Android营造雪花和雨滴浪漫效果

<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();  }  }; } 

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;  } } 

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();  }  }; } 

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];  }  }