需要仿照ios时钟界面，android系统中实现，首先分析android系统应用DeskClock

分析方法，首先分析AndroidManifest文件

分析AosDeskClock AndroidManifest.xml文件

    <application android:label=”@string/app_label”
                 android:icon=”@mipmap/ic_launcher_alarmclock”
                 android:requiredForAllUsers=”true”
                 android:supportsRtl=”true”>
application层级 设置了label icon supportsRtl  
以及                 android:requiredForAllUsers=”true”——此句意义不明确  
               

        <activity android:name=”DeskClock”
                android:label=”@string/app_label”
                android:theme=”@style/DeskClock”
                android:icon=”@mipmap/ic_launcher_alarmclock”
                android:launchMode=”singleTask”
                android:screenOrientation=”portrait”
                android:windowSoftInputMode=”adjustNothing”
                >

            <intent-filter>
                <action android:name=”android.intent.action.MAIN” />
                <category android:name=”android.intent.category.DEFAULT” />
                <category android:name=”android.intent.category.LAUNCHER” />
            </intent-filter>
        </activity>
第一个activity name DeskClock 桌面时钟，与整个application有相同的label，theme 主题风格，应该是设置字体颜色等，icon图标，activity的launchmode singletask，screenOrientation，竖直方向，windowsoftinputmode，此属性用来协调虚拟键盘弹出的显示情况，此属性有待研究
还适配了一个intent-filter action category已经给出，应该是用于外部启动这个activity

        <activity-alias android:name=”DockClock”
                android:targetActivity=”DeskClock”
                android:label=”@string/app_label”
                android:theme=”@style/DeskClock”
                android:icon=”@mipmap/ic_launcher_alarmclock”
                android:launchMode=”singleTask”
                android:enabled=”@bool/config_dockAppEnabled”
                >
            <intent-filter>
                <action android:name=”android.intent.action.MAIN” />
                <category android:name=”android.intent.category.DEFAULT” />
                <category android:name=”android.intent.category.DESK_DOCK” />
            </intent-filter>
        </activity-alias>
一个activity-alias层级 activity-alias通过指定targetActivity来决定入口相连接的activity,给该程序更改一个不同的label和icon，两个图标进入同一个activity

         <activity android:name=”SettingsActivity”
                android:label=”@string/settings”
                android:theme=”@style/Theme.Settings”
                android:taskAffinity=””
                android:excludeFromRecents=”true”
                >
            <intent-filter>
                <action android:name=”android.intent.action.MAIN” />
            </intent-filter>
        </activity>
第二个activity name SettingsActivity 有一个label，theme，taskAffinity空， android:excludeFromRecents控制在不在recent列表中显示。true时不显示；false显示，默认。运行如下activity后，不会显示在recent列表中。依然有意个intent-filter

        <activity android:name=”AgoldSetAlarmAcitivity”
                android:label=”@string/settings”
                android:theme=”@style/SettingsTheme”
                android:taskAffinity=””
                android:excludeFromRecents=”true”
                >
            <intent-filter>
                <action android:name=”android.intent.action.MAIN” />
            </intent-filter>
        </activity>
第三个activity, name AgoldSetAlarmActivity，有一个lable，theme，taskAffinity为空，依然不显示在最近列表中，适配一个filter 其中只含有一个action

        <activity android:name=”.worldclock.CitiesActivity”
                android:label=”@string/cities_activity_title”
                android:theme=”@style/CitiesTheme”
                android:taskAffinity=””
                android:excludeFromRecents=”true”
                >
            <intent-filter>
                <action android:name=”android.intent.action.MAIN” />
            </intent-filter>
        </activity>
第四个activity 名称 .worldclock.CitiesActivity  有一个lable，theme，taskAffinity为空，依然不显示在最近列表中，适配一个filter 其中只含有一个action

        <activity android:name=”.alarms.AlarmActivity”
                android:taskAffinity=””
                android:excludeFromRecents=”true”
                android:theme=”@style/AlarmAlertFullScreenTheme”
                android:windowSoftInputMode=”stateAlwaysHidden”
                android:showOnLockScreen=”true”
                android:configChanges=”orientation|screenSize|keyboardHidden|keyboard|navigation”/>
第五个activity name .alarms.AlarmActivity  ，android:showOnLockScreen=”true”根据这个基本可以判断是闹钟显示界面，     android:configChanges，定义属性时会去重新调用各个activity的各个生命周期

