From 787f8439811bf152303a22512cd949d54c90f8c2 Mon Sep 17 00:00:00 2001
From: Filip Strajnar <filip.strajnar@gmail.com>
Date: Tue, 22 Oct 2024 23:34:29 +0200
Subject: [PATCH] Initial implementation of CreateDocumentGuide.

---
 .../storageaccess/CreateDocumentGuide.java    | 83 +++++++++++++++++++
 .../storageaccess/OutputStreamHandler.java    |  7 ++
 .../common/storageaccess/UriHandler.java      |  7 ++
 3 files changed, 97 insertions(+)
 create mode 100644 common/src/main/java/com/proculite/androidagain/common/storageaccess/CreateDocumentGuide.java
 create mode 100644 common/src/main/java/com/proculite/androidagain/common/storageaccess/OutputStreamHandler.java
 create mode 100644 common/src/main/java/com/proculite/androidagain/common/storageaccess/UriHandler.java

diff --git a/common/src/main/java/com/proculite/androidagain/common/storageaccess/CreateDocumentGuide.java b/common/src/main/java/com/proculite/androidagain/common/storageaccess/CreateDocumentGuide.java
new file mode 100644
index 0000000..00aa39d
--- /dev/null
+++ b/common/src/main/java/com/proculite/androidagain/common/storageaccess/CreateDocumentGuide.java
@@ -0,0 +1,83 @@
+package com.proculite.androidagain.common.storageaccess;
+
+import android.content.Context;
+import android.net.Uri;
+import android.os.Bundle;
+import android.os.PersistableBundle;
+import android.util.Log;
+
+import androidx.activity.result.ActivityResultCallback;
+import androidx.activity.result.ActivityResultCaller;
+import androidx.activity.result.ActivityResultLauncher;
+import androidx.activity.result.contract.ActivityResultContracts;
+
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.nio.charset.StandardCharsets;
+import java.util.function.Consumer;
+
+public class CreateDocumentGuide implements ActivityResultCallback<Uri> {
+    private final String TAG = ActivityResultContracts.CreateDocument.class.getName();
+    private final ActivityResultLauncher<String> createDocumentLauncher;
+    private final Context context;
+    private UriHandler uriHandler;
+
+    /**
+     * This constructor registers a request to start an activity for a result, therefore it must
+     * be called unconditionally, as part of the initialization path, typically as a field
+     * initializer of an Activity or Fragment. A suitable location to call it would be the within
+     * {@link android.app.Activity#onCreate(Bundle, PersistableBundle)} method.
+     * @param activityResultCaller Activity result callback, such as
+     * {@link androidx.fragment.app.Fragment} or {@link androidx.appcompat.app.AppCompatActivity}.
+     * @param mimeType Mime type of document.
+     */
+    public CreateDocumentGuide(
+            Context context,
+            ActivityResultCaller activityResultCaller,
+            String mimeType
+    ){
+        this.context = context;
+        ActivityResultContracts.CreateDocument createDocumentContract =
+                new ActivityResultContracts.CreateDocument(mimeType);
+
+        createDocumentLauncher = activityResultCaller
+                .registerForActivityResult(createDocumentContract, this);
+    }
+
+    @Override
+    public final void onActivityResult(Uri o) {
+        uriHandler.handleUri(o);
+    }
+
+    public void writeToOutputStream(String suggestedFileName, OutputStreamHandler outputStreamHandler){
+        uriHandler = uri -> {
+            try {
+                OutputStream outputStream = context.getContentResolver().openOutputStream(uri);
+                outputStreamHandler.handleOutputStream(outputStream);
+                if(outputStream != null) {
+                    outputStream.close();
+                }
+            } catch (FileNotFoundException e) {
+                Log.e(TAG, "FileNotFoundException occurred on write to OutputStream.");
+            } catch (IOException e) {
+                Log.e(TAG, "IOException occurred on write to OutputStream.");
+            }
+        };
+        createDocumentLauncher.launch(suggestedFileName);
+    }
+
+    public void writeBytes(String suggestedFileName, byte[] bytesToWrite){
+        writeToOutputStream(suggestedFileName, outputStream -> {
+            try {
+                outputStream.write(bytesToWrite);
+            } catch (IOException e) {
+                Log.e(TAG, "IOException occurred when writing bytes.");
+            }
+        });
+    }
+
+    public void writeString(String suggestedFileName, String stringToWrite){
+        writeBytes(suggestedFileName, stringToWrite.getBytes(StandardCharsets.UTF_8));
+    }
+}
diff --git a/common/src/main/java/com/proculite/androidagain/common/storageaccess/OutputStreamHandler.java b/common/src/main/java/com/proculite/androidagain/common/storageaccess/OutputStreamHandler.java
new file mode 100644
index 0000000..c5a882d
--- /dev/null
+++ b/common/src/main/java/com/proculite/androidagain/common/storageaccess/OutputStreamHandler.java
@@ -0,0 +1,7 @@
+package com.proculite.androidagain.common.storageaccess;
+
+import java.io.OutputStream;
+
+public interface OutputStreamHandler {
+    void handleOutputStream(OutputStream outputStream);
+}
diff --git a/common/src/main/java/com/proculite/androidagain/common/storageaccess/UriHandler.java b/common/src/main/java/com/proculite/androidagain/common/storageaccess/UriHandler.java
new file mode 100644
index 0000000..31cbb54
--- /dev/null
+++ b/common/src/main/java/com/proculite/androidagain/common/storageaccess/UriHandler.java
@@ -0,0 +1,7 @@
+package com.proculite.androidagain.common.storageaccess;
+
+import android.net.Uri;
+
+public interface UriHandler {
+    void handleUri(Uri uri);
+}