Android Nativescript：如何在外部存储器（SD卡）中保存文件

在谷歌搜索了很多次，并尝试了很多“断章取义”的代码之后，我请求你帮助我

我试图弄清楚是否可以使用Nativescript在外部存储器上进行写入。我对在应用程序上下文中编写不感兴趣。所以这些文件显示的不是我想要的

我已经通过Nativescript论坛上的一个线程实现了这一点：

android.os.Environment.getExternalStoragePublicDirectory（android.os.Environment.DIRECTORY_下载）.toString（）

它起作用了，它给了我一条路，但当我有了这条路，我就不知道该怎么办了。如何在该路径内创建文件、读取文件等

我需要实现的是创建一个用户和应用程序都可以轻松访问的文件夹。用户应该能够使用内置文件资源管理器访问此文件夹

应用程序以角度运行。
您知道外部（sd卡）路径吗？
如果类似于/storage/emulated/0，则可以尝试创建文件夹或文件

import * as fs from "tns-core-modules/file-system";

  let externalPath= fs.path.join(android.os.Environment.getExternalStorageDirectory().getAbsolutePath().toString());
  //Create a folder with known path
  var folder: fs.Folder = fs.Folder.fromPath(sdCardPath+"/test");
  //Create a file 
  var testFile: fs.File = folder.getFile("test.txt");
  console.log("Path " + folder.path)

用户应该能够访问此文件夹和文件。它位于设备内部存储器中，即“外部”文件夹

我仍在尝试如何访问sd卡，但希望上面的代码对您有用。
我在Android设备上遇到了这个问题，最终是因为：

不确保应用程序中的用户已授予所需的权限
在我的Macbook上使用“Android文件传输”来验证文件是否已创建并下载
tns信息

nativescript 6.0.3
tns-core-modules 6.0.7
tns-android 6.0.2 

tns插件

nativescript-permissions 1.3.7

示例代码

        import * as fs from "tns-core-modules/file-system"

        ...

        // First get the required permissions
        // Note: this permissions should also be in your AndroidManifest.xml file as:
        //   <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
        const permissions = require('nativescript-permissions')
        permissions.requestPermission(android.Manifest.permission.WRITE_EXTERNAL_STORAGE)
        .then(() => {
            console.log('Required Android permissions have been granted');
        })
        .catch(() => {
            console.error('Required Android permissions have been denied!');
        });

        // Get the publicly accessable Downloads directory path
        const sdDownloadPath = android.os.Environment.getExternalStoragePublicDirectory(android.os.Environment.DIRECTORY_DOWNLOADS).toString()
        console.log('sdDownloadPath: ' + sdDownloadPath)

        // Get a specific folder in that path (will be created if it does not exist)
        const myAppFolder = fs.Folder.fromPath(fs.path.join(sdDownloadPath, 'myApp'))
        console.log('myApp path: ' + myAppFolder.path)

        // Get a file in that path (will be created if it does not exist)
        // Note: In this case we try to get a unique file every time this code is run
        let date = new Date()
        date = date.toISOString().replace('.', '')
        const myFile = myAppFolder.getFile(`myfile_${date}.txt`) 
        console.log('myFile path: ' + myFile.path)

        // Write some data to this new file
        myFile.writeText('Hello duder 123')
        .then(() => {})
        .catch((err) => console.log(`Error writing to file: ${err}`))

        // Try and read back the data that was written
        myFile.readText()
        .then((res) => {
            console.log(`Text read back: ${res}`)
        }).catch((err) => {
            console.log(err.stack);
        });

        // List all files in the myApp folder
        myAppFolder.getEntities()
        .then((entities) => {
            // entities is array with the document's files and folders.
            entities.forEach((entity) => {
                console.log(entity)
            });
        }).catch((err) => {
            console.log(err.stack);
        });

import*作为fs从“tns核心模块/文件系统”
...
//首先获取所需的权限
//注意：此权限也应位于AndroidManifest.xml文件中，如下所示：
//   
const permissions=require（'nativescript-permissions'）
permissions.requestPermission（android.Manifest.permission.WRITE\u外部存储）
.然后（（）=>{
log（'已授予所需的Android权限'）；
})
.catch（（）=>{
错误（'所需的Android权限已被拒绝！'）；
});
//获取可公开访问的下载目录路径
const sdDownloadPath=android.os.Environment.getExternalStoragePublicDirectory（android.os.Environment.DIRECTORY\u DOWNLOADS）.toString（）
console.log（'sdDownloadPath:'+sdDownloadPath）
//获取该路径中的特定文件夹（如果不存在，将创建该文件夹）
const myAppFolder=fs.Folder.fromPath（fs.path.join（sdDownloadPath，'myApp'））
console.log（'myApp路径：'+myAppFolder.path）
//获取该路径中的文件（如果不存在，将创建该文件）
//注意：在这种情况下，每次运行此代码时，我们都会尝试获取一个唯一的文件
let date=新日期（）
日期=日期.toISOString（）。替换（'.'，''）
const myFile=myAppFolder.getFile（`myFile{date}.txt`）
console.log（'myFile路径：'+myFile.path）
//将一些数据写入此新文件
myFile.writeText（'Hello duder 123'）
.然后（（）=>{}）
.catch（（err）=>console.log（`写入文件时出错：${err}`））
//试着读回写入的数据
myFile.readText（）文件
。然后（（res）=>{
log（`Text read back:${res}`）
}).catch（（错误）=>{
console.log（err.stack）；
});
//列出myApp文件夹中的所有文件
myAppFolder.getEntities（）
。然后（（实体）=>{
//实体是文档文件和文件夹的数组。
实体。forEach（（实体）=>{
console.log（实体）
});
}).catch（（错误）=>{
console.log（err.stack）；
});

android文件传输问题

        import * as fs from "tns-core-modules/file-system"

        ...

