【HarmonyOS】【ARKUI】ets怎么实现文件操作

ets 怎么实现文件操作？

关于文件操作的我们可以学习HarmonyOS文件管理和Ability上下文 这两篇文档，我这边实现”文件路径读取”、“文件写入”“文件读取”，“运行效果”四个方面实现，具体操作如下

1. 文件路径读取

参考context.getFilesDir来进行获取文件路径，代码如下

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. 文件写入

参考fileio.openSync的api，实现代码如下

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("写入成功");
        }
    });
}

3. 文件读取

参考 fileio.read这个api ，代码如下

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));//没有这一步中文会乱码
            console.log("读取文件内容"+decodedString);
        }
    });
}

4. 运行效果

全部代码如下

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("写入成功")
      }
    });
 
  }
  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));//没有这一步中文会乱码
        console.log("读取文件内容"+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('获取文件目录')
        .fontSize(50)
        .fontWeight(FontWeight.Bold)
        .onClick(this.getFilesDirNew.bind(this));
 
      Text('写文件 你好 2022 到文件中')
        .fontSize(50)
        .fontWeight(FontWeight.Bold)
        .backgroundColor(Color.Red)
        .onClick(this.writeFiles.bind(this));
 
      Text('读文件内容')
        .fontSize(50)
        .fontWeight(FontWeight.Bold)
        .backgroundColor(Color.White)
        .onClick(this.ReadFile.bind(this));
    }
    .width('100%')
    .height('100%')
  }
}

效果图如下：