (int i = 0; i < mPointsList.size(); i++)
			{
				mPointsList.get(i).setX(mPointsList.get(i).getX() + SPEED);
				switch (i % 4)
				{
				case 0:
				case 2:
					mPointsList.get(i).setY(mLevelLine);
					break;
				case 1:
					mPointsList.get(i).setY(mLevelLine + mWaveHeight);
					break;
				case 3:
					mPointsList.get(i).setY(mLevelLine - mWaveHeight);
					break;
				}
			}
			if (mMoveLen >= mWaveWidth)
			{
				mMoveLen = 0;
				resetPoints();
			}
			invalidate();
		}

	};

	/**
	 * ���е��x��궼��ԭ����ʼ״̬��Ҳ����һ������ǰ��״̬
	 */
	private void resetPoints()
	{
		mLeftSide = -mWaveWidth;
		for (int i = 0; i < mPointsList.size(); i++)
		{
			mPointsList.get(i).setX(i * mWaveWidth / 4 - mWaveWidth);
		}
	}

	public WaveView2(Context context)
	{
		super(context);
		init();
	}

	public WaveView2(Context context, AttributeSet attrs)
	{
		super(context, attrs);
		init();
	}

	public WaveView2(Context context, AttributeSet attrs, int defStyle)
	{
		super(context, attrs, defStyle);
		init();
	}

	private void init()
	{
		mPointsList = new ArrayList<Point>();
		timer = new Timer();

		mPaint = new Paint();
		mPaint.setAntiAlias(true);
		mPaint.setStyle(Style.FILL);
		mPaint.setColor(Color.BLUE);

		mTextPaint = new Paint();
		mTextPaint.setColor(Color.WHITE);
		mTextPaint.setTextAlign(Align.CENTER);
		mTextPaint.setTextSize(30);

		mWavePath = new Path();
	}

	@Override
	public void onWindowFocusChanged(boolean hasWindowFocus)
	{
		super.onWindowFocusChanged(hasWindowFocus);
		start();
	}

	private void start()
	{
		if (mTask != null)
		{
			mTask.cancel();
			mTask = null;
		}
		mTask = new MyTimerTask(updateHandler);
		timer.schedule(mTask, 0, 10);
	}

	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
	{
		super.onMeasure(widthMeasureSpec, heightMeasureSpec);
		if (!isMeasured)
		{
			isMeasured = true;
			mViewHeight = getMeasuredHeight();
			mViewWidth = getMeasuredWidth();
			// ˮλ�ߴ�����¿�ʼ����
			mLevelLine = mViewHeight;
			// ���View��ȼ��㲨�η�ֵ
			mWaveHeight = mViewWidth / 2.5f;
			// ���������ı�View���Ҳ����View��ֻ�ܿ����ķ�֮һ�����Σ��������ʹ��������
			mWaveWidth = mViewWidth * 4;
			// ������صľ���Ԥ��һ������
			mLeftSide = -mWaveWidth;
			// ��������ڿɼ��View����������ɼ������Σ�ע��n��ȡ��
			int n = (int) Math.round(mViewWidth / mWaveWidth + 0.5);
			// n��������Ҫ4n+1���㣬��������ҪԤ��һ�������������������������Ҫ4n+5����
			for (int i = 0; i < (4 * n + 5); i++)
			{
				// ��P0��ʼ��ʼ����P4n+4���ܹ�4n+5����
				float x = i * mWaveWidth / 4 - mWaveWidth;
				float y = 0;
				switch (i % 4)
				{
				case 0:
				case 2:
					// ���λ��ˮλ����
					y = mLevelLine;
					break;
				case 1:
					// ���²����Ŀ��Ƶ�
					y = mLevelLine + mWaveHeight;
					break;
				case 3:
					// ���ϲ����Ŀ��Ƶ�
					y = mLevelLine - mWaveHeight;
					break;
				}
				mPointsList.add(new Point(x, y));
			}
		}
	}

	@Override
	protected void onDraw(Canvas canvas)
	{

		mWavePath.reset();
		int i = 0;
		mWavePath.moveTo(mPointsList.get(0).getX(), mPointsList.get(0).getY());
		for (; i < mPointsList.size() - 2; i = i + 2)
		{
			mWavePath.quadTo(mPointsList.get(i + 1).getX(),
					mPointsList.get(i + 1).getY(), mPointsList.get(i + 2)
							.getX(), mPointsList.get(i + 2).getY());
		}
		mWavePath.lineTo(mPointsList.get(i).getX(), mViewHeight);
		mWavePath.lineTo(mLeftSide, mViewHeight);
		mWavePath.close();

		// mPaint��Style��FILL����������Path����
		canvas.drawPath(mWavePath, mPaint);
		// ���ưٷֱ�
		canvas.drawText("" + ((int) ((1 - mLevelLine / mViewHeight) * 100))
				+ "%", mViewWidth / 2, mLevelLine + mWaveHeight
				+ (mViewHeight - mLevelLine - mWaveHeight) / 2, mTextPaint);
	}

	class MyTimerTask extends TimerTask
	{
		Handler handler;

		public MyTimerTask(Handler handler)
		{
			this.handler = handler;
		}

		@Override
		public void run()
		{
			handler.sendMessage(handler.obtainMessage());
		}

	}

	class Point
	{
		private float x;
		private float y;

		public float getX()
		{
			return x;
		}

		public void setX(float x)
		{
			this.x = x;
		}

		public float getY()
		{
			return y;
		}

		public void setY(float y)
		{
			this.y = y;
		}

		public Point(float x, float y)
		{
			this.x = x;
			this.y = y;
		}

	}

}