本文在实现雪花效果的基础上，根据漫天飞舞雪花，实现下雨天场景的效果，使用eclipse android 版本，具体内容如下

雪花效果图：

具体代码：

1、漫天飞舞的雪花主要代码

SnowView

package com.example.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];

}

}

雨滴效果图：

以上就是本文的全部内容，帮助大家轻松实现浪漫的雪花雨滴效果，大家可以把效果运用到自己的项目中，希望大家喜欢。