android 实现漫天飞舞雪花以及下雨天的效果

BigWang 9年前

来自： http://blog.csdn.net/qq_16064871/article/details/50603105

前言：

这个效果实现的原作者是国外一位大神。我在其基础上测试，以及在代码上加了不少注释，以及局部修改。后面我有根据漫天飞舞雪花，实现下雨天场景的效果。原作者项目还是android studio版本的。我改成eclipse android 版本。

英文原文地址：https://blog.stylingandroid.com/snowfall/

中文翻译地址：http://www.open-open.com/lib/view/open1452263908573.html

国外大神实现效果油Tube视频地址：https://www.油Tube.com/watch?v=pk66ZziTfOw

中文翻译是open开发者经验库一位作者翻译，翻译的很好。在那篇文章也能看到实现的最原始的效果。

实现漫天飞舞的雪花下载地址：http://download.csdn.net/detail/qq_16064871/9420804

实现下雨天效果的下载地址：http://download.csdn.net/detail/qq_16064871/9420808

1、漫天飞舞的雪花主要代码

SnowView

<span style="font-size:14px;">package com.ex</span>ample.snowflake.view;    import android.content.Context;  import android.graphics.Canvas;  import android.graphics.Color;  import android.graphics.Paint;  import android.util.AttributeSet;  import android.view.View;    /**   * 雪花视图, DELAY时间重绘, 绘制NUM_SNOWFLAKES个雪花   */  public class SnowView extends View {        private static final int NUM_SNOWFLAKES = 150; // 雪花数量      private static final int DELAY = 5; // 延迟      private SnowFlake[] mSnowFlakes; // 雪花        public SnowView(Context context) {          super(context);      }        public SnowView(Context context, AttributeSet attrs) {          super(context, attrs);      }        public SnowView(Context context, AttributeSet attrs, int defStyleAttr) {          super(context, attrs, defStyleAttr);      }        @Override       protected void onSizeChanged(int w, int h, int oldw, int oldh) {          super.onSizeChanged(w, h, oldw, oldh);          if (w != oldw || h != oldh) {              initSnow(w, h);          }      }        private void initSnow(int width, int height) {          Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG); // 抗锯齿          paint.setColor(Color.WHITE); // 白色雪花          paint.setStyle(Paint.Style.FILL); // 填充;          mSnowFlakes = new SnowFlake[NUM_SNOWFLAKES];          //mSnowFlakes所有的雪花都生成放到这里面          for (int i = 0; i < NUM_SNOWFLAKES; ++i) {              mSnowFlakes[i] = SnowFlake.create(width, height, paint);          }      }        @Override       protected void onDraw(Canvas canvas) {          super.onDraw(canvas);          //for返回SnowFlake          for (SnowFlake s : mSnowFlakes) {           //然后进行绘制              s.draw(canvas);          }          // 隔一段时间重绘一次, 动画效果          getHandler().postDelayed(runnable, DELAY);      }        // 重绘线程      private Runnable runnable = new Runnable() {          @Override          public void run() {           //自动刷新              invalidate();          }      };  }

