在我的应用程序中，我为我的活动构建了一个日历小部件，当我将其滚动到上个月或下个月时，我让它做一个祝酒并显示它。
问题是，吐司需要时间显示，当我滚动得足够快时，例如，我滚动到“2012/05”和“2012/06”并滚动到“2012/07”而没有停顿，我必须等待“2012/05”，“2012/06”，“2012/07”的Toast慢慢逐一显示。
似乎Android有一个不可见的队列来管理祝酒词
我该如何清洁并只显示最后一片吐司？我可以在不等待的情况下立即显示特定的Toast吗？
我搜索了“android.widget.Toast.java”并找到了一个方法cancel()，但遗憾的是它无法正常工作。
if (t != null) {
t.cancel();
}
t = Toast.makeText(this.mContext, mHelper.getYear() + "年"
+ (mHelper.getMonth() + 1) + "月", Toast.LENGTH_SHORT);
t.show();
答案 0 :(得分：22)
这是我在这里从另一个类似问题复制的答案：
Boast课程完全符合您的需要。最近的代码可以在GitHub上找到：
诀窍是跟踪显示的最后一个Toast，并取消那个。
我所做的是创建一个Toast包装器，其中包含对显示的最后一个Toast的静态引用。
当我需要显示一个新的时，我首先取消静态参考，然后再显示新参考（并将其保存在静态参考中）。
这是我制作的Boast包装器的完整代码 - 它模仿了Toast方法，足以让我使用它。默认情况下，Boast将取消前一个，因此您不会构建等待显示的Toasts队列。
如果您只是想知道如何在退出应用时取消通知，那么您会在那里找到很多帮助。
package mobi.glowworm.lib.ui.widget;
import android.annotation.SuppressLint;
import android.content.Context;
import android.content.res.Resources;
import android.support.annotation.Nullable;
import android.widget.Toast;
import java.lang.ref.WeakReference;
/**
* {@link Toast} decorator allowing for easy cancellation of notifications. Use this class if you
* want subsequent Toast notifications to overwrite current ones. </p>
* <p/>
* By default, a current {@link Boast} notification will be cancelled by a subsequent notification.
* This default behaviour can be changed by calling certain methods like {@link #show(boolean)}.
*/
public class Boast {
/**
* Keeps track of certain Boast notifications that may need to be cancelled. This functionality
* is only offered by some of the methods in this class.
* <p>
* Uses a {@link WeakReference} to avoid leaking the activity context used to show the original {@link Toast}.
*/
@Nullable
private volatile static WeakReference<Boast> weakBoast = null;
@Nullable
private static Boast getGlobalBoast() {
if (weakBoast == null) {
return null;
}
return weakBoast.get();
}
private static void setGlobalBoast(@Nullable Boast globalBoast) {
Boast.weakBoast = new WeakReference<>(globalBoast);
}
// ////////////////////////////////////////////////////////////////////////////////////////////////////////
/**
* Internal reference to the {@link Toast} object that will be displayed.
*/
private Toast internalToast;
// ////////////////////////////////////////////////////////////////////////////////////////////////////////
/**
* Private constructor creates a new {@link Boast} from a given {@link Toast}.
*
* @throws NullPointerException if the parameter is <code>null</code>.
*/
private Boast(Toast toast) {
// null check
if (toast == null) {
throw new NullPointerException("Boast.Boast(Toast) requires a non-null parameter.");
}
internalToast = toast;
}
// ////////////////////////////////////////////////////////////////////////////////////////////////////////
/**
* Make a standard {@link Boast} that just contains a text view.
*
* @param context The context to use. Usually your {@link android.app.Application} or
* {@link android.app.Activity} object.
* @param text The text to show. Can be formatted text.
* @param duration How long to display the message. Either {@link Toast#LENGTH_SHORT} or
* {@link Toast#LENGTH_LONG}
*/
@SuppressLint("ShowToast")
public static Boast makeText(Context context, CharSequence text, int duration) {
return new Boast(Toast.makeText(context, text, duration));
}
/**
* Make a standard {@link Boast} that just contains a text view with the text from a resource.
