Migrate to BLE Library v2; New Sample App

All changes made in this commit are courtesy of @philips77 

Major Additions/Changes
-------------------------
* Migrates the old nordic Android-BLE-Library v1 to v2 and 
overhauls the McuManager BLE scheme implementation.
* Add new (more functional) sample app
* Update FirmwareUpgradeManager to be cleaner and more
configurable.
* Implement FileSystemManager
* Add additional functionality to McuMgrTransport for 
connection observation and shutdown.

Full list of commits from @philips77 squashed in merge:
-------------------------------------------------------
* Android Studio 3.1.2
* Switching to external BLE Library v2
* Migrating to BLE Library v2
* Code cleanup, comments, warnings etc.
* Fix Mcu Mgr Transport to match BLE lib changes
* Refactoring in the sample app
* Reverting access modifiers
* Minor: code and comments cleanup
* Increasing polling interval to 7 sec + minor changes
* Improved packet length calculation
* Refactoring, FirmwareUpgradeController added
* MTU fixed again
* Documentation added
* Bug fix: looping with the same MTU fixed
* Exceptions improved
* BLE transport migrated to reflect BLE Lib changes, release method added to the mcu mgr transport interface.
* Licenses added
* Comments
* Response field made public
* Resource files removed from the library
* Annotations added, MTU moved to McuManager
* MTU moved to McuManager: Image and FirmwareUpgradeManager updated,
erase() fixed
* Annotations added,
Bug fixed in McuMgrBleManager: calling onError if rc != 0,
Refactoring
* Warning hidden
* FsManager added
* Sample app rebuilt. FsManager not yet supported.
* Tabs to Spaces
* Line wrapping
* Handling notification timeouts and disconnection
* Support for handling Bluetooth disabled event
* Bug fixed: cancelling upload
* Annotations added
* Adding State and Connection observers
* Android Studio 3.1.3
* State observers removed
* Basic and Advanced views on Image tab,
Disabling controls when the device is busy,
Reset moved to Image->Advanced tab
* Keeping only English resources
* Work indicator added
* Tabs to spaces
* continueUpload -> continueTransfer
* UI for FsManager, other bug fixes
* Moving common code to base class
* Test file generation
* Displaying graphical files as images
* Destination added to Files Upload
* New lines
* Comments
* Minor refactoring in EchoFragment
* Hello! as initial text for Echo
* Saving recent file names
* Unused imports removed, warnings suppressed.
* Bugs fixed: value validation added
* Bug fixed: Recreating MainActivity fails as BluetoothDevice wasn't saved.
* Image Manager: Erase state command added
* McuMgr responses comments.
* Initially, move the cursor to the end.
* Adjusting to library changes
* BLE Library imported from jcenter
* Constraint-layout 1.1.2
* License changed to Apache 2.0
* Bug fixed: Ble Library must be available for the app.
* Bug fixed
* Bug fix: confirm slot 0 in test mode
* BLE Library v2.0-alpha2
* BLE Library v2.0-alpha3
* License of the Sample app changed to Apache 2.0
* Zephyr icon fixed
* Other device icons
* Feature: option to filter device list by UUID and RSSI.
* Info text updated
* Bug fixed: formatting stats fixed
* BLE Library version 2.0-alpha4
* Improved device filtering
* Vector drawables set using scrCompat
* Improved UI for smaller phones
* BLE Library version 2.0-alpha5
* LogCat disabled
* Bug fixed: Buttons get invalid state after screen rotation during upload
* Bug fixed: Displaying long echos fixed
* Bug fixed: Scanning progress bar fixed on Lollipop

Author: philips77

build.gradle

@@ -12,7 +12,7 @@ buildscript {
         jcenter()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.1.2'
+        classpath 'com.android.tools.build:gradle:3.1.3'
         classpath 'com.github.dcendents:android-maven-gradle-plugin:2.0'
     }
 }

mcumgr-android-lib/build.gradle

@@ -28,6 +28,9 @@ android {
 }
 
 dependencies {
+    // Import the BLE Library
+    api 'no.nordicsemi.android:ble:2.0-alpha5'
+
     implementation fileTree(include: ['*.jar'], dir: 'libs')
 
     // Test

mcumgr-android-lib/src/main/java/io/runtime/mcumgr/McuManager.java

@@ -7,24 +7,26 @@
 
 package io.runtime.mcumgr;
 