SnowFlake

package com.example.snowflake.view;    import com.example.snowflake.RandomGenerator;    import android.graphics.Canvas;  import android.graphics.Paint;  import android.graphics.Point;    /**   * 雪花的类, 移动, 移出屏幕会重新设置位置.   */  public class SnowFlake {      // 雪花的角度      private static final float ANGE_RANGE = 0.1f; // 角度范围      private static final float HALF_ANGLE_RANGE = ANGE_RANGE / 2f; // 一般的角度      private static final float HALF_PI = (float) Math.PI / 2f; // 半PI      private static final float ANGLE_SEED = 25f; // 角度随机种子      private static final float ANGLE_DIVISOR = 10000f;      // 雪花的移动速度      private static final float INCREMENT_LOWER = 2f;      private static final float INCREMENT_UPPER = 4f;        // 雪花的大小      private static final float FLAKE_SIZE_LOWER = 7f;      private static final float FLAKE_SIZE_UPPER = 20f;        private final RandomGenerator mRandom; // 随机控制器      private final Point mPosition; // 雪花位置      private float mAngle; // 角度      private final float mIncrement; // 雪花的速度      private final float mFlakeSize; // 雪花的大小      private final Paint mPaint; // 画笔        private SnowFlake(RandomGenerator random, Point position, float angle, float increment, float flakeSize, Paint paint) {          mRandom = random;          mPosition = position;          mIncrement = increment;          mFlakeSize = flakeSize;          mPaint = paint;          mAngle = angle;      }        public static SnowFlake create(int width, int height, Paint paint) {          RandomGenerator random = new RandomGenerator();          int x = random.getRandom(width);          int y = random.getRandom(height);          Point position = new Point(x, y);          float angle = random.getRandom(ANGLE_SEED) / ANGLE_SEED * ANGE_RANGE + HALF_PI - HALF_ANGLE_RANGE;          float increment = random.getRandom(INCREMENT_LOWER, INCREMENT_UPPER);          float flakeSize = random.getRandom(FLAKE_SIZE_LOWER, FLAKE_SIZE_UPPER);          return new SnowFlake(random, position, angle, increment, flakeSize, paint);      }        // 绘制雪花      public void draw(Canvas canvas) {          int width = canvas.getWidth();          int height = canvas.getHeight();          move(width, height);          canvas.drawCircle(mPosition.x, mPosition.y, mFlakeSize, mPaint);      }        // 移动雪花      private void move(int width, int height) {       //x水平方向，那么需要晃动，主要设置这个值就可以，现在取消晃动了       //如果 mPosition.x不加上后面那个值，就不会晃动了       double x = mPosition.x + (mIncrement * Math.cos(mAngle));          //y是竖直方向，就是下落          double y = mPosition.y + (mIncrement * Math.sin(mAngle));             mAngle += mRandom.getRandom(-ANGLE_SEED, ANGLE_SEED) / ANGLE_DIVISOR;          //这个是设置雪花位置，如果在很短时间内刷新一次，就是连起来的动画效果          mPosition.set((int) x, (int) y);            // 移除屏幕, 重新开始          if (!isInside(width, height)) {              // 重置雪花              reset(width);          }      }            // 判断是否在其中      private boolean isInside(int width, int height) {          int x = mPosition.x;          int y = mPosition.y;          return x > mFlakeSize -5 && x + mFlakeSize <= width && y >= -mFlakeSize - 1 && y - mFlakeSize < height;      }        // 重置雪花      private void reset(int width) {          mPosition.x = mRandom.getRandom(width);          mPosition.y = (int) (-mFlakeSize - 1); // 最上面          mAngle = mRandom.getRandom(ANGLE_SEED) / ANGLE_SEED * ANGE_RANGE + HALF_PI - HALF_ANGLE_RANGE;      }  }

