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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 
     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