Android自定义view实现雪花特效实例代码-编程学习网

一、前言

这个冬天，老家一直没有下雨，正好圣诞节，就想着制作一个下雪的特效。

圣诞祝福：平安夜，舞翩阡。雪花飘，飞满天。心与心，永相伴。

圣诞节是传统的宗教节日，对于基督徒，那是庆祝耶稣的诞生，纪念耶稣和发扬基督精神。现在整个西方社会都在过圣诞节，像许多宗教节日一样，它已经越来越民俗化了。

尽管如此，圣诞节依然倍受尊重。人们在圣诞快乐中怀有对耶稣的敬仰，欢乐的节庆里含有庄严肃穆的神念。欢度圣诞佳节的人都不拒绝耶稣的教诲，要仁爱、善良、诚实、忍耐、感恩……在信神的国度，不是基督徒的人们，也都知道人应该感恩，心存谢意。对需要帮助的人给予关爱；对他人的帮助给予感谢。这是西方社会价值观的一部份，而不是说圣诞夜就只是一家坐在壁炉前，共进有火鸡或烤鹅的圣诞大餐或是冬季里开的一个最热闹的大派对。

二、创意名

Android实现雪花特效自定义view

三、效果展示

四、实现步骤

1.创建一个view，里面加载雪花类的集合，有一个死循环线程，一直执行动画

 public class myRunnable implements Runnable {
        @Override
        public void run() {
            while (true){
                Canvas canvas =null;
                try {
                    synchronized (holder){
                        canvas = holder.lockCanvas();
                        //清除画布
                        canvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR);
                        for (Snowflake snowflake :list){
                            snowflake.draw(canvas);
                            snowflake.update();
                        }
                    }
                }catch (Exception e){
                    e.printStackTrace();
                }finally {
                    if (canvas!=null){
                        holder.unlockCanvasAndPost(canvas);
                    }
                }

            }
        }
    }

这样的话，可以让所有的雪花图片动起来

2.创建雪花类，其实就是一个bitmap，然后设置不同尺寸和动画

这步相对来说简单一些，其实就是将bitmap绘制到画布上面

public void reset(){
        size = randomizer.randomInt(sizeMinInPx, sizeMaxInPx, true);
        if (image!=null){
            if (bitmap==null){
                bitmap = Bitmap.createScaledBitmap(image, size, size, false);
            }
        }
        float speed =  (float)(size - sizeMinInPx) / (sizeMaxInPx - sizeMinInPx) * (speedMax - speedMin) + speedMin;
        double angle = Math.toRadians(randomizer.randomDouble(angleMax) * randomizer.randomSignum());
        speedX = speed* Math.sin(angle);
        speedY = speed* Math.cos(angle);

        alpha = randomizer.randomInt(alphaMin, alphaMax, false);
        paint.setAlpha(alpha);

        positionX = randomizer.randomDouble(parentWidth);

        this.positionY=randomizer.randomDouble(parentHeight);
        if (!alreadyFalling){
            this.positionY = this.positionY-parentHeight-size;
        }
    }

3.界面展示

实现manifest加载视图即可

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#000"
    tools:context="com.marvin.snowfall_master.MainActivity">

    <com.itbird.SnowfallView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/sf_snow"
        app:snowflakesNum="200"
        app:snowflakeAlphaMin="150"
        app:snowflakeAlphaMax="255"
        app:snowflakeAngleMax="5"
        app:snowflakeSizeMin="2dp"
        app:snowflakeSizeMax="40dp"
        app:snowflakeSpeedMin="2"
        app:snowflakeSpeedMax="10"
        app:snowflakesFadingEnabled="true"
        app:snowflakesAlreadyFalling="false"
        app:snowflakeImage="@mipmap/snowflake"
        />

