[android] Can an Android Toast be longer than Toast.LENGTH_LONG?

When using setDuration() for a Toast, is it possible to set a custom length or at least something longer than Toast.LENGTH_LONG?

No, and most/all of the hacks listed here no longer work in android 9. But there's a much better solution: if you message needs to hang around, use a dialog box.

(new AlertDialog.Builder(this)).setTitle("Sorry!")
.setMessage("Please let me know by posting a beta comment on the play store .")
.setPositiveButton("OK", null).create().show();

You can set the desired time in milliseconds in the Toast.makeText(); method like this:

//40 seconds
long mToastLength = 40*1000 
//this toast will be displayed for 40 seconds.
Toast.makeText(this, "Hello!!!!!", mToastLength).show(); 

I have developed a Custom Toast class with which you can show Toast for a desired amount of duration (in Milli seconds)

import android.content.Context;
import android.os.Build;
import android.os.Handler;
import android.util.Log;
import android.util.TypedValue;
import android.view.Gravity;
import android.view.View;
import android.view.WindowManager;
import android.widget.TextView;

public final class ToastHelper {

    private static final String TAG = ToastHelper.class.getName();

    public static interface OnShowListener {
        public void onShow(ToastHelper toast);
    }

    public static interface OnDismissListener {
        public void onDismiss(ToastHelper toast);
    }

    private static final int WIDTH_PADDING_IN_DIP = 25;
    private static final int HEIGHT_PADDING_IN_DIP = 15;
    private static final long DEFAULT_DURATION_MILLIS = 2000L;

    private final Context context;
    private final WindowManager windowManager;
    private View toastView;

    private int gravity = Gravity.CENTER_HORIZONTAL | Gravity.BOTTOM;
    private int mX;
    private int mY;
    private long duration = DEFAULT_DURATION_MILLIS;
    private CharSequence text = "";
    private int horizontalMargin;
    private int verticalMargin;
    private WindowManager.LayoutParams params;
    private Handler handler;
    private boolean isShowing;
    private boolean leadingInfinite;

    private OnShowListener onShowListener;
    private OnDismissListener onDismissListener;

    private final Runnable timer = new Runnable() {

        @Override
        public void run() {
            cancel();
        }
    };

    public ToastHelper(Context context) {
        Context mContext = context.getApplicationContext();
        if (mContext == null) {
            mContext = context;
        }
        this.context = mContext;
        windowManager = (WindowManager) mContext
                .getSystemService(Context.WINDOW_SERVICE);
        init();
    }

    private void init() {
        mY = context.getResources().getDisplayMetrics().widthPixels / 5;
        params = new WindowManager.LayoutParams();
        params.height = WindowManager.LayoutParams.WRAP_CONTENT;
        params.width = WindowManager.LayoutParams.WRAP_CONTENT;
        params.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
                | WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE
                | WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON;
        params.format = android.graphics.PixelFormat.TRANSLUCENT;
        params.type = WindowManager.LayoutParams.TYPE_TOAST;
        params.setTitle("ToastHelper");
        params.alpha = 1.0f;
        // params.buttonBrightness = 1.0f;
        params.packageName = context.getPackageName();
        params.windowAnimations = android.R.style.Animation_Toast;
    }

    @SuppressWarnings("deprecation")
    @android.annotation.TargetApi(Build.VERSION_CODES.JELLY_BEAN)
    private View getDefaultToastView() {
        TextView textView = new TextView(context);
        textView.setText(text);
        textView.setGravity(Gravity.CENTER_VERTICAL | Gravity.START);
        textView.setClickable(false);
        textView.setFocusable(false);
        textView.setFocusableInTouchMode(false);
        textView.setTextColor(android.graphics.Color.WHITE);
        // textView.setBackgroundColor(Color.BLACK);
        android.graphics.drawable.Drawable drawable = context.getResources()
                .getDrawable(android.R.drawable.toast_frame);
        if (Build.VERSION.SDK_INT < 16) {
            textView.setBackgroundDrawable(drawable);
        } else {
            textView.setBackground(drawable);
        }
        int wP = getPixFromDip(context, WIDTH_PADDING_IN_DIP);
        int hP = getPixFromDip(context, HEIGHT_PADDING_IN_DIP);
        textView.setPadding(wP, hP, wP, hP);
        return textView;
    }

