如何在 Xamarin Android 中清除 EditText
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【中文标题】如何在 Xamarin Android 中清除 EditText【英文标题】：How Clear EditText in Xamarin Android 【发布时间】：2019-07-25 12:40:20 【问题描述】：单击按钮后，我想在 onfocus 时清除我的 EditText 字段。
此代码是一个短信应用程序，当我点击按钮发送以再次输入另一条消息后，当我专注于 EditText 字段时，我想清除 EditTExt 字段..
我尝试将 gotfocus 属性放在 axml 文件中，但它不起作用.. 我尝试在谷歌上搜索但找不到任何解决方案，其他程序员使用了 gotfocus 属性，但我认为 gotFocus 属性仅在 xaml 文件中可用，而不在 axml 中。
using android.App;
using Android.OS;
using Android.Support.V7.App;
using Android.Runtime;
using Android.Widget;
using Android.Content.PM;
using Android.Telephony;
using System;
using Android;
using Android.Content;
using Android.Support.V4.Content;
using Android.Support.V4.App;
using Android.Util;
using Android.Support.Design.Widget;
using Android.Views;
using Android.Text;
using System.Threading;
namespace MhylesOrderingApp
[Activity(Label = "@string/app_name", Theme = "@style/AppTheme", MainLauncher = true)]
public class MainActivity : AppCompatActivity, ActivityCompat.IOnRequestPermissionsResultCallback
static readonly int REQUEST_SENDSMS = 0;
private SmsManager _smsManager;
private BroadcastReceiver _smsSentBroadcastReceiver, _smsDeliveredBroadcastReceiver;
View layout;
//private ProgressBar spinner;
static Android.App.ProgressDialog progress;
//Android.App.ProgressDialog.progress;
//public virtual ViewStates Visibility get; set;
//SMSSentReceiver receiver;
//private SmsManager smsManager;
protected override void OnCreate(Bundle savedInstanceState)
base.OnCreate(savedInstanceState);
// Set our view from the "main" layout resource
SetContentView(Resource.Layout.activity_main);
layout = FindViewById(Resource.Id.sample_main_layout);
//spinner = (ProgressBar)FindViewById(Resource.Id.progressBar1);
var smsBtn = FindViewById<Button>(Resource.Id.btnSend);
var phoneNum = FindViewById<EditText>(Resource.Id.phoneNum);
var smsDate = "";
var smsCustomer = FindViewById<EditText>(Resource.Id.txtCustomer);
var smsAddress = FindViewById<EditText>(Resource.Id.txtAddress);
var smsCustNo = FindViewById<EditText>(Resource.Id.txtCustomerNo);
var smsOrderProd = FindViewById<EditText>(Resource.Id.txtOrderedProduct);
var smsProdQty = FindViewById<EditText>(Resource.Id.txtProductQty);
var smsUnit = FindViewById<EditText>(Resource.Id.txtUnit);
var smsAgentName = FindViewById<EditText>(Resource.Id.txtAgentName);
var scrollView = FindViewById<ScrollView>(Resource.Id.scrollViewing);
DateTime now = DateTime.Now.ToLocalTime();
smsDate = now.ToString();
scrollView.SetBackgroundResource(Resource.Drawable.TextViewStyle);
phoneNum.SetBackgroundResource(Resource.Drawable.EditTextStyle);
smsCustomer.SetBackgroundResource(Resource.Drawable.EditTextStyle);
smsAddress.SetBackgroundResource(Resource.Drawable.EditTextStyle);
smsCustNo.SetBackgroundResource(Resource.Drawable.EditTextStyle);
smsOrderProd.SetBackgroundResource(Resource.Drawable.EditTextStyle);
smsProdQty.SetBackgroundResource(Resource.Drawable.EditTextStyle);
