我正在尝试在我的应用程序中实现一个菜单项。代码在这里用于BaseScreen类
package com.kcrw.ui;
import net.rim.device.api.ui.Field;
import net.rim.device.api.ui.Graphics;
import net.rim.device.api.ui.Keypad;
import net.rim.device.api.ui.Manager;
import net.rim.device.api.ui.MenuItem;
import net.rim.device.api.ui.UiApplication;
import net.rim.device.api.ui.component.Dialog;
import net.rim.device.api.ui.component.Menu;
import net.rim.device.api.ui.component.RichTextField;
import net.rim.device.api.ui.container.FullScreen;
import net.rim.device.api.ui.container.MainScreen;
public class BaseScreen extends MainScreen {
/*BaseScreen(){
super();
}*/
class NextQuesMenu extends MenuItem {
public NextQuesMenu() {
super("Live", 40, 10);
}
public void run() {
UiApplication.getUiApplication().pushScreen(new LiveScreen());
UiApplication.getUiApplication().popScreen(getScreen());
}
}
protected void makeMenu(Menu menu, int instance) {
menu.add(new NextQuesMenu());
super.makeMenu(menu, instance);
}
}
现在我从LiveScreen类扩展此类
package com.kcrw.ui;
import net.rim.device.api.system.Bitmap;
import net.rim.device.api.system.Display;
import net.rim.device.api.ui.*;
import net.rim.device.api.ui.component.*;
import net.rim.device.api.ui.container.*;
import com.kcrw.model.LiveStream;
import java.util.Vector;
import net.rim.device.api.system.Display;
import net.rim.device.api.ui.Color;
import net.rim.device.api.ui.DrawStyle;
import net.rim.device.api.ui.Field;
import net.rim.device.api.ui.Graphics;
import net.rim.device.api.ui.Keypad;
import net.rim.device.api.ui.Manager;
import net.rim.device.api.ui.MenuItem;
import net.rim.device.api.ui.UiApplication;
import net.rim.device.api.ui.XYRect;
import net.rim.device.api.ui.component.ListField;
import net.rim.device.api.ui.component.ListFieldCallback;
import net.rim.device.api.ui.component.Menu;
import net.rim.device.api.ui.container.FullScreen;
import net.rim.device.api.ui.container.HorizontalFieldManager;
import net.rim.device.api.ui.container.MainScreen;
import net.rim.device.api.ui.container.VerticalFieldManager;
import com.kcrw.model.LiveStream;
import com.kcrw.util.Constants;
import java.util.Vector;
public class LiveScreen extends BaseScreen {
private static final String NOT_FOUND = "Not Found";
private static final String NEWS_CHANNEL = "NEWS CHANNEL";
private static final String MUSIC_CHANNEL = "MUSIC CHANNEL";
private static final String ON_AIR_NOW = "ON AIR NOW";
public static LiveStream liveStream;
public static LiveStream musicStream;
public static LiveStream newsStream;
public static DrawStyle topLive;
public static DrawStyle bottomLive;
MainScreen mainScreen;
/*switch (position) {
case 0:
if (liveStream.getProgram() == null)
return;
pid = "kcrwlive";
url = liveStream.getProgram().getMobilePlayingImage()
.getImageUrl();
showUrl = liveStream.getProgram().getPageUrl();
title = ON_AIR_NOW;
desc = liveStream.getProgram().getDescription();
if(bitRate==0) {
audioUrl = Constants.liveAudioUrl_64k;
} else {
audioUrl = Constants.liveAudioUrl_128k;
}
break;
case 1:
if (musicStream.getProgram() == null)
return;
pid = "kcrwmusic";
url = musicStream.getProgram().getMobilePlayingImage()
.getImageUrl();
showUrl = musicStream.getProgram().getPageUrl();
title = MUSIC_CHANNEL;
desc = musicStream.getProgram().getDescription();
if(bitRate==0) {
audioUrl = Constants.musicAudioUrl_64k;
} else {
audioUrl = Constants.musicAudioUrl_128k;
}
break;
case 2:
if (newsStream.getProgram() == null)
return;
pid = "kcrwnews";
url = newsStream.getProgram().getMobilePlayingImage()
.getImageUrl();
showUrl = newsStream.getProgram().getPageUrl();
title = NEWS_CHANNEL;
desc = newsStream.getProgram().getDescription();
if(bitRate==0) {
audioUrl = Constants.newsAudioUrl_64k;
} else {
audioUrl = Constants.newsAudioUrl_128k;
}
break;
}
intent.putExtra(PlayerActivity.ALBUM_ID, pid);
intent.putExtra(PlayerActivity.ALBUM_TITLE, title);
intent.putExtra(PlayerActivity.ALBUM_IMAGE_URL, url);
intent.putExtra(PlayerActivity.ALBUM_AUDIO_URL, audioUrl);
intent.putExtra(PlayerActivity.ALBUM_SHOW_URL, showUrl);
intent.putExtra(PlayerActivity.ALBUM_DESCRIPTION, desc);
