Android锁屏的问题

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  • android系统
 
本文主要讨论Android锁屏的问题,具体有2个需求: 

1、如何让Android开机后不自动锁屏 

2、如何让Android设备永远不锁屏 

   阅读Android的源代码可知:Android的锁屏策略在\frameworks\policies\base\phone\com\android\internal\policy\impl目录下,因此,今天我们的这两个问题将在这里找到答案。 

   首先解决第一个问题:如何让Android开机后不自动锁屏 

   在\frameworks\policies\base\phone\com\android\internal\policy\impl目录下,在KeyguardViewMediator.java文件中有一个方法:onSystemReady();从方法名字可以看出,就是当系统启动完毕并已经做好准备了。 

在此方法中会调用一个方法:doKeyguard();此方法就是让系统锁屏,因此,我们只要不让此方法执行就可以实现我们的目标了。呵呵~ 

  接下来解决第二个问题:http://blog.csdn.net/sustzombie/article/details/6161381 
  本文转载自: 

本文介绍一下怎样让Android 设备永不锁屏。     Android系统 的锁屏时间 存放在Setting数据库中,字段为Settings.System.SCREEN_OFF_TIMEOUT。查看SettingsProvider源码,查看如下文件 的源码: 
frameworks/base/packages/SettingsProvider/src/com/android/providers/settings/DatabaseHelper.java 
查看loadSystemSettings()函数的代码如下 : 
private void loadSystemSettings(SQLiteDatabase db) { 
        SQLiteStatement stmt = db.compileStatement("INSERT OR IGNORE INTO system(name,value) " 
                + " VALUES(?,?); "); 

        Resources r = mContext.getResources(); 

        loadBooleanSetting(stmt, Settings.System.DIM_SCREEN, 
                R.bool.def_dim_screen); 
        loadSetting(stmt, Settings.System.STAY_ON_WHILE_PLUGGED_IN, 
                "1 ".equals(SystemProperties.get("ro.kernel.qemu ")) ? 1 : 0); 
        loadIntegerSetting(stmt, Settings.System.SCREEN_OFF_TIMEOUT, 
                R.integer.def_screen_off_timeout); 

        // Set default cdma emergency tone 
        loadSetting(stmt, Settings.System.EMERGENCY_TONE, 0); 

        // Set default cdma call auto retry 
        loadSetting(stmt, Settings.System.CALL_AUTO_RETRY, 0); 

        // Set default cdma DTMF type 
        loadSetting(stmt, Settings.System.DTMF_TONE_TYPE_WHEN_DIALING, 0); 

        // Set default hearing aid 
        loadSetting(stmt, Settings.System.HEARING_AID, 0); 

        // Set default tty mode 
        loadSetting(stmt, Settings.System.TTY_MODE, 0); 

        loadBooleanSetting(stmt, Settings.System.AIRPLANE_MODE_ON, 
                R.bool.def_airplane_mode_on); 

        loadStringSetting(stmt, Settings.System.AIRPLANE_MODE_RADIOS, 
                R.string.def_airplane_mode_radios); 

        loadStringSetting(stmt, Settings.System.AIRPLANE_MODE_TOGGLEABLE_RADIOS, 
                R.string.airplane_mode_toggleable_radios); 

        loadBooleanSetting(stmt, Settings.System.AUTO_TIME, 
                R.bool.def_auto_time); // Sync time to NITZ 

        loadIntegerSetting(stmt, Settings.System.SCREEN_BRIGHTNESS, 
                R.integer.def_screen_brightness); 

        loadBooleanSetting(stmt, Settings.System.SCREEN_BRIGHTNESS_MODE, 
                R.bool.def_screen_brightness_automatic_mode); 

        loadDefaultAnimationSettings(stmt); 

        loadBooleanSetting(stmt, Settings.System.ACCELEROM ETER_ROTATION, 
                R.bool.def_accelerometer_rotation); 

        loadDefaultHapticSettings(stmt); 

