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j2ee综合--总结在java编程中的经验教训 (1)

【赛迪网-it技术报道】我实际工作中的经验教训,在这里与大家共享,空的字符串是””,不带空格outputstream在打印时,打印的内容后面不要加\n,否则对方接受和判断不正确!

  g:\projection\ic2n\1c2njava>javac jsubnetframe.java

  jsubnetframe.java:22: jsubnetframe should be declared abstract; it does not defi

  ne valuechanged(javax.swing.event.listselectionevent) in jsubnetframe

  public class jsubnetframe extends jframe implements listselectionlistener {

  ^

  jsubnetframe.java:68: cannot resolve symbol

  symbol : class tablemodel

  location: class jsubnetframe

  tablemodel datamodel = new abstracttablemodel() {

  ^

  jsubnetframe.java:68: cannot resolve symbol

  symbol : class abstracttablemodel

  location: class jsubnetframe

  tablemodel datamodel = new abstracttablemodel() {

  ^

  jsubnetframe.java:89: addactionlistener(java.awt.event.actionlistener) in javax.

  swing.abstractbutton cannot be applied to (jsubnetframe)

  cancelb.addactionlistener(this);

  ^

  note: jsubnetframe.java uses or overrides a deprecated api.

  note: recompile with -deprecation for details.

  4 errors

  原因是没有import javax.swing.table.*;

  g:\projection\ic2n\1c2njava>javac jhpportframe.java

  jhpportframe.java:27: jhpportframe should be declared abstract; it does not defi

  ne mousepressed(java.awt.event.mouseevent) in jhpportframe

  public class jhpportframe extends jframe implements

  ^

  note: jhpportframe.java uses or overrides a deprecated api.

  note: recompile with -deprecation for details.

  1 error

  jhpportframe should be declared abstract; it does not defi   原因是因为在这里必须用mouselistener 的相关方法进行覆盖,也就是说必须加入如下的方法:

  public void mousepressed(mouseevent evt) {//if (audio != null) audio.play();}

  public void mouseentered (mouseevent me) {}

  public void mouseexited (mouseevent me) {}

  public void mousereleased(mouseevent me) {}

  鼠标左键和右件的事件获取:

  public void mousepressed(mouseevent evt) {

  point point1=evt.getpoint();

  int x,y;

  int onmask = evt.button1_down_mask;//左键的id号

  if ((evt.getmodifiersex() & onmask ) == onmask)   // 点击左键时

  {

  }

  else                     //点击右键时

  抽象类,不能进行初始化或者生成实例

  hpportimg=new image(getdocumentbase(),”aaa.gif”);

  这句话是错的,因为image()是抽象类,不能进行初始化或者生成实例.,应该用:

  hpportimg=getimage(“adf.gif”);

  并且应该注意它不能放在构造函数中,而应该放在init()等方法中.

  各种动作和事件的处理:

  监视键盘的动作,用usertf.addkeylistener(this);它的接口软件包是keylistener,应该import java.awt.event.*;  必须重载的接口函数是

  public void keypressed(keyevent e){}

  public void keyreleased(keyevent e){}

  public void keytyped(keyevent e){}

  监视焦点的动作,用usertf.add focuslistener (this);它的接口软件包是focuslistener应该import java.awt.event.*;  必须重载的接口函数是

  public void focuslost(focusevent e) { }

  public void focusgained(focusevent e) {}

  监视鼠标的动作,用usertf.addmouselistener(this);它的接口软件包是mouseylistener,应该import java.awt.event.*;

  //必须增加mouselistener(this) 或component. mouselistener(this)

  必须重载的接口函数是

  public void mouseclicked(mouseevent e){ }

  public void mousepressed(mouseevent evt) {}

  public void mouseentered (mouseevent me) {}

  public void mouseexited (mouseevent me) {}

  public void mousereleased(mouseevent me) {}

监视鼠标移动的动作,用usertf.addmouselistener(this);它的接口软件包是mouseymotionlistener,应该import java.awt.event.*;  必须重载的接口函数是

  public void mousemoved(mouseevent e){}

  public void mousedragged(mouseevent e){ }

  以上各种事件必须在组件上增加相应的侦听,如

  user.addkeylistener(this);

  pass.addkeylistener(this);

  user.addfocuslistener(this);

  pass.addfocuslistener(this);

  按钮事件的执行在java2中应该用下列函数,无须重载:

  public void actionperformed(actionevent ae) {

  jbutton source=(jbutton)ae.getsource();

  if(source==okb)

  { slkdfjalskdjflaksdjlfjads;flkjasld;kjfl;kasjdfl;k}

  焦点事件:focuslost(),focusgain()

  transferfocus()是将焦点传递到下一个组件

  requestfocus()是将焦点传递到指定的组件,

  if(e.getcomponent()==user) user.transferfocus();

  else if(e.getcomponent()==pass) pass.transferfocus();

  else if(e.getcomponent()==ok) ok.transferfocus();

  经过观察发现,焦点可以在文本框上传递,但是在按钮上好象没法传递.

  在表格中

  subnettable.reshape(0,0,300,200); //一定要,用以刷新屏幕

  jtable中的每一行可否设置不同的背景颜色???

  可以的,使用自己的tablecellrenderer从tablemodel中的value获取颜色值.

  请参见:

  http://www2.gol.com/users/tame/swing/examples/

  有关玻璃层:

  1、 glasspane不能设置大小,它将布满整个工作区, //jtv.reshape(300,300,300,200); 没用

  2、 先建立一个jcomponent 的组件,jtv=new jtopview(jlp);其中jlp是新建母窗口的jlayeredpane

  3、 将这个组建用setglasspane(jtv)方法设置

  4、 如果要求它透明,这一句不能少jtv.setopaque(false);

  5、 这一句是显示的,也不能少jtv.setvisible(true);

  6、 玻璃层下面层的组建获取动作用redispatchmouseevent(mouseevent me)

  这段代码是我在英文网址上拿下来修改的,同时参照了<<精通java2>>p437页

  public void redispatchmouseevent(mouseevent me,boolean repaint)

  {

  //能够直接取到的组件,用广义的component 就可以了

  point point=me.getpoint();

  int eventid = me.getid();

  component component=jlp.getcomponentat(point);

  point componentpoint = swingutilities.convertpoint(

  jlp,

  point,

  component);

  boolean componentbool=component.contains(componentpoint );

  if(componentbool){

  //system.out.println("7777777777777777" component);

  component.dispatchevent(new mouseevent(component,eventid,me.getwhen(),me.getmodifiers(),

  componentpoint.x,componentpoint.y,me.getclickcount(),me.ispopuptrigger()));

  }

  ////不能够直接取到的组件,用具体的组件名字

  point alarmtablepoint = swingutilities.convertpoint(

  jlp,

  point,

  alarmtable);

  boolean alarmtablebool= alarmtable.contains(alarmtablepoint );

  if (alarmtablebool ) {

  alarmtable.dispatchevent(new mouseevent(alarmtable,eventid,me.getwhen(),

  me.getmodifiers(),

  alarmtablepoint.x,

  alarmtablepoint.y,

  me.getclickcount(),

  me.ispopuptrigger()));

  }

  }

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