黑莓中的自定義多行文本框

Question

任何人都可以告訴我如何創建多行文本框與增加背景顏色的高度。

謝謝

Answer 1

public class CustomTextBox extends Manager 
{ 
    /** 
    * Default margins 
    */ 
    private final static int DEFAULT_LEFT_MARGIN = 10; 
    private final static int DEFAULT_RIGHT_MARGIN = 10; 
    private final static int DEFAULT_TOP_MARGIN = 5; 
    private final static int DEFAULT_BOTTOM_MARGIN = 5; 

    /** 
    * Default paddings 
    */ 
    private final static int DEFAULT_LEFT_PADDING = 10; 
    private final static int DEFAULT_RIGHT_PADDING = 10; 
    private final static int DEFAULT_TOP_PADDING = 5; 
    private final static int DEFAULT_BOTTOM_PADDING = 5; 

    /** 
    * Margins around the text box 
    */ 
    private int topMargin = DEFAULT_TOP_MARGIN; 
    private int bottomMargin = DEFAULT_BOTTOM_MARGIN; 
    private int leftMargin = DEFAULT_LEFT_MARGIN; 
    private int rightMargin = DEFAULT_RIGHT_MARGIN; 

    /** 
    * Padding around the text box 
    */ 
    private int topPadding = DEFAULT_TOP_PADDING; 
    private int bottomPadding = DEFAULT_BOTTOM_PADDING; 
    private int leftPadding = DEFAULT_LEFT_PADDING; 
    private int rightPadding = DEFAULT_RIGHT_PADDING; 

    /** 
    * Amount of empty space horizontally around the text box 
    */ 
    private int totalHorizontalEmptySpace = leftMargin + leftPadding 
            + rightPadding + rightMargin; 

    /** 
    * Amount of empty space vertically around the text box 
    */ 
    private int totalVerticalEmptySpace = topMargin + topPadding 
            + bottomPadding + bottomMargin; 

    /** 
    * Minimum height of the text box required to display the text entered 
    */ 
    private int minHeight = getFont().getHeight() + totalVerticalEmptySpace; 

    /** 
    * Width of the text box 
    */ 
    private int width = Display.getWidth(); 

    /** 
    * Height of the text box 
    */ 
    private int height = minHeight; 

    /** 
    * Background image for the text box 
    */ 
    private EncodedImage backgroundImage; 

    /** 
    * Bitmap version of the backgroundImage. 
    * Needed to reduce the calculation overhead incurred by 
    * scaling of the given image 
    * and derivation of Bitmap from the 
    * EncodedImage every time it is needed. 
    */ 
    private Bitmap bitmapBackgroundImage; 

    /** 
    * The core element of this text box 
    */ 
    private EditField editField; 
    //private BasicEditField editField; 

    //private String entireText; 

    public CustomTextBox() 
    { 
     // Let the super class initialize the core 
     super(0); 

     // An edit field is the sole field of this manager. 
     editField = new EditField(); 
     //editField = new CustomEditField(); 
     add(editField); 
    } 

    public CustomTextBox(EncodedImage backgroundImage) 
    { 
     this();   
     setBackgroundImage(backgroundImage); 
    } 

    public void setSize(int width, int height) 
    { 
     boolean isChanged = false; 

     if (width > 0 // Ignore invalid width 
       && this.width != width) 
     { 
      this.width = width; 
      isChanged = true; 
     } 

     // Ignore the specified height if it is less 
     // than the minimum height required to display the text. 
     if (height > minHeight && height != this.height) 
     { 
      this.height = height; 
      isChanged = true; 
     } 

     // If width/height has been changed and background image 
     // is available, adapt it to the new dimension 
     if (isChanged == true && backgroundImage != null) 
     { 
      bitmapBackgroundImage = getScaledBitmapImage(backgroundImage, 
            this.width - (leftMargin+rightMargin), 
            this.height - (topMargin+bottomMargin)); 
     } 
    } 

    public void setWidth(int width) 
    { 

     if (width > 0 && width != this.width) 
     { 
      this.width = width; 

      // If background image is available, adapt it to the new width 
      if (backgroundImage != null) 
      { 
       bitmapBackgroundImage = getScaledBitmapImage(backgroundImage, 
             this.width - (leftMargin+rightMargin), 
             this.height - (topMargin+bottomMargin)); 
      } 
     } 
    } 

    public void setHeight(int height) 
    { 
     // Ignore the specified height if it is 
     // less than the minimum height required to display the text. 
     if (height > minHeight) 
     { 
      this.height = height; 

      // If background image is available, adapt it to the new width 
      if (backgroundImage != null) 
      { 
       bitmapBackgroundImage = getScaledBitmapImage(backgroundImage, 
             this.width - (leftMargin+rightMargin), 
             this.height - (topMargin+bottomMargin)); 
      } 
     } 
    } 

    public void setBackgroundImage(EncodedImage backgroundImage) 
    { 
     this.backgroundImage = backgroundImage; 

