textviewerform.java

textviewer 一个手机上的文本浏览器实现

package textViewer;

import java.lang.*;
import javax.microedition.lcdui.*;
import javax.microedition.midlet.*;
import java.io.InputStream;
import java.util.Vector;


public class TextViewerForm extends Form implements CommandListener, PageChangable {

    private MIDlet myMidlet;

    private Command moreCmd, gotoCmd, findCmd;
    Command[] jumpCommands;

    String[] jumpCommandStrings = {"Prev", "Jump +10", "Jump -10", "Jump +50", "Jump -50", "Jump +100", "Jump -100", "Jump +500", "Jump -500", "Jump +1000", "Jump -1000"};

    int[] jumpCommandValues = {-1,10,-10,50,-50,100,-100,500,-500,1000,-1000};


    private String text;

    
    private StringItem textItem;
    private StringItem pageString;
 
    private GotoDialog gotoDialog;

    private FindDialog findDialog;

    private Paginator paginator;
    private Vector pages;


    private PageCounter pageCounter;

    public TextViewerForm (String name, String text, MIDlet myMidlet) {
	super(name);

	this.myMidlet = myMidlet;
	this.pageCounter = new PageCounter(this);
	this.paginator = new Paginator();

	initFormElems();

	setInitText(text);
    }



    public void setInitText (String text) {
	setText(text);
    }

    private void initFormElems() {

	textItem = new StringItem("","");


	/* PORTABILITY: "More" should not be of category BACK, but that's the only way I could get my Nokia Series 40 phone (6800) to display it outside of the menu -- priority alone didn't work, neither did ITEM or OK. It would have an "Options" menu and just leave the other soft menu slot blank. 


didn't try switching the ORDER yet, though! TODO

*/

	moreCmd = new Command("More", Command.BACK,1);
	this.addCommand(moreCmd);

	gotoCmd = new Command("Goto", Command.SCREEN,3);
	this.addCommand(gotoCmd);

	initJumpCommands();

	findCmd = new Command("Find", Command.SCREEN,3);
	this.addCommand(findCmd);

	this.setCommandListener(this);
	//	this.setItemStateListener(this);


	this.append(textItem);


	pageString = new StringItem(" -- \n","1");
				  //TODO: constant
	this.append(pageString);

	gotoDialog = new GotoDialog(this, (Display.getDisplay(myMidlet)), pageCounter); 
	// note that pageCounter must be initialized before this

	findDialog = new FindDialog(this, (Display.getDisplay(myMidlet)), text, paginator, pageCounter); 

    }
    
    private void initJumpCommands() {
	
	jumpCommands = new Command[jumpCommandStrings.length];

	for(int i=0; i<jumpCommands.length; i++) {
	    jumpCommands[i] = new Command(jumpCommandStrings[i], Command.SCREEN,3);
	    this.addCommand(jumpCommands[i]);
	}
    }

    public void setText(String text)
    {
	this.text = text;
	findDialog.setText(text);
	pages = paginator.paginate(text);
	//	pageField.setLabel("Goto page # (max " + Integer.toString(pages.size()) + "):");
	pageCounter.setMax(pages.size());

	pageChanged();	
    }

    public void commandAction(Command cmd, Displayable target)
    {
	if (target instanceof Form) {
	    Form targetForm = (Form) target;
	    if (targetForm == this) {
		if (cmd == moreCmd) {
		    pageCounter.addAsFarAsYouCan(1);
		}
		else if (handleJumpCommands(cmd)) {}

		else if (cmd == gotoCmd) {
		    gotoDialog.setMaxPage(pageCounter.getMax());
		    (Display.getDisplay(myMidlet)).setCurrent(gotoDialog);
		}

		else if (cmd == findCmd) {

		    (Display.getDisplay(myMidlet)).setCurrent(findDialog);

		} 

	    }

	} 
    }
    // TODO: cleanup previous

    private boolean handleJumpCommands (Command cmd)
    {

	boolean ret = false;

	for(int i=0; i<jumpCommands.length; i++)
	    {
		if (cmd == jumpCommands[i]) {
		    pageCounter.addAsFarAsYouCan( jumpCommandValues[i] );
		    ret = true;
		    break;
		}
	    }
	
	return ret;
    }


    private void gotoPage(int newPage)
    {
	pageCounter.setValue(newPage);
    }



    //    protected void pageChanged() {
    public void pageChanged() {
	textItem.setText((pages.elementAt(pageCounter.getValue()-1)).toString());
	updatePageString();

	System.gc();
    }

    protected void updatePageString() {
		pageString.setText(Integer.toString(pageCounter.getValue()));
   }


   public int getTextChunkLength() {return paginator.getTextChunkLength();}

}