LWUIT 一些细节疑难杂症整理笔记

1、textArea 显示文本内容,在部分手机上无法显示全部内容,每一行的最后几个字被挡住
琢磨了很久终于找了出来，解决方案如下：
TextArea txtContent = new TextArea(strContent, 12, 24);
//添加这一句即可
txtContent.setWidestChar('一');
2、若要对文本框中的内容设置补丁：
txtContent.getStyle().setPadding(Component.RIGHT, 10);
内容往右10像素。
3、如果list上不想要显示文字多余时的省略号
name.setEndsWith3Points(false);
4、重写Dialog要让标题与Form的样式一致
dialog.show(100, 100，100，100, true);
5、声音播放
try {
InputStream is = getClass().getResourceAsStream(
"/res/NewMailSound.wav");
Player player = Manager.createPlayer(is, "audio/x-wav");
player.start();
} catch (Exception e) {
e.printStackTrace();
}
6、使得TextField也能够在触屏手机上点击时出现输入编辑
解决方法：
在TextField源码上 加上editString();函数：
public void pointerReleased(int x, int y) {
// unlike text area the text field supports shifting the cursor with the touch screen
editString();
String text = getText();
int textLength = text.length();
int position = 0;
Font f = getStyle().getFont();
x -= getAbsoluteX();
for(int iter = 0 ; iter < textLength ; iter++) {
int width = f.substringWidth(text, 0, iter);
if(x > width) {
position = iter;
} else {
break;
}
}
if(position == textLength - 1) {
if(f.stringWidth(text) < x) {
position = textLength;
}
}
setCursorPosition(position);
repaint();
}
或者官方的解决方法：http://forums.java.net/jive/thread.jspa?threadID=52716
7、震动
public void MakeVibrate() {
new Thread() {
public void run() {
try {
Display.getInstance().vibrate(2000);
} catch (Exception e) {
e.printStackTrace();
}
}
}.start();
}
8、导致内存激增的原因（可以用自动模拟器的内存检测器进行监测C:\WTK2.5.2\bin\prefs.exe将你要的设置勾选）
而lwuit里面的源码有两句是会导致内存一直占用，一个是TextField中的这段代码

view plaincopy to clipboardprint?
// public boolean animate() {
// boolean ani = super.animate();
// if (hasFocus()) {
// long currentTime = System.currentTimeMillis();
// if (drawCursor) {
// if ((currentTime - cursorBlinkTime) > blinkOnTime) {
// cursorBlinkTime = currentTime;
// drawCursor = false;
// return true;
// }
// } else {
// if ((currentTime - cursorBlinkTime) > blinkOffTime) {
// cursorBlinkTime = currentTime;
// drawCursor = true;
// return true;
// }
// }
// if (pressedAndNotReleased) {
// if (currentTime - pressTime >= getLongClickDuration()) {
// longClick(pressedKeyCode);
// }
// } else {
// if (pendingCommit && currentTime - releaseTime > commitTimeout) {
// commitChange();
// }
// }
// } else {
// drawCursor = false;
// }
// return ani;
// }
// public boolean animate() {
// boolean ani = super.animate();
// if (hasFocus()) {
// long currentTime = System.currentTimeMillis();
// if (drawCursor) {
// if ((currentTime - cursorBlinkTime) > blinkOnTime) {
// cursorBlinkTime = currentTime;
// drawCursor = false;
// return true;
// }
// } else {
// if ((currentTime - cursorBlinkTime) > blinkOffTime) {
// cursorBlinkTime = currentTime;
// drawCursor = true;
// return true;
// }
// }
// if (pressedAndNotReleased) {
// if (currentTime - pressTime >= getLongClickDuration()) {
// longClick(pressedKeyCode);
// }
// } else {
// if (pendingCommit && currentTime - releaseTime > commitTimeout) {
// commitChange();
// }
// }
// } else {
// drawCursor = false;
// }
// return ani;
// }