+import android.support.annotation.NonNull;
+
 import io.runtime.mcumgr.exception.McuMgrException;
 import io.runtime.mcumgr.response.McuMgrResponse;
 
 /**
- * Callback for asynchronous Newt Manager commands.
+ * Callback for asynchronous Mcu Manager commands.
  */
 public interface McuMgrCallback<T extends McuMgrResponse> {
     /**
-     * Newt Manager has received a response.
+     * Mcu Manager has received a response.
      *
-     * @param response the response
+     * @param response the response.
      */
-    void onResponse(T response);
+    void onResponse(@NonNull T response);
 
     /**
-     * Newt Manager has encountered a transport error while sending the command.
+     * Mcu Manager has encountered a transport error while sending the command.
      *
-     * @param error the error
+     * @param error the error.
      */
-    void onError(McuMgrException error);
+    void onError(@NonNull McuMgrException error);
 }

mcumgr-android-lib/src/main/java/io/runtime/mcumgr/McuMgrCallback.java

@@ -6,51 +6,53 @@
 
 package io.runtime.mcumgr;
 
+import android.support.annotation.NonNull;
+
 /**
  * Almost all requests are responded to with an Mcu Manager return code in the response payload.
  * This value determines whether the request has been successful (rc = 0) or has failed (rc != 0).
- *
+ * <p>
  * This return code is not supposed to be very descriptive and the actual error reason must be
  * determined based on the request and error code. Since McuManager errors are vague and often the
  * same error code could be caused by different reasons, the best way to debug errors here is
  * step through the handler on the device to determine the cause.
  */
 public enum McuMgrErrorCode {
     /**
-     * Success
+     * Success.
      */
     OK(0),
     /**
-     * Unknown error
+     * Unknown error.
      */
     UNKNOWN(1),
     /**
-     * The device has encountered an error due to running out of memory
+     * The device has encountered an error due to running out of memory.
      */
     NO_MEMORY(2),
     /**
-     * The request header/payload is malformed or payload values are incorrect
+     * The request header/payload is malformed or payload values are incorrect.
      */
     IN_VALUE(3),
     /**
-     * Timeout error
+     * Timeout error.
      */
     TIMEOUT(4),
     /**
      * No entry was found for the request. This commonly means that the command group has not been
-     * enabled on the device, although the exact meaning
+     * enabled on the device, although the exact meaning.
      */
     NO_ENTRY(5),
     /**
-     * The device is not currently in a state to handle the request
+     * The device is not currently in a state to handle the request.
      */
     BAD_STATE(6),
     /**
-     * The response is too large
+     * The response is too large.
      */
     TOO_LARGE(7),
     /**
-     * Command is not supported
+     * Command is not supported.
      */
     NOT_SUPPORTED(8),
     PER_USER(256);
@@ -67,9 +69,10 @@ public int value() {
 
     @Override
     public String toString() {
-        return "McuMgrError: " + super.toString() + "(" + mCode + ")";
+        return super.toString() + " (" + mCode + ")";
     }
 
+    @NonNull
     public static McuMgrErrorCode valueOf(int error) {
         switch (error) {
             case 0:
@@ -93,7 +96,7 @@ public static McuMgrErrorCode valueOf(int error) {
             case 256:
                 return PER_USER;
             default:
-                return null;
+                return UNKNOWN;
         }
     }
 }

mcumgr-android-lib/src/main/java/io/runtime/mcumgr/McuMgrErrorCode.java

@@ -7,6 +7,8 @@
 
 package io.runtime.mcumgr;
 
+import android.support.annotation.NonNull;
+
 import io.runtime.mcumgr.util.ByteUtil;
 import io.runtime.mcumgr.util.Endian;
 
@@ -15,8 +17,8 @@
  * fields for optional values such as flags and sequence numbers. This class is used to parse
  * and build headers.
  */
+@SuppressWarnings({"unused", "WeakerAccess"})
 public class McuMgrHeader {
-
     public final static int HEADER_LENGTH = 8;
 
     private int mOp;
@@ -87,31 +89,39 @@ public void setCommandId(int commandId) {
         this.mCommandId = commandId;
     }
 
