A utility module has been created to work with android external storage files

android/src/toga_android/dialogs.py

@@ -1,10 +1,12 @@
 from android import R
 from android.app import AlertDialog
-from android.content import DialogInterface
+from android.content import DialogInterface, Intent
 from java import dynamic_proxy
 
 import toga
 
+from .libs import utilfile as uf
+
 
 class OnClickListener(dynamic_proxy(DialogInterface.OnClickListener)):
     def __init__(self, fn=None, value=None):
@@ -31,12 +33,12 @@ def show(self, host_window, future):
 
 class TextDialog(BaseDialog):
     def __init__(
-        self,
-        title,
-        message,
-        positive_text,
-        negative_text=None,
-        icon=None,
+            self,
+            title,
+            message,
+            positive_text,
+            negative_text=None,
+            icon=None,
     ):
         super().__init__()
 
@@ -104,10 +106,10 @@ def __init__(self, title, message):
 
 class StackTraceDialog(BaseDialog):
     def __init__(
-        self,
-        title,
-        message,
-        **kwargs,
+            self,
+            title,
+            message,
+            **kwargs,
     ):
         super().__init__()
 
@@ -117,11 +119,11 @@ def __init__(
 
 class SaveFileDialog(BaseDialog):
     def __init__(
-        self,
-        title,
-        filename,
-        initial_directory,
-        file_types=None,
+            self,
+            title,
+            filename,
+            initial_directory,
+            file_types=None,
     ):
         super().__init__()
 
@@ -130,25 +132,39 @@ def __init__(
 
 
 class OpenFileDialog(BaseDialog):
+    class HandlerOpenDialog(uf.HandlerFileDialog):
+        def show(self):
+            intent = Intent(Intent.ACTION_OPEN_DOCUMENT)
+            intent.addCategory(Intent.CATEGORY_OPENABLE)
+            intent.setType("*/*")
+            self.app.start_activity(intent, on_complete=self.parent.handler)
+
     def __init__(
-        self,
-        title,
-        initial_directory,
-        file_types,
-        multiple_select,
+            self,
+            title,
+            initial_directory,
+            file_types,
+            multiple_select,
     ):
-        super().__init__()
+        self.native = OpenFileDialog.HandlerOpenDialog(self, toga.App.app.current_window)
+        self.mActive = self.native.mActive
 
-        toga.App.app.factory.not_implemented("dialogs.OpenFileDialog()")
-        self.native = None
+    def handler(self, code, indent):
+        self._handler(indent.getData())
+
+    def _handler(self, uri):
+        ist = self.mActive.getContentResolver().openInputStream(uri)
+        isr = uf.InputStreamReader(uf.Objects.requireNonNull(ist))
+        reader = uf.VFile(uf.BufferedReader(isr))
+        self.future.set_result(reader)
 
 
 class SelectFolderDialog(BaseDialog):
     def __init__(
-        self,
-        title,
-        initial_directory,
-        multiple_select,
+            self,
+            title,
+            initial_directory,
+            multiple_select,
     ):
         super().__init__()
 

android/src/toga_android/libs/utilfile.py

@@ -0,0 +1,58 @@
+import abc
+import io
+
+import java
+
+BufferedReader = java.jclass("java.io.BufferedReader")
+InputStreamReader = java.jclass("java.io.InputStreamReader")
+Objects = java.jclass("java.util.Objects")
+
+
+class HandlerFileDialog(abc.ABC):
+    """Абстрактный класс вызова файлового менеджера"""
+
+    def __init__(self, parent, app_toga):
+        self.parent = parent
+        self.app = app_toga._impl
+        self.mActive = app_toga._impl.native
+
+    @abc.abstractmethod
+    def show(self):
+        """Запуск менеджера"""
+        pass
+
+
+class VFile(io.TextIOBase):
+    """Файл для работы с внешнем хранилищем андроида"""
+
+    def __init__(self, bufferedReader):
+        self._bfr = bufferedReader
+
+    def __del__(self):
+        self.close()
+
+    def close(self):
+        self._bfr.close()
+
+    def readline(self, size: int = 0) -> str:
+        """Функция для чтения строки
+        :param size: количество строк, которые нужно считать.
+        Если он равен 0, то будет прочтен весь файл
+        :return: Строка"""
+        return self._bfr.readLine()
+
+    def read(self, size: int = 0) -> str:
+        """Функция для чтения строки
+        :param size: количество символов, которые нужно считать.
+        Если он равен 0, то будет прочтен весь файл
+        :return: Строка"""
+        res = ""
+        counter = size if size else "+"
+        while counter:
+            resp = self._bfr.read()
+            if resp == -1:
+                break
+            res += chr(resp)
+            if isinstance(counter, int):
+                counter -= 1
+        return res

changes/2910.misc.rst

@@ -0,0 +1 @@
+Partial OpenFileDialog implementation