在之前的android版本中修改外接键盘ESC为BACK按键做返回键使用，直接修改如下代码即可：
--- a/frameworks/base/data/keyboards/Generic.kcm
+++ b/frameworks/base/data/keyboards/Generic.kcm
@@ -499,7 +499,7 @@ key PLUS {### Non-printing keys ###key ESCAPE {
- base: none
+ base: fallback BACKalt, meta: fallback HOMEctrl: fallback MENU现在在android14上面发现这样修改后没有效果。查看log，追踪到framework下PhoneWindowManager.java里面对按键做了拦截处理。
09-12 07:06:46.239 734 832 W ContextImpl: Calling a method in the system process without a qualified user: android.app.ContextImpl.sendBroadcast:1319 android.app.ContextImpl.cl
owManager.interceptUnhandledKey:4006 com.android.server.policy.PhoneWindowManager.dispatchUnhandledKey:3912 com.android.server.wm.InputManagerCallback.dispatchUnhandledKey:193
public KeyEvent dispatchUnhandledKey(IBinder focusedToken, KeyEvent event, int policyFlags) {// Note: This method is only called if the initial down was unhandled.if (DEBUG_INPUT) {final KeyInterceptionInfo info =mWindowManagerInternal.getKeyInterceptionInfoFromToken(focusedToken);final String title = info == null ? "<unknown>" : info.windowTitle;Slog.d(TAG, "Unhandled key: inputToken=" + focusedToken+ ", title=" + title+ ", action=" + event.getAction()+ ", flags=" + event.getFlags()+ ", keyCode=" + event.getKeyCode()+ ", scanCode=" + event.getScanCode()+ ", metaState=" + event.getMetaState()+ ", repeatCount=" + event.getRepeatCount()+ ", policyFlags=" + policyFlags);}if (interceptUnhandledKey(event)) {return null;}上面是打印log的地方，函数里面调用了interceptUnhandledKey。可以看到函数里面对KeyEvent.KEYCODE_ESCAPE做了处理返回了true，导致没有继续上报BACK键。
private boolean interceptUnhandledKey(KeyEvent event) {final int keyCode = event.getKeyCode();final int repeatCount = event.getRepeatCount();final boolean down = event.getAction() == KeyEvent.ACTION_DOWN;final int metaState = event.getModifiers();switch(keyCode) {case KeyEvent.KEYCODE_SPACE:if (down && repeatCount == 0) {// Handle keyboard layout switching. (CTRL + SPACE)if (KeyEvent.metaStateHasModifiers(metaState & ~KeyEvent.META_SHIFT_MASK,KeyEvent.META_CTRL_ON)) {int direction = (metaState & KeyEvent.META_SHIFT_MASK) != 0 ? -1 : 1;sendSwitchKeyboardLayout(event, direction);return true;}}break;case KeyEvent.KEYCODE_Z:if (down && KeyEvent.metaStateHasModifiers(metaState,KeyEvent.META_CTRL_ON | KeyEvent.META_ALT_ON)) {// Intercept the Accessibility keychord (CTRL + ALT + Z) for keyboard users.if (mAccessibilityShortcutController.isAccessibilityShortcutAvailable(isKeyguardLocked())) {mHandler.sendMessage(mHandler.obtainMessage(MSG_ACCESSIBILITY_SHORTCUT));return true;}}break;case KeyEvent.KEYCODE_SYSRQ:if (down && repeatCount == 0) {interceptScreenshotChord(SCREENSHOT_KEY_OTHER, 0 /*pressDelay*/);}return true;case KeyEvent.KEYCODE_ESCAPE:if (down && repeatCount == 0) {mContext.closeSystemDialogs();}return true;}return false;}修改屏蔽KeyEvent.KEYCODE_ESCAPE的处理重新编译修改就可以了。