        <activity android:name=”ScreensaverActivity”
                android:excludeFromRecents=”true”
                android:taskAffinity=””
                android:theme=”@style/ScreensaverActivityTheme”
                android:configChanges=”orientation|screenSize|keyboardHidden|keyboard” />
第六个activity name ScreensaverActivity 通过名称判断是一个截屏activity，设置了configChanges，

        <activity android:name=”HandleApiCalls”
                android:theme=”@android:style/Theme.NoDisplay”
                android:excludeFromRecents=”true”
                android:permission=”com.android.alarm.permission.SET_ALARM”>
            <intent-filter>
                <action android:name=”android.intent.action.SET_ALARM” />
                <category android:name=”android.intent.category.DEFAULT” />
            </intent-filter>
            <intent-filter>
                <action android:name=”android.intent.action.SHOW_ALARMS” />
                <category android:name=”android.intent.category.DEFAULT” />
            </intent-filter>
            <intent-filter>
                <action android:name=”android.intent.action.SET_TIMER” />
                <category android:name=”android.intent.category.DEFAULT” />
            </intent-filter>
        </activity>
第七个activity name HandleApiCalls，此activity设置了三个intent-filter，此activity待查看具体作用

        <activity-alias android:name=”HandleSetAlarm”
            android:targetActivity=”.HandleApiCalls”
            android:exported=”true”>
        </activity-alias>
第七个activitys的alias

        <!– Settings activity for screensaver –>
        <activity android:name=”.ScreensaverSettingsActivity”
                android:label=”@string/screensaver_settings”
                android:theme=”@android:style/Theme.Holo.Light”
                android:taskAffinity=””
                android:excludeFromRecents=”true”
                android:exported=”true”
                >
            <intent-filter>
                <action android:name=”android.intent.action.MAIN” />
            </intent-filter>
        </activity>
第八个activity name .ScreensaverSettingsActivity    android:exported 代表是否支持其它应用调用当前组件。默认值：如果包含有intent-filter 默认值为true; 没有intent-filter默认值为false。            
                         
                    

        <!– This activity is basically like the TimerFragment in DeskClock
         but only during lock screen
         so that is only has the fired timers –>
        <activity android:name=”com.android.deskclock.timer.TimerAlertFullScreen”
                android:excludeFromRecents=”true”
                android:theme=”@style/AlarmAlertFullScreenTheme”
                android:launchMode=”singleInstance”
                android:showOnLockScreen=”true”
                android:taskAffinity=””
                android:configChanges=”orientation|screenSize|keyboardHidden|keyboard|navigation”/>
第九个activity name com.android.deskclock.timer.TimerAlertFullScreen 这个activity就像是时钟里面的timerFragement 但是仅仅在锁屏上出现