    private static int getPixFromDip(Context context, int dip) {
        return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,
                dip, context.getResources().getDisplayMetrics());
    }

    public void cancel() {
        removeView(true);
    }

    private void removeView(boolean invokeListener) {
        if (toastView != null && toastView.getParent() != null) {
            try {
                Log.i(TAG, "Cancelling Toast...");
                windowManager.removeView(toastView);
                handler.removeCallbacks(timer);
            } finally {
                isShowing = false;
                if (onDismissListener != null && invokeListener) {
                    onDismissListener.onDismiss(this);
                }
            }
        }
    }

    public void show() {
        if (leadingInfinite) {
            throw new InfiniteLoopException(
                    "Calling show() in OnShowListener leads to infinite loop.");
        }
        cancel();
        if (onShowListener != null) {
            leadingInfinite = true;
            onShowListener.onShow(this);
            leadingInfinite = false;
        }
        if (toastView == null) {
            toastView = getDefaultToastView();
        }
        params.gravity = android.support.v4.view.GravityCompat
                .getAbsoluteGravity(gravity, android.support.v4.view.ViewCompat
                        .getLayoutDirection(toastView));
        if ((gravity & Gravity.HORIZONTAL_GRAVITY_MASK) == Gravity.FILL_HORIZONTAL) {
            params.horizontalWeight = 1.0f;
        }
        if ((gravity & Gravity.VERTICAL_GRAVITY_MASK) == Gravity.FILL_VERTICAL) {
            params.verticalWeight = 1.0f;
        }
        params.x = mX;
        params.y = mY;
        params.verticalMargin = verticalMargin;
        params.horizontalMargin = horizontalMargin;

        removeView(false);
        windowManager.addView(toastView, params);
        isShowing = true;
        if (handler == null) {
            handler = new Handler();
        }
        handler.postDelayed(timer, duration);
    }

    public boolean isShowing() {
        return isShowing;
    }

    public void setDuration(long durationMillis) {
        this.duration = durationMillis;
    }

    public void setView(View view) {
        removeView(false);
        toastView = view;
    }

    public void setText(CharSequence text) {
        this.text = text;
    }

    public void setText(int resId) {
        text = context.getString(resId);
    }

    public void setGravity(int gravity, int xOffset, int yOffset) {
        this.gravity = gravity;
        mX = xOffset;
        mY = yOffset;
    }

    public void setMargin(int horizontalMargin, int verticalMargin) {
        this.horizontalMargin = horizontalMargin;
        this.verticalMargin = verticalMargin;
    }

    public long getDuration() {
        return duration;
    }

    public int getGravity() {
        return gravity;
    }

    public int getHorizontalMargin() {
        return horizontalMargin;
    }

    public int getVerticalMargin() {
        return verticalMargin;
    }

    public int getXOffset() {
        return mX;
    }

    public int getYOffset() {
        return mY;
    }

    public View getView() {
        return toastView;
    }

    public void setOnShowListener(OnShowListener onShowListener) {
        this.onShowListener = onShowListener;
    }

    public void setOnDismissListener(OnDismissListener onDismissListener) {
        this.onDismissListener = onDismissListener;
    }

    public static ToastHelper makeText(Context context, CharSequence text,
            long durationMillis) {
        ToastHelper helper = new ToastHelper(context);
        helper.setText(text);
        helper.setDuration(durationMillis);
        return helper;
    }

    public static ToastHelper makeText(Context context, int resId,
            long durationMillis) {
        String string = context.getString(resId);
        return makeText(context, string, durationMillis);
    }

    public static ToastHelper makeText(Context context, CharSequence text) {
        return makeText(context, text, DEFAULT_DURATION_MILLIS);
    }

    public static ToastHelper makeText(Context context, int resId) {
        return makeText(context, resId, DEFAULT_DURATION_MILLIS);
    }

    public static void showToast(Context context, CharSequence text) {
        makeText(context, text, DEFAULT_DURATION_MILLIS).show();
    }

    public static void showToast(Context context, int resId) {
        makeText(context, resId, DEFAULT_DURATION_MILLIS).show();
    }

    private static class InfiniteLoopException extends RuntimeException {
        private static final long serialVersionUID = 6176352792639864360L;

        private InfiniteLoopException(String msg) {
            super(msg);
        }
    }
}

