如何在Android中设置吐司宽度？

import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Context;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

public class CancelProgressDialog extends Activity {

    ProgressDialog myProgressDialog = null;

    @Override
    public void onCreate(Bundle icicle) {

        super.onCreate(icicle);

        /* Create a very simple button */

        Button b = new Button(this);

        this.setContentView(b);

        b.setText(\"Show ProgressBar...\");

//      b.setOnClickListener(myProgressBarShower);
        Context context = getApplicationContext();

        LayoutInflater inflater = getLayoutInflater();

        View toastRoot = inflater.inflate(R.layout.customtoast, null);
        TextView tv = (TextView) toastRoot.findViewById(R.id.toasttext);
        tv.setWidth(200);
        tv.setHeight(100);

        Toast toast = new Toast(context);

        toast.setView(toastRoot);
        toast.show();
//      toast.setText(\"I am toast\");
        toast.setDuration(Toast.LENGTH_LONG);


    }
}

<?xml version=\"1.0\" encoding=\"utf-8\"?>


<TextView
    xmlns:android=\"http://schemas.android.com/apk/res/android\"
    android:layout_width=\"wrap_content\"
    android:layout_height=\"wrap_content\"
    android:text=\"I am toast\"
    android:textColor=\"#000000\"
    android:id=\"@+id/toasttext\"
    android:background=\"#ffffff\" />

Toast t = Toast.makeText(this, \"Hello\", Toast.LENGTH_SHORT);
t.setGravity(Gravity.FILL_HORIZONTAL, 0, 0);

<?xml version=\"1.0\" encoding=\"utf-8\"?>
<LinearLayout xmlns:android=\"http://schemas.android.com/apk/res/android\"
    android:orientation=\"vertical\"
    android:layout_width=\"wrap_content\"
    android:layout_height=\"wrap_content\"
    android:layout_gravity=\"center\"
    android:id=\"@+id/container\"
    android:background=\"@color/white\">

    <!-- customize your width and height here -->
    <LinearLayout
        android:layout_width=\"200dp\"
        android:layout_height=\"200dp\"
        android:orientation=\"vertical\"
        android:gravity=\"center\">
        <ImageView
            android:layout_width=\"wrap_content\"
            android:layout_height=\"wrap_content\"
            android:background=\"@drawable/ic_check_box\"/>
        <TextView
            android:layout_width=\"wrap_content\"
            android:layout_height=\"wrap_content\"
            android:text=\"@string/message\"/>
    </LinearLayout>
</LinearLayout>