Android 實現(xiàn)九宮格抽獎功能

更新時間：2021年03月25日 10:27:41 作者：itfitness

這篇文章主要介紹了Android 實現(xiàn)九宮格抽獎功能，幫助大家更好的理解和學(xué)習(xí)使用Android，感興趣的朋友可以了解下

效果展示

實現(xiàn)步驟

1.生成抽獎矩形：

其中每個矩形的寬高相同，長度為整個控件寬度的1/3。

代碼展示

public class NineLuckPan extends View {
 private Paint mPaint;
 private ArrayList<RectF> mRects;//存儲矩形的集合
 private float mStrokWidth = 5;//矩形的描邊寬度
 private int mRectSize;//矩形的寬和高（矩形為正方形）
 private int[] mItemColor = {Color.GREEN, Color.YELLOW};//矩形的顏色

 public NineLuckPan(Context context) {
  this(context, null);
 }

 public NineLuckPan(Context context, @Nullable AttributeSet attrs) {
  this(context, attrs, 0);
 }

 public NineLuckPan(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
  super(context, attrs, defStyleAttr);
  init();
 }

 /**
  * 初始化數(shù)據(jù)
  */
 private void init() {
  mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
  mPaint.setStyle(Paint.Style.FILL);
  mPaint.setStrokeWidth(mStrokWidth);
  mRects = new ArrayList<>();
 }

 @Override
 protected void onSizeChanged(int w, int h, int oldw, int oldh) {
  super.onSizeChanged(w, h, oldw, oldh);
  mRectSize = Math.min(w, h) / 3;//獲取矩形的寬和高
  mRects.clear();//當(dāng)控件大小改變的時候清空數(shù)據(jù)
  initRect();//重新加載矩形數(shù)據(jù)
 }

 /**
  * 加載矩形數(shù)據(jù)
  */
 private void initRect() {
  //加載前三個矩形
  for (int x = 0; x < 3; x++) {
   float left = x * mRectSize;
   float top = 0;
   float right = (x + 1) * mRectSize;
   float bottom = mRectSize;
   RectF rectF = new RectF(left, top, right, bottom);
   mRects.add(rectF);
  }
  //加載第四個
  mRects.add(new RectF(getWidth() - mRectSize, mRectSize, getWidth(), mRectSize * 2));
  //加載第五~七個
  for (int y = 3; y > 0; y--) {
   float left = getWidth() - (4 - y) * mRectSize;
   float top = mRectSize * 2;
   float right = (y - 3) * mRectSize + getWidth();
   float bottom = mRectSize * 3;
   RectF rectF = new RectF(left, top, right, bottom);
   mRects.add(rectF);
  }
  //加載第八個
  mRects.add(new RectF(0, mRectSize, mRectSize, mRectSize * 2));
  //加載第九個
  mRects.add(new RectF(mRectSize, mRectSize, mRectSize * 2, mRectSize * 2));
 }

 @Override
 protected void onDraw(Canvas canvas) {
  super.onDraw(canvas);
  drawRects(canvas);
 }

 /**
  * 畫矩形
  *
  * @param canvas
  */
 private void drawRects(Canvas canvas) {
  for (int x = 0; x < mRects.size(); x++) {
   RectF rectF = mRects.get(x);
   if (x == 8) {//中心的矩形背景為白色
    mPaint.setColor(Color.WHITE);
    canvas.drawRect(rectF, mPaint);
   } else {
    mPaint.setColor(mItemColor[x % 2]);
    canvas.drawRect(rectF, mPaint);
   }
  }
 }
}

效果展示

2.添加獎品圖片：

我們在矩形的中心點畫出圖片，圖片的寬高都為矩形寬高的1/2，其中矩形的中心點通過rectF.centerX()和rectF.centerY()獲取。

代碼展示（為了方便只展示部分代碼）

public class NineLuckPan extends View {
 private int[] mImgs = {R.drawable.ic_df, R.drawable.ic_jt, R.drawable.ic_mf, R.drawable.ic_scjx, R.drawable.ic_scng, R.drawable.ic_thl, R.drawable.ic_x, R.drawable.ic_xc, R.drawable.ic_j};

