效果展示

實(shí)現(xiàn)原理 首先需要生成繪制小花的坐標(biāo)點(diǎn)，坐標(biāo)點(diǎn)的橫坐標(biāo)是根據(jù)控件的寬度隨機(jī)生成的，而縱坐標(biāo)則設(shè)置為小花圖片高度的負(fù)值（這樣可以實(shí)現(xiàn)小花從屏幕外進(jìn)入）。 將這些點(diǎn)存儲(chǔ)到集合當(dāng)中。 遍歷集合根據(jù)點(diǎn)的位置繪制小花 繪制完后不斷增加各個(gè)點(diǎn)的縱坐標(biāo)實(shí)現(xiàn)步驟

1.定義變量將變量初始化

private SurfaceHolder mHolder; private boolean mFlag = true;//繪制小花線程的開(kāi)關(guān)標(biāo)志 private ArrayList<PointF> mFlowers;//小花點(diǎn)的坐標(biāo)集合 private Random mRandom;//負(fù)責(zé)隨機(jī)數(shù)生成 private Bitmap mBitmap;//小花的圖案 public FlowerView(Context context) {super(context);init(); } public FlowerView(Context context, AttributeSet attrs) {super(context, attrs);init(); } public FlowerView(Context context, AttributeSet attrs, int defStyleAttr) {super(context, attrs, defStyleAttr);init(); } private void init(){mHolder = getHolder();mHolder.addCallback(this);//設(shè)置背景透明this.setZOrderOnTop(true);mHolder.setFormat(PixelFormat.TRANSLUCENT);mFlowers = new ArrayList<>();mRandom = new Random();mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.ic_hua); }

2.實(shí)現(xiàn)添加花朵坐標(biāo)點(diǎn)的方法

/** * 添加花朵 */ private void addFlower(){PointF point = new PointF();point.x=mRandom.nextInt(getWidth());//根據(jù)控件寬度隨機(jī)生成X軸坐標(biāo)point.y=-mBitmap.getHeight();//縱坐標(biāo)設(shè)置為小花圖像的負(fù)值（產(chǎn)生從屏幕外進(jìn)入的效果）mFlowers.add(point);//將坐標(biāo)點(diǎn)添加進(jìn)集合 }

3.實(shí)現(xiàn)SurfaceHolder.Callback及Runnable接口

public class FlowerView extends SurfaceView implements SurfaceHolder.Callback,Runnable

4.在run方法中實(shí)現(xiàn)繪制邏輯

@Override public void run() {while (mFlag){ try {Thread.sleep(80);//控制小花的下落速度Canvas canvas = mHolder.lockCanvas();PointF pointF = null;//清屏操作（否則會(huì)殘留一些無(wú)用圖像）if(canvas!=null){ canvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR);}else { continue;}for(PointF point: mFlowers){ pointF = point; canvas.drawBitmap(mBitmap,pointF.x,pointF.y,null); int i = mRandom.nextInt(getHeight()/50)+getHeight()/50;//修改雨滴線的縱坐標(biāo)，使其看起來(lái)在下雨 pointF.y=pointF.y+i;}mHolder.unlockCanvasAndPost(canvas);addFlower();//當(dāng)繪制點(diǎn)的縱坐標(biāo)大于控件高度時(shí)，將該點(diǎn)移除if(mFlowers.size()>0&&pointF!=null&&pointF.y>=getHeight()){ mFlowers.remove(pointF);} }catch (Exception e){}} }

5.在SurfaceHolder.Callback的回調(diào)方法中開(kāi)啟繪制線程

@Override public void surfaceCreated(SurfaceHolder holder) {mFlag = true;//surface創(chuàng)建時(shí)將線程開(kāi)關(guān)打開(kāi)new Thread(this).start();//開(kāi)啟線程繪制 } @Override public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {mFlowers.clear();//當(dāng)控件發(fā)生改變時(shí)清除之前的繪制點(diǎn) } @Override public void surfaceDestroyed(SurfaceHolder holder) {mFlag = false;//當(dāng)surface銷毀時(shí)關(guān)掉繪制線程 }完整代碼展示

public class FlowerView extends SurfaceView implements SurfaceHolder.Callback,Runnable{ private SurfaceHolder mHolder; private boolean mFlag = true;//繪制小花線程的開(kāi)關(guān)標(biāo)志 private ArrayList<PointF> mFlowers;//小花點(diǎn)的坐標(biāo)集合 private Random mRandom;//負(fù)責(zé)隨機(jī)數(shù)生成 private Bitmap mBitmap;//小花的圖案 public FlowerView(Context context) {super(context);init(); } public FlowerView(Context context, AttributeSet attrs) {super(context, attrs);init(); } public FlowerView(Context context, AttributeSet attrs, int defStyleAttr) {super(context, attrs, defStyleAttr);init(); } private void init(){mHolder = getHolder();mHolder.addCallback(this);//設(shè)置背景透明this.setZOrderOnTop(true);mHolder.setFormat(PixelFormat.TRANSLUCENT);mFlowers = new ArrayList<>();mRandom = new Random();mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.ic_hua); } @Override public void surfaceCreated(SurfaceHolder holder) {mFlag = true;new Thread(this).start(); } @Override public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {mFlowers.clear(); } @Override public void surfaceDestroyed(SurfaceHolder holder) {mFlag = false; } @Override public void run() {while (mFlag){ try {Thread.sleep(80);Canvas canvas = mHolder.lockCanvas();PointF pointF = null;//清屏操作if(canvas!=null){ canvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR);}else { continue;}for(PointF point: mFlowers){ pointF = point; canvas.drawBitmap(mBitmap,pointF.x,pointF.y,null); int i = mRandom.nextInt(getHeight()/50)+getHeight()/50;//修改雨滴線的縱坐標(biāo)，使其看起來(lái)在下雨 pointF.y=pointF.y+i;}mHolder.unlockCanvasAndPost(canvas);addFlower();if(mFlowers.size()>0&&pointF!=null&&pointF.y>=getHeight()){ mFlowers.remove(pointF);} }catch (Exception e){}} } /** * 添加花朵 */ private void addFlower(){PointF point = new PointF();point.x=mRandom.nextInt(getWidth());point.y=-mBitmap.getHeight();mFlowers.add(point); }}

以上就是Android實(shí)現(xiàn)花瓣飄落效果的步驟的詳細(xì)內(nèi)容，更多關(guān)于Android實(shí)現(xiàn)花瓣飄落效果的資料請(qǐng)關(guān)注好吧啦網(wǎng)其它相關(guān)文章！