1 /* 2 * Copyright (C) 2014 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 package com.android.calculator2; 18 19 import android.content.Context; 20 import android.support.v4.view.PagerAdapter; 21 import android.support.v4.view.ViewPager; 22 import android.util.AttributeSet; 23 import android.view.View; 24 import android.view.ViewGroup; 25 26 public class CalculatorPadViewPager extends ViewPager { 27 28 private final PagerAdapter mStaticPagerAdapter = new PagerAdapter() { 29 @Override 30 public int getCount() { 31 return getChildCount(); 32 } 33 34 @Override 35 public Object instantiateItem(ViewGroup container, int position) { 36 return getChildAt(position); 37 } 38 39 @Override 40 public void destroyItem(ViewGroup container, int position, Object object) { 41 removeViewAt(position); 42 } 43 44 @Override 45 public boolean isViewFromObject(View view, Object object) { 46 return view == object; 47 } 48 49 @Override 50 public float getPageWidth(int position) { 51 return position == 1 ? 7.0f / 9.0f : 1.0f; 52 } 53 }; 54 55 private final OnPageChangeListener mOnPageChangeListener = new SimpleOnPageChangeListener() { 56 private void recursivelySetEnabled(View view, boolean enabled) { 57 if (view instanceof ViewGroup) { 58 final ViewGroup viewGroup = (ViewGroup) view; 59 for (int childIndex = 0; childIndex < viewGroup.getChildCount(); ++childIndex) { 60 recursivelySetEnabled(viewGroup.getChildAt(childIndex), enabled); 61 } 62 } else { 63 view.setEnabled(enabled); 64 } 65 } 66 67 @Override 68 public void onPageSelected(int position) { 69 if (getAdapter() == mStaticPagerAdapter) { 70 for (int childIndex = 0; childIndex < getChildCount(); ++childIndex) { 71 // Only enable subviews of the current page. 72 recursivelySetEnabled(getChildAt(childIndex), childIndex == position); 73 } 74 } 75 } 76 }; 77 78 private final PageTransformer mPageTransformer = new PageTransformer() { 79 @Override 80 public void transformPage(View view, float position) { 81 if (position < 0.0f) { 82 // Pin the left page to the left side. 83 view.setTranslationX(getWidth() * -position); 84 view.setAlpha(Math.max(1.0f + position, 0.0f)); 85 } else { 86 // Use the default slide transition when moving to the next page. 87 view.setTranslationX(0.0f); 88 view.setAlpha(1.0f); 89 } 90 } 91 }; 92 CalculatorPadViewPager(Context context)93 public CalculatorPadViewPager(Context context) { 94 this(context, null); 95 } 96 CalculatorPadViewPager(Context context, AttributeSet attrs)97 public CalculatorPadViewPager(Context context, AttributeSet attrs) { 98 super(context, attrs); 99 100 setAdapter(mStaticPagerAdapter); 101 setBackgroundColor(getResources().getColor(android.R.color.black)); 102 setOnPageChangeListener(mOnPageChangeListener); 103 setPageMargin(getResources().getDimensionPixelSize(R.dimen.pad_page_margin)); 104 setPageTransformer(false, mPageTransformer); 105 } 106 107 @Override onFinishInflate()108 protected void onFinishInflate() { 109 super.onFinishInflate(); 110 111 // Invalidate the adapter's data set since children may have been added during inflation. 112 if (getAdapter() == mStaticPagerAdapter) { 113 mStaticPagerAdapter.notifyDataSetChanged(); 114 } 115 } 116 } 117