Meminta file bersama
Tetap teratur dengan koleksi
Simpan dan kategorikan konten berdasarkan preferensi Anda.
Saat aplikasi ingin mengakses file yang dibagikan oleh aplikasi lain, aplikasi yang meminta (klien)
biasanya mengirimkan permintaan ke aplikasi untuk berbagi file (server). Dalam kebanyakan kasus, permintaan
memulai Activity
di aplikasi server yang menampilkan file yang dapat dibagikan.
Pengguna mengambil file, setelah itu aplikasi server mengembalikan URI konten file ke
aplikasi klien.
Pelajaran ini menunjukkan kepada Anda bagaimana aplikasi klien meminta file dari aplikasi server, menerima informasi
URI konten dari aplikasi server, dan membuka file menggunakan URI konten.
Mengirim permintaan untuk file
Untuk meminta file dari aplikasi server, aplikasi klien akan memanggil
startActivityForResult
dengan
Intent
yang berisi tindakan seperti
ACTION_PICK
dan jenis MIME yang digunakan aplikasi klien
dapat ditangani.
Misalnya, cuplikan kode berikut menunjukkan cara mengirim
Intent
ke aplikasi server untuk memulai
Activity
yang dijelaskan dalam Berbagi file:
Kotlin
class MainActivity : Activity() {
private lateinit var requestFileIntent: Intent
private lateinit var inputPFD: ParcelFileDescriptor
...
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
requestFileIntent = Intent(Intent.ACTION_PICK).apply {
type = "image/jpg"
}
...
}
...
private fun requestFile() {
/**
* When the user requests a file, send an Intent to the
* server app.
* files.
*/
startActivityForResult(requestFileIntent, 0)
...
}
...
}
Java
public class MainActivity extends Activity {
private Intent requestFileIntent;
private ParcelFileDescriptor inputPFD;
...
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
requestFileIntent = new Intent(Intent.ACTION_PICK);
requestFileIntent.setType("image/jpg");
...
}
...
protected void requestFile() {
/**
* When the user requests a file, send an Intent to the
* server app.
* files.
*/
startActivityForResult(requestFileIntent, 0);
...
}
...
}
Mengakses file yang diminta
Aplikasi server mengirimkan URI konten file kembali ke aplikasi klien dalam
Intent
. Intent
ini diteruskan ke klien
aplikasi dalam penggantiannya untuk onActivityResult()
. Satu kali
aplikasi klien memiliki URI konten file, dan dapat mengakses file dengan mendapatkan
FileDescriptor
.
Keamanan file dipertahankan dalam proses ini hanya selama Anda mengurai URI konten dengan benar
yang diterima aplikasi klien. Saat mengurai konten, Anda harus memastikan bahwa URI ini tidak mengarah
apa pun di luar direktori yang dimaksud, memastikan bahwa tidak
path traversal sedang dicoba.
Hanya aplikasi klien yang dapat memperoleh akses ke file, dan hanya untuk izin yang diberikan oleh
aplikasi server Anda. Izin bersifat sementara, jadi setelah tumpukan tugas aplikasi klien selesai,
file tidak lagi dapat diakses di luar aplikasi server.
Cuplikan berikutnya menunjukkan cara aplikasi klien menangani
Intent
yang dikirim dari aplikasi server, dan cara aplikasi klien mendapatkan
FileDescriptor
menggunakan URI konten:
Kotlin
/*
* When the Activity of the app that hosts files sets a result and calls
* finish(), this method is invoked. The returned Intent contains the
* content URI of a selected file. The result code indicates if the
* selection worked or not.
*/
public override fun onActivityResult(requestCode: Int, resultCode: Int, returnIntent: Intent) {
// If the selection didn't work
if (resultCode != Activity.RESULT_OK) {
// Exit without doing anything else
return
}
// Get the file's content URI from the incoming Intent
returnIntent.data?.also { returnUri ->
/*
* Try to open the file for "read" access using the
* returned URI. If the file isn't found, write to the
* error log and return.
*/
inputPFD = try {
/*
* Get the content resolver instance for this context, and use it
* to get a ParcelFileDescriptor for the file.
*/
contentResolver.openFileDescriptor(returnUri, "r")
} catch (e: FileNotFoundException) {
e.printStackTrace()
Log.e("MainActivity", "File not found.")
return
}
// Get a regular file descriptor for the file
val fd = inputPFD.fileDescriptor
...
