Question

我的屏幕中央有DateField

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当我触摸它时，我看到：

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但我希望看到：

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我的问题是：

如何将DateField的日期选择器弹出窗口居中？

Blackberry OS 6

更新

public class MyMainScreen extends MainScreen
{
    protected DateField dateField_ = null;
    protected VerticalFieldManager container_ = null;

    public MyMainScreen()
    {
        super();
        container_ = new VerticalFieldManager(VerticalFieldManager.VERTICAL_SCROLL
            | VerticalFieldManager.VERTICAL_SCROLLBAR | VerticalFieldManager.USE_ALL_HEIGHT)
        {
            protected void sublayout(int width, int height)
            {
                super.sublayout(width, height);

                layoutChild(dateField_ , 100, 40);
                setPositionChild(dateField_ , (width - 100) / 2, 50);

                setVirtualExtent(width, 50);
            }
        };

        add(container_);
        dateField_ = new DateField("", new Date(), new SimpleDateFormat("HH:mm"), Field.FIELD_HCENTER |
                DrawStyle.HCENTER | Field.FOCUSABLE);

        container_.add(dateField_);
        add(container_);
    }
}

Answer 1

好的，所以有一些问题：

DateField不会仅仅因为您将Field.FIELD_HCENTER | DrawStyle.HCENTER传递给构造函数而使字段居中。我认为DateField甚至不会识别这些旗帜。
VerticalFieldManager是一种特殊的Manager，旨在按照您add()的顺序从上到下垂直布置其子项。如果您不要以这种方式布置字段，那么我不知道您应该扩展VerticalFieldManager。如果您想实施Manager，只需直接延长sublayout()即可。此外，在您的实施中调用super.sublayout()可能会导致问题。
您正在硬编码DateField的高度/宽度。我不确定它是否允许。
您的代码实际上并没有为我编译，因为DateField构造函数的日期为long，而不是Date。这与居中无关。

所以，我建议这样的事情：

  super(MainScreen.VERTICAL_SCROLL | MainScreen.VERTICAL_SCROLLBAR);

  dateField_ = new DateField("", (new Date()).getTime(), new SimpleDateFormat("HH:mm"), Field.FOCUSABLE);

  container_ = new Manager(Manager.VERTICAL_SCROLL | Manager.VERTICAL_SCROLLBAR) {
     public int getPreferredHeight() {
        return Display.getHeight();
     }
     public int getPreferredWidth() {
        return Display.getWidth();
     }
     protected void sublayout(int width, int height) {            
        int h = Math.min(height, Display.getHeight());
        setExtent(width, h);
        // only needed if there's actually more content than fits in the visible area
        //setVirtualExtent(width, h + ?);

        int dfWidth = dateField_.getPreferredWidth();
        int dfHeight = dateField_.getPreferredHeight();
        layoutChild(dateField_, dfWidth, dfHeight);
        setPositionChild(dateField_, (width - dfWidth) / 2, (h - dfHeight) / 2);
     }                                      
  };

  container_.add(dateField_);      
  add(container_);

P.S。我不确定你是否想要滚动。只有DateField，没有理由滚动。但是，我知道您的真实Screen可能包含更多内容，因此您可能需要setVirtualExtent()，我已将其注释掉。

Answer 2

此解决方案也适用于我：

package com.my.package;

import java.util.Calendar;
import java.util.Date;

import net.rim.device.api.i18n.SimpleDateFormat;
import net.rim.device.api.ui.DrawStyle;
import net.rim.device.api.ui.Field;
import net.rim.device.api.ui.Manager;
import net.rim.device.api.ui.TouchEvent;
import net.rim.device.api.ui.UiApplication;
import net.rim.device.api.ui.component.DateField;
import net.rim.device.api.ui.container.VerticalFieldManager;
import net.rim.device.api.ui.picker.DateTimePicker;

public class MyDateManager extends VerticalFieldManager {
    protected DateField dateField_ = null;
    protected DateTimePicker dateTimePicker_ = null;
    protected SimpleDateFormat dateFormat_ = null;

    public MyDateManager() {
        super(Manager.FIELD_HCENTER | Manager.FIELD_VCENTER);
        dateFormat_ = new SimpleDateFormat("HH:mm");
        dateField_ = new DateField("", new Date().getTime(), dateFormat_,
                Field.FIELD_HCENTER | DrawStyle.HCENTER | Field.FOCUSABLE) {
            protected boolean touchEvent(TouchEvent paramTouchEvent) {
                if (paramTouchEvent.getEvent() == TouchEvent.CLICK) {
                    dateField_.setEnabled(false);
                    showDatePicker();
                }
                return super.touchEvent(paramTouchEvent);
            }

            protected boolean trackwheelClick(int paramInt1, int paramInt2) {
                dateField_.setEnabled(false);
                showDatePicker();

                return super.trackwheelClick(paramInt1, paramInt2);
            }
        };
        this.add(dateField_);
    }

    protected void sublayout(int width, int height) {
        layoutChild(dateField_, width, height);
        setPositionChild(dateField_, (width - dateField_.getWidth()) / 2,
                (height - dateField_.getHeight()) / 2);
        int h = dateField_.getHeight();
        if (h <= 0)
            h = height;
        setExtent(width, h);
    }

    protected void showDatePicker() {
        if (dateTimePicker_ == null) {
            Calendar cal = Calendar.getInstance();

            // HACK
            String dateFormat = dateFormat_.toPattern().indexOf("H", 0) == -1 ? dateFormat_
                    .toPattern() : null;
            String timeFormat = dateFormat_.toPattern().indexOf("H", 0) != -1 ? dateFormat_
                    .toPattern() : null;

            dateTimePicker_ = DateTimePicker.createInstance(cal, dateFormat,
                    timeFormat);
            UiApplication.getUiApplication().invokeLater(new Runnable() {
                public void run() {
                    if (dateTimePicker_.doModal()) {
                        dateField_.setDate(dateTimePicker_.getDateTime()
                                .getTime());
                    }

                    dateField_.setEnabled(true);
                    dateField_.setFocus();
                    dateTimePicker_ = null;
                }
            });
        }
    }
}

Blackberry - 如何使DateField的datepicker弹出窗口居中

2 个答案: