Android列表实现(3)_自定义列表适配器思路及实现代码

下面的例子为使用自定义的列表适配器来显示列表。

view code
import android.os.bundle;
import android.app.listactivity;
import android.content.context;
import android.view.view;
import android.view.viewgroup;
import android.widget.baseadapter;
import android.widget.linearlayout;
import android.widget.textview;
public class mainactivity extends listactivity {
@override
protected void oncreate(bundle savedinstancestate) {
super.oncreate(savedinstancestate);
setlistadapter(new speechlistadapter(this));
}
/**
* a sample listadapter that presents content from arrays of speeches and
* text.
*
*/
private class speechlistadapter extends baseadapter {
public speechlistadapter(context context) {
mcontext = context;
}
/**
* the number of items in the list is determined by the number of speeches
* in our array.
*
* @see android.widget.listadapter#getcount()
*/
public int getcount() {
return mtitles.length;
}
/**
* since the data comes from an array, just returning the index is
* sufficent to get at the data. if we were using a more complex data
* structure, we would return whatever object represents one row in the
* list.
*
* @see android.widget.listadapter#getitem(int)
*/
public object getitem(int position) {
return position;
}
/**
* use the array index as a unique id.
*
* @see android.widget.listadapter#getitemid(int)
*/
public long getitemid(int position) {
return position;
}
/**
* make a speechview to hold each row.
*
* @see android.widget.listadapter#getview(int, android.view.view,
* android.view.viewgroup)
*/
public view getview(int position, view convertview, viewgroup parent) {
speechview sv;
if (convertview == null) {
sv = new speechview(mcontext, mtitles[position],
mdialogue[position]);
} else {
sv = (speechview) convertview;
sv.settitle(mtitles[position]);
sv.setdialogue(mdialogue[position]);
}
return sv;
}
/**
* remember our context so we can use it when constructing views.
*/
private context mcontext;
/**
* our data, part 1.
*/
private string[] mtitles =
{
"henry iv (1)",
"henry v",
"henry viii",
"richard ii",
"richard iii",
"merchant of venice",
"othello",
"king lear"
};
/**
* our data, part 2.
*/
private string[] mdialogue =
{
"so shaken as we are, so wan with care," +
"find we a time for frighted peace to pant," +
"and breathe short-winded accents of new broils" +
"to be commenced in strands afar remote." +
"no more the thirsty entrance of this soil" +
"shall daub her lips with her own children's blood;" +
"nor more shall trenching war channel her fields," +
"nor bruise her flowerets with the armed hoofs" +
"of hostile paces: those opposed eyes," +
"which, like the meteors of a troubled heaven," +
"all of one nature, of one substance bred," +
"did lately meet in the intestine shock" +
"and furious close of civil butchery" +
"shall now, in mutual well-beseeming ranks," +
"march all one way and be no more opposed" +
"against acquaintance, kindred and allies:" +
"the edge of war, like an ill-sheathed knife," +
"no more shall cut his master. therefore, friends," +
"as far as to the sepulchre of christ," +
"whose soldier now, under whose blessed cross" +
"we are impressed and engaged to fight," +
"forthwith a power of english shall we levy;" +
"whose arms were moulded in their mothers' womb" +
"to chase these pagans in those holy fields" +
"over whose acres walk'd those blessed feet" +
"which fourteen hundred years ago were nail'd" +
"for our advantage on the bitter cross." +
"but this our purpose now is twelve month old," +
"and bootless 'tis to tell you we will go:" +
"therefore we meet not now. then let me hear" +
"of you, my gentle cousin westmoreland," +
"what yesternight our council did decree" +
"in forwarding this dear expedience.",
"hear him but reason in divinity," +
"and all-admiring with an inward wish" +
"you would desire the king were made a prelate:" +
"hear him debate of commonwealth affairs," +
"you would say it hath been all in all his study:" +
"list his discourse of war, and you shall hear" +
"a fearful battle render'd you in music:" +
"turn him to any cause of policy," +
"the gordian knot of it he will unloose," +