}
}
Java
/*
* When the Activity of the app that hosts files sets a result and calls
* finish(), this method is invoked. The returned Intent contains the
* content URI of a selected file. The result code indicates if the
* selection worked or not.
*/
@Override
public void onActivityResult(int requestCode, int resultCode,
Intent returnIntent) {
// If the selection didn't work
if (resultCode != RESULT_OK) {
// Exit without doing anything else
return;
} else {
// Get the file's content URI from the incoming Intent
Uri returnUri = returnIntent.getData();
/*
* Try to open the file for "read" access using the
* returned URI. If the file isn't found, write to the
* error log and return.
*/
try {
/*
* Get the content resolver instance for this context, and use it
* to get a ParcelFileDescriptor for the file.
*/
inputPFD = getContentResolver().openFileDescriptor(returnUri, "r");
} catch (FileNotFoundException e) {
e.printStackTrace();
Log.e("MainActivity", "File not found.");
return;
}
// Get a regular file descriptor for the file
FileDescriptor fd = inputPFD.getFileDescriptor();
...
}
}
Metode openFileDescriptor()
menampilkan ParcelFileDescriptor
untuk file tersebut. Dari objek ini, klien
aplikasi mendapatkan objek FileDescriptor
, yang kemudian dapat digunakan untuk membaca file.
Untuk informasi terkait lainnya, lihat:
Konten dan contoh kode di halaman ini tunduk kepada lisensi yang dijelaskan dalam Lisensi Konten. Java dan OpenJDK adalah merek dagang atau merek dagang terdaftar dari Oracle dan/atau afiliasinya.
Terakhir diperbarui pada 2025-07-27 UTC.
[[["Mudah dipahami","easyToUnderstand","thumb-up"],["Memecahkan masalah saya","solvedMyProblem","thumb-up"],["Lainnya","otherUp","thumb-up"]],[["Informasi yang saya butuhkan tidak ada","missingTheInformationINeed","thumb-down"],["Terlalu rumit/langkahnya terlalu banyak","tooComplicatedTooManySteps","thumb-down"],["Sudah usang","outOfDate","thumb-down"],["Masalah terjemahan","translationIssue","thumb-down"],["Masalah kode / contoh","samplesCodeIssue","thumb-down"],["Lainnya","otherDown","thumb-down"]],["Terakhir diperbarui pada 2025-07-27 UTC."],[],[],null,["# Requesting a shared file\n\nWhen an app wants to access a file shared by another app, the requesting app (the client)\nusually sends a request to the app sharing the files (the server). In most cases, the request\nstarts an [Activity](/reference/android/app/Activity) in the server app that displays the files it can share.\nThe user picks a file, after which the server app returns the file's content URI to the\nclient app.\n\n\nThis lesson shows you how a client app requests a file from a server app, receives the file's\ncontent URI from the server app, and opens the file using the content URI.\n\nSend a request for the file\n---------------------------\n\n\nTo request a file from the server app, the client app calls\n[startActivityForResult](/reference/android/app/Activity#startActivityForResult(android.content.Intent, int)) with an\n[Intent](/reference/android/content/Intent) containing the action such as\n[ACTION_PICK](/reference/android/content/Intent#ACTION_PICK) and a MIME type that the client app\ncan handle.\n\n\nFor example, the following code snippet demonstrates how to send an\n[Intent](/reference/android/content/Intent) to a server app in order to start the\n[Activity](/reference/android/app/Activity) described in [Sharing a file](/training/secure-file-sharing/share-file#SendURI): \n\n### Kotlin\n\n```kotlin\nclass MainActivity : Activity() {\n private lateinit var requestFileIntent: Intent\n private lateinit var inputPFD: ParcelFileDescriptor\n ...\n override fun onCreate(savedInstanceState: Bundle?) {\n super.onCreate(savedInstanceState)\n setContentView(R.layout.activity_main)\n requestFileIntent = Intent(Intent.ACTION_PICK).apply {\n type = \"image/jpg\"\n }\n ...\n }\n ...\n private fun requestFile() {\n /**\n * When the user requests a file, send an Intent to the\n * server app.\n * files.\n */\n startActivityForResult(requestFileIntent, 0)\n ...\n }\n ...\n}\n```\n\n### Java\n\n```java\npublic class MainActivity extends Activity {\n private Intent requestFileIntent;\n private ParcelFileDescriptor inputPFD;\n ...\n @Override\n protected void onCreate(Bundle savedInstanceState) {\n super.onCreate(savedInstanceState);\n setContentView(R.layout.activity_main);\n requestFileIntent = new Intent(Intent.ACTION_PICK);\n requestFileIntent.setType(\"image/jpg\");\n ...\n }\n ...