【android】关于android10-11存储的一些知识

val file = File(getExternalFilesDir(""),"安安安安安卓.txt")
            val fos = FileOutputStream(file)
            fos.write("公众号：安安安安安卓".toByteArray(Charsets.UTF_8))
            fos.close()
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ItemData(title = "访问外部存储空间",{
            val file = File(Environment.getExternalStorageDirectory().absolutePath)
            val fileAn = File(file,"安安安.txt")
            logEE(file.absolutePath)
            val fos = FileOutputStream(fileAn)
            fos.write("公众号：安安安安安卓".toByteArray(Charsets.UTF_8))
            fos.close()
        })
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val picFile = getExternalFilesDir(Environment.DIRECTORY_PICTURES)?.apply {
                if (!exists()) {
                    mkdirs()
                }
            }
            val file = File(picFile,"pic.jpg")
            FileOutputStream(file).apply {
                write(12)
                flush()
                close()
            }
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override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_directory_scan11)
        findViewById<Button>(R.id.btn_secletdirectory).setOnClickListener {
            val intent = Intent(Intent.ACTION_OPEN_DOCUMENT)
            intent.addCategory(Intent.CATEGORY_OPENABLE)
            intent.type = "image/jpeg"
            startActivityForResult(intent, 100)//跳转系统浏览器
        }
    }
    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
        super.onActivityResult(requestCode, resultCode, data)
        data?.data?.let {
            iv.setImageURI(it)//通过url处理图片
        }
    }
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openFileOutput("安安安安卓openfileoutput.txt", MODE_PRIVATE).apply {
    write("openFileOutput方法输入流".toByteArray(Charsets.UTF_8))
    flush()
    close()
}
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ItemData(title = "获取目录中所有文件路径",{
            fileList().forEach {
                logEE("文件路径:$it")
            }
        })
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E/安安安安卓: 文件路径:安安安安卓openfileoutput.txt
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context.getCacheDir()
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private fun getGallaryData(): MutableList<Image> {
        val cursor = contentResolver.query(
            MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
            null, null, null, "${MediaStore.Images.Media.DISPLAY_NAME} ASC"
        )
        val tempdatas = mutableListOf<Image>()
        cursor?.use {
            val idColumn = it.getColumnIndexOrThrow(MediaStore.Images.Media._ID)
            val nameColumn = it.getColumnIndexOrThrow(MediaStore.Images.Media.DISPLAY_NAME)
            while (it.moveToNext()) {
                val id = it.getLong(idColumn)
                val contentUrl =
                    ContentUris.withAppendedId(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, id)
                val name = it.getString(nameColumn)
                val image = Image(contentUrl, "")
                tempdatas.add(image)
                logEE("文件名：${contentUrl.path}")
            }
            it.close()
        }
        return tempdatas
    }
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private fun initData() {
        lifecycleScope.launch(Dispatchers.IO) {
            datas.addAll(getGallaryData())
            withContext(Dispatchers.Main) {
                recycle.adapter?.notifyDataSetChanged()
            }
        }
    }
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Environment.isExternalStorageManager()
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<uses-permission android:name="android.permission.MANAGE_EXTERNAL_STORAGE"/>
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if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
    startActivity(Intent(Settings.ACTION_MANAGE_ALL_FILES_ACCESS_PERMISSION))
}
```kt
3. 实现效果
![](https://p3-juejin.byteimg.com/tos-cn-i-k3u1fbpfcp/f9aa67860d724340b6ed82ab7091a364~tplv-k3u1fbpfcp-zoom-1.image)
### 其它
#### 权限方面
- 使用使用共享存储空间访问其它应用创建的应用需要申请存储权限，自己应用本次安装创建的文件不需要申请权限。
- 如果应用`target`版本大于 9，那么我们仅应该在<=9 的版本中进行权限申请，可以通过如下配置设置：
maxSdkVersion
```kt
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"
                 android:maxSdkVersion="28" />
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android:requestLegacyExternalStorage="true"
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