Android开发之底图局部加载移动的方法示例

public class MapMgr {  public static MapMgr mapMgr = null;  private int map_num = 28;  private int b_x = 0;  private int b_y = 0;  private int width = 0;  private int height = 0;  private Bitmap bmpView = null;  //create by danielinbiti，前提，你图片确实比屏幕大，如果不比屏幕大，下面注释行修改一下即可。  public static void init(int width,int height){    if(mapMgr==null){      mapMgr = new MapMgr(width,height);    }  }  public static MapMgr getInstance(){    return mapMgr;  }  public MapMgr(int width,int height){    this.width = width;    this.height = height;    Bitmap bmp = PicMgr.getInstance().getBackGroundBitmap();    b_x = (bmp.getWidth()-width)/2;//保证图片比屏幕大    b_y = (bmp.getHeight()-height)/2;    bmpView = Bitmap.createBitmap(bmp, b_x, b_y, width, height);  }  public void logic(){  }  public void mapDown(){    Bitmap bmp = PicMgr.getInstance().getBackGroundBitmap();    if(b_y+height<bmp.getHeight()){      b_y = b_y + bmp.getHeight()/map_num;      if(b_y+height>bmp.getHeight()){        b_y = bmp.getHeight() - height;      }    }    bmpView = Bitmap.createBitmap(bmp, b_x, b_y, width, height);  }  public void mapUp(){    Bitmap bmp = PicMgr.getInstance().getBackGroundBitmap();    if(b_y>0){      b_y = b_y - bmp.getHeight()/map_num;      if(b_y<0){        b_y = 0;      }    }    bmpView = Bitmap.createBitmap(bmp, b_x, b_y, width, height);  }  public void mapLeft(){    Bitmap bmp = PicMgr.getInstance().getBackGroundBitmap();    if(b_x>0){      b_x = b_x - bmp.getWidth()/map_num;      if(b_x<0){        b_x = 0;      }    }    bmpView = Bitmap.createBitmap(bmp, b_x, b_y, width, height);  }  public void mapRight(){    Bitmap bmp = PicMgr.getInstance().getBackGroundBitmap();    if(b_x+width<bmp.getWidth()){      b_x = b_x + bmp.getWidth()/map_num;      if(b_x+width>bmp.getWidth()){        b_x = bmp.getHeight() - width;      }    }    bmpView = Bitmap.createBitmap(bmp, b_x, b_y, width, height);  }  public void draw(Canvas canvas){    Paint paint = new Paint();    if(bmpView!=null){      canvas.drawBitmap(bmpView,0, 0, paint);    }  }}

public void onKeyDownDeal(int keyCode){    if(keyCode==KeyEvent.KEYCODE_DPAD_UP){      MapMgr.getInstance().mapUp();    }else if(keyCode==KeyEvent.KEYCODE_DPAD_DOWN){      MapMgr.getInstance().mapDown();    }else if(keyCode==KeyEvent.KEYCODE_DPAD_LEFT){      MapMgr.getInstance().mapLeft();    }else if(keyCode==KeyEvent.KEYCODE_DPAD_RIGHT){      MapMgr.getInstance().mapRight();    }}