android settings源代码分析（1）

1.Android settings源码的source code路径为：

kikat_4.4_CTS\packages\apps\Settings

2.settings主界面UI布局

Settings的启动类为：

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/**

* Top-level settings activity to handle single pane and double pane UI layout.

*/

public class Settings extends PreferenceActivity

implements ButtonBarHandler, OnAccountsUpdateListener

从继承关系可以看出，Settings类继承于PreferenceActivity，因此具有Preference的一些属性和结构。

从Google settings的UI看出，左边是一些tab，右边是tab对应的内容，那么这些tab以及tab对应的内容主要是什么，以及如何显示的呢？

对于tab的显示，对应的code为：

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/**

* Populate the activity with the top-level headers.

*/

@Override

public void onBuildHeaders(List<Header> headers) {

if (!onIsHidingHeaders()) {

loadHeadersFromResource(R.xml.settings_headers, headers);

updateHeaderList(headers);

}

}

可以看出，左边的tab实际是一些Header，从settings_headers.xml中获取这些header。settings_header.xml对应的code为：

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<?xml version="1.0" encoding="utf-8"?>

<!-- Copyright (C) 2010 The Android Open Source Project

Licensed under the Apache License, Version 2.0 (the "License");

you may not use this file except in compliance with the License.

You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software

distributed under the License is distributed on an "AS IS" BASIS,

WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

See the License for the specific language governing permissions and

limitations under the License.

-->

<preference-headers

xmlns:android="http://schemas.android.com/apk/res/android">

<!-- WIRELESS and NETWORKS -->

<header android:id="@+id/wireless_section"

android:title="@string/header_category_wireless_networks" />

<!-- Wifi -->

<!-- MStar Android Patch Begin -->

<header

android:id="@+id/wifi_settings"

android:fragment="com.android.settings.wifi.TvWifiSettings"

android:title="@string/wifi_settings_title"

android:icon="@drawable/ic_settings_wireless" />

<!-- MStar Android Patch End -->

<!-- Ethernet -->

<header

android:id="@+id/ethernet_settings"

android:fragment="com.android.settings.ethernet.EthernetSettings"

android:title="@string/ethernet_status_title"

android:icon="@drawable/ic_settings_ethernet" />

<!-- Bluetooth -->

<header

android:id="@+id/bluetooth_settings"

android:fragment="com.android.settings.bluetooth.TvBluetoothSettings"

android:title="@string/bluetooth_settings_title"

android:icon="@drawable/ic_settings_bluetooth2" />

<!-- Data Usage -->

<header

android:id="@+id/data_usage_settings"

android:fragment="com.android.settings.DataUsageSummary"

android:title="@string/data_usage_summary_title"

android:icon="@drawable/ic_settings_data_usage" />

<!-- Operator hook -->

<header

android:fragment="com.android.settings.WirelessSettings"

android:id="@+id/operator_settings">

<intent android:action="com.android.settings.OPERATOR_APPLICATION_SETTING" />

</header>

<!-- Other wireless and network controls -->

<header

android:id="@+id/wireless_settings"

android:title="@string/radio_controls_title"

android:breadCrumbTitle="@string/wireless_networks_settings_title"

android:fragment="com.android.settings.WirelessSettings"

android:icon="@drawable/empty_icon" />

<!-- DEVICE -->

<header android:id="@+id/device_section"

android:title="@string/header_category_device" />

<!-- Home -->

<header

android:id="@+id/home_settings"

android:icon="@drawable/ic_settings_home"

android:fragment="com.android.settings.HomeSettings"

android:title="@string/home_settings" />

<!-- Sound -->

<header

android:id="@+id/sound_settings"

android:icon="@drawable/ic_settings_sound"

android:fragment="com.android.settings.SoundSettings"

android:title="@string/sound_settings" />

<!-- Display -->

<header

android:id="@+id/display_settings"

android:icon="@drawable/ic_settings_display"

android:fragment="com.android.settings.DisplaySettings"

android:title="@string/display_settings" />

<!-- Storage -->

<header

android:id="@+id/storage_settings"

android:fragment="com.android.settings.deviceinfo.Memory"

android:icon="@drawable/ic_settings_storage"

android:title="@string/storage_settings" />

<!-- Battery -->

<header

android:id="@+id/battery_settings"

android:fragment="com.android.settings.fuelgauge.PowerUsageSummary"

android:icon="@drawable/ic_settings_battery"

android:title="@string/power_usage_summary_title" />

<!-- Application Settings -->

<header

android:fragment="com.android.settings.applications.ManageApplications"