*
* @param context The context to use. Usually your {@link android.app.Application} or
* {@link android.app.Activity} object.
* @param resId The resource id of the string resource to use. Can be formatted text.
* @param duration How long to display the message. Either {@link Toast#LENGTH_SHORT} or
* {@link Toast#LENGTH_LONG}
* @throws Resources.NotFoundException if the resource can't be found.
*/
@SuppressLint("ShowToast")
public static Boast makeText(Context context, int resId, int duration)
throws Resources.NotFoundException {
return new Boast(Toast.makeText(context, resId, duration));
}
/**
* Make a standard {@link Boast} that just contains a text view. Duration defaults to
* {@link Toast#LENGTH_SHORT}.
*
* @param context The context to use. Usually your {@link android.app.Application} or
* {@link android.app.Activity} object.
* @param text The text to show. Can be formatted text.
*/
@SuppressLint("ShowToast")
public static Boast makeText(Context context, CharSequence text) {
return new Boast(Toast.makeText(context, text, Toast.LENGTH_SHORT));
}
/**
* Make a standard {@link Boast} that just contains a text view with the text from a resource.
* Duration defaults to {@link Toast#LENGTH_SHORT}.
*
* @param context The context to use. Usually your {@link android.app.Application} or
* {@link android.app.Activity} object.
* @param resId The resource id of the string resource to use. Can be formatted text.
* @throws Resources.NotFoundException if the resource can't be found.
*/
@SuppressLint("ShowToast")
public static Boast makeText(Context context, int resId) throws Resources.NotFoundException {
return new Boast(Toast.makeText(context, resId, Toast.LENGTH_SHORT));
}
// ////////////////////////////////////////////////////////////////////////////////////////////////////////
/**
* Show a standard {@link Boast} that just contains a text view.
*
* @param context The context to use. Usually your {@link android.app.Application} or
* {@link android.app.Activity} object.
* @param text The text to show. Can be formatted text.
* @param duration How long to display the message. Either {@link Toast#LENGTH_SHORT} or
* {@link Toast#LENGTH_LONG}
*/
public static void showText(Context context, CharSequence text, int duration) {
Boast.makeText(context, text, duration).show();
}
/**
* Show a standard {@link Boast} that just contains a text view with the text from a resource.
*
* @param context The context to use. Usually your {@link android.app.Application} or
* {@link android.app.Activity} object.
* @param resId The resource id of the string resource to use. Can be formatted text.
* @param duration How long to display the message. Either {@link Toast#LENGTH_SHORT} or
* {@link Toast#LENGTH_LONG}
* @throws Resources.NotFoundException if the resource can't be found.
*/
public static void showText(Context context, int resId, int duration)
throws Resources.NotFoundException {
Boast.makeText(context, resId, duration).show();
}
/**
* Show a standard {@link Boast} that just contains a text view. Duration defaults to
* {@link Toast#LENGTH_SHORT}.
*
* @param context The context to use. Usually your {@link android.app.Application} or
* {@link android.app.Activity} object.
* @param text The text to show. Can be formatted text.
*/
public static void showText(Context context, CharSequence text) {
Boast.makeText(context, text, Toast.LENGTH_SHORT).show();
}
/**
* Show a standard {@link Boast} that just contains a text view with the text from a resource.
* Duration defaults to {@link Toast#LENGTH_SHORT}.
*
* @param context The context to use. Usually your {@link android.app.Application} or
* {@link android.app.Activity} object.
* @param resId The resource id of the string resource to use. Can be formatted text.
* @throws Resources.NotFoundException if the resource can't be found.
*/
public static void showText(Context context, int resId) throws Resources.NotFoundException {
Boast.makeText(context, resId, Toast.LENGTH_SHORT).show();
}
// ////////////////////////////////////////////////////////////////////////////////////////////////////////
/**
* Close the view if it's showing, or don't show it if it isn't showing yet. You do not normally
* have to call this. Normally view will disappear on its own after the appropriate duration.
*/
public void cancel() {
internalToast.cancel();
}
/**
* Show the view for the specified duration. By default, this method cancels any current
* notification to immediately display the new one. For conventional {@link Toast#show()}
* queueing behaviour, use method {@link #show(boolean)}.
