android.view.accessibility.AccessibilityManager#addTouchExplorationStateChangeListener ( )源码实例Demo

/**
 * Sets the current touch explore state change listener and removes the previous one if necessary
 * @param listener Null value unregisters the current listener, non-null unregisters previous one and registers new one
 *                 If the current listener is the same as the previous one, no operation is performed.
 */
protected void setTouchExploreChangeListener(@Nullable AccessibilityManager.TouchExplorationStateChangeListener listener) {

    // if current touchExplorerStateChangeListener is identical to previous one, no operation is necessary
    if (listener != touchExplorationStateChangeListener) {
        AccessibilityManager am = getAccessibilityManager();
        if (am != null) {

            /* touch explorer state listeners are additive (i.e. adding one doesn't remove the previous one), so we need to be careful
            * and only register one at a time. so, if the one we currently have is valid (non-null), unregister it.
            * If the new one is valid (non-null) register it.
            */
            if (touchExplorationStateChangeListener != null) {
                am.removeTouchExplorationStateChangeListener((AccessibilityManager.TouchExplorationStateChangeListener) touchExplorationStateChangeListener);
            }

            if (listener != null) {
                am.addTouchExplorationStateChangeListener(listener);
            }

            touchExplorationStateChangeListener = listener;
        }
    }
}
 

public void load() {
  am = (AccessibilityManager) getContext().getSystemService(ACCESSIBILITY_SERVICE);

  am.addTouchExplorationStateChangeListener(new AccessibilityManager.TouchExplorationStateChangeListener() {
    @Override
    public void onTouchExplorationStateChanged(boolean b) {
      JSObject ret = new JSObject();
      ret.put("value", b);
      notifyListeners(EVENT_SCREEN_READER_STATE_CHANGE, ret);
    }
  });
}
 

@SuppressLint("NewApi")
@Override
public void postInflationStartup() {
    super.postInflationStartup();

    mSnackbarManager = new SnackbarManager(this);
    mDataUseSnackbarController = new DataUseSnackbarController(this, getSnackbarManager());

    mAssistStatusHandler = createAssistStatusHandler();
    if (mAssistStatusHandler != null) {
        if (mTabModelSelector != null) {
            mAssistStatusHandler.setTabModelSelector(mTabModelSelector);
        }
        mAssistStatusHandler.updateAssistState();
    }

    // If a user had ALLOW_LOW_END_DEVICE_UI explicitly set to false then we manually override
    // SysUtils.isLowEndDevice() with a switch so that they continue to see the normal UI. This
    // is only the case for grandfathered-in svelte users. We no longer do so for newer users.
    if (!ChromePreferenceManager.getInstance(this).getAllowLowEndDeviceUi()) {
        CommandLine.getInstance().appendSwitch(
                BaseSwitches.DISABLE_LOW_END_DEVICE_MODE);
    }

    AccessibilityManager manager = (AccessibilityManager)
            getBaseContext().getSystemService(Context.ACCESSIBILITY_SERVICE);
    manager.addAccessibilityStateChangeListener(this);
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
        mTouchExplorationStateChangeListener = new TouchExplorationStateChangeListener() {
            @Override
            public void onTouchExplorationStateChanged(boolean enabled) {
                checkAccessibility();
            }
        };
        manager.addTouchExplorationStateChangeListener(mTouchExplorationStateChangeListener);
    }

    // Make the activity listen to policy change events
    getChromeApplication().addPolicyChangeListener(this);

    // Set up the animation placeholder to be the SurfaceView. This disables the
    // SurfaceView's 'hole' clipping during animations that are notified to the window.
    mWindowAndroid.setAnimationPlaceholderView(mCompositorViewHolder.getSurfaceView());

    // Inform the WindowAndroid of the keyboard accessory view.
    mWindowAndroid.setKeyboardAccessoryView((ViewGroup) findViewById(R.id.keyboard_accessory));
    initializeToolbar();
}
 

@SuppressLint("NewApi")
@Override
public void postInflationStartup() {
    super.postInflationStartup();

    mSnackbarManager = new SnackbarManager(this);
    mDataUseSnackbarController = new DataUseSnackbarController(this, getSnackbarManager());

    mAssistStatusHandler = createAssistStatusHandler();
    if (mAssistStatusHandler != null) {
        if (mTabModelSelector != null) {
            mAssistStatusHandler.setTabModelSelector(mTabModelSelector);
        }
        mAssistStatusHandler.updateAssistState();
    }

    // If a user had ALLOW_LOW_END_DEVICE_UI explicitly set to false then we manually override
    // SysUtils.isLowEndDevice() with a switch so that they continue to see the normal UI. This
    // is only the case for grandfathered-in svelte users. We no longer do so for newer users.
    if (!ChromePreferenceManager.getInstance(this).getAllowLowEndDeviceUi()) {
        CommandLine.getInstance().appendSwitch(
                BaseSwitches.DISABLE_LOW_END_DEVICE_MODE);
    }

