2 files changed, 32 insertions, 0 deletions
diff --git a/android/src/com/artifex/mupdf/MuPDFActivity.java b/android/src/com/artifex/mupdf/MuPDFActivity.java
index 194bc3d9..a177d092 100644
--- a/android/src/com/artifex/mupdf/MuPDFActivity.java
+++ b/android/src/com/artifex/mupdf/MuPDFActivity.java
@@ -919,4 +919,26 @@ public class MuPDFActivity extends Activity
 
 		super.onStop();
 	}
+
+	@Override
+	public void onBackPressed() {
+		if (core.hasChanges()) {
+			DialogInterface.OnClickListener listener = new DialogInterface.OnClickListener() {
+				public void onClick(DialogInterface dialog, int which) {
+					if (which == AlertDialog.BUTTON_POSITIVE)
+						core.save();
+
+					finish();
+				}
+			};
+			AlertDialog alert = mAlertBuilder.create();
+			alert.setTitle("MuPDF");
+			alert.setMessage("Document has changes. Save them?");
+			alert.setButton(AlertDialog.BUTTON_POSITIVE, "Yes", listener);
+			alert.setButton(AlertDialog.BUTTON_NEGATIVE, "No", listener);
+			alert.show();
+		} else {
+			super.onBackPressed();
+		}
+	}
 }
diff --git a/android/src/com/artifex/mupdf/MuPDFCore.java b/android/src/com/artifex/mupdf/MuPDFCore.java
index 98413504..13718508 100644
--- a/android/src/com/artifex/mupdf/MuPDFCore.java
+++ b/android/src/com/artifex/mupdf/MuPDFCore.java
@@ -48,6 +48,8 @@ public class MuPDFCore
 	private static native void startAlertsInternal();
 	private static native void stopAlertsInternal();
 	private static native void destroying();
+	private static native boolean hasChangesInternal();
+	private static native void saveInternal();
 
 	public static native boolean javascriptSupported();
 
@@ -196,4 +198,12 @@ public class MuPDFCore
 	public synchronized boolean authenticatePassword(String password) {
 		return authenticatePasswordInternal(password);
 	}
+
+	public synchronized boolean hasChanges() {
+		return hasChangesInternal();
+	}
+
+	public synchronized void save() {
+		saveInternal();
+	}
 }