黑莓GridFieldManager中的中心對象

Question

我想將對象置於GridFieldManager中。這可以從藍色區域中的選定圖像看到，就像在第一張圖片中一樣。我該如何居中這些對象（文本+圖片）？

這是我認爲你image是不是在中心及其Transparent面積不正確對準我的代碼

VerticalFieldManager manager = (VerticalFieldManager) getMainManager(); 


     gfm = new GridFieldManager(rows, columns, GridFieldManager.FIXED_SIZE); 

     manager.add(gfm); 
     int columnWidth = (Display.getWidth()/columns) 
       - gfm.getColumnPadding(); 
     for (i = 0; i < columns; i++) { 
      gfm.setColumnProperty(i, GridFieldManager.FIXED_SIZE, columnWidth); 
     } 

     BitmapField[] images = new BitmapField[6]; 
     EncodedImage Icon = null; 
     for (i = 0; i < 6; i++) { 


       Icon = EncodedImage 
         .getEncodedImageResource("img/HOME.png"); 



      images[i] = new BitmapField(Icon.getBitmap(), Field.FIELD_HCENTER 
        | Field.FIELD_VCENTER | Field.FOCUSABLE) { 


       protected void layout(int width, int height) { 
        setExtent(getPreferredWidth()+20, getPreferredHeight() + 15); 

        } 



       protected void paint(Graphics graphics) { 

        super.paint(graphics); 


        graphics.drawText("text", 0, 
        getBitmapHeight(), 2, getBitmapWidth() + 20); 


       } 

      }; 

      gfm.setPadding(10, 0, 0, 0); 
      gfm.setRowPadding(20); 
      images[i].setPadding(20, 10, 5, 10); 
      gfm.add(images[i]); 


     } 

    } 

Answer 1

。如果你想以簡單的方式做到這一點，則必須使用PictureBackgroundButtonField自定義類。在本課中，您可以使用兩個不同的圖像處理focus和unfocus。下面是這堂課。

package com.picturebackgroundbuttonfield; 
import net.rim.device.api.ui.*; 
import net.rim.device.api.system.*; 
public class PictureBackgroundButtonField extends Field 
{  
    private String _label; 
    private int _labelHeight; 
    private int _labelWidth; 
    private Font _font; 
    private Bitmap _onPicture, _offPicture; 
    private Bitmap _currentPicture; 



public PictureBackgroundButtonField(Bitmap onFocus, Bitmap offFocus, String text, long style) 
{ 
    super(style); 
    _onPicture = onFocus; 
    _offPicture = offFocus; 
    _font = getFont(); 
    _label = text; 
    _labelHeight = _onPicture.getHeight(); 
    _labelWidth = _onPicture.getWidth(); 
    _currentPicture = _offPicture; 
} 

/** 
* @return The text on the button 
*/ 
String getText() 
{ 
    return _label; 
} 

/** 
* Field implementation. 
* @see net.rim.device.api.ui.Field#getPreferredHeight() 
*/ 
public int getPreferredHeight() 
{ 
    return _labelHeight; 
} 

/** 
* Field implementation. 
* @see net.rim.device.api.ui.Field#getPreferredWidth() 
*/ 
public int getPreferredWidth() 
{ 
    return _labelWidth; 
} 

/** 
* Field implementation. Changes the picture when focus is gained. 
* @see net.rim.device.api.ui.Field#onFocus(int) 
*/ 
protected void onFocus(int direction) 
{ 
    _currentPicture = _onPicture; 
    // setFont(getFont().derive(Font.BOLD)); 
    invalidate(); 
} 

/** 
* Field implementation. Changes picture back when focus is lost. 
* @see net.rim.device.api.ui.Field#onUnfocus() 
*/ 

protected void onUnfocus() 
{ 
    _currentPicture = _offPicture; 
    // setFont(getFont().derive(Font.PLAIN)); 
    invalidate(); 
} 

/** 
* Field implementation. 
* @see net.rim.device.api.ui.Field#drawFocus(Graphics, boolean) 
*/ 
protected void drawFocus(Graphics graphics, boolean on) 
{ 
    // Do nothing 
} 

/** 
* Field implementation. 
* @see net.rim.device.api.ui.Field#layout(int, int) 
*/ 
protected void layout(int width, int height) 
{ 
    setExtent(Math.min(width, getPreferredWidth()), 
    Math.min(height, getPreferredHeight())); 
} 

/** 
* Field implementation. 
* @see net.rim.device.api.ui.Field#paint(Graphics) 
*/ 

/** 
* Overridden so that the Event Dispatch thread can catch this event 
* instead of having it be caught here.. 
* @see net.rim.device.api.ui.Field#navigationClick(int, int) 
*/ 
protected boolean navigationClick(int status, int time) 
{ 
    fieldChangeNotify(1); 
    return true; 
} 

/*protected void paint(Graphics graphics) { 
    // TODO Auto-generated method stub 

}*/ 

protected void paint(Graphics graphics) 
{  
    graphics.drawBitmap(0, 0, getWidth(), getHeight(), _currentPicture, 0, 0); 
    graphics.setBackgroundColor(Color.BLACK); 
    graphics.drawText(_label, 2, 0, 
      (int)(getStyle() & DrawStyle.ELLIPSIS | DrawStyle.HALIGN_MASK), 
      getWidth() - 6); 
} 

}

Answer 2

試試這個示例代碼：

public class PictureScreen extends MainScreen implements FieldChangeListener 
{ 
static EditField editField; 
private Bitmap lockBit; 
private BitmapField bitmapField[]; 
private int size=0, i=0;; 
public PictureScreen() 
{  
    lockBit=Bitmap.getBitmapResource("HOME.png");  
    size=10; 
    createGUI(); 
} 

private void createGUI() 
{   
    bitmapField=new BitmapField[size]; 
    HorizontalFieldManager hr=null; 
    for(i=0;i<size;i=i+3) 
    {   
     hr=new HorizontalFieldManager(Field.FIELD_HCENTER); 
     for(int j=i;j<i+3;j++) //Here I am taking 3 images per line(Horizontal Manager); 
     { 
      if(j<size) 
      { 
       final String _label="Text: "+(j+1); 
       bitmapField[j]=new BitmapField(null,Field.FOCUSABLE) 
       { 
        protected void layout(int width, int height) 
        { 
         setExtent(100,100); 
        } 
        protected void paint(Graphics g) 
        { 
         g.drawBitmap(50-24, 0,lockBit.getWidth(), lockBit.getHeight(), lockBit, 0, 0); //Here 24= image width is 48pixel so,48/2 and 50=setExtent(100,100); width=100/2; 
         g.setFont(Font.getDefault().derive(Font.BOLD|Font.ITALIC, 18));   
         g.drawText(_label, 50-24, 50); 
         super.paint(g); 
        } 
       }; 
       bitmapField[j].setChangeListener(this); 
       bitmapField[j].setPadding(10, 10, 10, 10); 
       hr.add(bitmapField[j]); 
      } 
     } 
     add(hr); 
    } 
} 

public void fieldChanged(Field field, int context) 
{ 
    for(int i=0;i<size;i++) 
    {   
     if(field==bitmapField[i]) 
     { 
      Status.show("Buy the Full Version", 500);   
     } 
    } 
} 
} 

然後，我得到這樣的：

試試這個，看到班裏的意見;