问题
How to re-arrange the items of a ListField? I want to select the item on click on Blackberry (Storm and Torch) Touch Phones. After select I want to (Move and Drag) Scroll item Vertically on another list item(list items scroll vertically in background) or screen. After scrolling, drop item any where on (in list field) Screen.
回答1:
I was also working on custom ListField recently and I hope the following code is going to help you.
In the example below, I've customized a VerticalFieldManager to create a ListField for both touch supported and non-touch BB devices.
Position of the ListField items can be changed-
-- by just DRAG an item and DROP on another item of the ListField (for touch supported devices)
or
-- by pressing SPACE-BAR on the first item and then on the second item (for both touch and non-touch devices).
Sample screenshot for (touch) Drag & Drop below:
Sample screenshot for (non-touch) SPACE-BAR pressing below:
In this sample I've implemented vertical scrolling in the ListField and have also created a traditional scrollbar.
Here is the code of my sample screen for ListField customization:
import net.rim.device.api.system.Characters;
import net.rim.device.api.ui.Field;
import net.rim.device.api.ui.Font;
import net.rim.device.api.ui.Graphics;
import net.rim.device.api.ui.TouchEvent;
import net.rim.device.api.ui.XYEdges;
import net.rim.device.api.ui.component.LabelField;
import net.rim.device.api.ui.component.ListField;
import net.rim.device.api.ui.component.ListFieldCallback;
import net.rim.device.api.ui.component.ObjectListField;
import net.rim.device.api.ui.container.MainScreen;
import net.rim.device.api.ui.container.VerticalFieldManager;
import net.rim.device.api.ui.decor.BackgroundFactory;
import net.rim.device.api.ui.decor.Border;
import net.rim.device.api.ui.decor.BorderFactory;
public class ListTestScreen extends MainScreen {
private VerticalFieldManager mainManager = new VerticalFieldManager( USE_ALL_WIDTH |FIELD_HCENTER);
public ListTestScreen() {
mainManager.setBackground(BackgroundFactory.createSolidBackground(0x808080));
LabelField lblTitle = new LabelField("FIFA World Cup Country List:",FIELD_HCENTER);
lblTitle.setBackground(BackgroundFactory.createSolidBackground(0xF0F0F0));
XYEdges edges = new XYEdges(2, 2, 2, 2);
lblTitle.setBorder(BorderFactory.createRoundedBorder(edges, 0xB0B0B0, Border.STYLE_FILLED));
mainManager.add(lblTitle);
mainManager.add(new MyList());
LabelField lblOther = new LabelField("Some Other Field",FIELD_HCENTER);
lblOther.setBackground(BackgroundFactory.createSolidBackground(0xF0F0F0));
lblOther.setBorder(BorderFactory.createRoundedBorder(edges, 0xB0B0B0, Border.STYLE_FILLED));
mainManager.add(lblOther);
add(mainManager);
}
}
class MyList extends VerticalFieldManager implements ListFieldCallback {
private int mouseDownY, mouseUpY;
private static int listRowHeight = 30;
private int mouseDownRowIndex, mouseUpRowIndex;
int firstSelectedRow=-1, secondSelectedRow=-1;
private int touchX;
private int touchY;
private int listVisibleHeight = 250;
private int listVisibleWidth = 200;
private boolean showShadow = false;
private ObjectListField list;
private Object[] listData = new Object[] { "South Africa", "Argentina", "Germany",
"Australia","Nigeria","Greece","England","Italy","Brazil","Spain","Paraguay","France","Uruguay",
"Mexico","Cameroon","Denmark","Portugal","Netherlands","Ghana","Chile",
"South Korea","USA","Algeria","Slovenia","Japan","Switzerland","Honduras"};