+    @Override
+    public String toString() {
+        return "Header (Op: " + mOp + ", Flags: " + mFlags + ", Len: " + mLen + ", Group: " + mGroupId + ", Seq: " + mSequenceNum + ", Command: " + mCommandId + ")";
+    }
+
     public static McuMgrHeader fromBytes(byte[] header) {
         if (header == null || header.length != HEADER_LENGTH) {
             return null;
         }
-        int op = ByteUtil.unsignedByteArrayToInt(header, 0, 1, Endian.BIG);
-        int flags = ByteUtil.unsignedByteArrayToInt(header, 1, 1, Endian.BIG);
-        int len = ByteUtil.unsignedByteArrayToInt(header, 2, 2, Endian.BIG);
-        int groupId = ByteUtil.unsignedByteArrayToInt(header, 4, 2, Endian.BIG);
+        int op          = ByteUtil.unsignedByteArrayToInt(header, 0, 1, Endian.BIG);
+        int flags       = ByteUtil.unsignedByteArrayToInt(header, 1, 1, Endian.BIG);
+        int len         = ByteUtil.unsignedByteArrayToInt(header, 2, 2, Endian.BIG);
+        int groupId     = ByteUtil.unsignedByteArrayToInt(header, 4, 2, Endian.BIG);
         int sequenceNum = ByteUtil.unsignedByteArrayToInt(header, 6, 1, Endian.BIG);
-        int commandId = ByteUtil.unsignedByteArrayToInt(header, 7, 1, Endian.BIG);
+        int commandId   = ByteUtil.unsignedByteArrayToInt(header, 7, 1, Endian.BIG);
         return new McuMgrHeader(op, flags, len, groupId, sequenceNum, commandId);
     }
 
     /**
      * Builds a new manager header.
      *
-     * @param op       the operation for this packet: NMGR_WRITE, NMGR_WRITE_RSP, NMGR_READ, NMGR_READ_RSP
-     * @param flags    newt manager flags
-     * @param len      the length (this field is NOT required for all default newt manager commands)
+     * @param op       the operation for this packet: ({@link McuManager#OP_READ OP_READ},
+     *                 {@link McuManager#OP_READ_RSP OP_READ_RSP}, {@link McuManager#OP_WRITE OP_WRITE},
+     *                 {@link McuManager#OP_WRITE_RSP OP_WRITE_RSP}).
+     * @param flags    newt manager flags.
+     * @param len      the length (this field is NOT required for all default newt manager commands).
      * @param group    the newt manager command group. Some groups such as GROUP_IMAGE must also
-     *                 specify a subcommand ID.
-     * @param sequence the newt manager sequence number
-     * @param id       the subcommand ID for certain groups
-     * @return the built newt manager header
+     *                 specify a sub-command ID.
+     * @param sequence the newt manager sequence number.
+     * @param id       the sub-command ID for certain groups.
+     * @return The built newt manager header.
      */
+    @NonNull
     public static byte[] build(int op, int flags, int len, int group, int sequence, int id) {
         return new byte[]{
                 (byte) op,

mcumgr-android-lib/src/main/java/io/runtime/mcumgr/McuMgrHeader.java

@@ -7,6 +7,8 @@
 
 package io.runtime.mcumgr;
 
+import android.support.annotation.NonNull;
+
 import io.runtime.mcumgr.exception.McuMgrException;
 import io.runtime.mcumgr.response.McuMgrResponse;
 
@@ -18,33 +20,72 @@
  */
 public interface McuMgrTransport {
 
+    interface ConnectionObserver {
+        /**
+         * A method called when the connection to the device has been established.
+         */
+        void onConnected();
+
+        /**
+         * A method called when the connection to the device has been lost.
+         */
+        void onDisconnected();
+    }
+
     /**
      * Gets the scheme for this transport (see {@link McuMgrScheme}).
-     * @return the transport's scheme
+     *
+     * @return The transport's scheme.
      */
+    @NonNull
     McuMgrScheme getScheme();
 
     /**
      * Send a synchronous Mcu Manager request. This method implementation should block until a
      * response has been received or a error has occurred.
-     * @param payload the request packet data to send to the device
-     * @param responseType the response type
-     * @param <T> the response type
-     * @return the response
+     *
+     * @param payload      the request packet data to send to the device.
+     * @param responseType the response type.
+     * @param <T>          the response type.
+     * @return The response.
      * @throws McuMgrException thrown on error. Set the cause of the error if caused by a different
-     * type of exception.
+     *                         type of exception.
      */
-    <T extends McuMgrResponse> T send(byte[] payload, Class<T> responseType) throws McuMgrException;
+    @NonNull
+    <T extends McuMgrResponse> T send(@NonNull byte[] payload, @NonNull Class<T> responseType)
+            throws McuMgrException;
 
