#冲刺创作新星#一起学做鸿蒙“羊了个羊” 原创 精华

简介

最近大火了一个小游戏火遍朋友圈，我们就一起看看如何能用OpenHarmony学习做个”羊了个羊“。本文中引用的图片资源均来自：https://github.com/Jetereting/ylgy。

开发

1. HAP应用建立

《#跟着小白一起学鸿蒙#[六]如何编写一个hap应用》里我们介绍了简单的Hap应用的开发以及基础控件的介绍，这里我们就不赘述Hap项目的建立过程，以下就是基础的Hap的page文件：index.ets

build() {
    Row() {
      Column() {
        Canvas(this.context)
          .width('100%')
          .height('100%')
          .onClick((ev: ClickEvent) => {
            console.log("screen.xy:"+ev.screenX+":"+ev.screenY)
            console.log("xy:"+ev.x+":"+ev.y)
          })
          .onReady(() =>{
            this.context.imageSmoothingEnabled = false
            this.drawBlock()
          })
      }
      .height("80%")
      .width("100%")
    }
    .height('100%')
    .width('100%')
    .backgroundImage($r("app.media.grass"))
    .backgroundImageSize(ImageSize.Cover)
}

build是基础页面的构造函数，用于界面的元素构造，其他的页面的生命周期函数如下：

declare class CustomComponent {
  /**
   * Customize the pop-up content constructor.
   * @since 7
   */
  build(): void;

  /**
   * aboutToAppear Method
   * @since 7
   */
  aboutToAppear?(): void;

  /**
   * aboutToDisappear Method
   * @since 7
   */
  aboutToDisappear?(): void;

  /**
   * onPageShow Method
   * @since 7
   */
  onPageShow?(): void;

  /**
   * onPageHide Method
   * @since 7
   */
  onPageHide?(): void;

  /**
   * onBackPress Method
   * @since 7
   */
  onBackPress?(): void;
}

2. Canvas介绍

canvas是画布组件用于自定义绘制图形，具体的API页面如下：

https://developer.harmonyos.com/cn/docs/documentation/doc-references/ts-components-canvas-canvas-0000001333641081

页面显示前会调用aboutToAppear()函数，此函数为页面生命周期函数

canvas组件初始化完毕后会调用onReady()函数，函数内部实现小游戏的初始页面的绘制

2.1 初始化页面数据

initBlocks() {
    for (let i=0;i<this.avaliableCnt;i++) {
      let lineCn = Math.floor(i/3)
      let rowCn = Math.floor(i%3)
      if (lineCn == 0) {
        this.blockList[i] = {
          img: "censer",
          isShow: true,
          x: this.startX+rowCn*30,
          y: this.startY,
          w: 55,
          h: 53,
        }
      } else if (lineCn == 1) {
        this.blockList[i] = {
          img: "cloud",
          isShow: true,
          x: this.startX+rowCn*30,
          y: this.startY+lineCn*90,
          w: 55,
          h: 53,
        }
      } else if (lineCn == 2) {
        this.blockList[i] = {
          img: "knif",
          isShow: true,
          x: this.startX+rowCn*30,
          y: this.startY+lineCn*90,
          w: 55,
          h: 53,
        }
      }
    }
  }

小游戏的每个卡片都是用canvas绘制的图片资源，用于进行排列以及点击判断所以在此设计了个数据结构

{
	img: 卡片资源类型，用于图片渲染和相似图片消除
	isShow: 卡片是否显示标志，用于渲染的时候进行判断
	x：卡片渲染左上角横坐标
	y：卡片渲染左上角纵坐标
	w：卡片渲染宽度
	h: 卡片渲染高度
}

