【Harmony OS】【ARK UI】ets實現文件讀寫操作

1. 準備階段

關於該功能的實現我們需要學習以下的資料：

1.1 【ARKUI】ets怎麼實現文件操作

1.2 文件管理

1.3 Ability上下文

2. demo 實現

2.1 文件路徑讀取

參考 context.getFilesDir 來進行獲取文件路徑，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);
    })
}

2.2 文件寫入操作

參考 fileio.createStream 和 write 和 flush 相關 Api，資料和代碼如下

實現代碼

private writeFile(){
    let ss= fileio.createStreamSync(this.path+"/111.txt", "w+");
    let num =  ss.write("你好 2022",null);
    ss.flush();
    console.log("寫入成功");
}

2.3 文件讀取文件操作

想實現文件的讀取，需要參考 read 的 Api，資料和代碼如下：

代碼如下：

private readFile(){
    let ss = fileio.createStreamSync(this.path+"/111.txt", "r+");
    ss.read(new ArrayBuffer(4096),null,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("讀取文件內容："+decodedString);
      }
  });
}

3. 運行效果

3.1 全部代碼如下

import fileio from '@ohos.fileio';
import ability_featureAbility from '@ohos.ability.featureAbility';
@Entry
@Component
struct MyFileStream {
  @State path:string="";
  private getFilesDirNew(){
    var context = ability_featureAbility.getContext();
    context.getFilesDir()
      .then((data) => {
        console.log('獲取文件路徑成功' + data);
        this.path=data;
      }).catch((error) => {
      console.error('Failed to obtain the file directory. Cause: ' + error.message);
    })
  }

  private writeFile(){
    let ss= fileio.createStreamSync(this.path+"/111.txt", "w+");
    let num =  ss.write("你好 2022",null);
    ss.flush();
    console.log("寫入成功")
  }

  private readFile(){
    let ss = fileio.createStreamSync(this.path+"/111.txt", "r+");
    ss.read(new ArrayBuffer(4096),null,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("讀取文件內容："+decodedString);
      }
    });
  }

  build() {
    Flex({ direction: FlexDirection.Column, alignItems: ItemAlign.Center, justifyContent: FlexAlign.Center }) {

      Text('獲取文件路徑')
        .fontSize(50)
        .fontWeight(FontWeight.Bold)
        .backgroundColor(Color.Red)
      .onClick(this.getFilesDirNew.bind(this))
      Text('寫入文字')
        .fontSize(50)
        .fontWeight(FontWeight.Bold)
        .backgroundColor(Color.White)
      .onClick(this.writeFile.bind(this))
      Text('讀取文字')
        .fontSize(50)
        .fontWeight(FontWeight.Bold)
        .backgroundColor(Color.Red)
      .onClick(this.readFile.bind(this))
    }
    .width('100%')
    .height('100%')
  }
}

3.2 運行效果如下