     /**
      * Send an asynchronous Mcu Manager request. This method should not be blocked. When the
      * response has been received or an error occurs, the appropriate method of the callback should
      * be called.
-     * @param payload the request packet data to send to the device
-     * @param responseType the response type
-     * @param callback the callback to call on response or error
-     * @param <T> the response type
+     *
+     * @param payload      the request packet data to send to the device.
+     * @param responseType the response type.
+     * @param callback     the callback to call on response or error.
+     * @param <T>          the response type.
+     */
+    <T extends McuMgrResponse> void send(@NonNull byte[] payload, @NonNull Class<T> responseType,
+                                         @NonNull McuMgrCallback<T> callback);
+
+    /**
+     * Releases the transport connection. When the connection is already closed this method does
+     * nothing.
+     */
+    void release();
+
+    /**
+     * Adds the connection observer. An observer will be notified whenever the connected device
+     * gets connected or disconnected.
+     *
+     * @param observer the observer.
+     */
+    void addObserver(@NonNull ConnectionObserver observer);
+
+    /**
+     * Removes previously registered observer.
+     *
+     * @param observer the observer.
      */
-    <T extends McuMgrResponse> void send(byte[] payload, Class<T> responseType,
-                                         McuMgrCallback<T> callback);
+    void removeObserver(@NonNull ConnectionObserver observer);
 }

mcumgr-android-lib/src/main/java/io/runtime/mcumgr/McuMgrTransport.java

@@ -1,16 +1,14 @@
 /*
- * Copyright (c) 2017-2018 Runtime Inc.
+ * Copyright (c) 2018, Nordic Semiconductor
  *
  * SPDX-License-Identifier: Apache-2.0
  */
 
 package io.runtime.mcumgr.ble;
 
 import android.bluetooth.BluetoothDevice;
-import android.bluetooth.BluetoothGattCharacteristic;
-import android.bluetooth.BluetoothGattDescriptor;
 
-import io.runtime.mcumgr.ble.manager.BleManagerCallbacks;
+import no.nordicsemi.android.ble.BleManagerCallbacks;
 
 /**
  * <b>DO NOT PERFORM ANY BLOCKING OPERATIONS INSIDE THESE CALLBACKS!</b>
@@ -19,27 +17,7 @@
  * <p>
  * Callbacks from {@link McuMgrBleTransport}.
  */
-public class McuMgrBleCallbacks implements BleManagerCallbacks {
-    public void onCharacteristicRead(BluetoothDevice device, BluetoothGattCharacteristic characteristic) {
-    }
-
-    public void onCharacteristicWrite(BluetoothDevice device, BluetoothGattCharacteristic characteristic) {
-    }
-
-    public void onDescriptorRead(BluetoothDevice device, BluetoothGattDescriptor descriptor) {
-    }
-
-    public void onDescriptorWrite(BluetoothDevice device, BluetoothGattDescriptor descriptor) {
-    }
-
-    public void onCharacteristicNotified(BluetoothDevice device, BluetoothGattCharacteristic characteristic) {
-    }
-
-    public void onCharacteristicIndicated(BluetoothDevice device, BluetoothGattCharacteristic characteristic) {
-    }
-
-    public void onMtuChanged(int mtu) {
-    }
+public class McuMgrBleCallbacksStub implements BleManagerCallbacks {
 
     @Override
     public void onDeviceConnecting(BluetoothDevice device) {
@@ -58,7 +36,7 @@ public void onDeviceDisconnected(BluetoothDevice device) {
     }
 
     @Override
-    public void onLinklossOccur(BluetoothDevice device) {
+    public void onLinkLossOccurred(BluetoothDevice device) {
     }
 
     @Override
@@ -82,6 +60,10 @@ public void onBatteryValueReceived(BluetoothDevice device, int value) {
     public void onBondingRequired(BluetoothDevice device) {
     }
 
+    @Override
+    public void onBondingFailed(BluetoothDevice device) {
+    }
+
     @Override
     public void onBonded(BluetoothDevice device) {
     }