Android 自带Apps 学习---AlarmClock-优快云博客

本文详细介绍了如何让App在锁屏状态下仍保持在前台显示，并管理系统资源如屏幕亮度、键盘锁、唤醒锁等，同时实现了定时任务的数据变动监听。

1：启动App在前台，即使已经锁屏

final Window win = getWindow();
win.addFlags(WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED
| WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD);

// 保持屏幕高亮

win.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
| WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON);

//去除Activity标题

requestWindowFeature(Window.FEATURE_NO_TITLE);

//布局解析器

LayoutInflater mFactory = LayoutInflater.from(this);

mFactory.inflate(AlarmClock.CLOCKS[position], null);

SharedPreferences 共享存储

SharedPreferences mPrefs = getSharedPreferences(AlarmClock.PREFERENCES, 0);

int face = mPrefs.getInt(AlarmClock.PREF_CLOCK_FACE, 0);

SharedPreferences.Editor ed = mPrefs.edit();
ed.putInt(AlarmClock.PREF_CLOCK_FACE, position);
ed.commit();

2：对Provider 数据改动注册监听

private class FormatChangeObserver extends ContentObserver {
public FormatChangeObserver() {
super(new Handler());
}
@Override
public void onChange(boolean selfChange) {
setDateFormat();
updateTime();
}
}

mFormatChangeObserver = new FormatChangeObserver();
mContext.getContentResolver().registerContentObserver(
Settings.System.CONTENT_URI, true, mFormatChangeObserver);
Settings.System.CONTENT_URI 可用任意Provider的URi进行替换，

在provider中可通过getContentResolver().notifyChange(uri,..)提示更改，call back ContentObserver

public void notifyChange (Uri uri, ContentObserver observer)

Since: API Level 1

Notify registered observers that a row was updated. To register, call registerContentObserver(). By default, CursorAdapter objects will get this notification.

Parameters

observer	The observer that originated the change, may be `null`

3：键盘锁管理器

KeyguardManager km =
(KeyguardManager) context.getSystemService(
Context.KEYGUARD_SERVICE);

//If keyguard screen is showing or in restricted key input mode

km.inKeyguardRestrictedInputMode()

//开启键盘锁

km.newKeyguardLock(String tag)

//关闭，带回调接口

km.exitKeyguardSecurely(OnKeyguardExitResult arg0)

4:PowerManager.WakeLock

在Android中,申请WakeLock可以让你的进程持续执行即使手机进入睡眠模式,

比较实用的是比如:

后台有网络功能,可以保证操作持续进行

PowerManager pm =
(PowerManager) context.getSystemService(Context.POWER_SERVICE);

sCpuWakeLock = pm.newWakeLock(
PowerManager.PARTIAL_WAKE_LOCK |
PowerManager.ACQUIRE_CAUSES_WAKEUP |
PowerManager.ON_AFTER_RELEASE, Log.LOGTAG);
sCpuWakeLock.acquire();

释放

if (sCpuWakeLock != null) {
sCpuWakeLock.release();
sCpuWakeLock = null;
}

5： Alarm Manager

AlarmManager am = (AlarmManager)
context.getSystemService(Context.ALARM_SERVICE);
am.set(AlarmManager.RTC_WAKEUP, atTimeInMillis, Intent);

am.setInexactRepeating (int type, long triggerAtTime, long interval, PendingIntent operation)

am.setRepeating (int type, long triggerAtTime, long interval, PendingIntent operation)