TabActivity.java

/* Modifications to use the included copies of TabHost and TabWidget
 * instead of in-built Android versions.
 * 
 * Modifications Copyright (C) 2009 Justin Shapcott, nEx.Software
 *
 * 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.
 */

/* Original Copyright Information
 * 
 * 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 my.android.app;

import my.android.widget.TabHost;
import my.android.widget.TabWidget;
import android.app.Activity;
import android.app.ActivityGroup;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
import be.benvd.mvforandroid.R;

/**
 * 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(android.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(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();
		}
	}