如何使用水平场将标签置于屏幕中心

Question

我想在屏幕中间垂直和水平居中显示徽标和文本字段。实现这一目标的最佳方法是什么？

到目前为止，我一直在尝试这个...

public upd8rMainScreen(){

    Bitmap logoBitmap = Bitmap.getBitmapResource("upd8rLOGO.png");
    bitmapField = new BitmapField(logoBitmap, Field.FIELD_VCENTER);
    labelfield = new LabelField("Tap Your Phone Onto The Reader To Activate",Field.FIELD_VCENTER);


    topHfm = new HorizontalFieldManager(Manager.VERTICAL_SCROLL);
    middleHfm = new HorizontalFieldManager(Manager.VERTICAL_SCROLL);

    vfm = new VerticalFieldManager();
    topHfm.add(bitmapField);
    middleHfm.add(labelfield);

    vfm.add(topHfm);
    vfm.add(middleHfm);
    add(vfm);

}

Answer 1

可能会帮助你试试这个

Bitmap logoBitmap = Bitmap.getBitmapResource("basket.png");
        bitmapField = new BitmapField(logoBitmap,Field.FIELD_HCENTER);
        labelfield = new LabelField("Tap Your Phone Onto ",Field.FIELD_HCENTER);
//     
        VerticalFieldManager vrt=new VerticalFieldManager(USE_ALL_WIDTH)
        {
            protected void sublayout(int maxWidth, int maxHeight) {

                super.sublayout(Display.getWidth(),Display.getHeight());
                setExtent(Display.getWidth(),Display.getHeight());
            }
        };
        Font f=labelfield.getFont();
        int hight1=f.getAdvance(labelfield.getText());
        int k=labelfield.getPreferredHeight();

        int number=hight1/Display.getWidth()+1;
        int hight2=logoBitmap.getHeight();
        int padding=(Display.getHeight()-((number*k)+hight2))/2;
        if(padding>0){
            bitmapField.setPadding(padding,0,0,0);
        }

        vrt.add(bitmapField);
        vrt.add(labelfield);

图像显示如下

Answer 2

您可以尝试重新设置 VerticalFieldManager 的保证金：

topHfm = new HorizontalFieldManager(Manager.FIELD_HCENTER | Manager.FIELD_VCENTER);
midHfm = new HorizontalFieldManager(Manager.FIELD_HCENTER | Manager.FIELD_VCENTER);

topHfm.add(bitmapField);
midHfm.add(new LabelField("My Label", Manager.FIELD_HCENTER));

VerticalFieldManager vfm = new VerticalFieldManager(Manager.FIELD_VCENTER);
vfm.add(topHfm);
vfm.add(midHfm);

int screenHeight = Display.getHeight();
int screenWidth = Display.getWidth();

int totalContentHeight = topHfm.getPreferredHeight()+ midHfm.getPreferredHeight();
int maxContentWidth = (topHfm.getPreferredWidth()>midHfm.getPreferredWidth()) ? topHfm.getPreferredWidth() : midHfm.getPreferredWidth() ;

int marginTop = (screenHeight>totalContentHeight)? (screenHeight - totalContentHeight) / 2 : 0;
int marginLeft = (screenWidth>maxContentWidth)? (screenWidth - maxContentWidth ) / 2 : 0;

vfm.setMargin(marginTop, 0, 0, marginLeft);

add(vfm);

我并不认为这是“最佳方式”，但我希望它能适用于您的情况。