</android.support.constraint.ConstraintLayout>

五、编码实现

界面类SnowfallView

public class SnowfallView extends SurfaceView implements SurfaceHolder.Callback {

    private int DEFAULT_SNOWFLAKES_NUM = 200;
    private int DEFAULT_SNOWFLAKE_ALPHA_MIN = 150;
    private int DEFAULT_SNOWFLAKE_ALPHA_MAX = 250;
    private int DEFAULT_SNOWFLAKE_ANGLE_MAX = 10;
    private int DEFAULT_SNOWFLAKE_SIZE_MIN_IN_DP = 2;
    private int DEFAULT_SNOWFLAKE_SIZE_MAX_IN_DP = 8;
    private int DEFAULT_SNOWFLAKE_SPEED_MIN = 2;
    private int DEFAULT_SNOWFLAKE_SPEED_MAX = 8;
    private boolean DEFAULT_SNOWFLAKES_FADING_ENABLED = false;
    private boolean DEFAULT_SNOWFLAKES_ALREADY_FALLING = false;

    private int snowflakesNum;
    private Bitmap snowflakeImage;
    private int snowflakeAlphaMin;
    private int snowflakeAlphaMax;
    private int snowflakeAngleMax;
    private int snowflakeSizeMinInPx;
    private int snowflakeSizeMaxInPx;
    private int snowflakeSpeedMin;
    private int snowflakeSpeedMax;
    private boolean snowflakesFadingEnabled;
    private boolean snowflakesAlreadyFalling;

    //雪花类集合
    private ArrayList<Snowflake> list =new ArrayList<>();

    private SnowfallView.myRunnable myRunnable = new myRunnable();
    private Thread myThread;
    private SurfaceHolder holder;


    public SnowfallView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        init(context,attrs);
    }

    private void init(Context context, AttributeSet attributeSet) {
        TypedArray typedArray = context.obtainStyledAttributes(attributeSet, R.styleable.SnowfallView);
        snowflakesNum = typedArray.getInt(R.styleable.SnowfallView_snowflakesNum, DEFAULT_SNOWFLAKES_NUM);
        snowflakeImage = drawable2Bitmap(typedArray.getDrawable(R.styleable.SnowfallView_snowflakeImage));
        snowflakeAlphaMin = typedArray.getInt(R.styleable.SnowfallView_snowflakeAlphaMin, DEFAULT_SNOWFLAKE_ALPHA_MIN);
        snowflakeAlphaMax = typedArray.getInt(R.styleable.SnowfallView_snowflakeAlphaMax, DEFAULT_SNOWFLAKE_ALPHA_MAX);
        snowflakeAngleMax = typedArray.getInt(R.styleable.SnowfallView_snowflakeAngleMax, DEFAULT_SNOWFLAKE_ANGLE_MAX);
        snowflakeSizeMinInPx = typedArray.getDimensionPixelSize(R.styleable.SnowfallView_snowflakeSizeMin, dp2Px(DEFAULT_SNOWFLAKE_SIZE_MIN_IN_DP));
        snowflakeSizeMaxInPx = typedArray.getDimensionPixelSize(R.styleable.SnowfallView_snowflakeSizeMax, dp2Px(DEFAULT_SNOWFLAKE_SIZE_MAX_IN_DP));
        snowflakeSpeedMin = typedArray.getInt(R.styleable.SnowfallView_snowflakeSpeedMin, DEFAULT_SNOWFLAKE_SPEED_MIN);
        snowflakeSpeedMax = typedArray.getInt(R.styleable.SnowfallView_snowflakeSpeedMax, DEFAULT_SNOWFLAKE_SPEED_MAX);
        snowflakesFadingEnabled = typedArray.getBoolean(R.styleable.SnowfallView_snowflakesFadingEnabled, DEFAULT_SNOWFLAKES_FADING_ENABLED);
        snowflakesAlreadyFalling = typedArray.getBoolean(R.styleable.SnowfallView_snowflakesAlreadyFalling, DEFAULT_SNOWFLAKES_ALREADY_FALLING);
        typedArray.recycle();

        holder = this.getHolder();
        holder.addCallback(this);

        //设置背景为透明
        setZOrderOnTop(true);
        holder.setFormat(PixelFormat.TRANSPARENT);
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        //获取雪花集合
        for (int i=0;i<snowflakesNum;i++){
            list.add(new Snowflake(w, h, snowflakeImage, snowflakeAlphaMin, snowflakeAlphaMax
                    , snowflakeAngleMax, snowflakeSizeMinInPx, snowflakeSizeMaxInPx, snowflakeSpeedMin, snowflakeSpeedMax
                    , snowflakesFadingEnabled, snowflakesAlreadyFalling));
        }
    }

    @Override
    protected void onVisibilityChanged(@NonNull View changedView, int visibility) {
        super.onVisibilityChanged(changedView, visibility);
        if (changedView==this&&visibility==GONE){
            //初始化雪花类
            try {
                for (Snowflake snowflake :list){
                    snowflake.reset();
                }
            }catch (Exception e){
                e.printStackTrace();
            }

        }
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        if (isInEditMode()){
            return;
        }
    }

    
    private int dp2Px(int dp){
        return (int) (dp*getResources().getDisplayMetrics().density);
    }

    
    private Bitmap drawable2Bitmap(Drawable drawable){
        Bitmap bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmap);
        drawable.setBounds(0,0,drawable.getIntrinsicWidth(),drawable.getIntrinsicHeight());
        drawable.draw(canvas);
        return bitmap;
    }

    @Override
    public void surfaceCreated(SurfaceHolder surfaceHolder) {
        if (myThread==null){
            myThread = new Thread(myRunnable);
        }
        if(!myThread.isAlive()){
            myThread.start();
        }

    }

    @Override
    public void surfaceChanged(SurfaceHolder surfaceHolder, int i, int i1, int i2) {

    }

    @Override
    public void surfaceDestroyed(SurfaceHolder surfaceHolder) {
        if (myThread!=null){
            myThread.interrupt();
        }
    }

    public class myRunnable implements Runnable {
        @Override
        public void run() {
            while (true){
                Canvas canvas =null;
                try {
                    synchronized (holder){
                        canvas = holder.lockCanvas();
                        //清除画布
                        canvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR);
                        for (Snowflake snowflake :list){
                            snowflake.draw(canvas);
                            snowflake.update();
                        }
                    }
                }catch (Exception e){
                    e.printStackTrace();
                }finally {
                    if (canvas!=null){
                        holder.unlockCanvasAndPost(canvas);
                    }
                }

            }
        }
    }
}

雪花类Snowflake


public class Snowflake {

    private int parentWidth;
    private int parentHeight;
    private int alphaMin;
    private int alphaMax;
    private int angleMax;
    private int sizeMinInPx;
    private int sizeMaxInPx;
    private int speedMin;
    private int speedMax;
    private Bitmap image;
    private boolean fadingEnabled;
    private boolean alreadyFalling;

    private int size = 0 ;
    private int alpha = 255;
    private Bitmap bitmap = null;
    private double speedX= 0.0;
    private double speedY = 0.0;
    private double positionX = 0.0;
    private double positionY = 0.0;
    private final Randomizer randomizer;

    private Paint paint;

    public Snowflake(int parentWidth, int parentHeight, Bitmap image
            ,int alphaMin,int alphaMax,int angleMax,int sizeMinInPx,int sizeMaxInPx,
                    int speedMin,int speedMax,boolean fadingEnabled,boolean alreadyFalling ){
        this.parentWidth = parentWidth;
        this.parentHeight = parentHeight;
        this.alphaMin = alphaMin;
        this.alphaMax = alphaMax;
        this.angleMax = angleMax;
        this.sizeMinInPx = sizeMinInPx;
        this.sizeMaxInPx = sizeMaxInPx;
        this.speedMin = speedMin;
        this.speedMax = speedMax;
        this.image = image;
        this.fadingEnabled=fadingEnabled;
        this.alreadyFalling=alreadyFalling;