"familiar as his garter: that, when he speaks," +
"the air, a charter'd libertine, is still," +
"and the mute wonder lurketh in men's ears," +
"to steal his sweet and honey'd sentences;" +
"so that the art and practic part of life" +
"must be the mistress to this theoric:" +
"which is a wonder how his grace should glean it," +
"since his addiction was to courses vain," +
"his companies unletter'd, rude and shallow," +
"his hours fill'd up with riots, banquets, sports," +
"and never noted in him any study," +
"any retirement, any sequestration" +
"from open haunts and popularity.",
"i come no more to make you laugh: things now," +
"that bear a weighty and a serious brow," +
"sad, high, and working, full of state and woe," +
"such noble scenes as draw the eye to flow," +
"we now present. those that can pity, here" +
"may, if they think it well, let fall a tear;" +
"the subject will deserve it. such as give" +
"their money out of hope they may believe," +
"may here find truth too. those that come to see" +
"only a show or two, and so agree" +
"the play may pass, if they be still and willing," +
"i'll undertake may see away their shilling" +
"richly in two short hours. only they" +
"that come to hear a merry bawdy play," +
"a noise of targets, or to see a fellow" +
"in a long motley coat guarded with yellow," +
"will be deceived; for, gentle hearers, know," +
"to rank our chosen truth with such a show" +
"as fool and fight is, beside forfeiting" +
"our own brains, and the opinion that we bring," +
"to make that only true we now intend," +
"will leave us never an understanding friend." +
"therefore, for goodness' sake, and as you are known" +
"the first and happiest hearers of the town," +
"be sad, as we would make ye: think ye see" +
"the very persons of our noble story" +
"as they were living; think you see them great," +
"and follow'd with the general throng and sweat" +
"of thousand friends; then in a moment, see" +
"how soon this mightiness meets misery:" +
"and, if you can be merry then, i'll say" +
"a man may weep upon his wedding-day.",
"first, heaven be the record to my speech!" +
"in the devotion of a subject's love," +
"tendering the precious safety of my prince," +
"and free from other misbegotten hate," +
"come i appellant to this princely presence." +
"now, thomas mowbray, do i turn to thee," +
"and mark my greeting well; for what i speak" +
"my body shall make good upon this earth," +
"or my divine soul answer it in heaven." +
"thou art a traitor and a miscreant," +
"too good to be so and too bad to live," +
"since the more fair and crystal is the sky," +
"the uglier seem the clouds that in it fly." +
"once more, the more to aggravate the note," +
"with a foul traitor's name stuff i thy throat;" +
"and wish, so please my sovereign, ere i move," +
"what my tongue speaks my right drawn sword may prove.",
"now is the winter of our discontent" +
"made glorious summer by this sun of york;" +
"and all the clouds that lour'd upon our house" +
"in the deep bosom of the ocean buried." +
"now are our brows bound with victorious wreaths;" +
"our bruised arms hung up for monuments;" +
"our stern alarums changed to merry meetings," +
"our dreadful marches to delightful measures." +
"grim-visaged war hath smooth'd his wrinkled front;" +
"and now, instead of mounting barded steeds" +
"to fright the souls of fearful adversaries," +
"he capers nimbly in a lady's chamber" +
"to the lascivious pleasing of a lute." +
"but i, that am not shaped for sportive tricks," +
"nor made to court an amorous looking-glass;" +
"i, that am rudely stamp'd, and want love's majesty" +
"to strut before a wanton ambling nymph;" +
"i, that am curtail'd of this fair proportion," +
"cheated of feature by dissembling nature," +
"deformed, unfinish'd, sent before my time" +
"into this breathing world, scarce half made up," +
"and that so lamely and unfashionable" +
"that dogs bark at me as i halt by them;" +
"why, i, in this weak piping time of peace," +
"have no delight to pass away the time," +
"unless to spy my shadow in the sun" +
"and descant on mine own deformity:" +