*
* @see #show(boolean)
*/
public void show() {
show(true);
}
/**
* Show the view for the specified duration. This method can be used to cancel the current
* notification, or to queue up notifications.
*
* @param cancelCurrent <code>true</code> to cancel any current notification and replace it with this new
* one
* @see #show()
*/
public void show(boolean cancelCurrent) {
// cancel current
if (cancelCurrent) {
final Boast cachedGlobalBoast = getGlobalBoast();
if ((cachedGlobalBoast != null)) {
cachedGlobalBoast.cancel();
}
}
// save an instance of this current notification
setGlobalBoast(this);
internalToast.show();
}
}
答案 1 :(得分：15)
你只需要声明一个像这样的“Toast”var：
if (jsonString.indexOf(..) > 0) {
//reading Person
} else {
//reading SomeRandomObject
}
然后在你的函数中，这样做：
Toast toastMessage;
答案 2 :(得分：12)
您需要在正确的对象上调用方法。
toastObject.cancel()
答案 3 :(得分：5)
这是守则。
final Toast toastobject = Toast.makeText(context, "This message will disappear when toast.close(); is called", Toast.LENGTH_SHORT);
现在您可以使用toastobject的Object。它的Reference
toastobject.cancel();
您可以在线程中使用它，或者只要您想要关闭Toast。
答案 4 :(得分：4)
您可以重复使用吐司，这会立即显示。
myToast.setText(toastMsg);
myToast.show();
答案 5 :(得分：3)
当我们要显示另一个Toast时，有很多方法可以取消上一个Toast。下面我写了一个最简单的方法来实现它。首先，我们必须创建一个可以在整个类中访问的变量。
private Toast toast;
在创建整个类都可以访问的变量之后，我们必须在我们的类中创建一个方法，该方法显示该Toast消息并检查是否显示了先前的Toast，然后将其取消。
public void showToast(String message) {
if (toast != null) {
toast.cancel();
}
toast = Toast.makeText(getApplicationContext(), message, Toast.LENGTH_SHORT);
toast.show();
}
您可以通过运行时调用上述方法来更改吐司消息。
showToast("message 1");
//一段时间后
showToast("message 2");
希望有帮助。
答案 6 :(得分：1)
Toast有一种隐藏当前Toast消息的方法
public void cancel() {
mTN.hide();
}
在必要时尝试调用t.cancel（）。
答案 7 :(得分：1)
您可以创建静态方法并使用它来显示祝酒词：
public static Toast toast = null;
public static showToast(Context context,String msg){
if(toast!=null) //this will cancel the toast on the screen if one exists
toast.cancel();
toast = Toast.makeText(context,msg);
toast.show();
}
答案 8 :(得分：1)
简单。一旦你想创建另一个吐司，只需在吐司上调用方法.cancel（）。
首先在类的顶部定义一个Toast变量，如
private Toast mToast;
稍后，当你想创建一个新的Toast（并让旧的Toast消失）时， 这样做。
if(mToast != null) {
mToast.cancel(); //if a toast exists it deletes it, allowing you to create a new one
}
mToast = Toast.makeText(this, "This will show up now!", Toast.LENGTH_LONG);
mToast.show(); //creates the new toast.
答案 9 :(得分：0)
public static Toast sToast=null;
// create Toast object;
public void showToast(String msg)
{
//here is checking whether toast object is null or not;if not null gonna cancel the toast that is showing in phone window and make it null;
if(sToast!=null)
{
sToast.cancel;
sToast=null;
}
//if toast object is null,gonna create new instance and make it shown on phone window.
if(sToast==null)
{
sToast=Toast.makeText(currentActivity.this,msg,Duration);
sToast.setGravity();
sToast.show();
}
}
答案 10 :(得分：-1)
你可以使用一种射击技术。 Oke让我们开始定义：
private Toast mToast;
private showOnce=false;
后来当你想要举杯祝酒时：
if(showOnce==false){
mToast=Toast.makeText(this, "Once!", Toast.LENGTH_LONG);
mToast.show();
showOnce=true;
}