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      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  */
     16 package com.android.browser;
     17 
     18 import android.os.SystemClock;
     19 import android.view.MotionEvent;
     20 import android.view.View;
     21 import android.view.View.OnTouchListener;
     22 import android.view.ViewConfiguration;
     23 import android.webkit.WebView;
     24 
     25 import 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  */
     31 public 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     private boolean mIsScrolling;
     50 
     51     public UrlBarAutoShowManager(BaseUi ui) {
     52         mUi = ui;
     53         ViewConfiguration config = ViewConfiguration.get(mUi.getActivity());
     54         mSlop = config.getScaledTouchSlop() * 2;
     55     }
     56 
     57     public void setTarget(BrowserWebView v) {
     58         if (mTarget == v) return;
     59 
     60         if (mTarget != null) {
     61             mTarget.setOnTouchListener(null);
     62             mTarget.setOnScrollChangedListener(null);
     63         }
     64         mTarget = v;
     65         if (mTarget != null) {
     66             mTarget.setOnTouchListener(this);
     67             mTarget.setOnScrollChangedListener(this);
     68         }
     69     }
     70 
     71     @Override
     72     public void onScrollChanged(int l, int t, int oldl, int oldt) {
     73         mLastScrollTime = SystemClock.uptimeMillis();
     74         mIsScrolling = true;
     75         if (t != 0) {
     76             // If it is showing, extend it
     77             if (mUi.isTitleBarShowing()) {
     78                 long remaining = mLastScrollTime - mTriggeredTime;
     79                 remaining = Math.max(BaseUi.HIDE_TITLEBAR_DELAY - remaining,
     80                         SCROLL_TIMEOUT_DURATION);
     81                 mUi.showTitleBarForDuration(remaining);
     82             }
     83         } else {
     84             mUi.suggestHideTitleBar();
     85         }
     86     }
     87 
     88     void stopTracking() {
     89         if (mIsTracking) {
     90             mIsTracking = false;
     91             mIsScrolling = false;
     92             if (mUi.isTitleBarShowing()) {
     93                 mUi.showTitleBarForDuration();
     94             }
     95         }
     96     }
     97 
     98     @Override
     99     public boolean onTouch(View v, MotionEvent event) {
    100         if (event.getPointerCount() > 1) {
    101             stopTracking();
    102         }
    103         switch (event.getAction()) {
    104         case MotionEvent.ACTION_DOWN:
    105             if (!mIsTracking && event.getPointerCount() == 1) {
    106                 long sinceLastScroll =
    107                         SystemClock.uptimeMillis() - mLastScrollTime;
    108                 if (sinceLastScroll < IGNORE_INTERVAL) {
    109                     break;
    110                 }
    111                 mStartTouchY = event.getY();
    112                 mStartTouchX = event.getX();
    113                 mIsTracking = true;
    114                 mHasTriggered = false;
    115             }
    116             break;
    117         case MotionEvent.ACTION_MOVE:
    118             if (mIsTracking && !mHasTriggered) {
    119                 WebView web = (WebView) v;
    120                 float dy = event.getY() - mStartTouchY;
    121                 float ady = Math.abs(dy);
    122                 float adx = Math.abs(event.getX() - mStartTouchX);
    123                 if (ady > mSlop) {
    124                     mHasTriggered = true;
    125                     float angle = (float) Math.atan2(ady, adx);
    126                     if (dy > mSlop && angle > V_TRIGGER_ANGLE
    127                             && !mUi.isTitleBarShowing()
    128                             && (web.getVisibleTitleHeight() == 0
    129                             || (!mIsScrolling && web.getScrollY() > 0))) {
    130                         mTriggeredTime = SystemClock.uptimeMillis();
    131                         mUi.showTitleBar();
    132                     }
    133                 }
    134             }
    135             break;
    136         case MotionEvent.ACTION_CANCEL:
    137         case MotionEvent.ACTION_UP:
    138             stopTracking();
    139             break;
    140         }
    141         return false;
    142     }
    143 
    144 }
    145