Add a fragment that can display charon's log file

It continuously reads from the log file in a separate thread while displayed.

src/frontends/android/res/layout/log_fragment.xml

@@ -0,0 +1,41 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+    Copyright (C) 2012 Tobias Brunner
+    Copyright (C) 2012 Giuliano Grassi
+    Copyright (C) 2012 Ralf Sager
+    Hochschule fuer Technik Rapperswil
+
+    This program is free software; you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by the
+    Free Software Foundation; either version 2 of the License, or (at your
+    option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+
+    This program is distributed in the hope that it will be useful, but
+    WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+    or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+    for more details.
+-->
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical" >
+
+    <org.strongswan.android.ui.LogScrollView
+        android:id="@+id/scroll_view"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:layout_margin="10dp"
+        android:scrollbarFadeDuration="0"
+        android:scrollbarAlwaysDrawVerticalTrack="true" >
+
+        <TextView
+            android:id="@+id/log_view"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:textSize="9sp"
+            android:typeface="monospace" >
+        </TextView>
+
+    </org.strongswan.android.ui.LogScrollView>
+
+</LinearLayout>

src/frontends/android/src/org/strongswan/android/ui/LogFragment.java

@@ -0,0 +1,146 @@
+/*
+ * Copyright (C) 2012 Tobias Brunner
+ * Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+package org.strongswan.android.ui;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.FileReader;
+import java.io.StringReader;
+
+import org.strongswan.android.R;
+import org.strongswan.android.logic.CharonVpnService;
+
+import android.app.Fragment;
+import android.os.Bundle;
+import android.os.Handler;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.TextView;
+
+public class LogFragment extends Fragment implements Runnable
+{
+	private String mLogFilePath;
+	private Handler mLogHandler;
+	private TextView mLogView;
+	private LogScrollView mScrollView;
+	private BufferedReader mReader;
+	private Thread mThread;
+	private volatile boolean mRunning;
+
+	@Override
+	public void onCreate(Bundle savedInstanceState)
+	{
+		super.onCreate(savedInstanceState);
+
+		mLogFilePath = getActivity().getFilesDir() + File.separator + CharonVpnService.LOG_FILE;
+		/* use a handler to update the log view */
+		mLogHandler = new Handler();
+	}
+
+	@Override
+	public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
+	{
+		View view = inflater.inflate(R.layout.log_fragment, null);
+		mLogView = (TextView)view.findViewById(R.id.log_view);
+		mScrollView = (LogScrollView)view.findViewById(R.id.scroll_view);
+		return view;
+	}
+
+	@Override
+	public void onStart()
+	{
+		super.onStart();
+		mLogView.setText("");
+		try
+		{
+			mReader = new BufferedReader(new FileReader(mLogFilePath));
+		}
+		catch (FileNotFoundException e)
+		{
+			mReader = new BufferedReader(new StringReader(""));
+		}
+		mRunning = true;
+		mThread = new Thread(this);
+		mThread.start();
+	}
+
+	@Override
+	public void onStop()
+	{
+		super.onStop();
+		try
+		{
+			mRunning = false;
+			mThread.interrupt();
+			mThread.join();
+		}
+		catch (InterruptedException e)
+		{
+		}
+	}
+
+	/**
+	 * Write the given log line to the TextView. We strip the prefix off to save
+	 * some space (it is not that helpful for regular users anyway).
+	 * @param line log line to log
+	 */
+	public void logLine(final String line)
+	{
+		mLogHandler.post(new Runnable() {
+			@Override
+			public void run()
+			{
+				/* strip off prefix (month=3, day=2, time=8, thread=2, spaces=3) */
+				mLogView.append((line.length() > 18 ? line.substring(18) : line) + '\n');
+				/* calling autoScroll() directly does not work, probably because content
+				 * is not yet updated, so we post this to be done later */
+				mScrollView.post(new Runnable() {
+					@Override
+					public void run()
+					{
+						mScrollView.autoScroll();
+					}
+				});
+			}
+		});
+	}
+
+	@Override
+	public void run()
+	{
+		while (mRunning)
+		{
+			try
+			{
+				String line = mReader.readLine();
+				if (line == null)
+				{	/* wait until there is more to log */
+					Thread.sleep(1000);
+				}
+				else
+				{
+					logLine(line);
+				}
+			}
+			catch (Exception e)
+			{
+				break;
+			}
+		}
+	}
+}