Xamarin.Android之引导页的简单制作

Posted 2020-07-19 Catcher Wong

用Xamarin.android做个简单的引导页。

0x01 前言

 　　对于现在大部分的APP，第一次打开刚安装或更新安装的APP都会有几个引导界面，通常这几个引导页是告诉用户

APP有些什么功能或者修改了什么bug、新增了什么功能等等等。

　　下面就用Xamarin.Android来简单实现一下。主要用到的是ViewPager，当然也就离不开Xamarin.Android.Support.v4

如果遇到不能编译的问题，可以参考Xamarin.Android之简单的抽屉布局的出错处理方案。

 0x02 页面布局编写

新建一个Android项目

添加几个简单的布局页面。

首先是添加个启动页面，splash.axml

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     xmlns:tools="http://schemas.android.com/tools"
 4     android:layout_width="match_parent"
 5     android:layout_height="match_parent">
 6     <android.support.v4.view.ViewPager
 7         android:id="@+id/viewpager"
 8         android:layout_width="match_parent"
 9         android:layout_height="match_parent" />
10     <LinearLayout
11         android:id="@+id/ll"
12         android:orientation="horizontal"
13         android:layout_width="wrap_content"
14         android:layout_height="wrap_content"
15         android:layout_marginBottom="24.0dip"
16         android:layout_alignParentBottom="true"
17         android:layout_centerHorizontal="true">
18         <ImageView
19             android:layout_width="wrap_content"
20             android:layout_height="wrap_content"
21             android:layout_gravity="center_vertical"
22             android:clickable="true"
23             android:padding="15.0dip"
24             android:src="@drawable/dot" />
25         <ImageView
26             android:layout_width="wrap_content"
27             android:layout_height="wrap_content"
28             android:layout_gravity="center_vertical"
29             android:clickable="true"
30             android:padding="15.0dip"
31             android:src="@drawable/dot" />
32         <ImageView
33             android:layout_width="wrap_content"
34             android:layout_height="wrap_content"
35             android:layout_gravity="center_vertical"
36             android:clickable="true"
37             android:padding="15.0dip"
38             android:src="@drawable/dot" />
39     </LinearLayout>
40 </RelativeLayout>

引导页，用了一个ViewPager，下面的线性布局是用来存放的三个点就是当前所在的引导页面。

用到的ImageView有个src指向drawable下面的dot.xml。内容如下：

1 <?xml version="1.0" encoding="utf-8" ?>
2 <selector
3   xmlns:android="http://schemas.android.com/apk/res/android">
4   <item android:state_enabled="true" android:drawable="@drawable/dark_dot" />
5   <item android:state_enabled="false" android:drawable="@drawable/white_dot" />
6 </selector>

然后是3个引导页的具体内容。

guide_first.axml

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     android:layout_width="match_parent"
 4     android:layout_height="match_parent"
 5     android:orientation="vertical">
 6     <TextView
 7         android:layout_width="match_parent"
 8         android:layout_height="match_parent"
 9         android:gravity="center"
10         android:text="guide---first"
11         android:textSize="30sp" />
12 </LinearLayout>

guide_second.axml

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     android:layout_width="match_parent"
 4     android:layout_height="match_parent"
 5     android:orientation="vertical">
 6     <TextView
 7         android:layout_width="match_parent"
 8         android:layout_height="match_parent"
 9         android:gravity="center"
10         android:text="guide--second"
11         android:textSize="30sp" />
12 </LinearLayout>

guide_third.axml

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     android:layout_width="match_parent"
 4     android:layout_height="match_parent"
 5     android:orientation="vertical">
 6     <TextView
 7         android:layout_width="match_parent"
 8         android:layout_height="wrap_content"
 9         android:layout_marginTop="250dp"
10         android:gravity="center"
11         android:text="guide--third"
12         android:textSize="30sp" />
13     <Button
14         android:id="@+id/startBtn"
15         android:layout_width="wrap_content"
16         android:layout_height="wrap_content"
17         android:layout_alignParentBottom="true"
18         android:layout_centerHorizontal="true"
19         android:text="begin now"
20         android:layout_gravity="center"
21         android:layout_marginBottom="55dp" />
22 </LinearLayout>

这里没有用图片来展示，就简单的用了文字，没有设计师设计，so....随意一点。

最后是Main.axml

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     android:layout_width="fill_parent"
 4     android:layout_height="fill_parent">
 5     <TextView
 6         android:layout_width="fill_parent"
 7         android:layout_height="wrap_content"
 8         android:gravity="center"
 9         android:layout_gravity="center_vertical"
10         android:text="the main page"
11         android:textSize="30sp" />
12 </LinearLayout>

0x03 Activity的编写

首先SplashActivity

 1 using Android.App;
 2 using Android.Content;
 3 using Android.Content.PM;
 4 using Android.OS;
 5 using Android.Widget;
 6 namespace GuideDemo
 7 {
 8     [Activity(Label = "GuideDemo", MainLauncher = true, Icon = "@drawable/icon")]
 9     public class SplashActivity : Activity
10     {
11         protected override void OnCreate(Bundle savedInstanceState)
12         {
13             base.OnCreate(savedInstanceState);
14             SetContentView(Resource.Layout.splash);
15             //version\'s infomation
16             var version = PackageManager.GetPackageInfo(this.PackageName, PackageInfoFlags.MatchAll).VersionName;
17             var tvVersion = FindViewById<TextView>(Resource.Id.tv_version);
18             tvVersion.Text = "Version " + version;
19             //get infomation from shared preferences
20             var sp = GetSharedPreferences("app_setting", FileCreationMode.Private);
21             new Handler().PostDelayed(() =>
22             {
23                 Intent intent;
24                 //first or not
25                 if (sp.GetString("version", "") != version)
26                 {
27                     intent = new Intent(this, typeof(GuideActivity));
28                 }
29                 else
30                 {
31                     intent = new Intent(this, typeof(MainActivity));
32                 }                
33                 StartActivity(intent);
34                 this.Finish();
35             }, 1000);
36         }
37     }
38 }

