Added the ability to customize keyboard shortcuts. Fix for: #92 and #13

app/src/main/java/net/christianbeier/droidvnc_ng/HotkeyBinding.java

@@ -0,0 +1,55 @@
+package net.christianbeier.droidvnc_ng;
+
+public class HotkeyBinding implements Comparable<HotkeyBinding> {
+    private final VNCKey[] keys = new VNCKey[3];
+    // placeholder for command to execute by this hotkey
+    private final ICommand command;
+    // user-friendly name. Uses in GUI
+    public final String friendlyName;
+    // uses for settings serialization
+    public final String PREFS_NAME;
+
+    public HotkeyBinding(String friendlyName, String prefsName, VNCKey key1, VNCKey key2, VNCKey key3, ICommand command) {
+        keys[0] = key1;
+        keys[1] = key2;
+        keys[2] = key3;
+        this.command = command;
+        this.friendlyName = friendlyName;
+        this.PREFS_NAME = prefsName;
+    }
+
+    public boolean isTriggered() {
+        for (VNCKey key : keys) {
+            if (key != null && key != VNCKey.Empty && key.isNotDown())
+                return false;
+        }
+        return true;
+    }
+
+    public boolean tryExecute() {
+        if (isTriggered()) {
+            command.execute();
+            return true;
+        }
+        return false;
+    }
+
+    public VNCKey getKey(int index) {
+        if (index > 3) return VNCKey.Empty;
+        return keys[index];
+    }
+
+    public void setKey(int index, VNCKey key) {
+        if (index > 3) return;
+        keys[index] = key;
+    }
+
+    @Override
+    public int compareTo(HotkeyBinding hotkeyBinding) {
+        return hotkeyBinding.keys.length - keys.length;
+    }
+
+    public interface ICommand {
+        void execute();
+    }
+}