现在制作的是用固定方法初始化卡片的方法即渲染3行，每行3个图片，之后改进可以改成明确一个区域，然后采用随机算法进行位置和卡片类型生成。

2.2 初始化页面绘制

drawBlock() {
    //初始化消除区域的卡片
    this.blockList.forEach((block)=>{
      if (block.isShow) {
        let imgItem:ImageBitmap = null
        switch(block.img) {
          case "censer":
            imgItem = this.censerImg
            break
          case "cloud":
            imgItem = this.cloudImg
            break
          case "knif":
            imgItem = this.knifImg
            break
          default:
            imgItem = this.censerImg
            break
        }
        this.context.drawImage( this.cardImg,block.x,block.y,this.blockw,this.blockh)
        this.context.drawImage( imgItem,block.x+5,block.y+5,block.w,block.h)
      }
    })
	//初始化选择卡片区域
    this.context.drawImage( this.slotImg,this.slotX,this.slotY,300,39)
    let pos = 0
    for (let i=0;i<5;i++) {
      this.context.drawImage( this.cardImg,this.slotX + pos,this.slotY+40,61,69)
      if (i < this.emptyList.length) {
        let emptyText = this.emptyList[i]
        let pItem = null;
        switch (emptyText) {
          case "censer":
            pItem = this.censerImg;
            break;
          case "cloud":
            pItem = this.cloudImg;
            break;
          case "knif":
            pItem = this.knifImg;
            break;
          default:
            break;
        }
        if (pItem) {
          this.context.drawImage(pItem,this.slotX + pos + 3,this.slotY+40,55,59)
        }
      }
      pos += 60
    }
  }

整个绘制区域分两个区域：

• 消除区域：绘制卡片背景和卡片类型，利用初始化的卡片数据进行卡片绘制；
• 选择区域：绘制栏杆，卡片背景，以及选择的卡片

3. 游戏逻辑

简单的小游戏主体游戏逻辑为：初始化（之前的章节已经介绍），点击（选中，选不中，消除，选择区域满，消除区域空）流程图如下：

graph LR
init[初始化] --> click[点击]
click[点击] --> isSelect{是否点中}
isSelect -->|点中| yes[点中]
isSelect -->|没点中| no[没点中]
yes --> isEmpty{是否选择区域满}
isEmpty -->|满| full[无法消除]
isEmpty -->|不满| notfull[加入选择区域]
notfull --> canClear{有3个相同}
canClear -->|能消除| clear[消除]
canClear -->|不能消除| append[进入选择区域]
append --> 重绘

.onClick((ev: ClickEvent) => {
            if (this.needRestart) {
              this.needRestart = false
              this.emptyList.splice(0, this.emptyList.length)
              this.blockList.splice(0, this.blockList.length)
              this.emptyCnt = 5
              this.avaliableCnt = 9
              this.initBlocks()
              this.context.clearRect(0,0,this.context.width,this.context.height)
              this.drawBlock()
              return
            }
            console.log("screen.xy:"+ev.screenX+":"+ev.screenY)
            console.log("xy:"+ev.x+":"+ev.y)
            //判断是否点中方块
            let flag = this.isSelect(ev.x, ev.y)
            console.info("flag:"+flag)
            if (flag == 1) {
              //如果可以移动或消除则清空重填
              this.context.clearRect(0,0,this.context.width,this.context.height)
              this.drawBlock();
            } else if (flag == 2) {
              //如果清空显示胜利画面
              this.context.drawImage( this.blackImg,0,0,this.context.width,this.context.height)
              this.context.drawImage( this.winImg,this.slotX+50,this.slotY-300,200,200)
              this.context.font="100px bold"
              this.context.fillText("欢迎你加入羊群", this.slotX+50,this.slotY-350,500)
              this.needRestart = true
            } else if (flag == 3) {
              this.context.clearRect(0,0,this.context.width,this.context.height)
              this.drawBlock();
              this.context.drawImage( this.blackImg,0,0,this.context.width,this.context.height)
              this.context.drawImage( this.ylgyImg,this.slotX+50,this.slotY-300,200,100)
              this.context.font="100px bold"
              this.context.fillText("加入羊群失败", this.slotX+50,this.slotY-350,500)
              this.needRestart = true
            }
          })

4. 完整逻辑

@Entry
@Component
struct Index {
  @State message: string = 'Hello World'
  @State _translate: TranslateOptions = {
    x: 0,
    y: 0,
    z: 0
  }
  @State _scale: ScaleOptions = {
    x: 1,
    y: 1,
    z: 1
  }
  private settings: RenderingContextSettings = new RenderingContextSettings(true);
  private context: CanvasRenderingContext2D = new CanvasRenderingContext2D(this.settings);
  private cardImg:ImageBitmap = new ImageBitmap("common/images/iback.png")
  private slotImg:ImageBitmap = new ImageBitmap("common/images/lan.png")
  private ylgyImg:ImageBitmap = new ImageBitmap("common/images/ylgy.png")
  private blackImg:ImageBitmap = new ImageBitmap("common/images/black.png")
  private censerImg:ImageBitmap = new ImageBitmap("common/images/censer.png")
  private cloudImg:ImageBitmap = new ImageBitmap("common/images/cloud.png")
  private knifImg:ImageBitmap = new ImageBitmap("common/images/knif.png")
  private winImg:ImageBitmap = new ImageBitmap("common/images/win.png")
  private startX = 50;
  private startY = 10;
  private slotX = 20;
  private slotY = 450;
  private blockw = 62;
  private blockh = 69;
  private blockList = []
  private emptyList = []
  private emptyCnt =  5;
  private avaliableCnt = 9;
  private clearLen = 3;
  private needRestart = false;
  animationStep(value: AnimateParam, event: () => void) {
    return () => {
      return new Promise((resolve) => {
        let onFinish = value.onFinish
        value.onFinish = () => {
          if(onFinish) onFinish()
          resolve(true)
        }
        animateTo(value, event)
      })
    }
  }
  async pulse(time) {
    // 0% - 50%
    let step1 = this.animationStep({
      duration: time * 0.5, // 动画时长
      tempo: 0.5, // 播放速率
      curve: Curve.EaseInOut, // 动画曲线
      delay: 0, // 动画延迟
      iterations: 1, // 播放次数
      playMode: PlayMode.Normal, // 动画模式
    }, () => {
      this._scale = {
        x: 1.05,
        y: 1.05,
        z: 1.05
      }
    })

