Android example source code file (TextSwitcher.java)

This example Android source code file (TextSwitcher.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

android, attributeset, content, illegalargumentexception, override, textswitcher, textview, ui, util, utilities, view, viewswitcher

The TextSwitcher.java Android example source code

/*
 * Copyright (C) 2006 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.widget;


import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;

/**
 * Specialized {@link android.widget.ViewSwitcher} that contains
 * only children of type {@link android.widget.TextView}.
 *
 * A TextSwitcher is useful to animate a label on screen. Whenever
 * {@link #setText(CharSequence)} is called, TextSwitcher animates the current text
 * out and animates the new text in. 
 */
public class TextSwitcher extends ViewSwitcher {
    /**
     * Creates a new empty TextSwitcher.
     *
     * @param context the application's environment
     */
    public TextSwitcher(Context context) {
        super(context);
    }

    /**
     * Creates a new empty TextSwitcher for the given context and with the
     * specified set attributes.
     *
     * @param context the application environment
     * @param attrs a collection of attributes
     */
    public TextSwitcher(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    /**
     * {@inheritDoc}
     *
     * @throws IllegalArgumentException if child is not an instance of
     *         {@link android.widget.TextView}
     */
    @Override
    public void addView(View child, int index, ViewGroup.LayoutParams params) {
        if (!(child instanceof TextView)) {
            throw new IllegalArgumentException(
                    "TextSwitcher children must be instances of TextView");
        }

        super.addView(child, index, params);
    }

    /**
     * Sets the text of the next view and switches to the next view. This can
     * be used to animate the old text out and animate the next text in.
     *
     * @param text the new text to display
     */
    public void setText(CharSequence text) {
        final TextView t = (TextView) getNextView();
        t.setText(text);
        showNext();
    }

    /**
     * Sets the text of the text view that is currently showing.  This does
     * not perform the animations.
     *
     * @param text the new text to display
     */
    public void setCurrentText(CharSequence text) {
        ((TextView)getCurrentView()).setText(text);
    }
}