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。

60000

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。

锁屏的代码在LockScreen.java中，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：

/**

* External apps (like the phone app) can tell us to disable the keygaurd.

*/

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：

/**

* Same semantics as {@link WindowManagerPolicy#enableKeyguard}; provide

* a way for external stuff to override normal keyguard behavior. For instance

* the phone app disables the keyguard when it receives incoming calls.

*/

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。