2、实现下雨天效果代码

RainView

package com.example.raindrop.view;    import com.example.raindrop.R;    import android.content.Context;  import android.graphics.Canvas;  import android.graphics.Paint;  import android.util.AttributeSet;  import android.view.View;    /**   * 雨滴视图, DELAY时间重绘, 绘制NUM_SNOWFLAKES个雨滴   */  public class RainView extends View {        private static final int NUM_SNOWFLAKES = 150; // 雨滴数量      private static final int DELAY = 5; // 延迟      private RainFlake[] mSnowFlakes; // 雨滴        public RainView(Context context) {          super(context);      }        public RainView(Context context, AttributeSet attrs) {          super(context, attrs);      }        public RainView(Context context, AttributeSet attrs, int defStyleAttr) {          super(context, attrs, defStyleAttr);      }        @Override       protected void onSizeChanged(int w, int h, int oldw, int oldh) {          super.onSizeChanged(w, h, oldw, oldh);          if (w != oldw || h != oldh) {              initSnow(w, h);          }      }        private void initSnow(int width, int height) {          Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG); // 抗锯齿          paint.setColor(getResources().getColor(R.color.colorWater)); // 雨滴的颜色          paint.setStyle(Paint.Style.FILL); // 填充;          mSnowFlakes = new RainFlake[NUM_SNOWFLAKES];          //mSnowFlakes所有的雨滴都生成放到这里面          for (int i = 0; i < NUM_SNOWFLAKES; ++i) {              mSnowFlakes[i] = RainFlake.create(width, height, paint);          }      }        @Override       protected void onDraw(Canvas canvas) {          super.onDraw(canvas);          //for返回SnowFlake          for (RainFlake s : mSnowFlakes) {           //然后进行绘制              s.draw(canvas);          }          // 隔一段时间重绘一次, 动画效果          getHandler().postDelayed(runnable, DELAY);      }        // 重绘线程      private Runnable runnable = new Runnable() {          @Override          public void run() {           //自动刷新              invalidate();          }      };  }

RainFlake

package com.example.raindrop.view;    import com.example.raindrop.RandomGenerator;    import android.graphics.Canvas;  import android.graphics.Paint;    /**   * 雨滴的类, 移动, 移出屏幕会重新设置位置.   */  public class RainFlake {        // 雨滴的移动速度      private static final float INCREMENT_LOWER = 6f;      private static final float INCREMENT_UPPER = 8f;        // 雨滴的大小      private static final float FLAKE_SIZE_LOWER = 2f;      private static final float FLAKE_SIZE_UPPER = 5f;        private final float mIncrement; // 雨滴的速度      private final float mFlakeSize; // 雨滴的大小      private final Paint mPaint; // 画笔            private Line mLine; // 雨滴            private RandomGenerator mRandom;        private RainFlake(RandomGenerator random,Line line, float increment, float flakeSize, Paint paint) {       mRandom = random;       mLine = line;          mIncrement = increment;          mFlakeSize = flakeSize;          mPaint = paint;      }        //生成雨滴      public static RainFlake create(int width, int height, Paint paint) {       RandomGenerator random = new RandomGenerator();    int [] nline;    nline = random.getLine(width, height);                    Line line = new Line(nline[0], nline[1], nline[2], nline[3]);          float increment = random.getRandom(INCREMENT_LOWER, INCREMENT_UPPER);          float flakeSize = random.getRandom(FLAKE_SIZE_LOWER, FLAKE_SIZE_UPPER);          return new RainFlake(random,line, increment, flakeSize, paint);      }        // 绘制雨滴      public void draw(Canvas canvas) {          int width = canvas.getWidth();          int height = canvas.getHeight();          drawLine(canvas, width, height);      }        /**       * 改成线条，类似于雨滴效果       * @param canvas       * @param width       * @param height       */   private void drawLine(Canvas canvas, int width, int height) {    //设置线宽     mPaint.setStrokeWidth(mFlakeSize);    //y是竖直方向，就是下落        double y1 = mLine.y1 + (mIncrement * Math.sin(1.5));        double y2 = mLine.y2 + (mIncrement * Math.sin(1.5));          //这个是设置雨滴位置，如果在很短时间内刷新一次，就是连起来的动画效果         mLine.set(mLine.x1,(int) y1,mLine.x2 ,(int) y2);        if (!isInsideLine(height)) {     resetLine(width,height);    }        canvas.drawLine(mLine.x1, mLine.y1, mLine.x2, mLine.y2, mPaint);   }         // 判断是否在其中      private boolean isInsideLine(int height) {          return mLine.y1 < height && mLine.y2 < height;      }        // 重置雨滴      private void resetLine(int width, int height) {    int [] nline;    nline = mRandom.getLine(width, height);    mLine.x1 = nline[0];    mLine.y1 = nline[1];    mLine.x2 = nline[2];    mLine.y2 = nline[3];      }    }