黑莓 - TouchEvent在多个经理

Question

我是新来的黑莓应用程序开发这里是我的问题，我在我的应用程序中使用两个verticalfieldmanager“布局”和“经理”。布局有三个自定义按钮字段，布局在管理器内部。

我不能够实现触摸事件，这里是我的代码：

public class MenuScreen extends MainScreen { 
    public MenuScreen() { 
     super(Screen.DEFAULT_CLOSE); 
     Bitmap menuBackgroundImage = Bitmap 
       .getBitmapResource("com/greetings/Images/MenuBackground.jpg"); 
     final VerticalFieldManager layout = new VerticalFieldManager() { 
      public boolean touchEvent(TouchEvent message) { 
       int x = message.getGlobalX(1); 
       int y = message.getGlobalY(1); 
       if (getExtent().contains(x, y)) { 
        int fieldI = getFieldAtLocation(x, y); 
        Field field = getField(fieldI); 
        field.setFocus(); 
        return super.touchEvent(message); 
       } 
       return false; 
      } 
     }; 
     ButtonField categories = new ButtonField("Categories") { 
      public void run() { 
       Dialog.alert("one"); 
      } 
      public boolean touchEvent(TouchEvent message) { 
       int x = message.getX(1); 
       int y = message.getY(1); 
       int w = getWidth(); 
       int h = getHeight(); 
       if (x >= 0 && x <= w && y >= 0 && y <= h) { 
        switch (message.getEvent()) { 
        case TouchEvent.DOWN: 
         setFocus(); 
         return true; 
        case TouchEvent.UNCLICK: 
         run(); 
         return true; 
        } 
       } 
       return false; 
      } 
     }; 
     ButtonField help = new ButtonField("Help") { 
      public void run() { 
       Dialog.alert("help"); 
      } 
      public boolean touchEvent(TouchEvent message) { 
       int x = message.getX(1); 
       int y = message.getY(1); 
       int w = getWidth(); 
       int h = getHeight(); 
       if (x >= 0 && x <= w && y >= 0 && y <= h) { 
        switch (message.getEvent()) { 
        case TouchEvent.DOWN: 
         setFocus(); 
         return true; 
        case TouchEvent.UNCLICK: 
         run(); 
         return true; 
        } 
       } 
       return false; 
      } 
     }; 
     ButtonField developer = new ButtonField("Developer") { 
      public void run() { 
       Dialog.alert("Developer"); 
      } 
      public boolean touchEvent(TouchEvent message) { 
       int x = message.getX(1); 
       int y = message.getY(1); 
       int w = getWidth(); 
       int h = getHeight(); 
       if (x >= 0 && x <= w && y >= 0 && y <= h) { 
        switch (message.getEvent()) { 
        case TouchEvent.DOWN: 
         setFocus(); 
         return true; 
        case TouchEvent.UNCLICK: 
         run(); 
         return true; 
        } 
       } 
       return false; 
      } 
     }; 
     layout.add(categories); 
     layout.add(help); 
     layout.add(developer); 
     VerticalFieldManager manager = new VerticalFieldManager() { 
      protected void sublayout(int width, int height) { 
       width = Display.getWidth(); 
       height = Display.getHeight(); 
       super.sublayout(width, height); 
       setPositionChild(layout, width - 245, height - 350); 
       setExtent(width, height); 
      } 
     }; 
     manager.setBackground(BackgroundFactory 
       .createBitmapBackground(menuBackgroundImage)); 
     manager.add(layout); 
     add(manager); 
    } 
} 

Answer 1

这里有几个建议：

• 使用Button.CONSUME_CLICK风格
• 如果有一种方法，使用FieldChangeListeners代替触摸事件（为了兼容性和简单性）
• 请看How to - Implement advanced buttons, fields, and managers
• 在sublayout尺寸经理不仅setExtent，而且还覆盖getPrefferredWidth /身高
• 的方法之外声明字段，sothey将可以访问其他方法

该经理应是任意大小和要围绕孩子的字段垂直&水平：

class SizableVerticalButtonFieldSet extends Manager { 
    int mWidth = 0; 
    int mHeight = 0; 

    public SizableVerticalButtonFieldSet(int width, int height) { 
     this(width, height, Field.FIELD_HCENTER); 
    } 

    public SizableVerticalButtonFieldSet(int width, int height, long style) { 
     super(style); 
     mWidth = width; 
     mHeight = height; 
    } 

    public int getPreferredWidth() { 
     return mWidth; 
    } 

    public int getPreferredHeight() { 
     return mHeight; 
    } 

    protected void sublayout(int width, int height) { 
     width = getPreferredWidth(); 
     height = getPreferredHeight(); 

     int numChildren = this.getFieldCount(); 
     int prevTopMargin = 0; 
     int usedHeight = 0; 
     // calculate start y 
     for (int i = 0; i < numChildren; i++) { 