I know I am a bit late, but I took Regis_AG's answer and wrapped it in a helper class and it works great.

public class Toaster {
  private static final int SHORT_TOAST_DURATION = 2000;

  private Toaster() {}

  public static void makeLongToast(String text, long durationInMillis) {
    final Toast t = Toast.makeText(App.context(), text, Toast.LENGTH_SHORT);
    t.setGravity(Gravity.TOP | Gravity.CENTER_HORIZONTAL, 0, 0);

    new CountDownTimer(Math.max(durationInMillis - SHORT_TOAST_DURATION, 1000), 1000) {
      @Override
      public void onFinish() {
        t.show();
      }

      @Override
      public void onTick(long millisUntilFinished) {
        t.show();
      }
    }.start();
  }
}

In your application code, just do something like this:

    Toaster.makeLongToast("Toasty!", 8000);

As mentioned by others Android Toasts can either be LENGTH_LONG or LENGTH_SHORT. There is no way around this, nor should you follow any of the 'hacks' posted.

The purpose of Toasts are to display "non-essential" information and due to their lingering effect, messages may be put far out of context if their duration exceeds a certain threshold. If stock Toasts were modified so that they can display longer than LENGTH_LONG the message would linger on the screen until the application's process is terminated as toast views are added to the WindowManager and not a ViewGroup in your app. I would assume this is why it is hard coded.

If you absolutely need to show a toast style message longer than three and a half seconds I recommend building a view that gets attached to the Activity's content, that way it will disappear when the user exits the application. My SuperToasts library deals with this issue and many others, feel free to use it! You would most likely be interested in using SuperActivityToasts

Schedule a countdown until a time in the future, with regular notifications on intervals along the way. Example of showing a 30 second countdown in a text field:

     new CountDownTimer(30000, 1000) {

     public void onTick(long millisUntilFinished) {
         mTextField.setText("seconds remaining: " + millisUntilFinished / 1000);
     }

     public void onFinish() {
         mTextField.setText("done!");
     }
  }.start();

A toast with custom background and view did the trick for me. I tested it in nexus 7 tablet and I noticed no fadein fadeout animation during looping. Heres the implementation:

public static void customToast(Context context, String message, int duration) {

    for (int i = 0; i < duration; i++) {
        Toast toast = new Toast(context);
        toast.setDuration(Toast.LENGTH_LONG);
        toast.setGravity(Gravity.CENTER, 0, 0);
        LayoutInflater inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View view = inflater.inflate(R.layout.toast_layout, null);
        TextView textViewToast = (TextView) view
                .findViewById(R.id.textViewToast);
        textViewToast.setText(message);
        toast.setView(view);
        toast.show();
    }

}

Heres the custom textview used in above code:

<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/textViewToast"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/fragment_background"
android:padding="8dp"
android:text="Large Text"
android:textAppearance="?android:attr/textAppearanceLarge"
android:textColor="@color/blue" />

@drawable/fragment_background is making my toast have rounded corner as in kitkat version. You can add other views too in the file. Any modifications for improvement and comments are encouraged as I am planning to implement this in my live app.

A very simple approach to creating a slightly longer message is as follows:

private Toast myToast;

public MyView(Context context) {
  myToast = Toast.makeText(getContext(), "", Toast.LENGTH_LONG);
}

private Runnable extendStatusMessageLengthRunnable = new Runnable() {
  @Override
    public void run() {
    //Show the toast for another interval.
    myToast.show();
   }
}; 

public void displayMyToast(final String statusMessage, boolean extraLongDuration) {
  removeCallbacks(extendStatusMessageLengthRunnable);

  myToast.setText(statusMessage);
  myToast.show();

  if(extraLongDuration) {
    postDelayed(extendStatusMessageLengthRunnable, 3000L);
  }
}

Note that the above example eliminates the LENGTH_SHORT option to keep the example simple.