\n protected void requestFile() {\n /**\n * When the user requests a file, send an Intent to the\n * server app.\n * files.\n */\n startActivityForResult(requestFileIntent, 0);\n ...\n }\n ...\n}\n```\n\nAccess the requested file\n-------------------------\n\n\nThe server app sends the file's content URI back to the client app in an\n[Intent](/reference/android/content/Intent). This [Intent](/reference/android/content/Intent) is passed to the client\napp in its override of [onActivityResult()](/reference/android/app/Activity#onActivityResult(int, int, android.content.Intent)). Once\nthe client app has the file's content URI, it can access the file by getting its\n[FileDescriptor](/reference/java/io/FileDescriptor).\n\n\nFile security is preserved in this process only as long as you properly parse the content URI\nthat the client app receives. When parsing content, you must ensure that this URI does not point\nto anything outside of the intended directory, ensuring that no\n[path traversal](/privacy-and-security/risks/path-traversal) is being attempted.\nOnly the client app should gain access to the file, and only for the permissions granted by the\nserver app. Permissions are temporary, so once the client app's task stack is finished, the\nfile is no longer accessible outside the server app.\n\n\nThe next snippet demonstrates how the client app handles the\n[Intent](/reference/android/content/Intent) sent from the server app, and how the client app gets the\n[FileDescriptor](/reference/java/io/FileDescriptor) using the content URI: \n\n### Kotlin\n\n```kotlin\n/*\n * When the Activity of the app that hosts files sets a result and calls\n * finish(), this method is invoked. The returned Intent contains the\n * content URI of a selected file. The result code indicates if the\n * selection worked or not.\n */\npublic override fun onActivityResult(requestCode: Int, resultCode: Int, returnIntent: Intent) {\n // If the selection didn't work\n if (resultCode != Activity.RESULT_OK) {\n // Exit without doing anything else\n return\n }\n // Get the file's content URI from the incoming Intent\n returnIntent.data?.also { returnUri -\u003e\n /*\n * Try to open the file for \"read\" access using the\n * returned URI. If the file isn't found, write to the\n * error log and return.\n */\n inputPFD = try {\n /*\n * Get the content resolver instance for this context, and use it\n * to get a ParcelFileDescriptor for the file.\n */\n contentResolver.openFileDescriptor(returnUri, \"r\")\n } catch (e: FileNotFoundException) {\n e.printStackTrace()\n Log.e(\"MainActivity\", \"File not found.\")\n return\n }\n\n // Get a regular file descriptor for the file\n val fd = inputPFD.fileDescriptor\n ...\n }\n}\n```\n\n### Java\n\n```java\n /*\n * When the Activity of the app that hosts files sets a result and calls\n * finish(), this method is invoked. The returned Intent contains the\n * content URI of a selected file. The result code indicates if the\n * selection worked or not.\n */\n @Override\n public void onActivityResult(int requestCode, int resultCode,\n Intent returnIntent) {\n // If the selection didn't work\n if (resultCode != RESULT_OK) {\n // Exit without doing anything else\n return;\n } else {\n // Get the file's content URI from the incoming Intent\n Uri returnUri = returnIntent.getData();\n /*\n * Try to open the file for \"read\" access using the\n * returned URI. If the file isn't found, write to the\n * error log and return.\n */\n try {\n /*\n * Get the content resolver instance for this context, and use it\n * to get a ParcelFileDescriptor for the file.\n */\n inputPFD = getContentResolver().openFileDescriptor(returnUri, \"r\");\n } catch (FileNotFoundException e) {\n e.printStackTrace();\n Log.e(\"MainActivity\", \"File not found.\");\n return;\n }\n // Get a regular file descriptor for the file\n FileDescriptor fd = inputPFD.getFileDescriptor();\n ...\n }\n }\n```\n\n\nThe method [openFileDescriptor()](/reference/android/content/ContentResolver#openFileDescriptor(android.net.Uri, java.lang.String))\nreturns a [ParcelFileDescriptor](/reference/android/os/ParcelFileDescriptor) for the file. From this object, the client\napp gets a [FileDescriptor](/reference/java/io/FileDescriptor) object, which it can then use to read the file.\n\nFor additional related information, refer to:\n\n- [Intents and Intent Filters](/guide/components/intents-filters)\n- [Retrieving Data from the Provider](/guide/topics/providers/content-provider-basics#SimpleQuery)"]]