diff --git a/media/Camera2Basic/Application/src/main/java/com/example/android/camera2basic/Camera2BasicFragment.java b/media/Camera2Basic/Application/src/main/java/com/example/android/camera2basic/Camera2BasicFragment.java
index 4b55358..2414ed6 100644
--- a/media/Camera2Basic/Application/src/main/java/com/example/android/camera2basic/Camera2BasicFragment.java
+++ b/media/Camera2Basic/Application/src/main/java/com/example/android/camera2basic/Camera2BasicFragment.java
@@ -43,6 +43,7 @@
 import android.os.Bundle;
 import android.os.Handler;
 import android.os.HandlerThread;
+import android.os.Message;
 import android.util.Log;
 import android.util.Size;
 import android.util.SparseIntArray;
@@ -315,6 +316,32 @@
     };
 
     /**
+     * A {@link Handler} for showing {@link Toast}s.
+     */
+    private Handler mMessageHandler = new Handler() {
+        @Override
+        public void handleMessage(Message msg) {
+            Activity activity = getActivity();
+            if (activity != null) {
+                Toast.makeText(activity, (String) msg.obj, Toast.LENGTH_SHORT).show();
+            }
+        }
+    };
+
+    /**
+     * Shows a {@link Toast} on the UI thread.
+     *
+     * @param text The message to show
+     */
+    private void showToast(String text) {
+        // We show a Toast by sending request message to mMessageHandler. This makes sure that the
+        // Toast is shown on the UI thread.
+        Message message = Message.obtain();
+        message.obj = text;
+        mMessageHandler.sendMessage(message);
+    }
+
+    /**
      * Given {@code choices} of {@code Size}s supported by a camera, chooses the smallest one whose
      * width and height are at least as large as the respective requested values, and whose aspect
      * ratio matches with the specified value.
@@ -573,10 +600,7 @@
 
                         @Override
                         public void onConfigureFailed(CameraCaptureSession cameraCaptureSession) {
-                            Activity activity = getActivity();
-                            if (null != activity) {
-                                Toast.makeText(activity, "Failed", Toast.LENGTH_SHORT).show();
-                            }
+                            showToast("Failed");
                         }
                     }, null
             );
@@ -689,7 +713,7 @@
                 @Override
                 public void onCaptureCompleted(CameraCaptureSession session, CaptureRequest request,
                                                TotalCaptureResult result) {
-                    Toast.makeText(getActivity(), "Saved: " + mFile, Toast.LENGTH_SHORT).show();
+                    showToast("Saved: " + mFile);
                     unlockFocus();
                 }
             };
diff --git a/media/Camera2Basic/README.md b/media/Camera2Basic/README.md
index 73b9eac..b848e02 100644
--- a/media/Camera2Basic/README.md
+++ b/media/Camera2Basic/README.md
@@ -1,16 +1,55 @@
 Android Camera2Basic Sample
-==============================
+===================================
 
-This sample demonstrates the basic use of Camera2 API. Check the source code to see how you can
-display camera preview and take pictures.
+This sample demonstrates how to use basic functionalities of Camera2
+API. You can learn how to iterate through characteristics of all the
+cameras attached to the device, display a camera preview, and take
+pictures.
+
+Introduction
+------------
+
+The [Camera2 API][1] provides an interface to individual camera
+devices connected to an Android device. It replaces the deprecated
+Camera class.
+
+Use [getCameraIdList][2] to get a list of all the available
+cameras. You can then use [getCameraCharacteristics][3] and find the
+best camera that suits your need (front/rear facing, resolution etc).
+
+Create an instance of [CameraDevice.StateCallback][4] and open a
+camera. It is ready to start camera preview when the camera is opened.
+
+This sample uses TextureView to show the camera preview. Create a
+[CameraCaptureSession][5] and set a repeating [CaptureRequest][6] to it.
+
+Still image capture takes several steps. First, you need to lock the
+focus of the camera by updating the CaptureRequest for the camera
+preview. Then, in a similar way, you need to run a precapture
+sequence. After that, it is ready to capture a picture. Create a new
+CaptureRequest and call [capture][7]. Don't forget to unlock the focus
+when you are done.
+
+[1]: https://developer.android.com/reference/android/hardware/camera2/package-summary.html
+[2]: https://developer.android.com/reference/android/hardware/camera2/CameraManager.html#getCameraIdList()
+[3]: https://developer.android.com/reference/android/hardware/camera2/CameraManager.html#getCameraCharacteristics(java.lang.String)
+[4]: https://developer.android.com/reference/android/hardware/camera2/CameraDevice.StateCallback.html
+[5]: https://developer.android.com/reference/android/hardware/camera2/CameraCaptureSession.html
+[6]: https://developer.android.com/reference/android/hardware/camera2/CaptureRequest.html
+[7]: https://developer.android.com/reference/android/hardware/camera2/CameraCaptureSession.html#capture(android.hardware.camera2.CaptureRequest, android.hardware.camera2.CameraCaptureSession.CaptureCallback, android.os.Handler)
 
 Pre-requisites
 --------------
 
-- Android SDK (L Developer Preview)
-- Android Build Tools v20
+- Android SDK v21
+- Android Build Tools v21.1.1
 - Android Support Repository
 
+Screenshots
+-------------
+
+<img src="screenshots/main.png" height="400" alt="Screenshot"/> 
+
 Getting Started
 ---------------
 
@@ -32,7 +71,7 @@
 License
 -------
 
-Copyright 2014 The Android Open Source Project
+Copyright 2014 The Android Open Source Project, Inc.
 
 Licensed to the Apache Software Foundation (ASF) under one or more contributor
 license agreements.  See the NOTICE file distributed with this work for
@@ -41,7 +80,7 @@
 use this file except in compliance with the License.  You may obtain a copy of
 the License at
 
-  http://www.apache.org/licenses/LICENSE-2.0
+http://www.apache.org/licenses/LICENSE-2.0
 
 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS, WITHOUT