Xamarin 简明教程
Xamarin - Android Dialogs
Alert Dialog
在本节中,我们将创建一个按钮,单击后显示一个警示对话框。对话框包含两个按钮,即 Delete 和 Cancel 按钮。
首先,转至 main.axml 并创建线性布局内的按钮,如下面的代码所示。
<?xml version = "1.0" encoding = "utf-8"?>
<LinearLayout xmlns:android = "http://schemas.android.com/apk/res/android"
android:orientation = "vertical"
android:layout_width = "fill_parent"
android:background = "#d3d3d3"
android:layout_height = "fill_parent">
<Button
android:id="@+id/MyButton"
android:layout_width = "fill_parent"
android:layout_height = "wrap_content"
android:text = "Click to Delete"
android:textColor = "@android:color/background_dark"
android:background = "@android:color/holo_green_dark" />
</LinearLayout>
接下来,打开 MainActivity.cs 来创建警示对话框并添加其功能。
protected override void OnCreate(Bundle bundle) {
base.OnCreate(bundle);
SetContentView(Resource.Layout.Main);
Button button = FindViewById<Button>(Resource.Id.MyButton);
button.Click += delegate {
AlertDialog.Builder alertDiag = new AlertDialog.Builder(this);
alertDiag.SetTitle("Confirm delete");
alertDiag.SetMessage("Once deleted the move cannot be undone");
alertDiag.SetPositiveButton("Delete", (senderAlert, args) => {
Toast.MakeText(this, "Deleted", ToastLength.Short).Show();
});
alertDiag.SetNegativeButton("Cancel", (senderAlert, args) => {
alertDiag.Dispose();
});
Dialog diag = alertDiag.Create();
diag.Show();
};
}
完成后,构建并运行你的应用程序来查看输出。
在上面的代码中,我们创建了一个称为 alertDiag 的警报对话框,它具有以下两个按钮 -
-
setPositiveButton - 它包含 Delete 按钮操作,单击后会显示确认消息 Deleted 。
-
setNegativeButton - 它包含一个 Cancel 按钮,单击该按钮会直接关闭警报对话框。