        // First get the required permissions
        // Note: this permissions should also be in your AndroidManifest.xml file as:
        //   <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
        const permissions = require('nativescript-permissions')
        permissions.requestPermission(android.Manifest.permission.WRITE_EXTERNAL_STORAGE)
        .then(() => {
            console.log('Required Android permissions have been granted');
        })
        .catch(() => {
            console.error('Required Android permissions have been denied!');
        });

        // Get the publicly accessable Downloads directory path
        const sdDownloadPath = android.os.Environment.getExternalStoragePublicDirectory(android.os.Environment.DIRECTORY_DOWNLOADS).toString()
        console.log('sdDownloadPath: ' + sdDownloadPath)

        // Get a specific folder in that path (will be created if it does not exist)
        const myAppFolder = fs.Folder.fromPath(fs.path.join(sdDownloadPath, 'myApp'))
        console.log('myApp path: ' + myAppFolder.path)

        // Get a file in that path (will be created if it does not exist)
        // Note: In this case we try to get a unique file every time this code is run
        let date = new Date()
        date = date.toISOString().replace('.', '')
        const myFile = myAppFolder.getFile(`myfile_${date}.txt`) 
        console.log('myFile path: ' + myFile.path)

        // Write some data to this new file
        myFile.writeText('Hello duder 123')
        .then(() => {})
        .catch((err) => console.log(`Error writing to file: ${err}`))

        // Try and read back the data that was written
        myFile.readText()
        .then((res) => {
            console.log(`Text read back: ${res}`)
        }).catch((err) => {
            console.log(err.stack);
        });

        // List all files in the myApp folder
        myAppFolder.getEntities()
        .then((entities) => {
            // entities is array with the document's files and folders.
            entities.forEach((entity) => {
                console.log(entity)
            });
        }).catch((err) => {
            console.log(err.stack);
        });

我浪费了很多时间的一个问题是，我可以通过
getEntities（）
查看文件，但在Mac上使用第三方工具“Android文件传输（AFT）”时无法查看它们。我最终偶然发现了“Android Studio的->设备文件浏览器”，可以看到我创建的所有文件和文件夹，因此意识到问题在于AFT

我现在利用浏览和下载设备文件

适用参考

        import * as fs from "tns-core-modules/file-system"

        ...

        // First get the required permissions
        // Note: this permissions should also be in your AndroidManifest.xml file as:
        //   <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
        const permissions = require('nativescript-permissions')
        permissions.requestPermission(android.Manifest.permission.WRITE_EXTERNAL_STORAGE)
        .then(() => {
            console.log('Required Android permissions have been granted');
        })
        .catch(() => {
            console.error('Required Android permissions have been denied!');
        });

        // Get the publicly accessable Downloads directory path
        const sdDownloadPath = android.os.Environment.getExternalStoragePublicDirectory(android.os.Environment.DIRECTORY_DOWNLOADS).toString()
        console.log('sdDownloadPath: ' + sdDownloadPath)

        // Get a specific folder in that path (will be created if it does not exist)
        const myAppFolder = fs.Folder.fromPath(fs.path.join(sdDownloadPath, 'myApp'))
        console.log('myApp path: ' + myAppFolder.path)

        // Get a file in that path (will be created if it does not exist)
        // Note: In this case we try to get a unique file every time this code is run
        let date = new Date()
        date = date.toISOString().replace('.', '')
        const myFile = myAppFolder.getFile(`myfile_${date}.txt`) 
        console.log('myFile path: ' + myFile.path)

        // Write some data to this new file
        myFile.writeText('Hello duder 123')
        .then(() => {})
        .catch((err) => console.log(`Error writing to file: ${err}`))

        // Try and read back the data that was written
        myFile.readText()
        .then((res) => {
            console.log(`Text read back: ${res}`)
        }).catch((err) => {
            console.log(err.stack);
        });

        // List all files in the myApp folder
        myAppFolder.getEntities()
        .then((entities) => {
            // entities is array with the document's files and folders.
            entities.forEach((entity) => {
                console.log(entity)
            });
        }).catch((err) => {
            console.log(err.stack);
        });


（角度文档，但也与nativescript vue相关）
我有同样的问题，最后通过在AndroidManifest.xml文件中添加
android:requestLegacyExternalStorage=“true”
解决了这个问题
按照线程进行操作
尝试以下操作：