You will generally not want to use a Toast message to display messages for very long intervals, as that is not the Toast class' intended purpose. But there are times when the amount of text you need to display could take the user longer than 3.5 seconds to read, and in that case a slight extension of time (e.g., to 6.5 seconds, as shown above) can, IMO, be useful and consistent with the intended usage.

Here is a custom Toast class I made using the above code:

import android.content.Context;
import android.os.CountDownTimer;
import android.widget.Toast;

public class CustomToast extends Toast {
    int mDuration;
    boolean mShowing = false;
    public CustomToast(Context context) {
        super(context);
        mDuration = 2;
    }


    /**
     * Set the time to show the toast for (in seconds) 
     * @param seconds Seconds to display the toast
     */
    @Override
    public void setDuration(int seconds) {
        super.setDuration(LENGTH_SHORT);
        if(seconds < 2) seconds = 2; //Minimum
        mDuration = seconds;
    }

    /**
     * Show the toast for the given time 
     */
    @Override
    public void show() {
        super.show();

        if(mShowing) return;

        mShowing = true;
        final Toast thisToast = this;
        new CountDownTimer((mDuration-2)*1000, 1000)
        {
            public void onTick(long millisUntilFinished) {thisToast.show();}
            public void onFinish() {thisToast.show(); mShowing = false;}

        }.start();  
    }
}

Use Crouton, it is a very flexible Toast library.

Crouton

You can use it just like toasts:

Crouton.makeText(context, "YOUR_MESSAGE", Style.INFO);

or you can even go a little deeper and customise it more, like setting the time to infinite! for example here I want to show a toast message until the user acknowledges it by clicking on it.

private static void showMessage(final Activity context, MessageType type, String header, String message) {
    View v = context.getLayoutInflater().inflate(R.layout.toast_layout, null);
    TextView headerTv = (TextView) v.findViewById(R.id.toastHeader);
    headerTv.setText(header);
    TextView messageTv = (TextView) v.findViewById(R.id.toastMessage);
    messageTv.setText(message);
    ImageView toastIcon = (ImageView) v.findViewById(R.id.toastIcon);

    final Crouton crouton = getCrouton(context, v);
    v.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Crouton.hide(crouton);
        }
    });

    crouton.show();
}

private static Crouton getCrouton(final Activity context, View v) {
    Crouton crouton = Crouton.make(context, v);
    crouton.setConfiguration(new Configuration.Builder().setDuration(Configuration.DURATION_INFINITE).build());
    return crouton;
}

Custome Layout that will be inflated for the toast.

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:animateLayoutChanges="true"
    android:background="@drawable/shadow_container"
    android:gravity="center_vertical"
    android:orientation="horizontal"
    android:padding="@dimen/default_margin"
    tools:ignore="Overdraw">

    <ImageView
        android:id="@+id/toastIcon"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="@dimen/default_spacing_full"
        android:layout_weight="1"
        android:orientation="vertical">

        <TextView
            android:id="@+id/toastHeader"
            style="@style/ItemText"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />

        <TextView
            android:id="@+id/toastMessage"
            style="@style/ItemSubText"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />

    </LinearLayout>

</LinearLayout>

LONG_DELAY toast display for 3.5 sec and SHORT_DELAY toast display for 2 sec.

Toast internally use INotificationManager and calls it's enqueueToast method every time a Toast.show() is called.

Call the show() with SHORT_DELAY twice will enqueue same toast again. it will display for 4 sec ( 2 sec + 2 sec).

similarly, call the show() with LONG_DELAY twice will enqueue same toast again. it will display for 7 sec ( 3.5 sec + 3.5 sec)

If you want a Toast to persist, I found you can hack your way around it by having a Timer call toast.show() repeatedly (every second or so should do). Calling show() doesn't break anything if the Toast is already showing, but it does refresh the amount of time it stays on the screen.

