ACTION_CREATE_DOCUMENT 根据 url 响应写一个 pdf 文件，android？

Question

我正在使用共享存储来编写 pdf 文件。文件已创建，但它是 0 字节。无法理解问题所在。

下面是我的代码

ACTION_CREATE_DOCUMENT

fun saveFile() {

 val exportIntent = Intent(Intent.ACTION_CREATE_DOCUMENT)
 exportIntent.addCategory(Intent.CATEGORY_OPENABLE)
 exportIntent.type = "application/pdf"
 val filename = "test.pdf"
 exportIntent.putExtra(Intent.EXTRA_TITLE, filename)
 startForResult.launch(exportIntent)
}

Activity 结果

private val MEGABYTE = 1024 * 1024

val startForResult =
 registerForActivityResult(ActivityResultContracts.StartActivityForResult()) { result: ActivityResult ->
     if (result.resultCode == Activity.RESULT_OK) {
         val intent = result.data
         if (intent?.data != null) {
             val uri: Uri = intent.data!!
             GlobalScope.launch {
                 writeFile(uri)
             }


         }
     }
 }

写文件方法

 fun writeFile(uri:Uri){
 val outputStream: OutputStream? =
     requireContext().contentResolver.openOutputStream(uri)
 if (outputStream != null) {
     val url = URL(some url)
     val urlConnection: HttpURLConnection =
         url.openConnection() as HttpURLConnection
     urlConnection.setRequestMethod("GET")       
     urlConnection.setDoOutput(true)
     urlConnection.connect()

     val inputStream: InputStream = urlConnection.getInputStream()

     val buffer = ByteArray(MEGABYTE)
     var bufferLength = 0
     while (inputStream.read(buffer).also { bufferLength = it } > 0) {
         outputStream.write(buffer, 0, bufferLength)
     }

     outputStream.close()
 }
 }

Answer 1

通过记录 inputStream.available() 检查输入流是否可访问必须 >0

使用此逻辑将输入流写入输出流

byte[] buffer = new byte[1024];
int len;
while ((len = inputStream.read(buffer)) != -1) {
    outputStream.write(buffer, 0, len);
}
outputStream.close()

Answer 2

感谢@blackapps 的评论才得以解决删除了以下内容

urlConnection.setRequestMethod("GET")
urlConnection.setDoOutput(true)

正确的函数变为

fun writeFile(uri: Uri, docUrl: String) {
    val outputStream: OutputStream? =
        requireContext().contentResolver.openOutputStream(uri)
    if (outputStream != null) {
        val url =
            URL(docUrl)
        val urlConnection: HttpURLConnection =
            url.openConnection() as HttpURLConnection
        urlConnection.connect()

        val inputStream: InputStream = urlConnection.getInputStream()
        val buffer = ByteArray(1024 * 1024)
        var bufferLength = 0
        while (inputStream.read(buffer).also { bufferLength = it } > 0) {
            outputStream.write(buffer, 0, bufferLength)
        }
        outputStream.close()
    }
}

ACTION_CREATE_DOCUMENT 根据 url 响应写一个 pdf 文件，android？

ACTION_CREATE_DOCUMENT write a pdf file from url response, android?

android

file

storage