Android 10.0 Settings源码分析之主界面加载（三） |
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前两篇分别记录了Settings主界面 静态xml加载设置项Android 10.0 Settings源码分析之主界面加载（一） 动态从AndroidManifest.xml中加载设置项Android 10.0 Settings源码分析之主界面加载（二） 本篇主要记录设置项加载完成后，界面显示更新流程。 先来继续接着前两篇分析，来看refreshAllPreferences()方法后面逻辑: packages/apps/Settings/src/com/android/settings/dashboard/DashboardFragment.java refreshAllPreferences(): final Activity activity = getActivity(); if (activity != null) { Log.d(TAG, "All preferences added, reporting fully drawn"); activity.reportFullyDrawn(); } updatePreferenceVisibility(mPreferenceControllers);当所有的preference加载完成后，通知activity进行重绘显示；调用updatePreferenceVisibility()方法： @VisibleForTesting void updatePreferenceVisibility( Map preferenceControllers) { final PreferenceScreen screen = getPreferenceScreen(); if (screen == null || preferenceControllers == null || mBlockerController == null) { return; } final boolean visible = mBlockerController.isBlockerFinished(); for (List controllerList : preferenceControllers.values()) { for (AbstractPreferenceController controller : controllerList) { final String key = controller.getPreferenceKey(); final Preference preference = findPreference(key); if (preference != null) { preference.setVisible(visible && controller.isAvailable()); } } } }可以看到需要满足screen、preferenceControllers、mBlockerController都不为null，才能执行后续操作。后续主要是遍历该界面所有preference设置项的controller集合mPreferenceControllers，设置是否可显示在界面上； mBlockerController的初始化： DashboardFragment.java#onAttach()方法： checkUiBlocker(controllers); @VisibleForTesting void checkUiBlocker(List controllers) { final List keys = new ArrayList(); controllers .stream() .filter(controller -> controller instanceof BasePreferenceController.UiBlocker) .forEach(controller -> { ((BasePreferenceController) controller).setUiBlockListener(this); Log.d("zcl"," checkUiBlocker addkey = " + controller.getPreferenceKey()); keys.add(controller.getPreferenceKey()); }); Log.d("zcl"," checkUiBlocker size = " + keys.size()); if (!keys.isEmpty()) { mBlockerController = new UiBlockerController(keys); mBlockerController.start(()->updatePreferenceVisibility(mPreferenceControllers)); } }过滤该界面所有preference设置项的controller集合mPreferenceControllers内是否存在实现了BasePreferenceController.UiBlocker接口的controller元素，添加到keys集合内。目前Settings主界面未有实现，故此集合为null，即mBlockerController也为null。 即updatePreferenceVisibility()方法在主界面加载时暂不执行。 至此refreshAllPreferences()方法分析完成。 onStart()再来看设置主界面TopLevelSettings.java的其他生命周期方法，由于其未实现onStart() 、onResume()生命周期方法，直接看父类DashboardFragment.java的onStart()方法： public void onStart() { super.onStart(); final DashboardCategory category = mDashboardFeatureProvider.getTilesForCategory(getCategoryKey()); if (category == null) { return; } if (mSummaryLoader != null) { // SummaryLoader can be null when there is no dynamic tiles. mSummaryLoader.setListening(true); } final Activity activity = getActivity(); if (activity instanceof SettingsBaseActivity) { mListeningToCategoryChange = true; ((SettingsBaseActivity) activity).addCategoryListener(this); } }获取当前界面是否存在可以动态显示的DashboardCategory对象；调用setListening方法进行“监听”，判断当前fragment所在的activity是否继承至SettingsBaseActivity，决定是否设置CategoryListener监听。 onResume()fragment的生命周期onResume()方法： @Override public void onResume() { super.onResume(); updatePreferenceStates(); }调用updatePreferenceStates()方法，每个controller根据自身需要去管理更新对应preference项： /** * Update state of each preference managed by PreferenceController. */ protected void updatePreferenceStates() { final PreferenceScreen screen = getPreferenceScreen(); Collection controllerLists = mPreferenceControllers.values(); for (List controllerList : controllerLists) { for (AbstractPreferenceController controller : controllerList) { if (!controller.isAvailable()) { continue; } final String key = controller.getPreferenceKey(); if (TextUtils.isEmpty(key)) { Log.d(TAG, String.format("Preference key is %s in Controller %s", key, controller.getClass().getSimpleName())); continue; } final Preference preference = screen.findPreference(key); if (preference == null) { Log.d(TAG, String.format("Cannot find preference with key %s in Controller %s", key, controller.getClass().getSimpleName())); continue; } controller.updateState(preference); } } }遍历mPreferenceControllers集合判断集合内每个controller元素，对应的preference是否可用可显示；对应的preference是否定义了key属性。再根据获取到的key，获取界面上对应的preference，再调用updateState()方法去更新preference状态。 updateState()如果相关controller内部自己实现了updateState()方法，则调用其自身方法的updateState()方法； 如果未定义则调用其父类updateState()方法： frameworks/base/packages/SettingsLib/src/com/android/settingslib/core/AbstractPreferenceController.java /** * Updates the current status of preference (summary, switch state, etc) */ public void updateState(Preference preference) { refreshSummary(preference); }调用refreshSummary()方法，同样的如果相关controller内部自己实现了refreshSummary()方法，则调用自身实现的refreshSummary()方法； 如果未定义则调用AbstractPreferenceController.java内部的refreshSummary()方法： /** * Refresh preference summary with getSummary() */ protected void refreshSummary(Preference preference) { if (preference == null) { return; } final CharSequence summary = getSummary(); if (summary == null) { // Default getSummary returns null. If subclass didn't override this, there is nothing // we need to do. return; } preference.setSummary(summary); }调用getSummary()方法，规则同上，获取需要显示的summary字串并设置给preference。 至此主界面设置项加载流程记录完毕。 |
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