 @Override
 protected void onDraw(Canvas canvas) {
  super.onDraw(canvas);
  drawRects(canvas);//畫矩形
  drawImages(canvas);//畫圖片
 }

 /**
  * 畫圖片
  *
  * @param canvas
  */
 private void drawImages(Canvas canvas) {
  for (int x = 0; x < mRects.size(); x++) {
   RectF rectF = mRects.get(x);
   float left = rectF.centerX() - mRectSize / 4;
   float top = rectF.centerY() - mRectSize / 4;
   canvas.drawBitmap(Bitmap.createScaledBitmap(BitmapFactory.decodeResource(getResources(), mImgs[x]), mRectSize / 2, mRectSize / 2, false), left, top, null);
  }
 }
}

效果展示

3.實現(xiàn)抽獎動畫：

這里我們使用ValueAnimator使數(shù)字從0遞增到我們的中獎位置比如3，然后改變遞增所在的位置的矩形的背景以實現(xiàn)抽獎的效果，另外為了讓用戶感到逼真我們需要讓抽獎色塊多轉(zhuǎn)幾圈，同時我們需要將下一次的開始位置設(shè)為上一次的結(jié)束位置。

代碼展示（為了方便只展示部分代碼）

NineLuckPan:

public class NineLuckPan extends View {
 private int mRepeatCount = 3;//轉(zhuǎn)的圈數(shù)
 private int mLuckNum = 3;//最終中獎位置
 private int mPosition = -1;//抽獎塊的位置
 private int mStartLuckPosition = 0;//開始抽獎的位置
 /**
  * 畫矩形
  * @param canvas
  */
 private void drawRects(Canvas canvas) {
  for (int x = 0;x<mRects.size();x++){
   RectF rectF = mRects.get(x);
   if(x == 8){
    mPaint.setColor(Color.WHITE);
    canvas.drawRect(rectF, mPaint);
   }else {
    mPaint.setColor(mItemColor[x%2]);
    if(mPosition == x){
     mPaint.setColor(Color.BLUE);
    }
    canvas.drawRect(rectF, mPaint);
   }
  }
 }
 public void setPosition(int position){
  mPosition = position;
  invalidate();
 }
 /**
  * 開始動畫
  */
 public void startAnim(){
  ValueAnimator valueAnimator = ValueAnimator.ofInt(mStartLuckPosition, mRepeatCount * 8 + mLuckNum).setDuration(5000);
  valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
   @Override
   public void onAnimationUpdate(ValueAnimator animation) {
    int position = (int) animation.getAnimatedValue();
    setPosition(position%8);
   }
  });
  valueAnimator.addListener(new AnimatorListenerAdapter() {
   @Override
   public void onAnimationEnd(Animator animation) {
    mStartLuckPosition = mLuckNum;
   }
  });
  valueAnimator.start();
 }
}

Activity:

public class MainActivity extends AppCompatActivity {
 private NineLuckPan luckpan;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  luckpan = (NineLuckPan) findViewById(R.id.luckpan);
  luckpan.setOnClickListener(new View.OnClickListener() {
   @Override
   public void onClick(View v) {
    luckpan.startAnim();
   }
  });
 }
}

效果展示

雖然效果實現(xiàn)了但是我們發(fā)現(xiàn)好像點哪里都能啟動動畫，因此我們需要調(diào)整一下代碼使只有點擊中心的矩形才開始動畫。

//（為了方便只展示部分代碼）
public class NineLuckPan extends View {
 private boolean mClickStartFlag = false;//是否點擊中間矩形的標(biāo)記

 //這樣需要我們將Activity里的啟動動畫的邏輯刪掉
 @Override
 public boolean onTouchEvent(MotionEvent event) {
  if(event.getAction() == MotionEvent.ACTION_DOWN){
   if(mRects.get(8).contains(event.getX(),event.getY())){
    mClickStartFlag = true;
   }else {
    mClickStartFlag = false;
   }
   return true;
  }
  if(event.getAction() == MotionEvent.ACTION_UP){
   if(mClickStartFlag){
    if(mRects.get(8).contains(event.getX(),event.getY())){
     startAnim();//判斷只有手指落下和抬起都在中間的矩形內(nèi)才開始抽獎
    }
    mClickStartFlag = false;
   }
  }
  return super.onTouchEvent(event);
 }
}

