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 17 18 package com.android.email.view; 19 20 import android.content.Context; 21 import android.util.AttributeSet; 22 import android.view.MotionEvent; 23 import android.widget.ScrollView; 24 25 /** 26 * A {@link ScrollView} that will never lock scrolling in a particular direction. 27 * 28 * Usually ScrollView will capture all touch events once a drag has begun. In some cases, 29 * we want to delegate those touches to children as normal, even in the middle of a drag. This is 30 * useful when there are childviews like a WebView tha handles scrolling in the horizontal direction 31 * even while the ScrollView drags vertically. 32 * 33 * This is only tested to work for ScrollViews where the content scrolls in one direction. 34 */ 35 public class NonLockingScrollView extends ScrollView { NonLockingScrollView(Context context)36 public NonLockingScrollView(Context context) { 37 super(context); 38 } NonLockingScrollView(Context context, AttributeSet attrs)39 public NonLockingScrollView(Context context, AttributeSet attrs) { 40 super(context, attrs); 41 } NonLockingScrollView(Context context, AttributeSet attrs, int defStyle)42 public NonLockingScrollView(Context context, AttributeSet attrs, int defStyle) { 43 super(context, attrs, defStyle); 44 } 45 46 /** 47 * Whether or not this view is in the middle of a drag. 48 */ 49 private boolean mInDrag = false; 50 51 @Override onInterceptTouchEvent(MotionEvent ev)52 public boolean onInterceptTouchEvent(MotionEvent ev) { 53 final int action = ev.getActionMasked(); 54 final boolean isUp = action == MotionEvent.ACTION_UP; 55 56 if (isUp && mInDrag) { 57 // An up event after a drag should be intercepted so that child views don't handle 58 // click events falsely after a drag. 59 mInDrag = false; 60 onTouchEvent(ev); 61 return true; 62 } 63 64 // Note the normal scrollview implementation is to intercept all touch events after it has 65 // detected a drag starting. We will handle this ourselves. 66 mInDrag = super.onInterceptTouchEvent(ev); 67 if (mInDrag) { 68 onTouchEvent(ev); 69 } 70 71 // Don't intercept events - pass them on to children as normal. 72 return false; 73 } 74 } 75