smsUnit.SetBackgroundResource(Resource.Drawable.EditTextStyle);
smsAgentName.SetBackgroundResource(Resource.Drawable.EditTextStyle);
//spinner.Visibility = (ViewStates.Gone);
progress = new Android.App.ProgressDialog(this);
progress.Indeterminate = true;
progress.SetProgressStyle(Android.App.ProgressDialogStyle.Spinner);
progress.SetMessage("Sending.. Please wait!");
progress.SetCancelable(false);
_smsManager = SmsManager.Default;
//receiver = new SMSSentReceiver();
//smsManager = SmsManager.Default;
//IntentFilter intentFilter = new IntentFilter("SMS_SENT");
//intentFilter.AddAction("android.permission.SEND_SMS");
////RegisterReceiver(receiver, intentFilter);
//smsBtn.Click += (s, e) =>
//
// var phone = phoneNum.Text;
// var message = sms.Text;
// var piSent = PendingIntent.GetBroadcast(this, 0, new Android.Content.Intent("SMS_SENT"), 0);
// //var piDelivered = PendingIntent.GetBroadcast(this, 0, new Android.Content.Intent("SMS_DELIVERED"), 0);
// smsManager.SendTextMessage(phone, null, message, piSent, null);
//;
smsBtn.Click += (s, e) =>
progress.Show();
if (TextUtils.IsEmpty(smsDate) || TextUtils.IsEmpty(phoneNum.Text) || TextUtils.IsEmpty(smsCustomer.Text)
|| TextUtils.IsEmpty(smsAddress.Text) || TextUtils.IsEmpty(smsCustNo.Text) || TextUtils.IsEmpty(smsOrderProd.Text)
|| TextUtils.IsEmpty(smsProdQty.Text) || TextUtils.IsEmpty(smsUnit.Text) || TextUtils.IsEmpty(smsAgentName.Text))
new Thread(new ThreadStart(delegate
RunOnUiThread(() => Toast.MakeText(this, "Please fill out all the fields", ToastLength.Long).Show());
RunOnUiThread(() => progress.Hide());
)).Start();
//Toast.MakeText(this, "Please fill out all the fields", ToastLength.Short).Show();
return;
else
var phone = phoneNum.Text;
var message = smsDate + "|" + smsCustomer.Text + "|" + smsAddress.Text + "|" + smsCustNo.Text
+ "|" + smsOrderProd.Text + "|" + smsProdQty.Text + "|" + smsUnit.Text + "|" + smsAgentName.Text;
var piSent = PendingIntent.GetBroadcast(this, 0, new Intent("SMS_SENT"), 0);
var piDelivered = PendingIntent.GetBroadcast(this, 0, new Intent("SMS_DELIVERED"), 0);
if ((int)Build.VERSION.SdkInt < 23)
//spinner.Visibility = (ViewStates.Visible);
_smsManager.SendTextMessage(phone, null, message, piSent, piDelivered);
new Thread(new ThreadStart(delegate
RunOnUiThread(() => Toast.MakeText(this, "Sending Orders error! please restart the app", ToastLength.Long).Show());
RunOnUiThread(() => progress.Hide());
)).Start();
//Toast.MakeText(this, "Sending Orders error! please restart the app", ToastLength.Short).Show();
return;
else
if (ActivityCompat.CheckSelfPermission(this, Manifest.Permission.SendSms) != (int)Permission.Granted)
// Permission is not granted. If necessary display rationale & request.
RequestSendSMSPermission();
//new Thread(new ThreadStart(delegate
//
// //RequestSendSMSPermission();
// RunOnUiThread(() => progress.Hide());
//)).Start();
else
// We have permission, go ahead and send SMS.
