UrlBarAutoShowManager.java revision da5d348361f46f9700e51f9ddd76ac5acee7a34c 
1/*
2 * Copyright (C) 2011 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16package com.android.browser;
17
18import android.os.SystemClock;
19import android.view.MotionEvent;
20import android.view.View;
21import android.view.View.OnTouchListener;
22import android.view.ViewConfiguration;
23import android.webkit.WebView;
24
25import com.android.browser.BrowserWebView.OnScrollChangedListener;
26
27/**
28 * Helper class to manage when to show the URL bar based off of touch
29 * input, and when to begin the hide timer.
30 */
31public class UrlBarAutoShowManager implements OnTouchListener,
32        OnScrollChangedListener {
33
34    private static float V_TRIGGER_ANGLE = .9f;
35    private static long SCROLL_TIMEOUT_DURATION = 150;
36    private static long IGNORE_INTERVAL = 250;
37
38    private BrowserWebView mTarget;
39    private BaseUi mUi;
40
41    private int mSlop;
42
43    private float mStartTouchX;
44    private float mStartTouchY;
45    private boolean mIsTracking;
46    private boolean mHasTriggered;
47    private long mLastScrollTime;
48    private long mTriggeredTime;
49
50    public UrlBarAutoShowManager(BaseUi ui) {
51        mUi = ui;
52        ViewConfiguration config = ViewConfiguration.get(mUi.getActivity());
53        mSlop = config.getScaledTouchSlop() * 2;
54    }
55
56    public void setTarget(BrowserWebView v) {
57        if (mTarget == v) return;
58
59        if (mTarget != null) {
60            mTarget.setOnTouchListener(null);
61            mTarget.setOnScrollChangedListener(null);
62        }
63        mTarget = v;
64        if (mTarget != null) {
65            mTarget.setOnTouchListener(this);
66            mTarget.setOnScrollChangedListener(this);
67        }
68    }
69
70    @Override
71    public void onScrollChanged(int l, int t, int oldl, int oldt) {
72        mLastScrollTime = SystemClock.uptimeMillis();
73        if (t != oldt) {
74            if (t != 0) {
75                // If it is showing, extend it
76                if (mUi.isTitleBarShowing()) {
77                    long remaining = mLastScrollTime - mTriggeredTime;
78                    remaining = Math.max(BaseUi.HIDE_TITLEBAR_DELAY - remaining,
79                            SCROLL_TIMEOUT_DURATION);
80                    mUi.showTitleBarForDuration(remaining);
81                }
82            } else {
83                mUi.suggestHideTitleBar();
84            }
85        }
86    }
87
88    void stopTracking() {
89        if (mIsTracking) {
90            mIsTracking = false;
91            if (mUi.isTitleBarShowing()) {
92                mUi.showTitleBarForDuration();
93            }
94        }
95    }
96
97    @Override
98    public boolean onTouch(View v, MotionEvent event) {
99        if (event.getPointerCount() > 1) {
100            stopTracking();
101        }
102        switch (event.getAction()) {
103        case MotionEvent.ACTION_DOWN:
104            if (!mIsTracking && event.getPointerCount() == 1) {
105                long sinceLastScroll =
106                        SystemClock.uptimeMillis() - mLastScrollTime;
107                if (sinceLastScroll < IGNORE_INTERVAL) {
108                    break;
109                }
110                mStartTouchY = event.getY();
111                mStartTouchX = event.getX();
112                mIsTracking = true;
113                mHasTriggered = false;
114            }
115            break;
116        case MotionEvent.ACTION_MOVE:
117            if (mIsTracking && !mHasTriggered) {
118                WebView web = (WebView) v;
119                float dy = event.getY() - mStartTouchY;
120                float ady = Math.abs(dy);
121                float adx = Math.abs(event.getX() - mStartTouchX);
122                if (ady > mSlop) {
123                    mHasTriggered = true;
124                    float angle = (float) Math.atan2(ady, adx);
125                    if (dy > mSlop && angle > V_TRIGGER_ANGLE
126                            && !mUi.isTitleBarShowing()
127                            && web.getVisibleTitleHeight() == 0) {
128                        mTriggeredTime = SystemClock.uptimeMillis();
129                        mUi.showTitleBar();
130                    }
131                }
132            }
133            break;
134        case MotionEvent.ACTION_CANCEL:
135        case MotionEvent.ACTION_UP:
136            stopTracking();
137            break;
138        }
139        return false;
140    }
141
142}
143