1 /* 2 * Copyright (C) 2015 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.example.android.supportv4.view; 18 19 import android.app.Activity; 20 import android.graphics.Color; 21 import android.os.Bundle; 22 import android.util.Pair; 23 import android.view.View; 24 import android.view.ViewGroup; 25 26 import androidx.viewpager.widget.PagerAdapter; 27 import androidx.viewpager.widget.PagerTitleStrip; 28 import androidx.viewpager.widget.ViewPager; 29 30 import com.example.android.supportv4.R; 31 32 import java.util.ArrayList; 33 34 public class ViewPagerActivity extends Activity { 35 private ViewPager mPager; 36 private PagerTitleStrip mTitles; 37 private ColorPagerAdapter mAdapter; 38 39 @Override 40 protected void onCreate(Bundle savedInstanceState) { 41 super.onCreate(savedInstanceState); 42 43 setContentView(R.layout.view_pager_layout); 44 45 mAdapter = new ColorPagerAdapter(); 46 mAdapter.add("Red", Color.RED); 47 mAdapter.add("Green", Color.GREEN); 48 mAdapter.add("Blue", Color.BLUE); 49 50 mPager = findViewById(R.id.pager); 51 mPager.setAdapter(mAdapter); 52 53 mTitles = findViewById(R.id.titles); 54 } 55 56 private static class ColorPagerAdapter extends PagerAdapter { 57 private ArrayList<Pair<String, Integer>> mEntries = new ArrayList<>(); 58 59 public void add(String title, int color) { 60 mEntries.add(new Pair<>(title, color)); 61 } 62 63 @Override 64 public int getCount() { 65 return mEntries.size(); 66 } 67 68 @Override 69 public Object instantiateItem(ViewGroup container, int position) { 70 final View view = new View(container.getContext()); 71 view.setBackgroundColor(mEntries.get(position).second); 72 73 // Unlike ListView adapters, the ViewPager adapter is responsible 74 // for adding the view to the container. 75 container.addView(view); 76 77 return new ViewHolder(view, position); 78 } 79 80 @Override 81 public void destroyItem(ViewGroup container, int position, Object object) { 82 // The adapter is also responsible for removing the view. 83 container.removeView(((ViewHolder) object).view); 84 } 85 86 @Override 87 public int getItemPosition(Object object) { 88 return ((ViewHolder) object).position; 89 } 90 91 @Override 92 public boolean isViewFromObject(View view, Object object) { 93 return ((ViewHolder) object).view == view; 94 } 95 96 @Override 97 public CharSequence getPageTitle(int position) { 98 return mEntries.get(position).first; 99 } 100 101 private static class ViewHolder { 102 final View view; 103 final int position; 104 105 public ViewHolder(View view, int position) { 106 this.view = view; 107 this.position = position; 108 } 109 } 110 } 111 } 112