"and therefore, since i cannot prove a lover," +
"to entertain these fair well-spoken days," +
"i am determined to prove a villain" +
"and hate the idle pleasures of these days." +
"plots have i laid, inductions dangerous," +
"by drunken prophecies, libels and dreams," +
"to set my brother clarence and the king" +
"in deadly hate the one against the other:" +
"and if king edward be as true and just" +
"as i am subtle, false and treacherous," +
"this day should clarence closely be mew'd up," +
"about a prophecy, which says that 'g'" +
"of edward's heirs the murderer shall be." +
"dive, thoughts, down to my soul: here" +
"clarence comes.",
"to bait fish withal: if it will feed nothing else," +
"it will feed my revenge. he hath disgraced me, and" +
"hindered me half a million; laughed at my losses," +
"mocked at my gains, scorned my nation, thwarted my" +
"bargains, cooled my friends, heated mine" +
"enemies; and what's his reason? i am a jew. hath" +
"not a jew eyes? hath not a jew hands, organs," +
"dimensions, senses, affections, passions? fed with" +
"the same food, hurt with the same weapons, subject" +
"to the same diseases, healed by the same means," +
"warmed and cooled by the same winter and summer, as" +
"a christian is? if you prick us, do we not bleed?" +
"if you tickle us, do we not laugh? if you poison" +
"us, do we not die? and if you wrong us, shall we not" +
"revenge? if we are like you in the rest, we will" +
"resemble you in that. if a jew wrong a christian," +
"what is his humility? revenge. if a christian" +
"wrong a jew, what should his sufferance be by" +
"christian example? why, revenge. the villany you" +
"teach me, i will execute, and it shall go hard but i" +
"will better the instruction.",
"virtue! a fig! 'tis in ourselves that we are thus" +
"or thus. our bodies are our gardens, to the which" +
"our wills are gardeners: so that if we will plant" +
"nettles, or sow lettuce, set hyssop and weed up" +
"thyme, supply it with one gender of herbs, or" +
"distract it with many, either to have it sterile" +
"with idleness, or manured with industry, why, the" +
"power and corrigible authority of this lies in our" +
"wills. if the balance of our lives had not one" +
"scale of reason to poise another of sensuality, the" +
"blood and baseness of our natures would conduct us" +
"to most preposterous conclusions: but we have" +
"reason to cool our raging motions, our carnal" +
"stings, our unbitted lusts, whereof i take this that" +
"you call love to be a sect or scion.",
"blow, winds, and crack your cheeks! rage! blow!" +
"you cataracts and hurricanoes, spout" +
"till you have drench'd our steeples, drown'd the cocks!" +
"you sulphurous and thought-executing fires," +
"vaunt-couriers to oak-cleaving thunderbolts," +
"singe my white head! and thou, all-shaking thunder," +
"smite flat the thick rotundity o' the world!" +
"crack nature's moulds, an germens spill at once," +
"that make ingrateful man!"
};
}
/**
* we will use a speechview to display each speech. it's just a linearlayout
* with two text fields.
*
*/
private class speechview extends linearlayout {
public speechview(context context, string title, string words) {
super(context);
this.setorientation(vertical);
// here we build the child views in code. they could also have
// been specified in an xml file.
mtitle = new textview(context);
mtitle.settext(title);
addview(mtitle, new linearlayout.layoutparams(
layoutparams.match_parent, layoutparams.wrap_content));
mdialogue = new textview(context);
mdialogue.settext(words);
addview(mdialogue, new linearlayout.layoutparams(
layoutparams.match_parent, layoutparams.wrap_content));
}
/**
* convenience method to set the title of a speechview
*/
public void settitle(string title) {
mtitle.settext(title);
}
/**
* convenience method to set the dialogue of a speechview
*/
public void setdialogue(string words) {
mdialogue.settext(words);
}
private textview mtitle;
private textview mdialogue;
}
}

该例子中自定义了适配器 speechlistadapter (其继承父类baseadapter)以及作为记录模板的 speechview（其父类为linearlayout）。
speechlistadapter中的方法getview实现了返回指定位置的记录显示对象的逻辑。