Android4.4 锁屏界面简单解析

 
Android4.4 锁屏界面简单解析
  1、锁屏界面永远不出现
     /frameworks/base/packages/Keyguard/src/com/android/keyguard/KeyguardViewMediator.java 
     将 private boolean mExternallyEnabled = true;
     修改为：private boolean mExternallyEnabled = false;

    @Override
        void onPhoneStateChanged(int phoneState) {
            synchronized (KeyguardViewMediator.this) {
                if (TelephonyManager.CALL_STATE_IDLE == phoneState  // call ending
                        && !mScreenOn                           // screen off
                        && mExternallyEnabled) {                // not disabled by any app

                    // note: this is a way to gracefully reenable the keyguard when the call
                    // ends and the screen is off without always reenabling the keyguard
                    // each time the screen turns off while in call (and having an occasional ugly
                    // flicker while turning back on the screen and disabling the keyguard again).
                    if (DEBUG) Log.d(TAG, "screen is off and call ended, let's make sure the "
                            + "keyguard is showing");
                    doKeyguardLocked(null);
                }
            }
        };

  2、取消自动关屏和休眠
    /frameworks/base/packages/SettingsProvider/res/values/defaults.xml
      <integer name="def_screen_off_timeout">-1</integer> <!--modify Await default 60000-->
    相对应的：
       private void upgradeScreenTimeout(SQLiteDatabase db) {
        // Change screen timeout to current default
        db.beginTransaction();
        SQLiteStatement stmt = null;
        try {
            stmt = db.compileStatement("INSERT OR REPLACE INTO system(name,value)"
                    + " VALUES(?,?);");
            loadIntegerSetting(stmt, Settings.System.SCREEN_OFF_TIMEOUT,
                    R.integer.def_screen_off_timeout);
            db.setTransactionSuccessful();
        } finally {
            db.endTransaction();
            if (stmt != null)
                stmt.close();
        }
    }

       private void loadSystemSettings(SQLiteDatabase db) {
        SQLiteStatement stmt = null;
        try {
            stmt = db.compileStatement("INSERT OR IGNORE INTO system(name,value)"
                    + " VALUES(?,?);");

            loadBooleanSetting(stmt, Settings.System.DIM_SCREEN,
                    R.bool.def_dim_screen);
            loadIntegerSetting(stmt, Settings.System.SCREEN_OFF_TIMEOUT,
                    R.integer.def_screen_off_timeout); //

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

        ...... 
        } finally {
            if (stmt != null) stmt.close();
        }
    }