Why eat Toast, when you can have the entire Snackbar: https://developer.android.com/reference/android/support/design/widget/Snackbar.html

Snackbar > Toast, Custom Toast, Crouton

  private Toast mToastToShow;
  public void showToast(View view) {
 // Set the toast and duration
 int toastDurationInMilliSeconds = 10000;
 mToastToShow = Toast.makeText(this, "Hello world, I am a toast.",  Toast.LENGTH_LONG);

 // Set the countdown to display the toast
 CountDownTimer toastCountDown;
 toastCountDown = new CountDownTimer(toastDurationInMilliSeconds, 1000 /*Tick duration*/) {
  public void onTick(long millisUntilFinished) {
     mToastToShow.show();
  }
  public void onFinish() {
     mToastToShow.cancel();
     }
    };

    // Show the toast and starts the countdown
     mToastToShow.show();
     toastCountDown.start();
      }

The user cannot custome defined the Toast's duration. because NotificationManagerService's scheduleTimeoutLocked() function not use the field duration. the source code is the following.

private void scheduleTimeoutLocked(ToastRecord r, boolean immediate)
    {
        Message m = Message.obtain(mHandler, MESSAGE_TIMEOUT, r);
        long delay = immediate ? 0 : (r.duration == Toast.LENGTH_LONG ? LONG_DELAY : SHORT_DELAY);
        mHandler.removeCallbacksAndMessages(r);
        mHandler.sendMessageDelayed(m, delay);
    }

After failing with every available solution, I finally had workaround using recursion.

Code:

//Recursive function, pass duration in seconds
public void showToast(int duration) {
    if (duration <= 0)
        return;

    Toast.makeText(this, "Hello, it's a toast", Toast.LENGTH_LONG).show();
    Handler handler = new Handler();
    handler.postDelayed(new Runnable() {
        @Override
        public void run() {
            showToast(duration-1);
        }
    }, 1000);
}

Toast duration can be hacked using a thread that runs the toast exclusively. This works (runs the toast for 10 secs, modify sleep and ctr to your liking):

final Toast toast = Toast.makeText(this, "Your Message", Toast.LENGTH_LONG);

Thread t = new Thread(){
    public void run(){
          int ctr = 0;
          try{
               while( ctr<10 ){
                    toast.show();
                    sleep(1000);
                    ctr++;
               }
          } catch (Exception e) {
               Log.e("Error", "", e);
          }
     }
 };
 t.start();

Toast.makeText(this, "Text", Toast.LENGTH_LONG).show(); 
Toast.makeText(this, "Text", Toast.LENGTH_LONG).show();

A very simple solution to the question. Twice or triple of them will make Toast last longer. It is the only way around.

Here is a very simple method which worked for me:

for (int i=0; i < 3; i++) { Toast.makeText(this, "MESSAGE", Toast.LENGTH_SHORT).show(); }

The duration of LENGTH_SHORT is 2 seconds and LENGTH_LONG is 3.5 seconds, Here the toast message will be shown for 6 Seconds since it is enclosed in a for loop. But a drawback of this method is after each 2 sec a small fading effect may arise. but it is not much noticeable. Hope it is helpful

This text will disappear in 5 seconds.

    final Toast toast = Toast.makeText(getApplicationContext(), "My Text", Toast.LENGTH_SHORT);
    toast.show();

    Handler handler = new Handler();
        handler.postDelayed(new Runnable() {
           @Override
           public void run() {
               toast.cancel(); 
           }
    }, 5000); // Change to what you want

Edit: As Itai Spector in comment said it will be shown about 3.5 seconds, So use this code:

    int toastDuration = 5000; // in MilliSeconds
    Toast mToast = Toast.makeText(this, "My text", Toast.LENGTH_LONG);
    CountDownTimer countDownTimer;
    countDownTimer = new CountDownTimer(toastDuration, 1000) {
        public void onTick(long millisUntilFinished) {
            mToast.show();
        }

        public void onFinish() {
            mToast.cancel();
        }
    };

    mToast.show();
    countDownTimer.start();

I've coded up a helper class for doing this. You can see the code at github: https://github.com/quiqueqs/Toast-Expander/blob/master/src/com/thirtymatches/toasted/ToastedActivity.java

This is how you'd display a toast for 5 seconds (or 5000 milliseconds):

Toast aToast = Toast.makeText(this, "Hello World", Toast.LENGTH_SHORT);
ToastExpander.showFor(aToast, 5000);

Simply use SuperToast to make an elegant toast on any situation. Make your toast colourful. Edit your font color and also it's size. Hope it will be all in one for you.