intent.putExtra(PlayerActivity.IS_PROGRAM, true);
LiveActivity.this.startActivity(intent);
}
});
}*/
public LiveScreen(){
//super();
HorizontalFieldManager _hfm;
//The _vfm will hold the ListField and we'll add it to the _hfm
VerticalFieldManager _vfm;
//Create the vars for ListField creation
final ListField myList;
ListCallback myCallback;
//Get the device width and height
final int width = Display.getWidth();
final int height = Display.getHeight();
//Create the mainScreen - this holds the _hfm and _vfm managers
//MainScreen mainScreen;
mainScreen = new MainScreen();
//Private class that we will create in a minute
myCallback = new ListCallback();
myCallback.erase();
myList = new MyListField();
myList.setCallback(myCallback);
//Populate the list with sample elements
for(int i=0;i<3;i++){
myList.insert(i);
myCallback.insert(ON_AIR_NOW , 0);
myCallback.insert(MUSIC_CHANNEL , 1);
myCallback.insert(NEWS_CHANNEL , 2);
}
//Draw background gradient on this manager and add VerticalFieldManager for scrolling.
_hfm = new HorizontalFieldManager() {
public void paint(Graphics g)
{
//Variables for drawing the gradient
int[] X_PTS_MAIN = { 0, width, width, 0};
int[] Y_PTS_MAIN = { 0, 0, height, height };
int[] drawColors_MAIN = { Color.BLACK, Color.BLACK, Color.DARKBLUE, Color.DARKBLUE};
try {
//Draw the gradients
g.drawShadedFilledPath(X_PTS_MAIN, Y_PTS_MAIN, null, drawColors_MAIN, null);
} catch (IllegalArgumentException iae) {
System.out.println("Bad arguments.");
}
//Call super to paint the graphics on the inherited window
super.paint(g);
}
//Sublayout is passed the width and height of the parent window and will tell the window manager
//how to layout the buttons, images, etc.
protected void sublayout(int w, int h) {
//GetFieldCount returns the number of fields attached to the instance of this manager.
//and lays out the position
if (getFieldCount() >0) {
Field searchRes = getField(0);
layoutChild(searchRes, width, height);
setPositionChild(searchRes,0,0);
}
setExtent(width,height);
}
};
_vfm = new VerticalFieldManager(Manager.VERTICAL_SCROLL|Manager.USE_ALL_HEIGHT|Manager.USE_ALL_WIDTH) {
/*public void paint(Graphics g)
{
g.setColor(Color.GRAY);
super.paint(g);
}
protected boolean navigationMovement(int dx, int dy, int status, int time){
this.invalidate();
return super.navigationMovement(dx,dy,status,time);
} */
protected void sublayout(int maxWidth, int maxHeight) {
layoutChild(myList, maxWidth, maxHeight);
setPositionChild(myList, 5, 385);
setExtent(maxWidth, maxHeight);
}
};
//Add the list to the verticalFieldManager
_vfm.add(myList);
//Add the verticalFieldManager to the HorizontalFieldManager
_hfm.add(_vfm);
//Finally, add the HorizontalFieldManager to the MainScreen and push it to the stack
mainScreen.add(_hfm);
//pushScreen(mainScreen);
UiApplication.getUiApplication().invokeLater(new Runnable() {
public void run() {
UiApplication.getUiApplication().pushScreen(mainScreen);
//UiApplication.getUiApplication().popScreen(getActiveScreen());
}
});
}//End Ctor
private class MyListField extends ListField{
//0,ListField.MULTI_SELECT
private boolean hasFocus = false;
public void onFocus(int direction){
hasFocus = true;
}
public void onUnfocus()
{
hasFocus = false;
super.onUnfocus();
invalidate();
}
public void paint(Graphics graphics)
{ int width = Display.getWidth();
//Get the current clipping region
XYRect redrawRect = graphics.getClippingRect();
if(redrawRect.y < 0)
{
throw new IllegalStateException("Error with clipping rect.");
}
//Determine the start location of the clipping region and end.
int rowHeight = getRowHeight();
int curSelected;
//If the ListeField has focus determine the selected row.
if (hasFocus)
{
curSelected = getSelectedIndex();
}
else
{
curSelected = -1;
}
int startLine = redrawRect.y / rowHeight;
int endLine = (redrawRect.y + redrawRect.height - 1) / rowHeight;
endLine = Math.min(endLine, getSize() - 1);
int y = startLine * rowHeight;
//Setup the data used for drawing.
int[] yInds = new int[]{y, y, y + rowHeight, y + rowHeight};
int[] xInds = new int[]{0, width, width, 0};
//Set the callback - assuming String values.