    AccessibilityManager manager = (AccessibilityManager)
            getBaseContext().getSystemService(Context.ACCESSIBILITY_SERVICE);
    manager.addAccessibilityStateChangeListener(this);
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
        mTouchExplorationStateChangeListener = new TouchExplorationStateChangeListener() {
            @Override
            public void onTouchExplorationStateChanged(boolean enabled) {
                checkAccessibility();
            }
        };
        manager.addTouchExplorationStateChangeListener(mTouchExplorationStateChangeListener);
    }

    // Make the activity listen to policy change events
    CombinedPolicyProvider.get().addPolicyChangeListener(this);

    // Set up the animation placeholder to be the SurfaceView. This disables the
    // SurfaceView's 'hole' clipping during animations that are notified to the window.
    mWindowAndroid.setAnimationPlaceholderView(mCompositorViewHolder.getSurfaceView());

    // Inform the WindowAndroid of the keyboard accessory view.
    mWindowAndroid.setKeyboardAccessoryView((ViewGroup) findViewById(R.id.keyboard_accessory));
    initializeToolbar();
    initializeTabModels();
    if (!isFinishing() && getFullscreenManager() != null) {
        getFullscreenManager().initialize(
                (ControlContainer) findViewById(R.id.control_container),
                getTabModelSelector(),
                getControlContainerHeightResource());
    }
}
 

@SuppressLint("NewApi")
@Override
public void postInflationStartup() {
    super.postInflationStartup();

    mSnackbarManager = new SnackbarManager(this, null);
    mDataUseSnackbarController = new DataUseSnackbarController(this, getSnackbarManager());

    mAssistStatusHandler = createAssistStatusHandler();
    if (mAssistStatusHandler != null) {
        if (mTabModelSelector != null) {
            mAssistStatusHandler.setTabModelSelector(mTabModelSelector);
        }
        mAssistStatusHandler.updateAssistState();
    }

    // If a user had ALLOW_LOW_END_DEVICE_UI explicitly set to false then we manually override
    // SysUtils.isLowEndDevice() with a switch so that they continue to see the normal UI. This
    // is only the case for grandfathered-in svelte users. We no longer do so for newer users.
    if (!ChromePreferenceManager.getInstance().getAllowLowEndDeviceUi()) {
        CommandLine.getInstance().appendSwitch(
                BaseSwitches.DISABLE_LOW_END_DEVICE_MODE);
    }

    AccessibilityManager manager = (AccessibilityManager)
            getBaseContext().getSystemService(Context.ACCESSIBILITY_SERVICE);
    manager.addAccessibilityStateChangeListener(this);
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
        mTouchExplorationStateChangeListener = new TouchExplorationStateChangeListener() {
            @Override
            public void onTouchExplorationStateChanged(boolean enabled) {
                checkAccessibility();
            }
        };
        manager.addTouchExplorationStateChangeListener(mTouchExplorationStateChangeListener);
    }

    // Make the activity listen to policy change events
    CombinedPolicyProvider.get().addPolicyChangeListener(this);
    mDidAddPolicyChangeListener = true;

    // Set up the animation placeholder to be the SurfaceView. This disables the
    // SurfaceView's 'hole' clipping during animations that are notified to the window.
    getWindowAndroid().setAnimationPlaceholderView(mCompositorViewHolder.getCompositorView());

    // Inform the WindowAndroid of the keyboard accessory view.
    getWindowAndroid().setKeyboardAccessoryView(
            (ViewGroup) findViewById(R.id.keyboard_accessory));
    initializeToolbar();
    initializeTabModels();
    if (!isFinishing() && getFullscreenManager() != null) {
        getFullscreenManager().initialize(
                (ControlContainer) findViewById(R.id.control_container),
                getTabModelSelector(),
                getControlContainerHeightResource());
    }

    if (mBottomSheet != null) {
        mBottomSheet.setTabModelSelector(mTabModelSelector);
        mBottomSheet.setFullscreenManager(mFullscreenManager);

        mFadingBackgroundView = (FadingBackgroundView) findViewById(R.id.fading_focus_target);
        mBottomSheet.addObserver(new EmptyBottomSheetObserver() {
            @Override
            public void onTransitionPeekToHalf(float transitionFraction) {
                mFadingBackgroundView.setViewAlpha(transitionFraction);
            }
        });
        mFadingBackgroundView.addObserver(mBottomSheet);

        mBottomSheetContentController =
                (BottomSheetContentController) ((ViewStub) findViewById(R.id.bottom_nav_stub))
                        .inflate();
        int controlContainerHeight =
                ((ControlContainer) findViewById(R.id.control_container)).getView().getHeight();
        mBottomSheetContentController.init(
                mBottomSheet, controlContainerHeight, mTabModelSelector, this);
    }
    ((BottomContainer) findViewById(R.id.bottom_container)).initialize(mFullscreenManager);
}