【HarmonyOS】【ARKUI】ets怎么實作檔案操作

ets 怎么實作檔案操作？

關于檔案操作的我們可以學習HarmonyOS檔案管理和Ability背景關系 這兩篇檔案，我這邊實作”檔案路徑讀取”、“檔案寫入”“檔案讀取”，“運行效果”四個方面實作，具體操作如下

1. 檔案路徑讀取

參考context.getFilesDir來進行獲取檔案路徑，代碼如下

private getCacheDir() {
    var context = ability_featureAbility.getContext();
    context.getFilesDir()
      .then((data) => {
        console.log('File directory obtained. Data:' + data);
        this.path=data;
    }).catch((error) => {
        console.error('Failed to obtain the file directory. Cause: ' + error.message);
    })
}

2. 檔案寫入

參考fileio.openSync的api，實作代碼如下

private writeFiles(){
    let fd = fileio.openSync(this.path+"/111.txt", 0o102, 0o666);
    fileio.write(fd, "你好 2022", function (err, bytesWritten) {
        if (!err) {
            console.log("寫入成功");
        }
    });
}

3. 檔案讀取

參考 fileio.read這個api ，代碼如下

private ReadFile() {
    let Filepath = this.path+"/111.txt";
    let fd = fileio.openSync(Filepath, 0o2);
    let buf = new ArrayBuffer(4096);
    fileio.read(fd, buf, function (err, readOut) {
        if (!err) {
            let  encodedString = String.fromCodePoint.apply(null, new Uint8Array(readOut.buffer));
            let decodedString = decodeURIComponent(escape(encodedString));//沒有這一步中文會亂碼
            console.log("讀取檔案內容"+decodedString);
        }
    });
}

4. 運行效果

全部代碼如下

import fileio from '@ohos.fileio';
import ability_featureAbility from '@ohos.ability.featureAbility';
@Entry
@Component
struct NewmyFileTwo {
  @State    path:string="";
  private getCacheDir(){
    var context = ability_featureAbility.getContext();
    context.getFilesDir()
      .then((data) => {
        console.log('File directory obtained. Data:' + data);
        this.path=data;
      }).catch((error) => {
      console.error('Failed to obtain the file directory. Cause: ' + error.message);
    })
  }
 
  private writeFiles(){
    let fd = fileio.openSync(this.path+"/111.txt", 0o102, 0o666);
    fileio.write(fd, "你好 2022", function (err, bytesWritten) {
      if (!err) {
        console.log("寫入成功")
      }
    });
 
  }
  private ReadFile(){
    let Filepath = this.path+"/111.txt";
    let fd = fileio.openSync(Filepath, 0o2);
    let buf = new ArrayBuffer(4096);
    fileio.read(fd, buf, function (err, readOut) {
      if (!err) {
        let  encodedString = String.fromCodePoint.apply(null, new Uint8Array(readOut.buffer));
        let decodedString = decodeURIComponent(escape(encodedString));//沒有這一步中文會亂碼
        console.log("讀取檔案內容"+decodedString);
      }
    });
  }
 
 
  private getFilesDirNew(){
    var context = ability_featureAbility.getContext();
    context.getFilesDir()
      .then((data) => {
        console.log('File directory obtained. Data:' + data);
        this.path=data;
      }).catch((error) => {
      console.error('Failed to obtain the file directory. Cause: ' + error.message);
    })
  }
 
  build() {
    Flex({ direction: FlexDirection.Column, alignItems: ItemAlign.Center, justifyContent: FlexAlign.Center }) {
      Text('獲取檔案目錄')
        .fontSize(50)
        .fontWeight(FontWeight.Bold)
        .onClick(this.getFilesDirNew.bind(this));
 
      Text('寫檔案 你好 2022 到檔案中')
        .fontSize(50)
        .fontWeight(FontWeight.Bold)
        .backgroundColor(Color.Red)
        .onClick(this.writeFiles.bind(this));
 
      Text('讀檔案內容')
        .fontSize(50)
        .fontWeight(FontWeight.Bold)
        .backgroundColor(Color.White)
        .onClick(this.ReadFile.bind(this));
    }
    .width('100%')
    .height('100%')
  }
}

效果圖如下：

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