4.實現(xiàn)動態(tài)設(shè)置參數(shù)：

效果基本實現(xiàn)了，接下來就需要實現(xiàn)動態(tài)設(shè)置數(shù)據(jù)了。

代碼展示（這里為了方便只展示部分代碼）

public class NineLuckPan extends View {
 private int mLuckNum = 3;//最終中獎位置
 private int [] mImgs = {R.drawable.ic_df,R.drawable.ic_jt,R.drawable.ic_mf,R.drawable.ic_scjx,R.drawable.ic_scng,R.drawable.ic_thl,R.drawable.ic_x,R.drawable.ic_xc,R.drawable.ic_j};
 private String[] mLuckStr = {"豆腐","雞腿","米飯","卷心菜","南瓜","糖葫蘆","大蝦","香腸"};//這是抽獎的提示信息

 public int getmLuckNum() {
  return mLuckNum;
 }

 public void setmLuckNum(int mLuckNum) {
  this.mLuckNum = mLuckNum;
 }

 public int[] getmImgs() {
  return mImgs;
 }

 public void setmImgs(int[] mImgs) {
  this.mImgs = mImgs;
  invalidate();//要注意設(shè)置完后要進行重繪
 }

 public String[] getmLuckStr() {
  return mLuckStr;
 }

 public void setmLuckStr(String[] mLuckStr) {
  this.mLuckStr = mLuckStr;
  invalidate();;//要注意設(shè)置完后要進行重繪
 }
}

5.添加抽獎結(jié)果回調(diào)

這里需要在動畫結(jié)束的回調(diào)里加入我們自定義的回調(diào)函數(shù)。

代碼展示（這里為了方便只展示部分代碼）

public class NineLuckPan extends View {
 private OnLuckPanAnimEndListener onLuckPanAnimEndListener;

 public OnLuckPanAnimEndListener getOnLuckPanAnimEndListener() {
  return onLuckPanAnimEndListener;
 }

 public void setOnLuckPanAnimEndListener(OnLuckPanAnimEndListener onLuckPanAnimEndListener) {
  this.onLuckPanAnimEndListener = onLuckPanAnimEndListener;
 }

 /**
  * 開始動畫
  */
 private void startAnim(){
  ValueAnimator valueAnimator = ValueAnimator.ofInt(mStartLuckPosition, mRepeatCount * 8 + mLuckNum).setDuration(5000);
  valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
   @Override
   public void onAnimationUpdate(ValueAnimator animation) {
    int position = (int) animation.getAnimatedValue();
    setPosition(position%8);
   }
  });
  valueAnimator.addListener(new AnimatorListenerAdapter() {
   @Override
   public void onAnimationEnd(Animator animation) {
    mStartLuckPosition = mLuckNum;
    //在動畫結(jié)束的回調(diào)函數(shù)里加入我們自定義的回調(diào)函數(shù)
    if(onLuckPanAnimEndListener!=null){
     onLuckPanAnimEndListener.onAnimEnd(mPosition,mLuckStr[mPosition]);
    }
   }
  });
  valueAnimator.start();
 }
 public interface OnLuckPanAnimEndListener{
  void onAnimEnd(int position,String msg);
 }
}

Activity代碼：

public class MainActivity extends AppCompatActivity {
 private NineLuckPan luckpan;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  luckpan = (NineLuckPan) findViewById(R.id.luckpan);
  luckpan.setOnLuckPanAnimEndListener(new NineLuckPan.OnLuckPanAnimEndListener() {
   @Override
   public void onAnimEnd(int position, String msg) {
    Toast.makeText(MainActivity.this, "位置："+position+"提示信息："+msg, Toast.LENGTH_SHORT).show();
   }
  });
 }
}

效果展示