即使定義變量，爲什麼變量未定義？

Question

我正在使用Ionic框架爲移動設備創建應用程序。正如你所看到的，我創建了加載欄，並且我想在完成所有工作後將其解除。但我也想改變我的布爾人。但控制檯說他們沒有定義。爲什麼？

export class AfterEditPage { 

    public loaded_image = base64Image; 
    public showMainContent: boolean = true; // I am interacting with this one 
    public showAdditionalContent: boolean = false; // and this one 
    public processing_Result: string = ""; 

    constructor(public loadingctrl: LoadingController, public alertctrl: AlertController, public navCtrl: NavController, public navParams: NavParams) { 

    } 

    recognizeImage() { 

    let resultText; 
    console.log(resultText); 
    let loader = this.loadingctrl.create({ 
      content: 'Processing...' 
    }); 

    console.log(this.processing_Result); 
    loader.present().then(() => { 
      Tesseract.recognize(this.loaded_image) 
      .progress(function (p) {}) 
      .then(function (result) { 
        resultText = result.text; console.log(resultText); 
        loader.dismiss().then(() => { 
          this.showMainContent = !this.showMainContent; // undefined 
        this.showAdditionalContent = !this.showAdditionalContent; // undefined 
        }); 
       }); 
       }); 
     } 
    } 

Answer 1

你需要，所以你需要更改您的代碼

loader.present().then(() => { 
      Tesseract.recognize(this.loaded_image) 
      .progress((p) => {}) 
      .then((result) => { 
        resultText = result.text; console.log(resultText); 
        loader.dismiss().then(() => { 
          this.showMainContent = !this.showMainContent; 
        this.showAdditionalContent = !this.showAdditionalContent; 
        }); 
       }); 
       }); 
     } 
    }