device.java

j2me联动菜单的开源代码

// Copyright (c) 2005 Sony Ericsson Mobile Communications AB
//
// This software is provided "AS IS," without a warranty of any kind. 
// ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, 
// INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A 
// PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. 
//
// THIS SOFTWARE IS COMPLEMENTARY OF JAYWAY AB (www.jayway.se)

package com.ultrapower.gui;

import javax.microedition.lcdui.Display;
import javax.microedition.midlet.MIDlet;

/**
 * The <code>Device</code> represents the 
 * device the MIDlet is running on.
 * 
 * @author Peter Andersson
 */
public final class Device
{
  /** Canvas keycode for left softbutton */
  public static final int KEYCODE_LEFT_SOFT = -6; 
  /** Canvas keycode for right softbutton */
  public static final int KEYCODE_RIGHT_SOFT = -7;
  /** Canvas keycode for back button */
  public static final int KEYCODE_BACK = -11;
  /** The display */
  protected static Display m_display;
  /** The midlet instance */
  protected static MIDlet m_midlet;
  
  /**
   * Bluetooth support flag, 0 mean unsearched, 1 means searched
   * and found, -1 means searched and not found.
   */
  private static int m_bluetoothSupport = 0;
  
  /**
   * Initializes the <code>Device</code> class.
   * @param midlet		The midlet instance.
   * @param display		The display.
   */
  public static void init(MIDlet midlet, Display display)
  {
    m_midlet = midlet;
    m_display = display;
  }
  
  /**
   * Returns the midlet instance.
   * @return	The midlet.
   */
  public static MIDlet getMidlet()
  {
    return m_midlet;
  }
  
  /**
   * Returns the display of this midlet.
   * @return	The display.
   */
  public static Display getDisplay()
  {
    return m_display;
  }
  
  /**
   * Returns whether this device implements bluetooth-apis or not.
   * @return	True if JSR82 is implemented, false otherwise.
   */
  public static boolean canBluetooth()
  {
    if (m_bluetoothSupport == 0)
    {
      try
      {
        Class.forName("javax.bluetooth.LocalDevice");
        m_bluetoothSupport = 1;
      }
      catch (Throwable t)
      {
        m_bluetoothSupport = -1;
      }
    }
    return m_bluetoothSupport == 1;
  }
  
  /**
   * Returns whether this device can vibrate via J2ME or not.
   * @return	True if vibration functionality is enabled, false otherwise.
   */
  public static boolean canVibrate()
  {
    return true;
  }
    
  
  /**
   * Calculates an indentifer from a string.
   * @param s	The string
   * @return	The id
   */
  protected static int calcIdFromString(String s)
  {
    int res = 0;
    // Left shift, XOR the char val, XOR shift overflow bit
    for (int i = s.length()-1; i >= 0; i--)
    {
      res = ((res << 1) ^ s.charAt(i)) ^ ((res & 0x80000000) != 0 ? 1 : 0);
    }
    return res;
  }

  /** Prohibit construction */
  private Device() {}
}