xamarin android alertdialog详解

说明一下：学习xamarin android一段时间，准备写一些xamarin android相关的例子，alertdialog也是使用的非常多得空间之一，非常感谢鸟巢上的小猪，我也是看着他写的教程学会的。参考他的那一章 http://www.runoob.com/w3cnote/android-tutorial-alertdialog.html

1.基本使用流程

Step 1：创建AlertDialog.Builder对象；

Step 2：调用setIcon()设置图标，setTitle()或setCustomTitle()设置标题；

Step 3：设置对话框的内容：setMessage()还有其他方法来指定显示的内容；

Step 4：调用setPositive/Negative/NeutralButton()设置：确定，取消，中立按钮；

Step 5：调用create()方法创建这个对象，再调用show()方法将对话框显示出来；

2.几种常用的对话框使用示例

运行效果图：

主要代码：MainActivity.class

public class MainActivity : Activity

    {

        int count = 1;

        private Button btn_alertDialog_one, btn_alertDialog_two, btn_alertDialog_three, btn_alertDialog_four;

        private bool[] checkItems;

        private AlertDialog alertDialog = null;

        private AlertDialog.Builder builder = null;

        protected override void OnCreate(Bundle bundle)

        {

            base.OnCreate(bundle);

            SetContentView(Resource.Layout.Main);

             bindViewClick();

        }

        private void bindViewClick()

        {

            btn_alertDialog_four = FindViewById<Button>(Resource.Id.btn_alertDialog_four);

            btn_alertDialog_three = FindViewById<Button>(Resource.Id.btn_alertDialog_three);

            btn_alertDialog_two = FindViewById<Button>(Resource.Id.btn_alertDialog_two);

            btn_alertDialog_one = FindViewById<Button>(Resource.Id.btn_alertDialog_one);

            btn_alertDialog_one.Click += delegate { onClick(btn_alertDialog_one); };

            btn_alertDialog_two.Click += delegate { onClick(btn_alertDialog_two); };

            btn_alertDialog_three.Click += delegate { onClick(btn_alertDialog_three); };

            btn_alertDialog_four.Click += delegate { onClick(btn_alertDialog_four); };

        }

        private void onClick(View v)

        {

            switch (v.Id)

            {

                case Resource.Id.btn_alertDialog_one:

                    alertDialog = null;

                    builder = new AlertDialog.Builder(this);

                    alertDialog = builder

                   .SetTitle("sure")

                   .SetMessage("are you sure exit?")

                   .SetNegativeButton("cancel", (s, e) =>

                    {

                        Toast.MakeText(this, "you click cancel", ToastLength.Short).Show();

                    })

                   .SetPositiveButton("sure", (s, e) =>

                   {

                       Toast.MakeText(this, "you click sure", ToastLength.Short).Show();

                   })

                   .SetNeutralButton("neutra", (s, e) => {

                       Toast.MakeText(this, "you click neutra", ToastLength.Short).Show();

                   })

                   .Create();       //创建alertDialog对象

                   alertDialog.Show();

                    var dialog = new AlertDialog.Builder(this);

                    break;

                case Resource.Id.btn_alertDialog_two:

                    alertDialog = null;

                    builder = new AlertDialog.Builder(this);

                    string[] players = new string[] {"杜兰特","汤普森","考辛斯","卡戴珊"};

                    alertDialog = builder

                        .SetIcon(Resource.Drawable.players)

                        .SetTitle("选择你喜欢的球员")

                         .SetItems(players, (s, e) =>

                         {

                             Toast.MakeText(this, "you selected " + players[e.Which], ToastLength.Short).Show();

                         })

                        .Create();

                    alertDialog.Show();

                    break;

                case Resource.Id.btn_alertDialog_three:

                    var a = new AlertDialog.Builder(this);

                    string[] teams = new string[] {"骑士","公牛","快船","马刺","勇士" };

                    a.SetTitle("你认为下个赛季哪只球队能夺冠")

                        .SetSingleChoiceItems(teams, 0, (s, e) =>

                        {

                            Toast.MakeText(this, "you selected " + teams[e.Which], ToastLength.Short).Show();

                        })

                        .Create();

                    a.Show();

                    break;

                 case Resource.Id.btn_alertDialog_four:

                    var b = new AlertDialog.Builder(this);

                    string[] menu = new string[] { "麻婆豆腐","羊蝎子","驴肉火烧","辣子鸡丁"};

                    checkItems = new bool[] {false,false,false,false};

                    b = b.SetIcon(Resource.Drawable.Icon)

                      .SetMultiChoiceItems(menu, checkItems, (s, e) => {

                            //Toast.MakeText(this, "you selected " + menu[e.Which], ToastLength.Short).Show();

                            checkItems[e.Which] = e.IsChecked;

                      })

                      .SetPositiveButton("确定", (s, e) => {

                          string result = string.Empty;

                          for (int i = 0; i < checkItems.Length; i++)

                          {

                              if (checkItems[i])

                              {

                                  result += menu[i] + ",";

                              }

                          }

                          Toast.MakeText(this, "you selected " + result, ToastLength.Short).Show();

                      });

                    b.Create();

                    b.Show();

                    break;

            }

        }

    }

用法非常简单创建一个Builder对象后，调用Create方法创建一个AlertDialog对象，最后调用show方法显示出来，当然你也可以像这样直接new 一个AlertDialog对象

 var b = new AlertDialog.Builder(this);

