gecko-dev/mobile/android/base/TextSelection.java

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this file,
 * You can obtain one at http://mozilla.org/MPL/2.0/. */

package org.mozilla.gecko;

import org.mozilla.gecko.gfx.BitmapUtils;
import org.mozilla.gecko.gfx.BitmapUtils.BitmapLoader;
import org.mozilla.gecko.gfx.Layer;
import org.mozilla.gecko.gfx.LayerView;
import org.mozilla.gecko.gfx.LayerView.DrawListener;
import org.mozilla.gecko.menu.GeckoMenu;
import org.mozilla.gecko.menu.GeckoMenuItem;
import org.mozilla.gecko.EventDispatcher;
import org.mozilla.gecko.util.FloatUtils;
import org.mozilla.gecko.util.GeckoEventListener;
import org.mozilla.gecko.util.ThreadUtils;
import org.mozilla.gecko.ActionModeCompat.Callback;

import android.content.Context;
import android.app.Activity;
import android.graphics.drawable.Drawable;
import android.view.Menu;
import android.view.MenuItem;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.util.Timer;
import java.util.TimerTask;

import android.util.Log;
import android.view.View;

class TextSelection extends Layer implements GeckoEventListener {
    private static final String LOGTAG = "GeckoTextSelection";

    private final TextSelectionHandle mStartHandle;
    private final TextSelectionHandle mMiddleHandle;
    private final TextSelectionHandle mEndHandle;
    private final EventDispatcher mEventDispatcher;

    private final DrawListener mDrawListener;
    private boolean mDraggingHandles;

    private float mViewLeft;
    private float mViewTop;
    private float mViewZoom;

    private String mCurrentItems;

    private TextSelectionActionModeCallback mCallback;

    // These timers are used to avoid flicker caused by selection handles showing/hiding quickly. For isntance
    // when moving between single handle caret mode and two handle selection mode.
    private Timer mActionModeTimer = new Timer("actionMode");
    private class ActionModeTimerTask extends TimerTask {
        @Override
        public void run() {
            ThreadUtils.postToUiThread(new Runnable() {
                @Override
                public void run() {
                    endActionMode();
                }
            });
        }
    };
    private ActionModeTimerTask mActionModeTimerTask;

    TextSelection(TextSelectionHandle startHandle,
                  TextSelectionHandle middleHandle,
                  TextSelectionHandle endHandle,
                  EventDispatcher eventDispatcher,
                  GeckoApp activity) {
        mStartHandle = startHandle;
        mMiddleHandle = middleHandle;
        mEndHandle = endHandle;
        mEventDispatcher = eventDispatcher;

        mDrawListener = new DrawListener() {
            @Override
            public void drawFinished() {
                if (!mDraggingHandles) {
                    GeckoAppShell.sendEventToGecko(GeckoEvent.createBroadcastEvent("TextSelection:LayerReflow", ""));
                }
            }
        };

        // Only register listeners if we have valid start/middle/end handles
        if (mStartHandle == null || mMiddleHandle == null || mEndHandle == null) {
            Log.e(LOGTAG, "Failed to initialize text selection because at least one handle is null");
        } else {
            EventDispatcher.getInstance().registerGeckoThreadListener(this,
                "TextSelection:ShowHandles",
                "TextSelection:HideHandles",
                "TextSelection:PositionHandles",
                "TextSelection:Update",
                "TextSelection:DraggingHandle");
        }
    }

    void destroy() {
        EventDispatcher.getInstance().unregisterGeckoThreadListener(this,
            "TextSelection:ShowHandles",
            "TextSelection:HideHandles",
            "TextSelection:PositionHandles",
            "TextSelection:Update",
            "TextSelection:DraggingHandle");
    }

    private TextSelectionHandle getHandle(String name) {
        if (name.equals("START")) {
            return mStartHandle;
        } else if (name.equals("MIDDLE")) {
            return mMiddleHandle;
        } else {
            return mEndHandle;
        }
    }

    @Override
    public void handleMessage(final String event, final JSONObject message) {
        if ("TextSelection:DraggingHandle".equals(event)) {
            mDraggingHandles = message.optBoolean("dragging", false);
            return;
        }

        ThreadUtils.postToUiThread(new Runnable() {
            @Override
            public void run() {
                try {
                    if (event.equals("TextSelection:ShowHandles")) {
                        final JSONArray handles = message.getJSONArray("handles");
                        for (int i=0; i < handles.length(); i++) {
                            String handle = handles.getString(i);
                            getHandle(handle).setVisibility(View.VISIBLE);
                        }

                        mViewLeft = 0.0f;
                        mViewTop = 0.0f;
                        mViewZoom = 0.0f;

                        // Create text selection layer and add draw-listener for positioning on reflows
                        LayerView layerView = GeckoAppShell.getLayerView();
                        if (layerView != null) {
                            layerView.addDrawListener(mDrawListener);
                            layerView.addLayer(TextSelection.this);
                        }

                        if (handles.length() > 1)
                            GeckoAppShell.performHapticFeedback(true);
                    } else if (event.equals("TextSelection:Update")) {
                        if (mActionModeTimerTask != null)
                            mActionModeTimerTask.cancel();
                        showActionMode(message.getJSONArray("actions"));
                    } else if (event.equals("TextSelection:HideHandles")) {
                        // Remove draw-listener and text selection layer
                        LayerView layerView = GeckoAppShell.getLayerView();
                        if (layerView != null) {
                            layerView.removeDrawListener(mDrawListener);
                            layerView.removeLayer(TextSelection.this);
                        }

                        mActionModeTimerTask = new ActionModeTimerTask();
                        mActionModeTimer.schedule(mActionModeTimerTask, 250);