     // Consider the height of background image in 
     // calculating the height of the text box. 
     // setHeight() does not ensure that specified 
     // height will be in effect, of course, for valid reasons. 
     // So derivation of Bitmap image in the setHeight() method is not sure. 
     setHeight(backgroundImage.getHeight() + topMargin + bottomMargin); 
     if (bitmapBackgroundImage == null) 
     { 
      bitmapBackgroundImage = getScaledBitmapImage(backgroundImage, 
            this.width - (leftMargin+rightMargin), 
            this.height - (topMargin+bottomMargin)); 
     } 
    } 

    /** 
    * Generate and return a Bitmap Image scaled according 
    * to the specified width and height. 
    * 
    * @param image  EncodedImage object 
    * @param width  Intended width of the returned Bitmap object 
    * @param height Intended height of the returned Bitmap object 
    * @return Bitmap object 
    */ 
    private Bitmap getScaledBitmapImage(EncodedImage image, int width, int height) 
    { 
     // Handle null image 
     if (image == null) 
     { 
      return null; 
     } 

     int currentWidthFixed32 = Fixed32.toFP(image.getWidth()); 
     int currentHeightFixed32 = Fixed32.toFP(image.getHeight()); 

     int requiredWidthFixed32 = Fixed32.toFP(width); 
     int requiredHeightFixed32 = Fixed32.toFP(height); 

     int scaleXFixed32 = Fixed32.div(currentWidthFixed32, requiredWidthFixed32); 
     int scaleYFixed32 = Fixed32.div(currentHeightFixed32, requiredHeightFixed32); 

     image = image.scaleImage32(scaleXFixed32, scaleYFixed32); 

     return image.getBitmap(); 
    } 


    protected void sublayout(int width, int height) 
    { 
     // We have one and only child - the edit field. 
     // Place it at the appropriate place. 
     Field field = getField(0); 
     layoutChild(field, this.width - totalHorizontalEmptySpace, 
        this.height - totalVerticalEmptySpace); 
     setPositionChild(field, leftMargin+leftPadding, topMargin+topPadding); 

     setExtent(this.width, this.height); 
    } 

    public void setTopMargin(int topMargin) 
    { 
     this.topMargin = topMargin; 
    } 

    public void setBottomMargin(int bottomMargin) 
    { 
     this.bottomMargin = bottomMargin; 
    } 


    protected void paint(Graphics graphics) 
    { 
     // Draw background image if available, otherwise draw a rectangle 
     if (bitmapBackgroundImage == null) 
     { 
      //graphics.drawRect(leftMargin, topMargin, 
           // width - (leftMargin+rightMargin), 
           //height - (topMargin+bottomMargin)); 
      graphics.drawRoundRect(leftMargin, topMargin, 
            width - (leftMargin+rightMargin), 
            height - (topMargin+bottomMargin), 5, 5); 
     } 
     else 
     { 
      graphics.drawBitmap(leftMargin, topMargin, 
           width - (leftMargin+rightMargin), 
           height - (topMargin+bottomMargin), 
           bitmapBackgroundImage, 0, 0); 
     } 

     // Determine the rightward text that can fit into the visible edit field 

     EditField ef = (EditField)getField(0); 
     String entireText = ef.getText(); 

     boolean longText = false; 
     String textToDraw = ""; 
     Font font = getFont(); 
     int availableWidth = width - totalHorizontalEmptySpace; 
     if (font.getAdvance(entireText) <= availableWidth) 
     { 
      textToDraw = entireText; 
     } 
     else 
     { 
      int endIndex = entireText.length(); 
      for (int beginIndex = 1; beginIndex < endIndex; beginIndex++) 
      { 
       textToDraw = entireText.substring(beginIndex); 
       if (font.getAdvance(textToDraw) <= availableWidth) 
       { 
        longText = true; 
        break; 
       } 
      } 
     } 

     if (longText == true) 
     {   
      // Force the edit field display only the truncated text 
      ef.setText(textToDraw); 

      // Now let the components draw themselves 
      super.paint(graphics); 

      // Return the text field its original text 
      ef.setText(entireText); 
     } 
     else 
     { 
      super.paint(graphics); 
     } 
    } 

    public int getPreferredWidth() 
    { 
     return width; 
    } 

    public int getPreferredHeight() 
    { 
     return height; 
    } 

    protected boolean keyChar(char ch, int status, int time) 
    { 
     if (ch == Characters.ENTER) 
     { 
      return true; 
     } 
     else 
     { 
      return super.keyChar(ch, status, time); 
     } 
    } 

    public String getText() 
    { 
     return ((EditField)getField(0)).getText(); 
    } 

    public void setText(final String text) 
    { 
     ((EditField)getField(0)).setText(text); 
    }  
} 

Answer 2

您可以在API使用EditField中，並通過指定一個背景是：

yourEditField.setBackground(yourBackground);