    // 50% - 100%
    let step2 = this.animationStep({
      duration: time * 0.5, // 动画时长
      tempo: 0.5, // 播放速率
      curve: Curve.EaseInOut, // 动画曲线
      delay: 0, // 动画延迟
      iterations: 1, // 播放次数
      playMode: PlayMode.Normal, // 动画模式
    }, () => {
      this._scale = {
        x: 1,
        y: 1,
        z: 1
      }
    })

    await step1()
    await step2()
  }
  initBlocks() {
    for (let i=0;i<this.avaliableCnt;i++) {
      let lineCn = Math.floor(i/3)
      let rowCn = Math.floor(i%3)
      if (lineCn == 0) {
        this.blockList[i] = {
          img: "censer",
          isShow: true,
          x: this.startX+rowCn*30,
          y: this.startY,
          w: 55,
          h: 53,
        }
      } else if (lineCn == 1) {
        this.blockList[i] = {
          img: "cloud",
          isShow: true,
          x: this.startX+rowCn*30,
          y: this.startY+lineCn*90,
          w: 55,
          h: 53,
        }
      } else if (lineCn == 2) {
        this.blockList[i] = {
          img: "knif",
          isShow: true,
          x: this.startX+rowCn*30,
          y: this.startY+lineCn*90,
          w: 55,
          h: 53,
        }
      }
    }
  }
  aboutToAppear() {
    this.initBlocks()
    let audioPlayer = media.createAudioPlayer();
    audioPlayer.on('dataLoad', () => {            //设置'dataLoad'事件回调，src属性设置成功后，触发此回调
      console.info('audio set source success');
      audioPlayer.play();                       //开始播放，并触发'play'事件回调
    });
//    audioPlayer.src = $r("app.media.background")
  }
  clearEmpty() {
    let emptyMap:Map<string, number> = new Map()
    console.info("emptylen:"+this.emptyList.length)
    for (let i=0;i<this.emptyList.length;i++) {
      let txt = this.emptyList[i]
      if (emptyMap[txt]) {
        let num = emptyMap[txt]
        emptyMap[txt] = num + 1
        if (emptyMap[txt] == 3) {
          for (let j=0;j<3;j++) {
            this.emptyList.splice(this.emptyList.indexOf(txt), 1)
          }
          this.emptyCnt += 3
          console.info("key:"+txt+"   n:"+this.emptyList.length)
        }
      } else {
        emptyMap[txt] = 1
      }
    }
  }
  isSelect(x, y) : number {
    let noshowCnt = 0
    let nofind = 0
    for (let i=0;i<this.blockList.length;i++) {
//    this.blockList.forEach((block)=>{
      let block = this.blockList[i]
      noshowCnt += 1
      x = Math.ceil(x)
      y = Math.ceil(y)
//      console.info("x:"+x+"y:"+y)
//      console.info("blockx:"+block.x+"block.y:"+block.y)
      let endx = block.x+this.blockw
      let endy = block.y+this.blockh

      if ((block.x <= x && endx >= x) &&
        (block.y <= y && endy >= y)) {
        console.info("isFind")
        if (block.isShow == true && this.emptyCnt > 0) {
          block.isShow = false;
          this.emptyCnt -= 1;
          this.avaliableCnt -= 1;
          this.emptyList.push(block.img)
          this.clearEmpty()
          //找到block
          if (this.avaliableCnt == 0) {
            return 2
          } else {
            if (this.emptyList.length == 5) {
              return 3
            } else {
              return 1
            }
          }
        } else if (this.emptyCnt == 0) {
          //没有空闲空间
          return 3
        } else if (block.isShow == false) {
          nofind += 1
        }
      } else {
        console.info("noFind")
        nofind += 1
      }
    }
    if (nofind == this.blockList.length) {
      //没有点中
      return 0
    }
    if (noshowCnt == this.blockList.length) {
      //没有block
      return 2
    }