android:icon="@drawable/ic_settings_applications"

android:title="@string/applications_settings"

android:id="@+id/application_settings" />

<!-- Manage users -->

<header

android:fragment="com.android.settings.users.UserSettings"

android:icon="@drawable/ic_settings_multiuser"

android:title="@string/user_settings_title"

android:id="@+id/user_settings" />

<!-- Manage NFC payment apps -->

<header

android:fragment="com.android.settings.nfc.PaymentSettings"

android:icon="@drawable/ic_settings_nfc_payment"

android:title="@string/nfc_payment_settings_title"

android:id="@+id/nfc_payment_settings" />

<!-- Manufacturer hook -->

<header

android:fragment="com.android.settings.WirelessSettings"

android:id="@+id/manufacturer_settings">

<intent android:action="com.android.settings.MANUFACTURER_APPLICATION_SETTING" />

</header>

<!-- PERSONAL -->

<header android:id="@+id/personal_section"

android:title="@string/header_category_personal" />

<!-- Location -->

<header

android:fragment="com.android.settings.location.LocationSettings"

android:icon="@drawable/ic_settings_location"

android:title="@string/location_settings_title"

android:id="@+id/location_settings" />

<!-- Security -->

<header

android:fragment="com.android.settings.SecuritySettings"

android:icon="@drawable/ic_settings_security"

android:title="@string/security_settings_title"

android:id="@+id/security_settings" />

<!-- Language -->

<header

android:id="@+id/language_settings"

android:fragment="com.android.settings.inputmethod.InputMethodAndLanguageSettings"

android:icon="@drawable/ic_settings_language"

android:title="@string/language_settings" />

<!-- Backup and reset -->

<header

android:fragment="com.android.settings.PrivacySettings"

android:icon="@drawable/ic_settings_backup"

android:title="@string/privacy_settings"

android:id="@+id/privacy_settings" />

<!-- @Patch: GTV specific changes -->

<!-- MStar Android Patch Begin -->

<!-- Update -->

<header

android:id="@+id/update_settings"

android:fragment="com.android.settings.update.UpdateSettings"

android:title="@string/update_settings" />

<!-- MStar Android Patch End -->

<!-- ACCOUNTS section -->

<header

android:id="@+id/account_settings"

android:title="@string/account_settings" />

<header

android:id="@+id/account_add"

android:title="@string/add_account_label"

android:icon="@drawable/ic_menu_add_dark">

<intent

android:action="android.settings.ADD_ACCOUNT_SETTINGS"/>

</header>

<!-- SYSTEM -->

<header android:id="@+id/system_section"

android:title="@string/header_category_system" />

<!-- Date & Time -->

<header

android:id="@+id/date_time_settings"

android:fragment="com.android.settings.DateTimeSettings"

android:icon="@drawable/ic_settings_date_time"

android:title="@string/date_and_time_settings_title" />

<!-- Accessibility feedback -->

<header

android:id="@+id/accessibility_settings"

android:fragment="com.android.settings.accessibility.AccessibilitySettings"

android:icon="@drawable/ic_settings_accessibility"

android:title="@string/accessibility_settings" />

<!-- Print -->

<header

android:id="@+id/print_settings"

android:fragment="com.android.settings.print.PrintSettingsFragment"

android:icon="@*android:drawable/ic_print"

android:title="@string/print_settings" />

<!-- Development -->

<header

android:id="@+id/development_settings"

android:fragment="com.android.settings.DevelopmentSettings"

android:icon="@drawable/ic_settings_development"

android:title="@string/development_settings_title" />

<!-- About Device -->

<header

android:id="@+id/about_settings"

android:fragment="com.android.settings.DeviceInfoSettings"

android:icon="@drawable/ic_settings_about"

android:title="@string/about_settings" />

</preference-headers>

从上述xml可以看出，header的内容是通过fragment来显示，定义了每一个header对应的fragment。

在private void updateHeaderList(List<Header> target)函数中，会根据当前平台是否支持某项feature，决定是否显示对应的header：

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else if (id == R.id.wifi_settings) {

// Remove WiFi Settings if WiFi service is not available.

if (!getPackageManager().hasSystemFeature(PackageManager.FEATURE_WIFI)) {

target.remove(i);

}

} else if (id == R.id.bluetooth_settings) {

// Remove Bluetooth Settings if Bluetooth service is not available.

if (!getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH)) {

target.remove(i);

}

}

原文地址：http://blog.csdn.net/zhudaozhuan/article/details/40618837