把是否是第一次开启信息存放到sharepreferences，我这里主要是通过版本号来控制。

然后是GuideActivity

 1 using Android.App;
 2 using Android.Content;
 3 using Android.Content.PM;
 4 using Android.OS;
 5 using Android.Support.V4.View;
 6 using Android.Views;
 7 using Android.Widget;
 8 using System;
 9 using System.Collections.Generic;
10 using static Android.Support.V4.View.ViewPager;
11 namespace GuideDemo
12 {
13     [Activity(Label = "GuideActivity")]
14     public class GuideActivity : Activity
15     {     
16         private ViewPager viewPager;
17      
18         private List<View> views;
19      
20         private View view1, view2, view3;
21      
22         private Button btnStart;
23             
24         private ImageView[] dots;
25         
26         private int currentIndex;
27         private LinearLayout ll;
28         protected override void OnCreate(Bundle savedInstanceState)
29         {
30             base.OnCreate(savedInstanceState);
31             SetContentView(Resource.Layout.activity_guide);
32             viewPager = FindViewById<ViewPager>(Resource.Id.viewpager);
33             //the layout
34             LayoutInflater mLi = LayoutInflater.From(this);
35             view1 = mLi.Inflate(Resource.Layout.guide_first, null);
36             view2 = mLi.Inflate(Resource.Layout.guide_second, null);
37             view3 = mLi.Inflate(Resource.Layout.guide_third, null);
38             views = new List<View>();
39             views.Add(view1);
40             views.Add(view2);
41             views.Add(view3);
42             
43             //the adapter
44             viewPager.Adapter = new ViewPagerAdapter(views);
45             //page selected
46             viewPager.PageSelected += PageSelected;
47             ll = FindViewById<LinearLayout>(Resource.Id.ll);
48             //the dot infomation
49             dots = new ImageView[3];
50             for (int i = 0; i < views.Count; i++)
51             {
52                 dots[i] = (ImageView)ll.GetChildAt(i);
53                 dots[i].Enabled = false;                
54             }
55             dots[0].Enabled = true;
56             //the button
57             btnStart = view3.FindViewById<Button>(Resource.Id.startBtn);
58             btnStart.Click += Start;
59         }
60         /// <summary>
61         /// page selected
62         /// </summary>
63         /// <param name="sender"></param>
64         /// <param name="e"></param>
65         private void PageSelected(object sender, PageSelectedEventArgs e)
66         {
67             ll = FindViewById<LinearLayout>(Resource.Id.ll);
68             for (int i = 0; i < views.Count; i++)
69             {
70                 dots[i] = (ImageView)ll.GetChildAt(i);
71                 dots[i].Enabled = false;
72             }
73             dots[e.Position].Enabled = true;
74         }
75         /// <summary>
76         /// start the main page
77         /// </summary>
78         /// <param name="sender"></param>
79         /// <param name="e"></param>
80         private void Start(object sender, EventArgs e)
81         {
82             //get infomation from shared preferences
83             var sp = GetSharedPreferences("app_setting", FileCreationMode.Private);
84             //the editor
85             var editor = sp.Edit();
86             //update
87             editor.PutString("version", PackageManager.GetPackageInfo(this.PackageName, PackageInfoFlags.MatchAll).VersionName).Commit() ;
88             StartActivity(typeof(MainActivity));
89             this.Finish();
90         }
91     }
92 }

主要是ViewPager处理、页面切换点的处理以及begin now 按钮的点击事件。

其中有个ViewPagerAdapter要自己实现

 1 using Android.Support.V4.View;
 2 using Android.Views;
 3 using System.Collections.Generic;
 4 namespace GuideDemo
 5 {
 6     internal class ViewPagerAdapter : PagerAdapter
 7     {
 8         private List<View> views;
 9         public ViewPagerAdapter(List<View> views)
10         {
11             this.views = views;
12         }
13         public override int Count
14         {
15             get
16             {
17                 if (views != null)
18                 {
19                     return views.Count;
20                 }
21                 else
22                 { 
23                     return 0;
24                 }
25             }
26         }
27         public override bool IsViewFromObject(View view, Java.Lang.Object objectValue)
28         {
29             return view== objectValue;
30         }
31         public override void DestroyItem(ViewGroup container, int position, Java.Lang.Object objectValue)
32         {
33             container.RemoveView(views[position]);
34         }
35         public override Java.Lang.Object InstantiateItem(ViewGroup container, int position)
36         {
37             container.AddView(views[position], 0);
38             return views[position];
39         }
40     }
41 }

最后是MainActivity

 1 using Android.App;
 2 using Android.OS;
 3 namespace GuideDemo
 4 {
 5     [Activity(Label = "GuideDemo")]
 6     public class MainActivity : Activity
 7     {        
 8         protected override void OnCreate(Bundle bundle)
 9         {
10             base.OnCreate(bundle);
11             
12             SetContentView(Resource.Layout.Main);         
13         }
14     }
15 }

到这里就OK了，下面就来看看效果。

0x04 效果图