android: images sharing

android/app/src/main/AndroidManifest.xml

@@ -19,11 +19,22 @@
             android:supportsRtl="true"
             android:theme="@style/Theme.Main">
 
+        <provider
+                android:name=".FileProvider"
+                android:authorities="mw.gri.android.fileprovider"
+                android:exported="false"
+                android:grantUriPermissions="true">
+            <meta-data
+                    android:name="android.support.FILE_PROVIDER_PATHS"
+                    android:resource="@xml/paths" />
+        </provider>
+
         <activity
                 android:launchMode="singleTask"
                 android:name=".MainActivity"
                 android:configChanges="orientation|screenSize"
                 android:exported="true">
+
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
                 <category android:name="android.intent.category.LAUNCHER" />

android/app/src/main/java/mw/gri/android/FileProvider.java

@@ -0,0 +1,7 @@
+package mw.gri.android;
+
+public class FileProvider extends androidx.core.content.FileProvider {
+    public FileProvider() {
+        super(R.xml.paths);
+    }
+}

android/app/src/main/java/mw/gri/android/MainActivity.java

@@ -4,6 +4,7 @@ import android.Manifest;
 import android.content.*;
 import android.content.pm.PackageManager;
 import android.content.res.Configuration;
+import android.net.Uri;
 import android.os.Build;
 import android.os.Bundle;
 import android.os.Process;
@@ -17,6 +18,7 @@ import androidx.annotation.NonNull;
 import androidx.camera.core.*;
 import androidx.camera.lifecycle.ProcessCameraProvider;
 import androidx.core.content.ContextCompat;
+import androidx.core.content.FileProvider;
 import androidx.core.graphics.Insets;
 import androidx.core.view.DisplayCutoutCompat;
 import androidx.core.view.ViewCompat;
@@ -24,6 +26,7 @@ import androidx.core.view.WindowInsetsCompat;
 import com.google.androidgamesdk.GameActivity;
 import com.google.common.util.concurrent.ListenableFuture;
 
+import java.io.File;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 
@@ -62,6 +65,11 @@ public class MainActivity extends GameActivity {
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
+        // Clear cache on start.
+        if (savedInstanceState == null) {
+            Utils.deleteDirectoryContent(new File(getExternalCacheDir().getPath()), false);
+        }
+
         // Setup environment variables for native code.
         try {
             Os.setenv("HOME", getExternalFilesDir("").getPath(), true);
@@ -70,6 +78,7 @@ public class MainActivity extends GameActivity {
         } catch (ErrnoException e) {
             throw new RuntimeException(e);
         }
+
         super.onCreate(null);
 
         // Register receiver to finish activity from the BackgroundService.
@@ -334,4 +343,14 @@ public class MainActivity extends GameActivity {
 
     // Pass image from camera into native code.
     public native void onCameraImage(byte[] buff, int rotation);
+
+    // Called from native code to share image from provided path.
+    public void shareImage(String path) {
+        File file = new File(path);
+        Uri uri = FileProvider.getUriForFile(this, "mw.gri.android.fileprovider", file);
+        Intent intent = new Intent(Intent.ACTION_SEND);
+        intent.putExtra(Intent.EXTRA_STREAM, uri);
+        intent.setType("image/*");
+        startActivity(Intent.createChooser(intent, "Share image"));
+    }
 }

android/app/src/main/java/mw/gri/android/Utils.java

@@ -8,6 +8,7 @@ import android.media.Image;
 import androidx.camera.core.ImageProxy;
 
 import java.io.ByteArrayOutputStream;
+import java.io.File;
 import java.nio.ByteBuffer;
 
 public class Utils {
@@ -135,4 +136,14 @@ public class Utils {
             rowStart += plane.getRowStride();
         }
     }
+
+    public static boolean deleteDirectoryContent(File directoryToBeDeleted, boolean deleteDirectory) {
+        File[] allContents = directoryToBeDeleted.listFiles();
+        if (allContents != null) {
+            for (File file : allContents) {
+                deleteDirectoryContent(file, true);
+            }
+        }
+        return directoryToBeDeleted.delete();
+    }
 }

android/app/src/main/res/xml/paths.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<paths>
+    <external-cache-path name="images" path="images/" />
+</paths>