Android 屏蔽返回键，home键以及其他实体按键

public boolean onKeyDown(int keyCode, KeyEvent event) {

switch (keyCode) {
case KeyEvent.KEYCODE_BACK:
return true;
}
return super.onKeyDown(keyCode, event);
}

public void onAttachedToWindow() {
this.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD);
super.onAttachedToWindow();
}

switch (keyCode) {
case KeyEvent.KEYCODE_HOME:
return true;
case KeyEvent.KEYCODE_BACK:
return true;
case KeyEvent.KEYCODE_CALL:
return true;
case KeyEvent.KEYCODE_SYM:
return true;
case KeyEvent.KEYCODE_VOLUME_DOWN:
return true;
case KeyEvent.KEYCODE_VOLUME_UP:
return true;
case KeyEvent.KEYCODE_STAR:
return true;
}

<activity android:name=".WelcomeActivity" android:label="@string/app_name"
android:theme="@android:style/Theme.NoTitleBar.Fullscreen"
>