Sets toast to a specific period in milli-seconds:

public void toast(int millisec, String msg) {
    Handler handler = null;
    final Toast[] toasts = new Toast[1];
    for(int i = 0; i < millisec; i+=2000) {
        toasts[0] = Toast.makeText(this, msg, Toast.LENGTH_SHORT);
        toasts[0].show();
        if(handler == null) {
            handler = new Handler();
            handler.postDelayed(new Runnable() {
                @Override
                public void run() {
                    toasts[0].cancel();
                }
            }, millisec);
        }
    }
}

You may want to try:

for (int i=0; i < 2; i++)
{
      Toast.makeText(this, "blah", Toast.LENGTH_LONG).show();
}

to double the time. If you specify 3 instead the 2 it will triple the time..etc.

If you dig deeper in android code, you can find the lines that clearly indicate, that we cannot change the duration of Toast message.

 NotificationManagerService.scheduleTimeoutLocked() {
    ...
    long delay = immediate ? 0 : (r.duration == Toast.LENGTH_LONG ? LONG_DELAY : SHORT_DELAY);
    }

and default values for duration are

private static final int LONG_DELAY = 3500; // 3.5 seconds
private static final int SHORT_DELAY = 2000; // 2 seconds

I know the answer is quite late .. I had the very same issue and decided to implement my own version of bare bones Toast , after looking into android's source code for toast .

Basically you need to create a new Window manager , and show and hide the window for the desired duration duration using a handler

 //Create your handler
 Handler mHandler = new Handler();

//Custom Toast Layout
mLayout = layoutInflater.inflate(R.layout.customtoast, null);

//Initialisation 

mWindowManager = (WindowManager) context.getApplicationContext()
            .getSystemService(Context.WINDOW_SERVICE);
WindowManager.LayoutParams params = new WindowManager.LayoutParams();

params.gravity = Gravity.BOTTOM
params.height = WindowManager.LayoutParams.WRAP_CONTENT;
params.width = WindowManager.LayoutParams.WRAP_CONTENT;
params.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
                | WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE
                | WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON;
params.format = PixelFormat.TRANSLUCENT;
params.windowAnimations = android.R.style.Animation_Toast;
params.type = WindowManager.LayoutParams.TYPE_TOAST;

After initialization of the layout you can use your own hide and show methods

    public void handleShow() {
    mWindowManager.addView(mLayout, mParams);
    }

    public void handleHide() {
        if (mLayout != null) {
            if (mLayout.getParent() != null) {
                mWindowManager.removeView(mLayout);
            }
                         mLayout = null;
        }

Now all you need is to add two runnable threads which calls the handleShow() and the handleHide() which you could post to the Handler.

    Runnable toastShowRunnable = new Runnable() {
        public void run() {
            handleShow();
        }
    };

 Runnable toastHideRunnable = new Runnable() {
        public void run() {
            handleHide();
        }
    }; 

and the final part

public void show() {

    mHandler.post(toastShowRunnable);
    //The duration that you want
    mHandler.postDelayed(toastHideRunnable, mDuration);

}

This was a quick and dirty implementation .. Have not taken any performance into consideration .

If you need a long Toast, there's a practical alternative, but it requires your user to click on an OK button to make it go away. You can use an AlertDialog like this:

String message = "This is your message";
new AlertDialog.Builder(YourActivityName.this)
    .setTitle("Optional Title (you can omit this)")
    .setMessage(message)
    .setPositiveButton("ok", null)
    .show();

If you have a long message, chances are, you don't know how long it will take for your user to read the message, so sometimes it is a good idea to require your user to click on an OK button to continue. In my case, I use this technique when a user clicks on a help icon.