ListFieldCallback callBack = this.getCallback();
//Draw each row
for(; startLine <= endLine; ++startLine)
{
//If the line we're drawing is the currentlySelected line then draw the fill path in LIGHTYELLOW and the
//font text in Black.
if(startLine == curSelected){
graphics.setColor(Color.LIGHTYELLOW);
graphics.drawFilledPath(xInds, yInds, null, null);
graphics.setColor(Color.BLACK);
graphics.drawText((String)callBack.get(this, startLine), 0, yInds[0]);
}
else{
//Draw the odd or selected rows.
graphics.setColor(Color.LIGHTGREY);
graphics.drawText((String)callBack.get(this, startLine), 0, yInds[0]);
}
//Assign new values to the y axis moving one row down.
y += rowHeight;
yInds[0] = y;
yInds[1] = yInds[0];
yInds[2] = y + rowHeight;
yInds[3] = yInds[2];
}
//super.paint(graphics);
}
}
//Private class to populate the ListField private variable
private class ListCallback implements ListFieldCallback{
private Vector listElements = new Vector();
public void drawListRow(ListField list, Graphics g,
int index, int y, int w) {
String text = (String)listElements.elementAt(index);
g.setColor(Color.LIGHTGREY);
g.drawText(text, 0, y, 0, w);
}
public Object get(ListField list, int index) {
return listElements.elementAt(index);
}
public int indexOfList(ListField list, String p, int s) {
//return listElements.getSelectedIndex();
return listElements.indexOf(p, s);
}
public void insert(String toInsert, int index) {
listElements.insertElementAt(toInsert, index);
}
public void add(String toInsert){
listElements.addElement(toInsert);
}
public void erase() {
listElements.removeAllElements();
}
public int getPreferredWidth(ListField listField) {
return 0;
}
}
}
然后我从SplashScreen＆amp;中调用LiveScreen（显示列表项）类。推动LiveScreen
但是当我运行应用程序时，以及控件进入LiveScreen时。我点击菜单，但菜单项没有显示。任何人都可以指导我在哪里犯错误。
答案 0 :(得分：2)
希望您会发现以下内容有帮助，如果您的问题没有得到解答，请随时回复并澄清您的问题。
当从BaseScreen启动菜单选项时，我会更新代码，使其包含对当前屏幕的引用，而不是使用getScreen（）。这是因为pushScreen方法立即返回，对我来说，看起来你已经要求代码将屏幕推到堆栈上然后立即将其弹出。
以下是BaseScreen的变化：
public void run() {
UiApplication.getUiApplication().pushScreen(new LiveScreen());
UiApplication.getUiApplication().popScreen(BaseScreen.this);
}
在实时屏幕上查看用户选择的内容，您可以使用主屏幕中的navigatorClick方法。编码的示例使用内联MainScreen（我通常会把它放在自己的类中）。
如果您创建myList和myListCallback类变量或重新排列它们在构造函数中创建的顺序，那么您可以扩充mainScreen实例化以包含一个新的navigationClick方法，该方法可以找出所点击的内容。
以下是LiveScreen中的内容：
final ListField myList;
final ListCallback myCallback;
...
// MainScreen mainScreen;
mainScreen = new MainScreen(){
protected boolean navigationClick(int status, int time) {
int selected = myList.getSelectedIndex();
if (selected != -1) {
final Object o = myCallback.get(myList, selected);
UiApplication.getUiApplication().invokeLater(new Runnable() {
public void run() {
Status.show("Clicked on "+o);
}
});
}
return true;
}
};
答案 1 :(得分：0)
您确定要与LiveScreen交互吗？看起来像LiveScreen调用
UiApplication.getUiApplication().pushScreen(mainScreen);
所以我的猜测（猜测因为很难读取如此格式化的代码）你在顶部有一个主屏幕，这就是为什么它不能保存你的“实时”菜单项。