跟著小白一起學(xué)鴻蒙—一起學(xué)做小蜜蜂

作者：王石 2023-03-30 09:32:27

系統(tǒng) OpenHarmony

本文主要介紹了小游戲的開發(fā)，畫布功能的使用，希望能夠幫助到你！

??51CTO 開源基礎(chǔ)軟件社區(qū)??

??https://ost.51cto.com??

簡(jiǎn)介

小時(shí)候我們有個(gè)熟悉的游戲叫小蜜蜂。本文中引用的圖片資源均來(lái)自與Github。

#創(chuàng)作者激勵(lì)# #跟著小白一起學(xué)鴻蒙# [番外四]一起學(xué)做小蜜蜂-開源基礎(chǔ)軟件社區(qū)

開發(fā)

1、HAP應(yīng)用建立

《#跟著小白一起學(xué)鴻蒙#[六]如何編寫一個(gè)hap應(yīng)用》里我們介紹了簡(jiǎn)單的Hap應(yīng)用的開發(fā)以及基礎(chǔ)控件的介紹，這里我們就不贅述Hap項(xiàng)目的建立過(guò)程，以下就是基礎(chǔ)的Hap的page文件：index.ets。

build() {
    Row() {
      Column() {
        Canvas(this.context)
          .width('100%')
          .height('100%')
          .onClick((ev: ClickEvent) => {
            console.info("click!!")
            this.doClick()
          })
          .onReady(() =>{
            this.context.imageSmoothingEnabled = false
            this.drawall()
          })
      }
      .width('100%')
    }
    .height('100%')
    .backgroundColor("#000000")
  }

build是基礎(chǔ)頁(yè)面的構(gòu)造函數(shù)，用于界面的元素構(gòu)造，其他的頁(yè)面的生命周期函數(shù)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介紹

canvas是畫布組件用于自定義繪制圖形，具體的API頁(yè)面如下：

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

頁(yè)面顯示前會(huì)調(diào)用aboutToAppear()函數(shù)，此函數(shù)為頁(yè)面生命周期函數(shù)。

canvas組件初始化完畢后會(huì)調(diào)用onReady()函數(shù)，函數(shù)內(nèi)部實(shí)現(xiàn)小游戲的初始頁(yè)面的繪制。

（1）初始化頁(yè)面數(shù)據(jù)

drawall() {
    this.context.clearRect(0,0,this.context.width,this.context.height)
    this.drawFj();
    this.drawEn();
    this.drawBullet();
    this.drawScore();
  }

（2）繪制飛機(jī)

drawFj() {
    this.context.drawImage( this.fjImg, this.fjStartX, this.fjslotY,this.birdH,this.birdW)
  }

（3）繪制害蟲

drawEn() {
    for (let line=0; line < this.enemylist.length; line++) {
      for (let row=0; row < this.enemylist[line].length; row++) {
        if (this.enemylist[line][row] == 1) {
          if (line == 0) {
            this.context.drawImage( this.en1Img, this.en1slotX+row*this.birdW,this.en1slotY-line*this.birdH,this.birdH,this.birdW);
          } else if (line == 1) {
            this.context.drawImage( this.en2Img, this.en1slotX+row*this.birdW,this.en1slotY-line*this.birdH,this.birdH,this.birdW);
          } else if (line == 2) {
            this.context.drawImage( this.en3Img, this.en1slotX+row*this.birdW,this.en1slotY-line*this.birdH,this.birdH,this.birdW);
          }
        }
      }
    }
  }

不同行的害蟲長(zhǎng)相不同，分值不同。

3、游戲邏輯

簡(jiǎn)單的小游戲主體游戲邏輯為：點(diǎn)擊鼠標(biāo)移動(dòng)飛機(jī)，飛機(jī)發(fā)射子彈，命中害蟲，計(jì)算分?jǐn)?shù)：

doClick() {
    if (this.en1slotX <= 50) {
      this.en1slotX += this.birdW
    } else {
      this.en1slotX -= this.birdW
    }
    console.log("doclick----")
    this.moveFj();
  }

4、完整邏輯

@Entry
@Component
struct Index {
  @State message: string = 'Hello World'
  private settings: RenderingContextSettings = new RenderingContextSettings(true);
  private context: CanvasRenderingContext2D = new CanvasRenderingContext2D(this.settings);
  private blockType: number = 0
  private blockSize: number = 30
  private en1Img:ImageBitmap = new ImageBitmap("common/images/mf1.png")
  private en2Img:ImageBitmap = new ImageBitmap("common/images/mf2.png")
  private en3Img:ImageBitmap = new ImageBitmap("common/images/mf3.png")
  private fjImg:ImageBitmap = new ImageBitmap("common/images/fj.png")