一个是Display

lwuitGraphics.setGraphics(impl.getNativeGraphics());
这两个暂时还没有仔细去研究，但是确实吃内存的所在。
还有就是要巧用System.gc();进行内存回收，这样就会尽量的减少内存溢出的情况。
9、滚动条拖拽方向与内容显示相反，component中的代码修改如下

view plaincopy to clipboardprint?
public void pointerDragged(int x, int y) {
if (isScrollable() && isSmoothScrolling()) {
int axisValue;
if (isScrollableY()) {
axisValue = y;
} else {
axisValue = x;
}
if (!dragActivated) {
dragActivated = true;
beforeLastScrollY = axisValue;
lastScrollY = axisValue;
getComponentForm().setDraggedComponent(this);
}
//save time and locations to create velocity when the
//pointer is released
long currentTime = System.currentTimeMillis();
if (currentTime != lastTime[(pLastDragged + lastTime.length + 1) % lastTime.length]) {
lastTime[pLastDragged] = System.currentTimeMillis();
lastDragged[pLastDragged] = axisValue;
pLastDragged = (++pLastDragged) % lastTime.length;
}
beforeLastScrollY = lastScrollY;
lastScrollY = axisValue;
// we drag inversly to get a feel of grabbing a physical screen
// and pulling it in the reverse direction of the drag
if (isScrollableY()) {
int scroll = getScrollY() - (beforeLastScrollY - axisValue);
if (scroll >= 0 && scroll < getPreferredH() - getHeight()) {
setScrollY(scroll);
}
} else {
int scroll = getScrollX() - (beforeLastScrollY - axisValue);
if (scroll >= 0 && scroll < getPreferredW() - getWidth()) {
setScrollX(scroll);
}
}
} else {
//try to find a scrollable element until you reach the Form
Component parent = getParent();
if (!(parent instanceof Form)) {
parent.pointerDragged(x, y);
}
}
}
public void pointerDragged(int x, int y) {
if (isScrollable() && isSmoothScrolling()) {
int axisValue;
if (isScrollableY()) {
axisValue = y;
} else {
axisValue = x;
}
if (!dragActivated) {
dragActivated = true;
beforeLastScrollY = axisValue;
lastScrollY = axisValue;
getComponentForm().setDraggedComponent(this);
}
//save time and locations to create velocity when the
//pointer is released
long currentTime = System.currentTimeMillis();
if (currentTime != lastTime[(pLastDragged + lastTime.length + 1) % lastTime.length]) {
lastTime[pLastDragged] = System.currentTimeMillis();
lastDragged[pLastDragged] = axisValue;
pLastDragged = (++pLastDragged) % lastTime.length;
}
beforeLastScrollY = lastScrollY;
lastScrollY = axisValue;
// we drag inversly to get a feel of grabbing a physical screen
// and pulling it in the reverse direction of the drag
if (isScrollableY()) {
int scroll = getScrollY() - (beforeLastScrollY - axisValue);
if (scroll >= 0 && scroll < getPreferredH() - getHeight()) {
setScrollY(scroll);
}
} else {
int scroll = getScrollX() - (beforeLastScrollY - axisValue);
if (scroll >= 0 && scroll < getPreferredW() - getWidth()) {
setScrollX(scroll);
}
}
} else {
//try to find a scrollable element until you reach the Form
Component parent = getParent();
if (!(parent instanceof Form)) {
parent.pointerDragged(x, y);
}
}
}

10、开启wtk模拟器的触摸屏功能
打开\wtklib\devices\DefaultColorPhone目录下的DefaultColorPhone.properties文件（最好先安装一个UltraEdit之类的文本编辑器）。
然后找到touch_screen选项，修改为touch_screen=true

11、设置模拟器权限，以免开发过程中弹出烦人的提示
打开wtk模拟器。
选择Edit->Preferences->Security
然后将Security domain的选项设置为maximum。

12、内存和性能监视器
Edit->Preferences->Memory Monitor
Edit->Preferences->Profiler

13、出现安装后无法打开问题
有些Nokia手机会出现安装后无法打开，原因是安装包名称包含中文导致。

本文来自CSDN博客，转载请标明出处：http://blog.csdn.net/lwuit/archive/2009/12/03/4930931.aspx