src/com/android/launcher2/LauncherAppWidgetHostView.java

/*
 * Copyright (C) 2009 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.launcher2;

import android.appwidget.AppWidgetHostView;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewConfiguration;
import android.view.ViewGroup;

import com.android.launcher.R;

/**
 * {@inheritDoc}
 */
public class LauncherAppWidgetHostView extends AppWidgetHostView
    implements VisibilityChangedBroadcaster {
    private boolean mHasPerformedLongPress;
    private CheckForLongPress mPendingCheckForLongPress;
    private LayoutInflater mInflater;
    private VisibilityChangedListener mOnVisibilityChangedListener;

    public LauncherAppWidgetHostView(Context context) {
        super(context);
        mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }
    
    @Override
    protected View getErrorView() {
        return mInflater.inflate(R.layout.appwidget_error, this, false);
    }

    public boolean onInterceptTouchEvent(MotionEvent ev) {
        // Consume any touch events for ourselves after longpress is triggered
        if (mHasPerformedLongPress) {
            mHasPerformedLongPress = false;
            return true;
        }
            
        // Watch for longpress events at this level to make sure
        // users can always pick up this widget
        switch (ev.getAction()) {
            case MotionEvent.ACTION_DOWN: {
                postCheckForLongClick();
                break;
            }
            
            case MotionEvent.ACTION_UP:
            case MotionEvent.ACTION_CANCEL:
                mHasPerformedLongPress = false;
                if (mPendingCheckForLongPress != null) {
                    removeCallbacks(mPendingCheckForLongPress);
                }
                break;
        }
        
        // Otherwise continue letting touch events fall through to children
        return false;
    }

    class CheckForLongPress implements Runnable {
        private int mOriginalWindowAttachCount;

        public void run() {
            if ((mParent != null) && hasWindowFocus()
                    && mOriginalWindowAttachCount == getWindowAttachCount()
                    && !mHasPerformedLongPress) {
                if (performLongClick()) {
                    mHasPerformedLongPress = true;
                }
            }
        }

        public void rememberWindowAttachCount() {
            mOriginalWindowAttachCount = getWindowAttachCount();
        }
    }

    private void postCheckForLongClick() {
        mHasPerformedLongPress = false;

        if (mPendingCheckForLongPress == null) {
            mPendingCheckForLongPress = new CheckForLongPress();
        }
        mPendingCheckForLongPress.rememberWindowAttachCount();
        postDelayed(mPendingCheckForLongPress, ViewConfiguration.getLongPressTimeout());
    }

    @Override
    public void cancelLongPress() {
        super.cancelLongPress();

        mHasPerformedLongPress = false;
        if (mPendingCheckForLongPress != null) {
            removeCallbacks(mPendingCheckForLongPress);
        }
    }

    public void setVisibilityChangedListener(VisibilityChangedListener listener) {
        mOnVisibilityChangedListener = listener;
    }

    @Override
    protected void onVisibilityChanged(View changedView, int visibility) {
        if (mOnVisibilityChangedListener != null) {
            mOnVisibilityChangedListener.receiveVisibilityChangedMessage(this);
        }
        super.onVisibilityChanged(changedView, visibility);
    }

    @Override
    public int getDescendantFocusability() {
        return ViewGroup.FOCUS_BLOCK_DESCENDANTS;
    }
}