public MyList() {
super(VERTICAL_SCROLL|FIELD_HCENTER);
init();
setBackground(BackgroundFactory.createSolidBackground(0xF0F0F0));
XYEdges edges = new XYEdges(6, 6, 6, 6);
setBorder(BorderFactory.createRoundedBorder(edges, 0xB0B0B0, Border.STYLE_FILLED));
}
private void init() {
list = new ObjectListField(FOCUSABLE|Field.FIELD_HCENTER);
list.setRowHeight(listRowHeight);
list.setCallback(this);
list.set(listData);
add(list);
}
private void changeRowPosition(int fromRow, int toRow) {
Object temp = listData[fromRow];
int increment = (fromRow<toRow)?1:-1, i;
for(i = fromRow+increment; i != toRow+increment ; i=i+increment) {
listData[i-increment] = listData[i];
}
listData[toRow] = temp;
invalidate();
}
public void drawListRow(ListField listField, Graphics graphics, int index,
int y, int width) {
graphics.setFont(Font.getDefault().derive(Font.PLAIN, listRowHeight-8));
graphics.drawText(listData[index].toString(), 25, y + 4);
}
public Object get(ListField listField, int index) {
return listData[index];
}
public int getPreferredWidth(ListField listField) {
return getPreferredWidth();
}
public int indexOfList(ListField listField, String prefix, int start) {
return 0;
}
public int indexOfRowAt(int posY) {
int index =(int) Math.floor(posY / listRowHeight * 1.0);
return index;
}
protected void sublayout(int maxWidth, int maxHeight) {
super.sublayout(listVisibleWidth, listVisibleHeight);
setExtent(listVisibleWidth, listVisibleHeight);
}
protected boolean keyChar(char ch, int status, int time) {
if(ch==Characters.SPACE) {
if(firstSelectedRow ==-1) {
firstSelectedRow = list.getSelectedIndex();
return true;
} else {
secondSelectedRow = list.getSelectedIndex();
if(firstSelectedRow == secondSelectedRow) {
firstSelectedRow = secondSelectedRow = -1;
invalidate();
return true;
} else {
changeRowPosition(firstSelectedRow, secondSelectedRow);
firstSelectedRow = secondSelectedRow = -1;
return true;
}
}
}
return super.keyChar(ch, status, time);
}
protected boolean navigationMovement(int dx, int dy, int status, int time) {
invalidate();
return super.navigationMovement(dx, dy, status, time);
}
protected boolean touchEvent(TouchEvent message) {
int eventCode = message.getEvent();
// Get the screen coordinates of the touch event
touchX = message.getX(1);
touchY = message.getY(1)+getVerticalScroll();
if(eventCode == TouchEvent.DOWN) {
mouseDownY = touchY;
mouseDownRowIndex = indexOfRowAt(mouseDownY);
showShadow = true;
invalidate();
return true;
}
else if(eventCode == TouchEvent.UP) {
showShadow = false;
mouseUpY = touchY;
mouseUpRowIndex = indexOfRowAt(mouseUpY);
if(mouseDownRowIndex != mouseUpRowIndex) {
changeRowPosition(mouseDownRowIndex, mouseUpRowIndex);
mouseDownRowIndex = mouseUpRowIndex = -1;
invalidate();
return true;
}
mouseDownRowIndex = mouseUpRowIndex = -1;
invalidate();
return true;
} else if(eventCode == TouchEvent.MOVE) {
int index = indexOfRowAt(touchY-listRowHeight/2);
if(touchY-getVerticalScroll()<5) {
if(index > 0) {
index--;
}
} else if(touchY> (getPreferredHeight()-5)) {
if(index<listData.length-1) {
index++;
}
}
if(list.getSelectedIndex()!=index)
list.setSelectedIndex(index);
invalidate();
return true;
}
return super.touchEvent(message);
}
protected void paint(Graphics graphics) {
// Save the original color and transparency values for the graphics
int preColor = graphics.getColor();
int preAlpha = graphics.getGlobalAlpha();
if(firstSelectedRow!=-1) {
