fix crash bug

Author: River

src/org/qpython/sample/MainActivity.java

@@ -91,11 +91,16 @@ public void onQPyExec(View v) {
 	@Override
 	protected void onActivityResult(int requestCode, int resultCode, Intent data) {  
 	    if (requestCode == SCRIPT_EXEC_PY) {
-	        Bundle bundle = data.getExtras();
-	        String flag = bundle.getString("flag"); // flag you set
-	        String param = bundle.getString("param"); // param you set 
-	        String result = bundle.getString("result"); // Result your Pycode generate
-	        Toast.makeText(this, "onQPyExec: return ("+result+")", Toast.LENGTH_SHORT).show();
+	    	if (data!=null) {
+		        Bundle bundle = data.getExtras();
+		        String flag = bundle.getString("flag"); // flag you set
+		        String param = bundle.getString("param"); // param you set 
+		        String result = bundle.getString("result"); // Result your Pycode generate
+		        Toast.makeText(this, "onQPyExec: return ("+result+")", Toast.LENGTH_SHORT).show();
+	    	} else {
+		        Toast.makeText(this, "onQPyExec: data is null", Toast.LENGTH_SHORT).show();
+
+	    	}
 	    }
 	}