AndroidのUI体验之ImmersiveMode沉浸模式

4.4带来了新的api——ImmersiveMode，可以使用户进入沉浸模式，享受更好的用户体验。

打开沉浸模式：

/**
     * Detects and toggles immersive mode (also known as "hidey bar" mode).
     */
    public void toggleHideyBar() {

        // BEGIN_INCLUDE (get_current_ui_flags)
        // The UI options currently enabled are represented by a bitfield.
        // getSystemUiVisibility() gives us that bitfield.
        int uiOptions = getActivity().getWindow().getDecorView().getSystemUiVisibility();
        int newUiOptions = uiOptions;
        // END_INCLUDE (get_current_ui_flags)
        // BEGIN_INCLUDE (toggle_ui_flags)
        boolean isImmersiveModeEnabled =
                ((uiOptions | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY) == uiOptions);
        if (isImmersiveModeEnabled) {
            Log.i(TAG, "Turning immersive mode mode off. ");
        } else {
            Log.i(TAG, "Turning immersive mode mode on.");
        }

        // Navigation bar hiding:  Backwards compatible to ICS.
        if (Build.VERSION.SDK_INT >= 14) {
            newUiOptions ^= View.SYSTEM_UI_FLAG_HIDE_NAVIGATION;
        }

        // Status bar hiding: Backwards compatible to Jellybean
        if (Build.VERSION.SDK_INT >= 16) {
            newUiOptions ^= View.SYSTEM_UI_FLAG_FULLSCREEN;
        }

        // Immersive mode: Backward compatible to KitKat.
        // Note that this flag doesn't do anything by itself, it only augments the behavior
        // of HIDE_NAVIGATION and FLAG_FULLSCREEN.  For the purposes of this sample
        // all three flags are being toggled together.
        // Note that there are two immersive mode UI flags, one of which is referred to as "sticky".
        // Sticky immersive mode differs in that it makes the navigation and status bars
        // semi-transparent, and the UI flag does not get cleared when the user interacts with
        // the screen.
        if (Build.VERSION.SDK_INT >= 18) {
            newUiOptions ^= View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY;
        }

        getActivity().getWindow().getDecorView().setSystemUiVisibility(newUiOptions);
        //END_INCLUDE (set_ui_flags)
    }

而这个状态发生变化可以显示这个监听器：

final View decorView = getActivity().getWindow().getDecorView();
        decorView.setOnSystemUiVisibilityChangeListener(
                new View.OnSystemUiVisibilityChangeListener() {
                    @Override
                    public void onSystemUiVisibilityChange(int i) {
                        int height = decorView.getHeight();
                        Log.i(TAG, "Current height: " + height);
                    }
                });

总共有5中Flag作用都不相同

 // BEGIN_INCLUDE (get_current_ui_flags)
        // The "Decor View" is the parent view of the Activity.  It's also conveniently the easiest
        // one to find from within a fragment, since there's a handy helper method to pull it, and
        // we don't have to bother with picking a view somewhere deeper in the hierarchy and calling
        // "findViewById" on it.
        View decorView = getActivity().getWindow().getDecorView();
        int uiOptions = decorView.getSystemUiVisibility();
        int newUiOptions = uiOptions;
        // END_INCLUDE (get_current_ui_flags)

        // BEGIN_INCLUDE (toggle_lowprofile_mode)
        // Low profile mode doesn't resize the screen at all, but it covers the nav & status bar
        // icons with black so they're less distracting.  Unlike "full screen" and "hide nav bar,"
        // this mode doesn't interact with immersive mode at all, but it's instructive when running
        // this sample to observe the differences in behavior.
        if (mLowProfileCheckBox.isChecked()) {
            newUiOptions |= View.SYSTEM_UI_FLAG_LOW_PROFILE;//低调模式：通知栏和虚拟键变暗
        } else {
            newUiOptions &= ~View.SYSTEM_UI_FLAG_LOW_PROFILE;
        }
        // END_INCLUDE (toggle_lowprofile_mode)

        // BEGIN_INCLUDE (toggle_fullscreen_mode)
        // When enabled, this flag hides non-critical UI, such as the status bar,
        // which usually shows notification icons, battery life, etc
        // on phone-sized devices.  The bar reappears when the user swipes it down.  When immersive
        // mode is also enabled, the app-drawable area expands, and when the status bar is swiped
        // down, it appears semi-transparently and slides in over the app, instead of pushing it
        // down.
        if (mHideStatusBarCheckBox.isChecked()) {//全屏模式：隐藏状态栏，但并不隐藏虚拟键
            newUiOptions |= View.SYSTEM_UI_FLAG_FULLSCREEN;
        } else {
            newUiOptions &= ~View.SYSTEM_UI_FLAG_FULLSCREEN;
        }
        // END_INCLUDE (toggle_fullscreen_mode)

        // BEGIN_INCLUDE (toggle_hidenav_mode)
        // When enabled, this flag hides the black nav bar along the bottom,
        // where the home/back buttons are.  The nav bar normally instantly reappears
        // when the user touches the screen.  When immersive mode is also enabled, the nav bar
        // stays hidden until the user swipes it back.
        if (mHideNavCheckbox.isChecked()) {//隐藏虚拟键，点击可出现
            newUiOptions |= View.SYSTEM_UI_FLAG_HIDE_NAVIGATION;
        } else {
            newUiOptions &= ~View.SYSTEM_UI_FLAG_HIDE_NAVIGATION;
        }
        // END_INCLUDE (toggle_hidenav_mode)

        // BEGIN_INCLUDE (toggle_immersive_mode)
        // Immersive mode doesn't do anything without at least one of the previous flags
        // enabled.  When enabled, it allows the user to swipe the status and/or nav bars
        // off-screen.  When the user swipes the bars back onto the screen, the flags are cleared
        // and immersive mode is automatically disabled.
        if (mImmersiveModeCheckBox.isChecked()) {
            newUiOptions |= View.SYSTEM_UI_FLAG_IMMERSIVE;
        } else {
            newUiOptions &= ~View.SYSTEM_UI_FLAG_IMMERSIVE;
        }
        // END_INCLUDE (toggle_immersive_mode)

        // BEGIN_INCLUDE (toggle_immersive_mode_sticky)
        // There's actually two forms of immersive mode, normal and "sticky".  Sticky immersive mode
        // is different in 2 key ways:
        //
        // * Uses semi-transparent bars for the nav and status bars
        // * This UI flag will *not* be cleared when the user interacts with the UI.
        //   When the user swipes, the bars will temporarily appear for a few seconds and then
        //   disappear again.
        if (mImmersiveModeStickyCheckBox.isChecked()) {
            newUiOptions |= View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY;
        } else {
            newUiOptions &= ~View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY;
        }
        // END_INCLUDE (toggle_immersive_mode_sticky)

        // BEGIN_INCLUDE (set_ui_flags)
        //Set the new UI flags.
        decorView.setSystemUiVisibility(newUiOptions);
        Log.i(TAG, "Current height: " + decorView.getHeight() + ", width: " + decorView.getWidth());
        // END_INCLUDE (set_ui_flags)

附件貌似传不了啊