ACTION_CREATE_DOCUMENT從url回應中寫入pdf檔案，android？-有解無憂

我正在使用共享存盤來撰寫 pdf 檔案。該檔案已創建，但它是 0 位元組。無法理解是什么問題。

下面是我的代碼

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)
}

活動結果

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)
             }


         }
     }
 }

寫檔案方法

 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()
 }
 }

uj5u.com熱心網友回復：

感謝@blackapps 的評論能夠解決它洗掉了以下內容

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

正確的函式變成

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()
    }
}

uj5u.com熱心網友回復：

通過記錄 inputStream.available() 來檢查輸入流是否可訪問必須>0

使用此邏輯將輸入流寫入輸出流

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

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標籤：安卓文件贮存

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