        <receiver android:name=”.alarms.AlarmStateManager”
                  android:exported=”false”>
        </receiver>
第一个receiver
        <receiver android:name=”.PackageDataClearedReceiver”
            android:exported=”false”>
            <intent-filter>
               <action android:name=”com.mediatek.intent.action.SETTINGS_PACKAGE_DATA_CLEARED” />
               <category android:name=”android.intent.category.DEFAULT” />
            </intent-filter>
            <intent-filter>
               <action android:name=”android.intent.action.LOCALE_CHANGED” />
            </intent-filter>
        </receiver>
第二个receiver
        <receiver android:name=”AlarmInitReceiver”>
            <intent-filter>
                <action android:name=”android.intent.action.BOOT_COMPLETED” />
                <action android:name=”android.intent.action.TIME_SET” />
                <action android:name=”android.intent.action.TIMEZONE_CHANGED” />
                <action android:name=”android.intent.action.LOCALE_CHANGED” />
            </intent-filter>
            <intent-filter android:priority=”100″>
                <action android:name=”android.intent.action.ACTION_BOOT_IPO” />
            </intent-filter>
        </receiver>
第三个receiver
        <receiver android:name=”com.android.alarmclock.AnalogAppWidgetProvider” android:label=”@string/analog_gadget”
           android:icon=”@mipmap/ic_launcher_alarmclock”>
            <intent-filter>
                <action android:name=”android.appwidget.action.APPWIDGET_UPDATE” />
            </intent-filter>
            <meta-data android:name=”android.appwidget.oldName” android:value=”com.android.deskclock.AnalogAppWidgetProvider” />
            <meta-data android:name=”android.appwidget.provider” android:resource=”@xml/analog_appwidget” />
        </receiver>
第四个receiver
        <receiver android:name=”com.android.alarmclock.DigitalAppWidgetProvider” android:label=”@string/digital_gadget”
           android:icon=”@mipmap/ic_launcher_alarmclock”>
            <intent-filter>
                <action android:name=”android.appwidget.action.APPWIDGET_UPDATE” />
                <action android:name=”com.android.deskclock.ON_QUARTER_HOUR” />
                <action android:name=”android.intent.action.DATE_CHANGED” />
                <action android:name=”android.intent.action.TIMEZONE_CHANGED” />
                <action android:name=”android.intent.action.SCREEN_ON” />
                <action android:name=”android.intent.action.TIME_SET” />
                <action android:name=”android.intent.action.LOCALE_CHANGED” />
                <action android:name=”android.intent.action.ALARM_CHANGED” />
                <action android:name=”android.app.action.NEXT_ALARM_CLOCK_CHANGED” />
                <action android:name=”com.android.deskclock.worldclock.update” />
                </intent-filter>
            <meta-data android:name=”android.appwidget.provider” android:resource=”@xml/digital_appwidget” />
        </receiver>
第五个receiver
        <receiver android:name=”com.android.alarmclock.DigitalWidgetViewsFactory”
             android:exported=”false” />
第六个receiver
        <receiver android:name=”com.android.deskclock.timer.TimerReceiver”
                android:exported=”false”>
            <intent-filter>
                <action android:name=”start_timer” />
                <action android:name=”delete_timer” />
                <action android:name=”times_up” />
                <action android:name=”timer_stop” />
                <action android:name=”timer_reset” />
                <action android:name=”timer_done” />
                <action android:name=”timer_update” />
                <action android:name=”notif_in_use_show” />
                <action android:name=”notif_in_use_cancel” />
                <action android:name=”notif_times_up_stop” />
                <action android:name=”notif_times_up_plus_one” />
                <action android:name=”notif_times_up_show” />
                <action android:name=”notif_times_up_cancel” />
                <action android:name=”android.intent.action.ACTION_PRE_SHUTDOWN” />
            </intent-filter>
        </receiver>
第七个receiver

        <service android:name=”.alarms.AlarmService”>
            <intent-filter>
                <action android:name=”com.android.deskclock.START_ALARM” />
            </intent-filter>
        </service>
第一个service 目测是闹钟服务
        <service android:name=”com.android.alarmclock.DigitalAppWidgetService”
             android:permission=”android.permission.BIND_REMOTEVIEWS”
             android:exported=”false” />
第二个service 数字时钟控件服务       
        <!– Dream (screensaver) implementation –>
        <service android:name=”Screensaver”
            android:exported=”true”
            android:label=”@string/app_label”
            android:permission=”android.permission.BIND_DREAM_SERVICE”>
            <intent-filter>
                <action android:name=”android.service.dreams.DreamService” />
                <action android:name=”android.app.action.NEXT_ALARM_CLOCK_CHANGED” />
                <category android:name=”android.intent.category.DEFAULT” />
            </intent-filter>
            <meta-data
                android:name=”android.service.dream”
                android:resource=”@xml/dream_info” />
        </service>
第三个services name Screensaver
        <service android:name=”TimerRingService”
                android:exported=”false”
                android:description=”@string/timer_ring_service_desc”>
            <intent-filter>
                <action android:name=”com.android.deskclock.TIMER_ALERT” />
            </intent-filter>
        </service>
第四个services 计时器响铃服务
        <service android:name=”com.android.deskclock.stopwatch.StopwatchService”
                android:exported=”false”
                android:description=”@string/stopwatch_service_desc”>
            <intent-filter>
                <action android:name=”start_stopwatch” />
                <action android:name=”lap_stopwatch” />
                <action android:name=”stop_stopwatch” />
                <action android:name=”reset_stopwatch” />
                <action android:name=”share_stopwatch” />
            </intent-filter>
        </service>
第五个services 秒表

        <provider android:name=”.provider.ClockProvider”
                android:authorities=”com.android.deskclock”
                android:exported=”false” />
第一个provider

整个AndroidManifest.xml文件中，含有9个activity，7个receiver，5个service，1个provider， 将这些组件去逐步了解deskclock

分析过程中，遇到了很多xml不同层级属性问题，有些甚至都无法百度到相关信息，感受到Google的重要性。