  }
  drawBlock() {
    this.blockList.forEach((block)=>{
      if (block.isShow) {
        let imgItem:ImageBitmap = null
        switch(block.img) {
          case "censer":
            imgItem = this.censerImg
            break
          case "cloud":
            imgItem = this.cloudImg
            break
          case "knif":
            imgItem = this.knifImg
            break
          default:
            imgItem = this.censerImg
            break
        }
        this.context.drawImage( this.cardImg,block.x,block.y,this.blockw,this.blockh)
        this.context.drawImage( imgItem,block.x+5,block.y+5,block.w,block.h)
      }
    })

    this.context.drawImage( this.slotImg,this.slotX,this.slotY,300,39)
    let pos = 0
    for (let i=0;i<5;i++) {
      this.context.drawImage( this.cardImg,this.slotX + pos,this.slotY+40,61,69)
      if (i < this.emptyList.length) {
        let emptyText = this.emptyList[i]
        let pItem = null;
        switch (emptyText) {
          case "censer":
            pItem = this.censerImg;
            break;
          case "cloud":
            pItem = this.cloudImg;
            break;
          case "knif":
            pItem = this.knifImg;
            break;
          default:
            break;
        }
        if (pItem) {
          this.context.drawImage(pItem,this.slotX + pos + 3,this.slotY+40,55,59)
        }
      }
      pos += 60
    }
  }
  build() {
    Row() {
      Column() {
        Canvas(this.context)
          .width('100%')
          .height('100%')
          .onClick((ev: ClickEvent) => {
            if (this.needRestart) {
              this.needRestart = false
              this.emptyList.splice(0, this.emptyList.length)
              this.blockList.splice(0, this.blockList.length)
              this.emptyCnt = 5
              this.avaliableCnt = 9
              this.initBlocks()
              this.context.clearRect(0,0,this.context.width,this.context.height)
              this.drawBlock()
              return
            }
            console.log("screen.xy:"+ev.screenX+":"+ev.screenY)
            console.log("xy:"+ev.x+":"+ev.y)
            //判断是否点中方块
            let flag = this.isSelect(ev.x, ev.y)
            console.info("flag:"+flag)
            if (flag == 1) {
              //如果可以移动或消除则清空充填
              this.context.clearRect(0,0,this.context.width,this.context.height)
              this.drawBlock();
            } else if (flag == 2) {
              //如果清空显示胜利画面
              this.context.drawImage( this.blackImg,0,0,this.context.width,this.context.height)
              this.context.drawImage( this.winImg,this.slotX+50,this.slotY-300,200,200)
              this.context.font="100px bold"
              this.context.fillText("欢迎你加入羊群", this.slotX+50,this.slotY-350,500)
              this.needRestart = true
            } else if (flag == 3) {
              this.context.clearRect(0,0,this.context.width,this.context.height)
              this.drawBlock();
              this.context.drawImage( this.blackImg,0,0,this.context.width,this.context.height)
              this.context.drawImage( this.ylgyImg,this.slotX+50,this.slotY-300,200,100)
              this.context.font="100px bold"
              this.context.fillText("加入羊群失败", this.slotX+50,this.slotY-350,500)
              this.needRestart = true
            }
          })
          .onReady(() =>{
            this.context.imageSmoothingEnabled = false
            this.drawBlock()
          })
      }
      .height("80%")
      .width("100%")
    }
    .height('100%')
    .width('100%')
    .backgroundImage($r("app.media.grass"))
    .backgroundImageSize(ImageSize.Cover)
  }
}

遗留问题：

1. 点击选择没有判断图层：可以在卡片数据结构里增加图层标识，最下面的卡片为图层标识为1，上面的多一层加1，点中选择的时候可以判断，增加是否可以选中的逻辑；

2. 消除区域布局可灵活配置：增加布局配置逻辑，使用数据结构设定布局逻辑，可规定卡片种类，数量，布局行数，列数以及层级

3. 游戏声音问题：目前ohos不支持音频播放资源音频，看之后版本是否支持

5. 获取源码

仓库地址：https://gitee.com/wshikh/ohosylgy.git

总结

本文主要介绍了小游戏的开发，画布功能的使用