//spinner.Visibility = (ViewStates.Visible);
_smsManager.SendTextMessage(phone, null, message, piSent, piDelivered);
//new Thread(new ThreadStart(delegate
//
// //_smsManager.SendTextMessage(phone, null, message, piSent, piDelivered);
// RunOnUiThread(() => progress.Hide());
//)).Start();
//_smsManager.SendTextMessage(phone, null, message, piSent, piDelivered);
;
public override void OnRequestPermissionsResult(int requestCode, string[] permissions, [GeneratedEnum] Android.Content.PM.Permission[] grantResults)
Xamarin.Essentials.Platform.OnRequestPermissionsResult(requestCode, permissions, grantResults);
base.OnRequestPermissionsResult(requestCode, permissions, grantResults);
public void RequestSendSMSPermission()
Log.Info("MainActivity", "Message permission has NOT been granted. Requesting permission.");
if (ActivityCompat.ShouldShowRequestPermissionRationale(this, Manifest.Permission.SendSms))
Log.Info("MainActivity", "Displaying message permission rationale to provide additional context.");
Snackbar.Make(layout, "Message permission is needed to send SMS.",
Snackbar.LengthIndefinite).SetAction("OK", new Action<View>(delegate (View obj)
ActivityCompat.RequestPermissions(this, new String[] Manifest.Permission.SendSms , REQUEST_SENDSMS);
)).Show();
else
ActivityCompat.RequestPermissions(this, new String[] Manifest.Permission.SendSms , REQUEST_SENDSMS);
//protected override void OnPause()
//
// base.OnPause();
// UnregisterReceiver(receiver);
//
protected override void OnResume()
//spinner.Visibility = (ViewStates.Gone);
base.OnResume();
//spinner.setVisibility(View.GONE);
_smsSentBroadcastReceiver = new SMSSentReceiver();
_smsDeliveredBroadcastReceiver = new SMSDeliveredReceiver();
RegisterReceiver(_smsSentBroadcastReceiver, new IntentFilter("SMS_SENT"));
RegisterReceiver(_smsDeliveredBroadcastReceiver, new IntentFilter("SMS_DELIVERED"));
//spinner.setVisibility(View.GONE);
protected override void OnPause()
base.OnPause();
UnregisterReceiver(_smsSentBroadcastReceiver);
UnregisterReceiver(_smsDeliveredBroadcastReceiver);
//[BroadcastReceiver(Exported = true, Permission = "//receiver/@android:android.permission.SEND_SMS")]
[BroadcastReceiver]
public class SMSSentReceiver : BroadcastReceiver
public override void OnReceive(Context context, Intent intent)
switch ((int)ResultCode)
case (int)Result.Ok:
Toast.MakeText(Application.Context, "SMS has been sent", ToastLength.Short).Show();
progress.Hide();
break;
case (int)SmsResultError.GenericFailure:
Toast.MakeText(Application.Context, "Generic Failure", ToastLength.Short).Show();
progress.Hide();
break;
case (int)SmsResultError.NoService:
Toast.MakeText(Application.Context, "No Service", ToastLength.Short).Show();
progress.Hide();
break;
case (int)SmsResultError.NullPdu:
Toast.MakeText(Application.Context, "Null PDU", ToastLength.Short).Show();
progress.Hide();
break;
case (int)SmsResultError.RadioOff:
Toast.MakeText(Application.Context, "Radio Off", ToastLength.Short).Show();
progress.Hide();
break;
default:
break;
//[BroadcastReceiver(Exported = true, Permission = "//receiver/@android:android.permission.SEND_SMS")]
[BroadcastReceiver]
public class SMSDeliveredReceiver : BroadcastReceiver
public override void OnReceive(Context context, Intent intent)
switch ((int)ResultCode)
case (int)Result.Ok:
Toast.MakeText(Application.Context, "SMS Delivered", ToastLength.Short).Show();
progress.Hide();
break;
case (int)Result.Canceled:
Toast.MakeText(Application.Context, "SMS not delivered", ToastLength.Short).Show();
progress.Hide();
break;
【问题讨论】：
如果不显示一些代码，就很难看出问题出在哪里。请将其添加到帖子中。 抱歉没有发布我的代码 @MarkusDeibel 先生。 这可能会帮助你***.com/a/48596962/2137237 【参考方案1】：你不能把 EditText 文本字段设置为 "" 吗？
像这样：
editText.Text = "";
【讨论】：
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