        randomizer = new Randomizer();
        initPaint();
        reset();
    }

    
    private void initPaint() {
        paint = new Paint(Paint.ANTI_ALIAS_FLAG);
        paint.setColor(Color.rgb(255,255,255));
        paint.setStyle(Paint.Style.FILL);
    }

    public void reset(double positionY){
        size = randomizer.randomInt(sizeMinInPx, sizeMaxInPx, true);
        if (image!=null){
            if (bitmap==null){
                bitmap = Bitmap.createScaledBitmap(image, size, size, false);
            }
        }
        float speed = (float)(size - sizeMinInPx) / (sizeMaxInPx - sizeMinInPx) * (speedMax - speedMin) + speedMin;

        double angle = Math.toRadians(randomizer.randomDouble(alphaMax) * randomizer.randomSignum());
        if (angle<-1||angle>1){
            angle = 0;
        }
        speedX = speed* Math.sin(angle);
        speedY = speed* Math.cos(angle);
        alpha = randomizer.randomInt(alphaMin, alphaMax, false);
        paint.setAlpha(alpha);

        positionX = randomizer.randomDouble(parentWidth);

        this.positionY = positionY;
    }

    public void reset(){
        size = randomizer.randomInt(sizeMinInPx, sizeMaxInPx, true);
        if (image!=null){
            if (bitmap==null){
                bitmap = Bitmap.createScaledBitmap(image, size, size, false);
            }
        }
        float speed =  (float)(size - sizeMinInPx) / (sizeMaxInPx - sizeMinInPx) * (speedMax - speedMin) + speedMin;
        double angle = Math.toRadians(randomizer.randomDouble(angleMax) * randomizer.randomSignum());
        speedX = speed* Math.sin(angle);
        speedY = speed* Math.cos(angle);

        alpha = randomizer.randomInt(alphaMin, alphaMax, false);
        paint.setAlpha(alpha);

        positionX = randomizer.randomDouble(parentWidth);

        this.positionY=randomizer.randomDouble(parentHeight);
        if (!alreadyFalling){
            this.positionY = this.positionY-parentHeight-size;
        }
    }

    public void update(){
        positionX = positionX+speedX;
        positionY = positionY+speedY;
        if (positionY>parentHeight){
            positionY = -(double)size;
            reset(positionY);
        }
        if (fadingEnabled){
            paint.setAlpha((int) (alpha * ((float) (parentHeight - positionY) / parentHeight)));
        }
    }

    public void draw(Canvas canvas){
        if (bitmap!=null){
            canvas.drawBitmap(bitmap,(float)positionX,(float)positionY,paint);
        }else {
            canvas.drawCircle((float)positionX,(float)positionY,(float)size,paint);
        }
    }
}

总结

到此这篇关于Android自定义view实现雪花特效的文章就介绍到这了,更多相关Android实现雪花特效内容请搜索编程网以前的文章或继续浏览下面的相关文章希望大家以后多多支持编程网！

文章详情

Android自定义view实现雪花特效实例代码

目录

一、前言

二、创意名

三、效果展示

四、实现步骤

五、编码实现

总结

软考中级精品资料免费领

相关文章

猜你喜欢

Android自定义view实现雪花特效实例代码

Android如何用自定义View实现雪花效果

Android 自定义View 密码框实例代码

android 自定义圆角button效果的实例代码（自定义view Demo）

Android 自定义View之倒计时实例代码

Android自定义View实现带数字的进度条实例代码

Android自定义View实现验证码

Android自定义View实现扫描效果

Android自定义View实现时钟效果

android自定义view实现钟表效果

Android实现自定义验证码输入框效果(实例代码)

Android自定义View实现水波纹效果

Android自定义view实现半圆环效果

Android自定义Animation实现View摇摆效果

Android自定义View实现折线图效果

Android自定义view系列之99.99%实现QQ侧滑删除效果实例代码详解

Android中自定义view实现侧滑效果

Android自定义view实现输入框效果

Android自定义ScrollView实现放大回弹效果实例代码

Android自定义popupwindow实例代码