int y = firstSelectedRow*listRowHeight;
graphics.setColor(0x808080);
graphics.fillRect(0, y, getWidth(), listRowHeight);
}
// Reset the previous color and transparency values for this graphics
graphics.setColor(preColor);
graphics.setGlobalAlpha(preAlpha) ;
super.paint(graphics);
if(firstSelectedRow != -1) {
int index = list.getSelectedIndex();
int y = index*listRowHeight;
String shadowText = listData[firstSelectedRow].toString();
Font preFont = graphics.getFont();
Font smallFont = preFont.derive(Font.BOLD, preFont.getHeight()-5);
y += (listRowHeight-smallFont.getHeight())/2;
graphics.setFont(smallFont);
int shadowTextLength = smallFont.getAdvance(shadowText);
graphics.setColor(0xE0E0E0);
graphics.setGlobalAlpha(100) ;
graphics.fillRoundRect(getWidth()/2-2, y, shadowTextLength+4, smallFont.getHeight(), 10, 10);
graphics.setColor(0x303030);
graphics.setGlobalAlpha(170) ;
graphics.drawText(shadowText, getWidth()/2, y);
graphics.setFont(preFont);
}
// Drawing the first selected SHADOW TEXT
if(showShadow && mouseDownRowIndex != -1) {
String shadowText = listData[mouseDownRowIndex].toString();
Font preFont = graphics.getFont();
Font smallFont = preFont.derive(Font.BOLD, preFont.getHeight()-5);
graphics.setFont(smallFont);
int shadowTextLength = smallFont.getAdvance(shadowText);
graphics.setColor(0xE0E0E0);
graphics.setGlobalAlpha(100) ;
graphics.fillRoundRect(touchX+10, touchY-smallFont.getHeight()/2, shadowTextLength, smallFont.getHeight(), 10, 10);
graphics.setColor(0x303030);
graphics.setGlobalAlpha(170) ;
graphics.drawText(shadowText, touchX+10, touchY-smallFont.getHeight()/2);
graphics.setFont(preFont);
}
// Drawing the VERTICAL SCROLLBAR
graphics.setColor(0x606060);
graphics.drawLine(getWidth()-18, getVerticalScroll(), getWidth()-18,getVerticalScroll()+getHeight());
graphics.drawLine(getWidth()-17, getVerticalScroll(), getWidth()-17,getVerticalScroll()+getHeight());
graphics.drawLine(getWidth()-16, getVerticalScroll(), getWidth()-16,getVerticalScroll()+getHeight());
int listTotalHeight = listRowHeight * (listData.length+5);
int y = list.getSelectedIndex()*listRowHeight ;
int yScrollPosition = (int)Math.floor(((y*getHeight()*1.0)/listTotalHeight*1.0));
graphics.fillRoundRect((getWidth()-17)-4, getVerticalScroll()+yScrollPosition, 8, listRowHeight, 2, 2);
}
}
回答2:
i am also working on Custom list field. Just Click on listitem. after click U can move (selected) listItem vertically. if u want to place any where in screen than click again on trackpad. when u click it will be place on that position Checkout. here is my code.
public class ListDemo extends MainScreen implements ListFieldCallback {
private VerticalFieldManager vfm, vfm_List;
private ListField myList;
private Vector vector;
private String[] str_arr;
int Height = Display.getHeight();
int Width = Display.getWidth();
int i ;
boolean bool = true;
int index = 0;
private boolean hasFocus = false;
private boolean b = true;
public static int curSelected ;
Channel obj;
public ListDemo() {
vector = new Vector();
for (i = 0; i < 8; i++) {
obj = new Channel();
if (i == 0) {
obj.setCh_icon("ajtak.jpg");
obj.setCh_Name("NightSuite");
obj.setCh_Move("move.png");
} else if (i == 1) {
obj.setCh_icon("cnbc.jpg");
obj.setCh_Name("Shirts");
obj.setCh_Move("move.png");
} else if (i == 2) {
obj.setCh_icon("zee.jpg");
obj.setCh_Name("Jeans");
obj.setCh_Move("move.png");
} else if (i == 3) {
obj.setCh_icon("astha.jpg");