                        mStartHandle.setVisibility(View.GONE);
                        mMiddleHandle.setVisibility(View.GONE);
                        mEndHandle.setVisibility(View.GONE);
                    } else if (event.equals("TextSelection:PositionHandles")) {
                        final boolean rtl = message.getBoolean("rtl");
                        final JSONArray positions = message.getJSONArray("positions");
                        for (int i=0; i < positions.length(); i++) {
                            JSONObject position = positions.getJSONObject(i);
                            int left = position.getInt("left");
                            int top = position.getInt("top");

                            TextSelectionHandle handle = getHandle(position.getString("handle"));
                            handle.setVisibility(position.getBoolean("hidden") ? View.GONE : View.VISIBLE);
                            handle.positionFromGecko(left, top, rtl);
                        }
                    }
                } catch (JSONException e) {
                    Log.e(LOGTAG, "JSON exception", e);
                }
            }
        });
    }

    private void showActionMode(final JSONArray items) {
	String itemsString = items.toString();
	if (itemsString.equals(mCurrentItems)) {
	    return;
	}
	mCurrentItems = itemsString;

        if (mCallback != null) {
            mCallback.updateItems(items);
            return;
        }

        final Context context = mStartHandle.getContext();
        if (context instanceof ActionModeCompat.Presenter) {
            final ActionModeCompat.Presenter presenter = (ActionModeCompat.Presenter) context;
            mCallback = new TextSelectionActionModeCallback(items);
            presenter.startActionModeCompat(mCallback);
        }
    }

    private void endActionMode() {
        Context context = mStartHandle.getContext();
        if (context instanceof ActionModeCompat.Presenter) {
            final ActionModeCompat.Presenter presenter = (ActionModeCompat.Presenter) context;
            presenter.endActionModeCompat();
        }
	mCurrentItems = null;
    }

    @Override
    public void draw(final RenderContext context) {
        // cache the relevant values from the context and bail out if they are the same. we do this
        // because this draw function gets called a lot (once per compositor frame) and we want to
        // avoid doing a lot of extra work in cases where it's not needed.
        final float viewLeft = context.viewport.left - context.offset.x;
        final float viewTop = context.viewport.top - context.offset.y;
        final float viewZoom = context.zoomFactor;

        if (FloatUtils.fuzzyEquals(mViewLeft, viewLeft)
                && FloatUtils.fuzzyEquals(mViewTop, viewTop)
                && FloatUtils.fuzzyEquals(mViewZoom, viewZoom)) {
            return;
        }
        mViewLeft = viewLeft;
        mViewTop = viewTop;
        mViewZoom = viewZoom;

        ThreadUtils.postToUiThread(new Runnable() {
            @Override
            public void run() {
                mStartHandle.repositionWithViewport(viewLeft, viewTop, viewZoom);
                mMiddleHandle.repositionWithViewport(viewLeft, viewTop, viewZoom);
                mEndHandle.repositionWithViewport(viewLeft, viewTop, viewZoom);
            }
        });
    }

    private class TextSelectionActionModeCallback implements Callback {
        private JSONArray mItems;
        private ActionModeCompat mActionMode;
    
        public TextSelectionActionModeCallback(JSONArray items) {
            mItems = items;
        }

        public void updateItems(JSONArray items) {
            mItems = items;
            if (mActionMode != null) {
                mActionMode.invalidate();
            }
        }

        @Override
        public boolean onPrepareActionMode(final ActionModeCompat mode, final Menu menu) {
            // Android would normally expect us to only update the state of menu items here
            // To make the js-java interaction a bit simpler, we just wipe out the menu here and recreate all
            // the javascript menu items in onPrepare instead. This will be called any time invalidate() is called on the
            // action mode.
            menu.clear();

            int length = mItems.length();
            for (int i = 0; i < length; i++) {
                try {
                    final JSONObject obj = mItems.getJSONObject(i);
                    final GeckoMenuItem menuitem = (GeckoMenuItem) menu.add(0, i, 0, obj.optString("label"));
                    final int actionEnum = obj.optBoolean("showAsAction") ? GeckoMenuItem.SHOW_AS_ACTION_ALWAYS : GeckoMenuItem.SHOW_AS_ACTION_NEVER;
                    menuitem.setShowAsAction(actionEnum, R.attr.menuItemActionModeStyle);

                    BitmapUtils.getDrawable(mStartHandle.getContext(), obj.optString("icon"), new BitmapLoader() {
                        public void onBitmapFound(Drawable d) {
                            if (d != null) {
                                menuitem.setIcon(d);
                            }
                        }
                    });
                } catch(Exception ex) {
                    Log.i(LOGTAG, "Exception building menu", ex);
                }
            }
            return true;
        }

        public boolean onCreateActionMode(ActionModeCompat mode, Menu menu) {
            mActionMode = mode;
            return true;
        }

        public boolean onActionItemClicked(ActionModeCompat mode, MenuItem item) {
            try {
                final JSONObject obj = mItems.getJSONObject(item.getItemId());
                GeckoAppShell.sendEventToGecko(GeckoEvent.createBroadcastEvent("TextSelection:Action", obj.optString("id")));
                return true;
            } catch(Exception ex) {
                Log.i(LOGTAG, "Exception calling action", ex);
            }
            return false;
        }

        // Called when the user exits the action mode
        public void onDestroyActionMode(ActionModeCompat mode) {
            mActionMode = null;
            mCallback = null;
            GeckoAppShell.sendEventToGecko(GeckoEvent.createBroadcastEvent("TextSelection:End", null));
        }
    }
}