        stmt.close (); 
    } 
     从代码中我们可以看出,假如Settings.System.SCREEN_OFF_TIMEOUT没有初始化的话(系统首次启动,这个字段肯定是没有初始化的),将会利用资源中的R.integer.def_screen_off_timeout来初始化。我们为了让系统永不锁屏,只需要把资源 R.integer.def_screen_off_timeout设为-1即可。查看文件 
frameworks/base/packages/SettingsProvider/res/values/defaults.xml 
可以找到R.integer.def_screen_off_timeout的定义。 
< integer name ="def_screen_off_timeout" > 60000</ integer > 
发现默认值为60000ms,也就是60s。我们只需要把这个参数改为-1。然后重新编译SettingsProvider模块,就OK了。 
     另外为了防止用户进入系统后,修改锁屏时间,在Setting模块中删除 对锁屏时间的设置 。这样Android设备就永不锁屏了。 
后来发现我的Android设备烧录好之后第一次启动永远不会锁屏,但是设备重启之后开机 就进入锁屏状态,解锁之后就再也不会锁屏了(因为永远不超时)。看来“革命尚未成功,同志仍需努力”啊。      那么为什么启动之后没有进入锁屏状态呢?是不会系统有把超时锁屏的值给修改了呢?我通过sqlite3去查看settings.db的内容,发现超时锁屏的值仍然是-1。说明启动之后,系统并没有去数据库中查看屏幕超时锁屏的值,就直接锁屏了。 
     但是怎样才能开机之后不进入锁屏状态呢?这个是个非常费思量的问题。经过go,我知道锁屏的代码在LockScreen.java中,然后顺藤摸瓜,终于找到了可以设置锁屏功能 开关的位置。代码位于: 
frameworks/policies/base/phone/com/android/internal/policy/impl/KeyguardViewMediator.java 
该文件中有一个变量定义如下: 
   
    private boolean mExternallyEnabled = true; 
mExternallyEnabled是用来管理是否开启屏幕锁的关键。默认值是打开屏锁,根据注释可以知道他是希望应用程序 来修改这个值。但是经过加打印信息发现开机的时候没有任何应用程序会修改它。修改这个值调用如下函数: 
   
    public void setKeyguardEnabled(boolean enabled) { 
        synchronized (this) { 
            if (DEBUG) Log.d(TAG, "setKeyguardEnabled(" + enabled + ")"); 

            mExternallyEnabled = enabled; 

            if (!enabled && mShowing) { 
                if (mExitSecureCallback != null) { 
                    if (DEBUG) Log.d(TAG, "in process of verifyUnlock request, ignoring"); 
                    // we're in the process of handling a request to verify the user 
                    // can get past the keyguard. ignore extraneous requests to disable / reenable 
                    return; 
                } 

                // hiding keyguard that is showing, remember to reshow later 
                if (DEBUG) Log.d(TAG, "remembering to reshow, hiding keyguard, " 
                        + "disabling status bar expansion"); 
                mNeedToReshowWhenReenabled = true; 
                hideLocked(); 
            } else if (enabled && mNeedToReshowWhenReenabled) { 
                // reenabled after previously hidden, reshow 
                if (DEBUG) Log.d(TAG, "previously hidden, reshowing, reenabling " 
                        + "status bar expansion"); 
                mNeedToReshowWhenReenabled = false; 

                if (mExitSecureCallback != null) { 
                    if (DEBUG) Log.d(TAG, "onKeyguardExitResult(false), resetting"); 
                    mExitSecureCallback.onKeyguardExitResult(false); 
                    mExitSecureCallback = null; 
                    resetStateLocked(); 
                } else { 
                    showLocked(); 

                    // block until we know the keygaurd is done drawing (and post a message 
                    // to unblock us after a timeout so we don't risk blocking too long 
                    // and causing an ANR). 
                    mWaitingUntilKeyguardVisible = true; 
                    mHandler.sendEmptyMessageDelayed(KEYGUARD_DONE_DRAWING, KEYGUARD_DONE_DRAWING_TIMEOUT_MS); 
                    if (DEBUG) Log.d(TAG, "waiting until mWaitingUntilKeyguardVisible is false"); 
                    while (mWaitingUntilKeyguardVisible) { 
                        try { 
                            wait(); 
                        } catch (InterruptedException e) { 
                            Thread.currentThread().interrupt(); 
                        } 
                    } 
                    if (DEBUG) Log.d(TAG, "done waiting for mWaitingUntilKeyguardVisible"); 
                } 
            } 
        } 
    } 
    经过上面的讨论我们可以发现我们有两个解决 方法: 
1、定义变量的时候,给其初始化为false。 
2、在launcher模块启动的时候,调用setKeyguardEnabled方法,关闭锁屏功能。 
    我懒得修改Laucher模块,我的解决方法就是在定义mExternallyEnabled时修改其初始值为false。各位朋友 可以根据自己的实际情况选择解决方案。我的代码如下: 
   
