1 /* 2 * Copyright (C) 2022 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.settings.accessibility; 18 19 import android.content.Context; 20 import android.util.AttributeSet; 21 import android.view.View; 22 23 import androidx.preference.Preference; 24 import androidx.preference.PreferenceViewHolder; 25 import androidx.viewpager.widget.ViewPager; 26 27 import com.android.internal.util.Preconditions; 28 import com.android.settings.R; 29 import com.android.settings.display.PreviewPagerAdapter; 30 import com.android.settings.widget.DotsPageIndicator; 31 32 /** 33 * A {@link Preference} that could show the preview related to the text and reading options. 34 */ 35 public class TextReadingPreviewPreference extends Preference { 36 private int mCurrentItem; 37 private int mLastLayerIndex; 38 private PreviewPagerAdapter mPreviewAdapter; 39 40 private final ViewPager.OnPageChangeListener mPageChangeListener = 41 new ViewPager.OnPageChangeListener() { 42 @Override 43 public void onPageScrolled(int i, float v, int i1) { 44 // Do nothing 45 } 46 47 @Override 48 public void onPageSelected(int i) { 49 mCurrentItem = i; 50 } 51 52 @Override 53 public void onPageScrollStateChanged(int i) { 54 // Do nothing 55 } 56 }; 57 TextReadingPreviewPreference(Context context)58 TextReadingPreviewPreference(Context context) { 59 super(context); 60 init(); 61 } 62 TextReadingPreviewPreference(Context context, AttributeSet attrs)63 public TextReadingPreviewPreference(Context context, AttributeSet attrs) { 64 super(context, attrs); 65 init(); 66 } 67 TextReadingPreviewPreference(Context context, AttributeSet attrs, int defStyleAttr)68 TextReadingPreviewPreference(Context context, AttributeSet attrs, int defStyleAttr) { 69 super(context, attrs, defStyleAttr); 70 init(); 71 } 72 TextReadingPreviewPreference(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes)73 TextReadingPreviewPreference(Context context, AttributeSet attrs, int defStyleAttr, 74 int defStyleRes) { 75 super(context, attrs, defStyleAttr, defStyleRes); 76 init(); 77 } 78 79 @Override onBindViewHolder(PreferenceViewHolder holder)80 public void onBindViewHolder(PreferenceViewHolder holder) { 81 super.onBindViewHolder(holder); 82 83 final ViewPager viewPager = (ViewPager) holder.findViewById(R.id.preview_pager); 84 viewPager.addOnPageChangeListener(mPageChangeListener); 85 final DotsPageIndicator pageIndicator = 86 (DotsPageIndicator) holder.findViewById(R.id.page_indicator); 87 updateAdapterIfNeeded(viewPager, pageIndicator, mPreviewAdapter); 88 updatePagerAndIndicator(viewPager, pageIndicator); 89 } 90 setPreviewAdapter(PreviewPagerAdapter previewAdapter)91 void setPreviewAdapter(PreviewPagerAdapter previewAdapter) { 92 if (previewAdapter != mPreviewAdapter) { 93 mPreviewAdapter = previewAdapter; 94 notifyChanged(); 95 } 96 } 97 setCurrentItem(int currentItem)98 void setCurrentItem(int currentItem) { 99 Preconditions.checkNotNull(mPreviewAdapter, 100 "Preview adapter is null, you should init the preview adapter first"); 101 102 if (currentItem != mCurrentItem) { 103 mCurrentItem = currentItem; 104 notifyChanged(); 105 } 106 } 107 setLastLayerIndex(int lastLayerIndex)108 void setLastLayerIndex(int lastLayerIndex) { 109 mLastLayerIndex = lastLayerIndex; 110 } 111 getCurrentItem()112 int getCurrentItem() { 113 return mCurrentItem; 114 } 115 updateAdapterIfNeeded(ViewPager viewPager, DotsPageIndicator pageIndicator, PreviewPagerAdapter previewAdapter)116 private void updateAdapterIfNeeded(ViewPager viewPager, DotsPageIndicator pageIndicator, 117 PreviewPagerAdapter previewAdapter) { 118 if (viewPager.getAdapter() == previewAdapter) { 119 return; 120 } 121 122 viewPager.setAdapter(previewAdapter); 123 124 if (previewAdapter != null) { 125 pageIndicator.setViewPager(viewPager); 126 } else { 127 mCurrentItem = 0; 128 } 129 } 130 updatePagerAndIndicator(ViewPager viewPager, DotsPageIndicator pageIndicator)131 private void updatePagerAndIndicator(ViewPager viewPager, DotsPageIndicator pageIndicator) { 132 if (viewPager.getAdapter() == null) { 133 return; 134 } 135 136 if (viewPager.getCurrentItem() != mCurrentItem) { 137 viewPager.setCurrentItem(mCurrentItem); 138 } 139 140 pageIndicator.setVisibility( 141 viewPager.getAdapter().getCount() > 1 ? View.VISIBLE : View.GONE); 142 } 143 init()144 private void init() { 145 setLayoutResource(R.layout.accessibility_text_reading_preview); 146 } 147 notifyPreviewPagerChanged(int pagerIndex)148 void notifyPreviewPagerChanged(int pagerIndex) { 149 Preconditions.checkNotNull(mPreviewAdapter, 150 "Preview adapter is null, you should init the preview adapter first"); 151 152 if (pagerIndex != mLastLayerIndex) { 153 mPreviewAdapter.setPreviewLayer(pagerIndex, mLastLayerIndex, getCurrentItem(), 154 /* animate= */ false); 155 } 156 157 mLastLayerIndex = pagerIndex; 158 } 159 } 160