Android的SAFE MODE（安全模式）

据说Android系统，按住MENU键开机，会安全模式进入系统。安全模式为何，暂未研究，现在看到了代码，先做下记号。

2.1代码位置：

frameworks/policies/base/phone/com/android/internal/policy/impl/PhoneWindowManager.java

收索SAFE MODE 这个tag会看到相关代码。

现分析如下：

步骤：在开机动画时，按住MENU键（或者字母S键，方向键的中间键，鼠标左键中的一个）直到开机，会进入安全模式。

得到log如下：

I/WindowManager(  101): SAFE MODE ENABLED (menu=1 s=-1 dpad=-1 trackball=-1)

现象：在机器左小脚显示“安全模式”。

源码

2.3版本：frameworks/base/policy/src/com/android/internal/policy/impl/PhoneWindowManager.java

2291     public boolean detectSafeMode() {
2292         try {
2293             int menuState = mWindowManager.getKeycodeState(KeyEvent.KEYCODE_MENU);
2294             int sState = mWindowManager.getKeycodeState(KeyEvent.KEYCODE_S);
2295             int dpadState = mWindowManager.getDPadKeycodeState(KeyEvent.KEYCODE_DPAD_CENTER);
2296             int trackballState = mWindowManager.getTrackballScancodeState(BTN_MOUSE);
2297             mSafeMode = menuState > 0 || sState > 0 || dpadState > 0 || trackballState > 0;
2298             performHapticFeedbackLw(null, mSafeMode
2299                     ? HapticFeedbackConstants.SAFE_MODE_ENABLED
2300                     : HapticFeedbackConstants.SAFE_MODE_DISABLED, true);
2301             if (mSafeMode) {
2302                 Log.i(TAG, "SAFE MODE ENABLED (menu=" + menuState + " s=" + sState
2303                         + " dpad=" + dpadState + " trackball=" + trackballState + ")");
2304             } else {
2305                 Log.i(TAG, "SAFE MODE not enabled");
2306             }
2307             return mSafeMode;
2308         } catch (RemoteException e) {
2309             // Doom! (it's also local)
2310             throw new RuntimeException("window manager dead");
2311         }
2312     }

要把safe mode禁止掉，把mSafeMode赋值为false即可。