Why my simple Toast doesn't want to appear and the app crashes?

Question

I everyone, I am trying to make such a dumb thing: center the text inside a Toast which is created inside an onclick event listener.

I have created a TextView inside the layout I use and when I try to call the event that should the display the toast the app crashes with this exception:

03-19 23:20:40.258: E/AndroidRuntime(3364): java.lang.IllegalArgumentException: View not   
attached to window manager

This is my code:

toastTextView = (TextView) findViewById(R.id.toastView); 
Toast toast = Toast.makeText(MyActivity.this, "Very very very long long text that should be displayed in the middle of this toast", 
                           Toast.LENGTH_SHORT);
                toast.setView(toastTextView);
                toast.show();

The xml:

<?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:layout_height="fill_parent">

<LinearLayout android:id="@+id/chart" android:orientation="horizontal"
              android:layout_width="fill_parent" android:layout_height="0dip" android:layout_weight="1"/>

<TextView
    android:id="@+id/toastView"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" />

<LinearLayout android:orientation="horizontal"
              android:layout_width="fill_parent" android:layout_height="wrap_content">

</LinearLayout>

Where's the problem with this simple code?

Thanks for the attention!

EDIT: this is the layout of the custom_toast.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center"
android:orientation="vertical" >

</LinearLayout>

Answer 1

You are using a view that is already attached to another view hierarchy. You have to inflate your custom toast view separately like this:

custom_toast.xml:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:background="@android:color/black"
                android:padding="5dp">

        <TextView
                android:id="@+id/tvToast"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerHorizontal="true"/>

</RelativeLayout>

And that's how you use it:

LayoutInflater inflater = LayoutInflater.from(context);
View customToastView = inflater.inflate(R.layout.custom_toast, null);

TextView tvToast = (TextView) customToastView.findViewById(R.id.tvToast);
tvToast.setText("This is a custom toast with centered text");

Toast toast = new Toast(context);
toast.setView(customToastView);
toast.setDuration(Toast.LENGTH_SHORT);
toast.show();

Answer 2

My guess is that you have to set the toast_layout.xml as the view of your toast, not only the single textView out of it. Try to add an id to your outermost linear layout, ...

toast_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
      android:id="@+id/toast_layout_root"
      android:orientation="vertical" android:layout_width="fill_parent"
      android:layout_height="fill_parent">

      <LinearLayout .../>
      <TextView .../>
</LinearLayout>

... inflate it with the layout inflater and set this as your toast view.

java.file

View toastRootView = getLayoutInflater().inflate(R.layout.toast_layout,
                           (ViewGroup) findViewById(R.id.toast_layout_root));
TextView text = findViewById(R.id.toastView);
text.setText("Very [...] long text [...]");    

Toast toast = new Toast(MyActivity.this)
.setView(toastRootView)
.setDuration(Toast.LENGTH_SHORT)
.show();

So "toast_layout" is the name of the xml file containing the layout and toast_layout_root is the id of the root element in this file (the outermost linear layout).

Hope this helps,
Kai

Follow up link:
http://meddington.hubpages.com/hub/How-To-Toast-In-Android

Answer 3

Try using a SpannableString to format your Toast, you can get a lot of mileage out of that without worrying about custom views.

String fancyText = "MyFancy long text";
SpannableStringBuilder span = new SpannableStringBuilder(fancyText);
span.setSpan(new AlignmentSpan(Layout.Alignment.ALIGN_CENTER), 0, fancyText.length(), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
Toast.makeText(MyActivity.this, span, Toast.LENGTH_SHORT).show();