    private boolean mExternallyEnabled = false; 
     这样修改之后,Android设备开机之后,默认不会进入锁屏状态,除非你在应用程序中调用setKeyguardEnabled方法显示打开这个功能。因为设置的超时时间为-1,则永远也不会进入锁屏界面。完全满足了我的需求,终于大功告成了。





 private void updateUserActivitySummaryLocked(long now, int dirty) {
        // Update the status of the user activity timeout timer.
        if ((dirty & (DIRTY_USER_ACTIVITY | DIRTY_WAKEFULNESS | DIRTY_SETTINGS)) != 0) {
            mHandler.removeMessages(MSG_USER_ACTIVITY_TIMEOUT);


            long nextTimeout = 0;
            if (mWakefulness != WAKEFULNESS_ASLEEP) {
                final int screenOffTimeout = getScreenOffTimeoutLocked();
                final int screenDimDuration = getScreenDimDurationLocked(screenOffTimeout);   //max 7S, dim to off 
                final int screenButtonLightDuration = getButtonLightDurationLocked(screenOffTimeout);


                mUserActivitySummary = 0;
                if (mLastUserActivityTime >= mLastWakeTime) {
                    if ( (mLastUserActivityButtonTime >= mLastWakeTime) && (now < mLastUserActivityButtonTime + screenButtonLightDuration) ) {
                        mUserActivitySummary |= USER_ACTIVITY_BUTTON_BRIGHT;
                        mUserActivitySummary |= USER_ACTIVITY_SCREEN_BRIGHT;
                        nextTimeout = mLastUserActivityButtonTime + screenButtonLightDuration;
                    } else if (now < mLastUserActivityTime + screenOffTimeout - screenDimDuration) {
                        nextTimeout = mLastUserActivityTime + screenOffTimeout - screenDimDuration;
                        mUserActivitySummary |= USER_ACTIVITY_SCREEN_BRIGHT;
                    } else {
                        nextTimeout = mLastUserActivityTime + screenOffTimeout;
                        if (now < nextTimeout) {
                            mUserActivitySummary |= USER_ACTIVITY_SCREEN_DIM;
                        }
                    }
                }
                if (mUserActivitySummary == 0
                        && mLastUserActivityTimeNoChangeLights >= mLastWakeTime) {
                    nextTimeout = mLastUserActivityTimeNoChangeLights + screenOffTimeout;
                    if (now < nextTimeout
                            && mDisplayPowerRequest.screenState
                                    != DisplayPowerRequest.SCREEN_STATE_OFF) {
                        mUserActivitySummary = mDisplayPowerRequest.screenState
                                == DisplayPowerRequest.SCREEN_STATE_BRIGHT ?
                                USER_ACTIVITY_SCREEN_BRIGHT : USER_ACTIVITY_SCREEN_DIM;
                    }
                }
                Slog.d(TAG,"mScreenOffTimeoutSetting ="+mScreenOffTimeoutSetting);
//modify by kerson  修改超时
                      //if (mUserActivitySummary != 0 ) {
                      
               if (mUserActivitySummary != 0 && mScreenOffTimeoutSetting > 0) {
                    Message msg = mHandler.obtainMessage(MSG_USER_ACTIVITY_TIMEOUT);
                    msg.setAsynchronous(true);
                    mHandler.sendMessageAtTime(msg, nextTimeout);
                }
            } else {
                mUserActivitySummary = 0;
            }


            if (DEBUG_SPEW) {
                Slog.d(TAG, "updateUserActivitySummaryLocked: mWakefulness="
                        + wakefulnessToString(mWakefulness)
                        + ", mUserActivitySummary=0x" + Integer.toHexString(mUserActivitySummary)
                        + ", nextTimeout=" + TimeUtils.formatUptime(nextTimeout));
            }
        }
    }
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