      Field currentField = getField(i); 
      usedHeight += Math.max(prevTopMargin, currentField 
        .getMarginBottom()); 
      usedHeight += currentField.getHeight(); 
      prevTopMargin = currentField.getMarginBottom(); 
     } 

     int x; 
     int y = (height - usedHeight) >> 1; 
     for (int i = 0; i < numChildren; i++) { 

      Field currentField = getField(i); 
      int currentPreferredWidth = currentField.getPreferredWidth() 
        + getBorderWidth(currentField); 
      if (currentPreferredWidth < width) { 
       int newPadding = (width - currentPreferredWidth)/2; 
       currentField 
         .setPadding(currentField.getPaddingTop(), newPadding, 
           currentField.getPaddingBottom(), newPadding); 
      } 
      layoutChild(currentField, width, height); 

      y += Math.max(prevTopMargin, currentField.getMarginBottom()); 
      x = (width - currentField.getWidth())/2; 
      setPositionChild(currentField, x, y); 
      y += currentField.getHeight(); 
      prevTopMargin = currentField.getMarginBottom(); 
     } 
     setExtent(width, height); 
    } 

    protected boolean navigationMovement(int dx, int dy, 
     int status, int time) { 
     int focusIndex = getFieldWithFocusIndex(); 
     if (dx < 0 && focusIndex == 0) { 
      // we cannot go left 
      return true; 
     } 
     if (dx > 0 && focusIndex == getFieldCount() - 1) { 
      // we cannot go right 
      return true; 
     } 
     return super.navigationMovement(dx, dy, status, time); 
    } 

    public static int getBorderWidth(Field field) { 
     int width = 0; 

     // #ifdef VER_4.1.0 | VER_4.2.0 | VER_4.2.1 | VER_4.3.0 | VER_4.5.0 
     width = field.getWidth() - field.getContentWidth() 
       - field.getPaddingLeft() - field.getPaddingRight(); 
     // #else 
     Border border = field.getBorder(); 
     if (border != null) { 
      width = border.getLeft() + border.getRight(); 
     } 
     // #endif 
     return width; 
    } 
} 

alt text http://img138.imageshack.us/img138/462/layoutbs.jpg

而这是使用的一个示例：

class MenuScreen extends MainScreen { 
    VerticalFieldManager layout; 
    ButtonField categories; 
    ButtonField help; 
    ButtonField developer; 
    SizableVerticalButtonFieldSet manager; 

    public MenuScreen() { 
     super(DEFAULT_CLOSE); 

     // generate background (for test only) 
     int fWidth = Display.getWidth(); 
     int fHeight = Display.getHeight(); 
     Bitmap menuBackgroundImage = new Bitmap(fWidth, fHeight); 
     Graphics g = Graphics.create(menuBackgroundImage); 
     g.setColor(Color.GREEN); 
     g.fillRect(0, 0, fWidth, fHeight); 
     g.setColor(Color.GOLD); 
     Font f = getFont().derive(Font.BOLD, 18); 
     g.setFont(f); 
     String text = "THIS IS A BACKGROUND"; 
     int tWidth = f.getAdvance(text); 
     int tHeight = f.getHeight(); 
     int tX = (fWidth - tWidth) >> 1; 
     int tY = (fHeight - tHeight) >> 1; 
     g.drawText(text, tX, tY, DrawStyle.HCENTER | DrawStyle.VCENTER); 

     layout = new VerticalFieldManager(); 

     // don't forget to set ButtonField.CONSUME_CLICK style 
     categories = new ButtonField("Categories", ButtonField.CONSUME_CLICK); 
     // use FieldChangeListener instead of touch events 
     categories.setChangeListener(new FieldChangeListener() { 
      public void fieldChanged(Field field, int context) { 
       Dialog.alert("one"); 
      } 
     }); 

     help = new ButtonField("Help", ButtonField.CONSUME_CLICK); 
     help.setChangeListener(new FieldChangeListener() { 
      public void fieldChanged(Field field, int context) { 
       Dialog.alert("help"); 
      } 
     }); 

     developer = new ButtonField("Developer", ButtonField.CONSUME_CLICK); 
     developer.setChangeListener(new FieldChangeListener() { 
      public void fieldChanged(Field field, int context) { 
       Dialog.alert("Developer"); 
      } 
     }); 
     layout.add(categories); 
     layout.add(help); 
     layout.add(developer); 

     // if you need to set size of manager, better use manager extantion 
     // use Display.getWidth(), Display.getHeight() for screen size manager 
     manager = new SizableVerticalButtonFieldSet(fWidth, fHeight); 
     manager.setBackground(BackgroundFactory 
       .createBitmapBackground(menuBackgroundImage)); 
     manager.add(layout); 
     add(manager); 
    } 
}