Android營造雪花和雨滴浪漫效果

2020-04-11 10:53:45

字體：大中小

來源：轉載

供稿：網友

本文在實現雪花效果的基礎上，根據漫天飛舞雪花，實現下雨天場景的效果，使用eclipse android 版本，具體內容如下

雪花效果圖：

具體代碼：

1、漫天飛舞的雪花主要代碼
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;  /**  * 雪花視圖, DELAY時間重繪, 繪制NUM_SNOWFLAKES個雪花  */ public class SnowView extends View {   private static final int NUM_SNOWFLAKES = 150; // 雪花數量  private static final int DELAY = 5; // 延遲  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); // 抗鋸齒  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這里面  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) {   //然后進行繪制   s.draw(canvas);  }  // 隔一段時間重繪一次, 動畫效果  getHandler().postDelayed(runnable, DELAY);  }   // 重繪線程  private Runnable runnable = new Runnable() {  @Override  public void run() {   //自動刷新   invalidate();  }  }; }

SnowFlake

package com.example.snowflake.view;  import com.example.snowflake.RandomGenerator;  import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.Point;  /**  * 雪花的類, 移動, 移出屏幕會重新設置位置.  */ public class SnowFlake {  // 雪花的角度  private static final float ANGE_RANGE = 0.1f; // 角度范圍  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; // 角度隨機種子  private static final float ANGLE_DIVISOR = 10000f;  // 雪花的移動速度  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; // 隨機控制器  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; // 畫筆   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);  }   // 繪制雪花  public void draw(Canvas canvas) {  int width = canvas.getWidth();  int height = canvas.getHeight();  move(width, height);  canvas.drawCircle(mPosition.x, mPosition.y, mFlakeSize, mPaint);  }   // 移動雪花  private void move(int width, int height) {  //x水平方向，那么需要晃動，主要設置這個值就可以，現在取消晃動了  //如果 mPosition.x不加上后面那個值，就不會晃動了  double x = mPosition.x + (mIncrement * Math.cos(mAngle));  //y是豎直方向，就是下落  double y = mPosition.y + (mIncrement * Math.sin(mAngle));   mAngle += mRandom.getRandom(-ANGLE_SEED, ANGLE_SEED) / ANGLE_DIVISOR;  //這個是設置雪花位置，如果在很短時間內刷新一次，就是連起來的動畫效果  mPosition.set((int) x, (int) y);   // 移除屏幕, 重新開始  if (!isInside(width, height)) {   // 重置雪花   reset(width);  }  }   // 判斷是否在其中  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、實現下雨天效果代碼
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;  /**  * 雨滴視圖, DELAY時間重繪, 繪制NUM_SNOWFLAKES個雨滴  */ public class RainView extends View {   private static final int NUM_SNOWFLAKES = 150; // 雨滴數量  private static final int DELAY = 5; // 延遲  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); // 抗鋸齒  paint.setColor(getResources().getColor(R.color.colorWater)); // 雨滴的顏色  paint.setStyle(Paint.Style.FILL); // 填充;  mSnowFlakes = new RainFlake[NUM_SNOWFLAKES];  //mSnowFlakes所有的雨滴都生成放到這里面  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) {   //然后進行繪制   s.draw(canvas);  }  // 隔一段時間重繪一次, 動畫效果  getHandler().postDelayed(runnable, DELAY);  }   // 重繪線程  private Runnable runnable = new Runnable() {  @Override  public void run() {   //自動刷新   invalidate();  }  }; }

RainFlake

package com.example.raindrop.view;  import com.example.raindrop.RandomGenerator;  import android.graphics.Canvas; import android.graphics.Paint;  /**  * 雨滴的類, 移動, 移出屏幕會重新設置位置.  */ public class RainFlake {   // 雨滴的移動速度  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; // 畫筆   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);  }   // 繪制雨滴  public void draw(Canvas canvas) {  int width = canvas.getWidth();  int height = canvas.getHeight();  drawLine(canvas, width, height);  }   /**  * 改成線條，類似于雨滴效果  * @param canvas  * @param width  * @param height  */  private void drawLine(Canvas canvas, int width, int height) {  //設置線寬  mPaint.setStrokeWidth(mFlakeSize);  //y是豎直方向，就是下落  double y1 = mLine.y1 + (mIncrement * Math.sin(1.5));  double y2 = mLine.y2 + (mIncrement * Math.sin(1.5));   //這個是設置雨滴位置，如果在很短時間內刷新一次，就是連起來的動畫效果  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);  }   // 判斷是否在其中  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];  }  }

雨滴效果圖：