设置一个setCancelable (true|false)看看有没有什么区别

3.通过Builder的setView()定制显示的AlertDialog

我们可以自定义一个与系统对话框不同的布局，然后调用setView()将我们的布局加载到AlertDialog上，上面我们来实现这个效果：

我就贴一下几个主要的布局和样式文件

1.对话框头部的取消按钮样式：在drawable文件下创建一个btn_selector_exit.xml文件，在这里要注意一点item下的属性android:background=“#dedede”,这样直接写会报错，我这里用的是换颜色，所以我在string.xml文件下写了两个颜色，大家要注意一下，我有点想不通的是为什么background属性直接写颜色代码会出错，有点郁闷，如果你有好的解释也可以告诉我这个android的菜鸟

<?xml version="1.0" encoding="utf-8" ?>

<selector xmlns:android="http://schemas.android.com/apk/res/android">

  <item android:state_pressed="true" android:drawable="@drawable/exit_press"/>

  <item android:drawable="@drawable/exit"/>

</selector>

2.底部两个按钮按下换背景色的样式新建一个btn_selector_choose.xml文件

<?xml version="1.0" encoding="utf-8" ?>

<selector xmlns:android="http://schemas.android.com/apk/res/android">

  <item android:state_pressed="true"  android:drawable="@drawable/pressed_color"  />

  <item  android:drawable="@drawable/default_color"  />

</selector>

3.最重要的还是<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:id="@+id/layout_relative"

    android:layout_width="match_parent"

    android:layout_height="match_parent">

<!--头部-->

    <RelativeLayout

        android:id="@+id/layout_title"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:layout_alignParentLeft="true"

        android:layout_alignParentTop="true"

        android:background="#53cc66"

        android:padding="5dp">

        <TextView

            android:layout_width="match_parent"

            android:layout_height="wrap_content"

            android:layout_centerVertical="true"

            android:text="提示文本"

            android:textSize="18sp"

            android:textStyle="bold"

           android:textColor="#ffffff"

        />

        <Button

            android:id="@+id/btn_cancel"

            android:layout_width="30dp"

            android:layout_height="30dp"

            android:layout_alignParentRight="true"

            android:background="@drawable/btn_selector_exit" />

    </RelativeLayout>

<!--中间内容-->

    <LinearLayout

        android:id="@+id/layout_detail"

        android:layout_height="wrap_content"

        android:layout_width="match_parent"

        android:layout_below="@+id/layout_title"

        android:layout_centerInParent="true"

        android:orientation="vertical"

       android:background="#f1f1f1"

        android:padding="20dp"

        >

        <TextView

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:text="通过setView方法定制alertDialog"

            android:textColor="#04AEDA"

            android:textSize="18sp" />

            <TextView

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:text="作者：张林"

            android:textColor="#04AEDA"

            android:textSize="18sp" />

    </LinearLayout>

<!--底部按钮-->

    <LinearLayout

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:layout_below="@+id/layout_detail"

        android:orientation="horizontal"

        android:background="#f1f1f1"

        android:padding="5dp"

      >

        <Button

            android:id="@+id/btn_blog"

            android:layout_width="match_parent"

            android:layout_height="40dp"

            android:layout_weight="1"

            android:background="@drawable/btn_selector_choose"

            android:text="访问博客"

            android:textColor="#ffffff"

            android:textSize="20sp"

            android:layout_marginRight="5dp"

      />

         <Button

            android:id="@+id/btn_close"

            android:layout_width="match_parent"

            android:layout_height="40dp"

            android:layout_weight="1"

            android:background="@drawable/btn_selector_choose"

            android:text="关闭对话框"

            android:textColor="#ffffff"

            android:textSize="20sp" />

    </LinearLayout>

</RelativeLayout>

mainactivity代码，这个布局我就不贴了。

  public class MainActivity : Activity

    {

        private AlertDialog alertDialog = null;

        private AlertDialog.Builder builder = null;

        private Button btn_show = null;

        protected override void OnCreate(Bundle bundle)

        {

            base.OnCreate(bundle);

            SetContentView(Resource.Layout.Main);

             bindViewClick();

            builder = new AlertDialog.Builder(this);

         

            LayoutInflater layoutInflater = LayoutInflater.From(this);

            var view_customer = layoutInflater.Inflate(Resource.Layout.view_dialog_custom, null, false);

            builder.SetView(view_customer);

            builder.SetCancelable(false);

            alertDialog = builder.Create();

            view_customer.FindViewById(Resource.Id.btn_cancel).Click += (s, e) =>

            {

                Toast.MakeText(this, "对话框已关闭", ToastLength.Short).Show();

                alertDialog.Dismiss();

            };

            view_customer.FindViewById(Resource.Id.btn_blog).Click += delegate

            {

                Toast.MakeText(this, "正在访问博客", ToastLength.Short).Show();

                Uri uri = Uri.Parse("http://blog.csdn.net/kebi007");

                Intent intent = new Intent(Intent.ActionView, uri);

                StartActivity(intent);

                alertDialog.Dismiss();

            };

            view_customer.FindViewById(Resource.Id.btn_close).Click += delegate

            {

                Toast.MakeText(this, "对话框已关闭", ToastLength.Short).Show();

                alertDialog.Dismiss();

            };

            btn_show = FindViewById<Button>(Resource.Id.btn_show);

            btn_show.Click += delegate { alertDialog.Show(); };

        }

    }

4.当然还有更高级的自定义的对话框，后面继续...........