  private startX = 30;
  private startY = 100;
  private enStartY = 140;
  private fjStartX = 50;
  private fjStartY = 610;
  private fjslotX = 50;
  private fjslotY = this.fjStartY;
  private en1slotX = 50;
  private en1slotY = this.enStartY;
  private en2slotX = 50;
  private en2slotY = this.enStartY;
  private bulletX = 65;
  private bulletY = 550;
  private birdH = 40;
  private birdW = 40;
  private score = 0;
  private fjDirection = 1;

  private enemylist = [
    [1,1,1,1,1],
    [1,1,1,1,1],
    [1,1,1,1,1],
  ]

  moveFj() {
    this.fjStartX = this.fjStartX + this.fjDirection * this.birdW
    if (this.fjStartX >= 210) {
      this.fjDirection = -1
    } else if (this.fjStartX <= 50) {
      this.fjDirection = 1
    }
  }

  drawFj() {
    this.context.drawImage( this.fjImg, this.fjStartX, this.fjslotY,this.birdH,this.birdW)
  }

  drawEn() {
    for (let line=0; line < this.enemylist.length; line++) {
      for (let row=0; row < this.enemylist[line].length; row++) {
        if (this.enemylist[line][row] == 1) {
          if (line == 0) {
            this.context.drawImage( this.en1Img, this.en1slotX+row*this.birdW,this.en1slotY-line*this.birdH,this.birdH,this.birdW);
          } else if (line == 1) {
            this.context.drawImage( this.en2Img, this.en1slotX+row*this.birdW,this.en1slotY-line*this.birdH,this.birdH,this.birdW);
          } else if (line == 2) {
            this.context.drawImage( this.en3Img, this.en1slotX+row*this.birdW,this.en1slotY-line*this.birdH,this.birdH,this.birdW);
          }
        }
      }
    }
  }

  drawBullet() {
    let isfind = false
    this.context.fillStyle = 'rgb(250,250,250)'
    this.context.font = '80px sans-serif'
    this.bulletX = this.fjStartX + 20
    this.context.fillText(":", this.fjStartX+20, this.bulletY)
    for (let line=0; line < this.enemylist.length; line++) {
      if (Math.abs(this.bulletY - (this.en1slotY-line*this.birdH)) <= this.birdH) {
        console.log("find line: "+line)
        for (let row = 0; row < this.enemylist[line].length; row++) {
          let matchsize = Math.abs(this.bulletX - (this.en1slotX+row*this.birdW))
//          console.log("find szie: "+matchsize.toString()+" row:"+row.toString()+" line:"+line.toString()+" bulletX:"+this.bulletX.toString()+" bulletY:"+
//          this.bulletY.toString()+" en1slotX"+this.en1slotX.toString()+" en1slotY"+this.en1slotY.toString())
          if (matchsize <= this.birdW) {
            if (this.enemylist[line][row] == 1) {
              console.log("row:"+row.toString()+" line:"+line.toString()+" bulletX:"+this.bulletX.toString()+" bulletY:"+
              this.bulletY.toString()+" en1slotX"+this.en1slotX.toString()+" en1slotY"+this.en1slotY.toString());
              this.enemylist[line][row] = 0
              isfind = true
              switch (line) {
                case 0:
                  this.score += 1;
                  break;
                case 1:
                  this.score += 2;
                  break;
                case 2:
                  this.score += 3;
                  break;
                default:
                  break;
              }
              //console.log("score: "+this.score.toString())
              break
            }
          }
        }
        if (isfind) {
          break;
        }
      }
    }
    if (this.bulletY <= 100 || isfind == true) {
      this.bulletY = 550
    } else {
      this.bulletY -= 50;
    }
  }

  drawScore() {
    this.context.fillStyle = 'rgb(250,250,250)'
    this.context.font = '80px sans-serif'
    this.context.fillText("Score:"+this.score.toString(), 20, 750)
    //    this.context.fillText(":", 65, 550)
  }

  drawall() {
    this.context.clearRect(0,0,this.context.width,this.context.height)
    this.drawFj();
    this.drawEn();
    this.drawBullet();
    this.drawScore();
  }

  async sleep(ms: number) {
    var that = this;
    return new Promise((r) => {
      setInterval(() => {
        if (that.en1slotX <= 50) {
          that.en1slotX += that.birdW
        } else {
          that.en1slotX -= that.birdW
        }

        console.log(that.en1slotX.toString())
        that.drawall()

      }, ms)
    })
  }

  doClick() {
    if (this.en1slotX <= 50) {
      this.en1slotX += this.birdW
    } else {
      this.en1slotX -= this.birdW
    }
    console.log("doclick----")
    this.moveFj();
  }

  aboutToAppear() {
    this.sleep(1000)
  }

  build() {
    Row() {
      Column() {
        Canvas(this.context)
          .width('100%')
          .height('100%')
          .onClick((ev: ClickEvent) => {
            console.info("click!!")
            this.doClick()
          })
          .onReady(() =>{
            this.context.imageSmoothingEnabled = false
            this.drawall()
          })
      }
      .width('100%')
    }
    .height('100%')
    .backgroundColor("#000000")
  }
}