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Android example source code file (TabActivity.java)

This example Android source code file (TabActivity.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

activitygroup, android, charsequence, os, override, runtimeexception, string, tabactivity, tabhost, tabwidget, textview, ui, view, widget, your

The TabActivity.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.app;

import android.os.Bundle;
import android.view.View;
import android.widget.TabHost;
import android.widget.TabWidget;
import android.widget.TextView;

/**
 * An activity that contains and runs multiple embedded activities or views.
 */
public class TabActivity extends ActivityGroup {
    private TabHost mTabHost;
    private String mDefaultTab = null;
    private int mDefaultTabIndex = -1;

    public TabActivity() {
    }

    /**
     * Sets the default tab that is the first tab highlighted.
     * 
     * @param tag the name of the default tab
     */
    public void setDefaultTab(String tag) {
        mDefaultTab = tag;
        mDefaultTabIndex = -1;
    }

    /**
     * Sets the default tab that is the first tab highlighted.
     * 
     * @param index the index of the default tab
     */
    public void setDefaultTab(int index) {
        mDefaultTab = null;
        mDefaultTabIndex = index;
    }

    @Override
    protected void onRestoreInstanceState(Bundle state) {
        super.onRestoreInstanceState(state);
        ensureTabHost();
        String cur = state.getString("currentTab");
        if (cur != null) {
            mTabHost.setCurrentTabByTag(cur);
        }
        if (mTabHost.getCurrentTab() < 0) {
            if (mDefaultTab != null) {
                mTabHost.setCurrentTabByTag(mDefaultTab);
            } else if (mDefaultTabIndex >= 0) {
                mTabHost.setCurrentTab(mDefaultTabIndex);
            }
        }
    }

    @Override
    protected void onPostCreate(Bundle icicle) {        
        super.onPostCreate(icicle);

        ensureTabHost();

        if (mTabHost.getCurrentTab() == -1) {
            mTabHost.setCurrentTab(0);
        }
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        String currentTabTag = mTabHost.getCurrentTabTag();
        if (currentTabTag != null) {
            outState.putString("currentTab", currentTabTag);
        }
    }

    /**
     * Updates the screen state (current list and other views) when the
     * content changes.
     * 
     *@see Activity#onContentChanged()
     */
    @Override
    public void onContentChanged() {
        super.onContentChanged();
        mTabHost = (TabHost) findViewById(com.android.internal.R.id.tabhost);

        if (mTabHost == null) {
            throw new RuntimeException(
                    "Your content must have a TabHost whose id attribute is " +
                    "'android.R.id.tabhost'");
        }
        mTabHost.setup(getLocalActivityManager());
    }

    private void ensureTabHost() {
        if (mTabHost == null) {
            this.setContentView(com.android.internal.R.layout.tab_content);
        }
    }

    @Override
    protected void
    onChildTitleChanged(Activity childActivity, CharSequence title) {
        // Dorky implementation until we can have multiple activities running.
        if (getLocalActivityManager().getCurrentActivity() == childActivity) {
            View tabView = mTabHost.getCurrentTabView();
            if (tabView != null && tabView instanceof TextView) {
                ((TextView) tabView).setText(title);
            }
        }
    }

    /**
     * Returns the {@link TabHost} the activity is using to host its tabs.
     *
     * @return the {@link TabHost} the activity is using to host its tabs.
     */
    public TabHost getTabHost() {
        ensureTabHost();
        return mTabHost;
    }

    /**
     * Returns the {@link TabWidget} the activity is using to draw the actual tabs.
     *
     * @return the {@link TabWidget} the activity is using to draw the actual tabs.
     */
    public TabWidget getTabWidget() {
        return mTabHost.getTabWidget();
    }
}

Other Android examples (source code examples)

Here is a short list of links related to this Android TabActivity.java source code file:

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