obj.setCh_Name("Bags");
obj.setCh_Move("move.png");
}else if (i == 4) {
obj.setCh_icon("fox_news.jpg");
obj.setCh_Name("Coat");
obj.setCh_Move("move.png");
}else if (i == 5) {
obj.setCh_icon("news.jpg");
obj.setCh_Name("Coat");
obj.setCh_Move("move.png");
} else if (i == 6) {
obj.setCh_icon("star_news.jpg");
obj.setCh_Name("Coat");
obj.setCh_Move("move.png");
} else {
obj.setCh_icon("assiant.jpg");
obj.setCh_Name("Shorts");
obj.setCh_Move("move.png");
}
vector.addElement(obj);
}
init();
}
public void init() {
vfm = new VerticalFieldManager(USE_ALL_HEIGHT | USE_ALL_WIDTH) {
protected void sublayout(int maxWidth, int maxHeight) {
super.sublayout(maxWidth, maxHeight);
setExtent(Width, Height);
}
};
vfm_List = new VerticalFieldManager(VERTICAL_SCROLL
| VERTICAL_SCROLLBAR) {
protected void sublayout(int maxHeight, int maxWidth) {
super.sublayout(maxWidth, maxHeight);
setExtent(Width, Height);
}
};
myList = new ListField()
{
public void onFocus(int direction){
hasFocus = true;
}
public void onUnfocus()
{
hasFocus = false;
super.onUnfocus();
invalidate();
}
public void paint(Graphics g) {
if (hasFocus)
{
curSelected = getSelectedIndex();
}
else
{
curSelected = -1;
}
super.paint(g);
}
};
myList.setCallback(this);
myList.setRowHeight(50);
myList.setFocusListener(new FocusChangeListener() {
public void focusChanged(Field field, int eventType) {
if (bool == false) {
index = myList.getSelectedIndex();
Channel temp = (Channel) vector
.elementAt(index);
vector.removeElementAt(index);
vector.insertElementAt(temp, curSelected);
myList.invalidate();
}
}
});
for (int i = 0; i < vector.size(); i++) {
myList.insert(i);
}
vfm_List.add(myList);
vfm.add(vfm_List);
add(vfm);
}
protected boolean navigationClick(int status, int time) {
if(bool)
{
bool = false;
}
else
{
bool = true;
}
return true;
}
public void drawListRow(ListField list, Graphics g, int index, int y, int w)
{
String text = ((Channel) vector.elementAt(index)).getCh_Name();
Bitmap arrow = Bitmap.getBitmapResource(((Channel) vector.elementAt(index)).getCh_icon());
if(bool == false)
{
if (g.isDrawingStyleSet(Graphics.DRAWSTYLE_FOCUS))
{
Bitmap move = Bitmap.getBitmapResource(((Channel) vector.elementAt(index)).getCh_Move());
g.drawBitmap(Width - 40, y + 13, 25, 25, move, 0, 0);
}
}
g.setBackgroundColor(Color.LIGHTBLUE);
g.setColor(Color.BLACK);
g.drawBitmap(0, y + 10, 48, 35, arrow, 0, 0);
g.drawText(text, 50, y + 18, 0, w);
g.setColor(Color.WHITE);
invalidate();
}
public Object get(ListField list, int index) {
return vector.elementAt(index);
}
public int indexOfList(ListField list, String p, int s) {
return vector.indexOf(p, s);
}
public int getPreferredWidth(ListField list) {
return Graphics.getScreenWidth();
}
public void insert(String toInsert, int index) {
vector.addElement(toInsert);
}
public void erase() {
vector.removeAllElements();
}
}
Here is another Channel Class
public class Channel {
private String ch_Name;
private String ch_icon;
private String ch_move;
public String getCh_Name() {
return ch_Name;
}
public void setCh_Name(String ch_Name) {
this.ch_Name = ch_Name;
}
public String getCh_icon() {
return ch_icon;
}
public void setCh_icon(String ch_icon) {
this.ch_icon = ch_icon;
}
public String getCh_Move() {
return ch_move;
}
public void setCh_Move(String ch_move) {
this.ch_move = ch_move;
}
}
Checkout its working on both touch and nontouch .
来源：https://stackoverflow.com/questions/10292259/how-to-re-arrange-listfield-in-blackberry