Launcher2分析-加载和绑定AllApp列表

launcher2分析-加载和绑定allapp列表。android应用列表的视图就在launcher.xml中，也就是说应用列表视图一开始就已经加载好了，只是没有显示出来，属性为invisible，它是和workspace在同一个viewgroup中。id为apps_customize_pane,实际类型为com.android.launcher2.appscustomizetabhost，继承自tabhost，而layout apps_customize_pane.xml中包含了一个id为apps_customize_pane_content，类型为appscustomizepagedview的child，改类型间接继承了pagedview，是应用列表的核心view。

从launchermodel$loadertask#loadandbindapps（）开始分析：

private void loadandbindallapps() {
            if (debug_loaders) {
                log.d(tag, "loadandbindallapps mallappsloaded=" + mallappsloaded);
            }
            if (!mallappsloaded) {//判断是否所有app都加载过了
                loadallappsbybatch();//加载所有app信息并且分批绑定
                synchronized (loadertask.this) {
                    if (mstopped) {
                        return;
                    }
                    mallappsloaded = true;
                }
            } else {
                onlybindallapps();//跳过加载过程，直接绑定
            }
        }

分析loadallappsbybatch():

private void loadallappsbybatch() {
            final long t = debug_loaders  systemclock.uptimemillis() : 0;

            // don't use these two variables in any of the callback runnables.
            // otherwise we hold a reference to them.
            final callbacks oldcallbacks = mcallbacks.get();
            if (oldcallbacks == null) {
                // this launcher has exited and nobody bothered to tell us.  just bail.
                log.w(tag, "loadertask running with no launcher (loadallappsbybatch)");
                return;
            }

            final intent mainintent = new intent(intent.action_main, null);//需要action为main的
            mainintent.addcategory(intent.category_launcher);//还需要category为launcher的
//跟linux多用户有关，有多少个用户，就有多少个userhandle，但是手机一般来说就一个吧
            final list profiles = musermanager.getuserprofiles();

            mbgallappslist.clear();
            final int profilecount = profiles.size();
            for (int p = 0; p < profilecount; p++) {
                userhandle user = profiles.get(p);
                list apps = null;
                int n = integer.max_value;//这个只是初始化指，后面会改变

                int startindex;
                int i = 0;
                int batchsize = -1;
                while (i < n && !mstopped) {//n为apps的size
                    if (i == 0) {
                        final long qiatime = debug_loaders  systemclock.uptimemillis() : 0;
                        apps = mlauncherapps.getactivitylist(null, user);//获取对应用户的所有app
                        if (debug_loaders) {
                            log.d(tag, "queryintentactivities took "
                                    + (systemclock.uptimemillis()-qiatime) + "ms");
                        }
                        if (apps == null) {
                            return;
                        }
                        n = apps.size();//在这里重新赋值给n，而不会是integer的max value
                        if (debug_loaders) {
                            log.d(tag, "queryintentactivities got " + n + " apps");
                        }
                        if (n == 0) {
                            // there are no apps!
                            return;
                        }
                        if (mbatchsize == 0) {
                            batchsize = n;
                        } else {
                            batchsize = mbatchsize;//设置怎么分批，一批有多少个应用。应该是太多一批可能会导致anr，导致其他事件无法被及时响应
                        }

                        final long sorttime = debug_loaders  systemclock.uptimemillis() : 0;
                        collections.sort(apps,
                                new launchermodel.shortcutnamecomparator(mlabelcache));//将apps重排序
                        if (debug_loaders) {
                            log.d(tag, "sort took "
                                    + (systemclock.uptimemillis()-sorttime) + "ms");
                        }
                    }

                    final long t2 = debug_loaders  systemclock.uptimemillis() : 0;

                    startindex = i;
                    for (int j=0; i added = mbgallappslist.added;//将added引用个对象发出去
                    final boolean firstprofile = p == 0;
                    mbgallappslist.added = new arraylist();//将added成员指向新的对象，因为这次是新增，那么下次就不是了
                    mhandler.post(new runnable() {
                        public void run() {
                            final long t = systemclock.uptimemillis();
                            if (callbacks != null) {
                                if (firstprofile) {//firstprofile应该代表的是root用户，需要加加载所有app
                                    callbacks.bindallapplications(added);//后面会重点分析这个方法
                                } else {
                                    callbacks.bindappsadded(added);//如果是其他用户，则只加载新增内容
                                }
                                if (debug_loaders) {
                                    log.d(tag, "bound " + added.size() + " apps in "
                                        + (systemclock.uptimemillis() - t) + "ms");
                                }
                            } else {
                                log.i(tag, "not binding apps: no launcher activity");
                            }
                        }
                    });

                    if (debug_loaders) {
                        log.d(tag, "batch of " + (i-startindex) + " icons processed in "
                                + (systemclock.uptimemillis()-t2) + "ms");
                    }

                    if (mallappsloaddelay > 0 && i < n) {
                        try {
                            if (debug_loaders) {
                                log.d(tag, "sleeping for " + mallappsloaddelay + "ms");
                            }
                            thread.sleep(mallappsloaddelay);//每批app的绑定任务交到主线程的队列中后，要休眠一段时间再向队列放入下一批任务
                        } catch (interruptedexception exc) { }
                    }
                }

                if (debug_loaders) {
                    log.d(tag, "cached all " + n + " apps in "
                            + (systemclock.uptimemillis()-t) + "ms"
                            + (mallappsloaddelay > 0  " (including delay)" : ""));
                }
            }
        }

分析一下mbgallappslist.add(new applicationinfo(apps.get(i), user, miconcache, mlabelcache));其中mbgallappslist是allappslist类型，其中add方法的如下：

public void add(applicationinfo info) {
        if (findactivity(data, info.componentname, info.user)) {//当对应用户已经存在这个component时，就不会添加到data和added中
            return;
        }
        data.add(info);//添加到data，存放所有app
        added.add(info);//添加到added，存放相对于上次加载来说为新增的app
    }

launcher实现了launchermodel的callback，下面分析launcher#bindallapplications（）

public void bindallapplications(final arraylist apps) {
        runnable setallappsrunnable = new runnable() {
            public void run() {
                if (mappscustomizecontent != null) {

//这个mappscustomizecontent就是一开始说的appscustomizepagedview类型对象，调用setapps方法后，就会去重绘这个view了。

 mappscustomizecontent.setapps(apps); } } }; 
// remove the progress bar entirely; we could also make it gone 
// but better to remove it since we know it's not going to be used 
view progressbar = mappscustomizetabhost. findviewbyid(r.id.apps_customize_progress_bar); 
if (progressbar != null) { 
((viewgroup)progressbar.getparent()).removeview(progressbar); 
// we just post the call to setapps so the user sees the progress bar 
// disappear-- otherwise, it just looks like the progress bar froze 
// which doesn't look great 
mappscustomizetabhost.post(setallappsrunnable);//会在progressbar消失后再post到消息队列中 
} else { 
// if we did not initialize the spinner in oncreate, then we can directly set the 
// list of applications without waiting for any progress bars views to be hidden. 
setallappsrunnable.run(); }
}