Android 导航方式切换

1.导航栏样式目前有，三键导航，也有全局手势导航，具体的设置是在setting里

setting里对应的代码逻辑在packages\apps\Settings\src\com\android\settings\gestures\SystemNavigationPreferenceController.java

    static boolean isOverlayPackageAvailable(Context context, String overlayPackage) {
        try {
            return context.getPackageManager().getPackageInfo(overlayPackage, 0) != null;
        } catch (PackageManager.NameNotFoundException e) {
            // Not found, just return unavailable
            return false;
        }
    }

    static boolean is2ButtonNavigationEnabled(Context context) {
        return NAV_BAR_MODE_2BUTTON == context.getResources().getInteger(
                com.android.internal.R.integer.config_navBarInteractionMode);
    }

    static boolean isGestureNavigationEnabled(Context context) {
        return NAV_BAR_MODE_GESTURAL == context.getResources().getInteger(
                com.android.internal.R.integer.config_navBarInteractionMode);
    }

系统默认的导航样式在配置文件中 frameworks\base\core\res\res\values\config.xml

<!-- Controls the navigation bar interaction mode:
         0: 3 button mode (back, home, overview buttons)
         1: 2 button mode (back, home buttons + swipe up for overview)
         2: gestures only for back, home and overview -->
    <integer name="config_navBarInteractionMode">0</integer>

导航方式的切换在packages\apps\Settings\src\com\android\settings\gestures\SystemNavigationGestureSettings.java

    static String getCurrentSystemNavigationMode(Context context) {
        if (SystemNavigationPreferenceController.isGestureNavigationEnabled(context)) {
            return KEY_SYSTEM_NAV_GESTURAL;
        } else if (SystemNavigationPreferenceController.is2ButtonNavigationEnabled(context)) {
            return KEY_SYSTEM_NAV_2BUTTONS;
        } else {
            return KEY_SYSTEM_NAV_3BUTTONS;
        }
    }

    @VisibleForTesting
    static void setCurrentSystemNavigationMode(IOverlayManager overlayManager, String key) {
        String overlayPackage = NAV_BAR_MODE_GESTURAL_OVERLAY;
        switch (key) {
            case KEY_SYSTEM_NAV_GESTURAL:
                overlayPackage = NAV_BAR_MODE_GESTURAL_OVERLAY;
                break;
            case KEY_SYSTEM_NAV_2BUTTONS:
                overlayPackage = NAV_BAR_MODE_2BUTTON_OVERLAY;
                break;
            case KEY_SYSTEM_NAV_3BUTTONS:
                overlayPackage = NAV_BAR_MODE_3BUTTON_OVERLAY;
                break;
        }

        try {
            overlayManager.setEnabledExclusiveInCategory(overlayPackage, USER_CURRENT);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

其中导航栏的具体方式定义在

frameworks\base\core\java\android\view\WindowManagerPolicyConstants.java

// Associated overlays for each nav bar mode
    String NAV_BAR_MODE_3BUTTON_OVERLAY = "com.android.internal.systemui.navbar.threebutton";
    String NAV_BAR_MODE_2BUTTON_OVERLAY = "com.android.internal.systemui.navbar.twobutton";
    String NAV_BAR_MODE_GESTURAL_OVERLAY = "com.android.internal.systemui.navbar.gestural";

使用Overlay替换原生导航栏

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
        package="com.android.internal.systemui.navbar.gestural"
        android:versionCode="1"
        android:versionName="1.0">
    <overlay android:targetPackage="android"
        android:category="com.android.internal.navigation_bar_mode"
        android:priority="1"/>

    <application android:label="@string/navigation_bar_mode_title" android:hasCode="false"/>
</manifest>

具体导航栏的逻辑在