水平滚动和TextField错误

时间:2012-05-16 11:44:35

标签: java blackberry customization textfield

我创建了一个CustomTextField  当我输入超出TextField宽度的文本时,它会向左滚动  为其使用Horizo​​nalFieldManager  但现在问题是如果我用鼠标右键单击并滚动它  它继续长度不足  但并没有停止到我输入的最后一个字 这里有什么问题 ?? 这是一个错误

我只需要在到达最后一个单词时禁用Horizo​​ntalScrolling 它应该能够在单词

中的最后一个单词的开头和结尾之间滚动

查看代码

import net.rim.device.api.ui.Color;
import net.rim.device.api.ui.Field;
import net.rim.device.api.ui.FocusChangeListener;
import net.rim.device.api.ui.Graphics;
import net.rim.device.api.ui.Manager;
import net.rim.device.api.ui.XYEdges;
import net.rim.device.api.ui.XYRect;
import net.rim.device.api.ui.component.BasicEditField;
import net.rim.device.api.ui.container.HorizontalFieldManager;
import net.rim.device.api.ui.container.VerticalFieldManager;
import net.rim.device.api.ui.decor.Border;
import net.rim.device.api.ui.decor.BorderFactory;


public class CustomTextField extends VerticalFieldManager {
    private int textWidth=0;
    private int textHeight=0;
    private BasicEditField basicEditField;
    private HorizontalFieldManager hfm;
    //Border border;

    public CustomTextField(int width,int height) {
        super();
        textWidth=width;
        textHeight=height;
        //border=BorderFactory.createSimpleBorder(new XYEdges(1, 1, 1, 1)); 


        hfm=new HorizontalFieldManager(Manager.HORIZONTAL_SCROLL){
            protected void sublayout(int maxWidth, int maxHeight) {
                super.sublayout(maxWidth, maxHeight);
                setExtent(textWidth, textHeight);
            }
        };  
        basicEditField=new BasicEditField("","",200,BasicEditField.NO_NEWLINE);
        //basicEditField.setBorder(border);

        hfm.add(basicEditField);
        add(hfm);
    }


    protected void sublayout(int maxWidth, int maxHeight) {
        super.sublayout(textWidth, textHeight);
        setExtent(textWidth, textHeight);

    }


    protected void paint(Graphics graphics) {
        super.paint(graphics);
        graphics.setColor(Color.BLACK);
        graphics.drawRect(0,0, textWidth, textHeight);
    }

}

我已将其初始化为

 CustomTextField textField=new CustomTextField(200, 20);
            add(textField);

我觉得需要为FrameFieldManager提供Scroll(滚动功能)...但尚未找到解决方案 请帮忙

1 个答案:

答案 0 :(得分:4)

因此,在BlackBerry字段中,范围是字段的实际可视大小。但是,虚拟范围是它可以使用的逻辑大小,其中一些可能不可见。对于您想要滚动的Managers,通常会将虚拟范围设置为大于范围。

我使用此概念动态更改HorizontalFieldManager的虚拟范围,具体取决于当前需要多少空间才能恰好适合BasicEditField中的文本。为此,我必须让HorizontalFieldManager通过实施BasicEditField来监听FieldChangeListener的更改。然后,当在编辑字段中键入每个字符时,水平字段管理器将重新计算现在在字段中的文本量需要多少宽度。然后它将虚拟宽度重新设置为该宽度。

这会导致水平字段管理器仅允许滚动到输入文本的末尾,而不是向右滚动,这是代码最初的工作方式。

所以,我不认为黑莓手机做错了什么......操作系统中没有任何错误。以前,虚拟范围没有设置。

我将您的Horizo​​ntalFieldManager拆分为一个新的私有类,因为当逻辑超过大约5行代码时,我不喜欢使用匿名类。所以,下面的解决方案看起来有点不同。

其他想法:

1)由于您尝试使用自定义paint()实现绘制边框,因此存在绘图工件。但是,那个bug本来就存在,我把这个问题解释为滚动问题。看起来您正在尝试使用Border个对象,这可能是实现滚动字段边框的更好方法。

2)使用我的新解决方案,实际的CustomTextField类没有太多内容。它只是Manager的容器(CustomHorizontalFieldManager)。如果你愿意,你可以摆脱那个外层。但是,我知道有时当您发布代码时,您会删除对您遇到问题不重要的细节。因此,可能需要VerticalFieldManager包含HorizontalFieldManager,其中包含BasicEditField。我会把它留给你......但它只是可选的 cleanup

3)我在5.0 Storm2模拟器上测试过它。

import net.rim.device.api.ui.Color;
import net.rim.device.api.ui.Field;
import net.rim.device.api.ui.FieldChangeListener;
import net.rim.device.api.ui.Graphics;
import net.rim.device.api.ui.Manager;
import net.rim.device.api.ui.component.BasicEditField;
import net.rim.device.api.ui.container.HorizontalFieldManager;
import net.rim.device.api.ui.container.VerticalFieldManager;
import net.rim.device.api.util.Arrays;

public class CustomTextField extends VerticalFieldManager {

   private int textWidth = 0;
   private int textHeight = 0;
   private CustomHorizontalFieldManager hfm;

   public CustomTextField(int width, int height) {
      super();

      textWidth = width;
      textHeight = height;

      hfm = new CustomHorizontalFieldManager();
      add(hfm);
   }

   protected void sublayout(int maxWidth, int maxHeight) {
      super.sublayout(textWidth, textHeight);
      setExtent(textWidth, textHeight);
   }

   protected void paint(Graphics graphics) {
      // TODO: change me!
      super.paint(graphics);
      graphics.setColor(Color.BLACK);
      graphics.drawRect(0, 0, textWidth, textHeight);
   }

   private class CustomHorizontalFieldManager extends HorizontalFieldManager implements FieldChangeListener {

      private BasicEditField basicEditField;
      /** the maximum virtual width of the edit field, based on the max num of chars */
      private int maxVirtualWidth;

      public CustomHorizontalFieldManager() {
         super(Manager.HORIZONTAL_SCROLL);

         int maxNumChars = 200;
         basicEditField = new BasicEditField("", "", maxNumChars, BasicEditField.NO_NEWLINE);

         // determine how wide the field would need to be to hold 'maxNumChars', with the font
         //   in use ... just pick a long string of all W's, since that's usually the widest char
         char[] buffer = new char[maxNumChars];
         Arrays.fill(buffer, 'W');
         String spacer = new String(buffer);
         maxVirtualWidth = basicEditField.getFont().getAdvance(spacer);

         // we need to listen as the user types in this field, so we can dynamically alter its
         //   virtual width
         basicEditField.setChangeListener(this);

         add(basicEditField);
      }

      protected void sublayout(int maxWidth, int maxHeight) {
         super.sublayout(maxWidth, maxHeight);
         // extent is the visible size, virtual extent can be wider if we want scrolling
         setExtent(textWidth, textHeight);
         setVirtualExtent(maxVirtualWidth, textHeight);
      }

      public void fieldChanged(Field f, int context) {
         if (f == basicEditField) {
            // recalculate how much virtual width the edit field needs, based on the 
            //  current text content
            int newWidth = basicEditField.getFont().getAdvance(basicEditField.getText());
            setVirtualExtent(newWidth, textHeight);
         }
      }
   }

}