TabActivity.java revision 9066cfe9886ac131c34d59ed0e2d287b0e3c0087 
1/*
2 * Copyright (C) 2006 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package android.app;
18
19import android.os.Bundle;
20import android.view.View;
21import android.widget.TabHost;
22import android.widget.TabWidget;
23import android.widget.TextView;
24
25/**
26 * An activity that contains and runs multiple embedded activities or views.
27 */
28public class TabActivity extends ActivityGroup {
29    private TabHost mTabHost;
30    private String mDefaultTab = null;
31    private int mDefaultTabIndex = -1;
32
33    public TabActivity() {
34    }
35
36    /**
37     * Sets the default tab that is the first tab highlighted.
38     *
39     * @param tag the name of the default tab
40     */
41    public void setDefaultTab(String tag) {
42        mDefaultTab = tag;
43        mDefaultTabIndex = -1;
44    }
45
46    /**
47     * Sets the default tab that is the first tab highlighted.
48     *
49     * @param index the index of the default tab
50     */
51    public void setDefaultTab(int index) {
52        mDefaultTab = null;
53        mDefaultTabIndex = index;
54    }
55
56    @Override
57    protected void onRestoreInstanceState(Bundle state) {
58        super.onRestoreInstanceState(state);
59        ensureTabHost();
60        String cur = state.getString("currentTab");
61        if (cur != null) {
62            mTabHost.setCurrentTabByTag(cur);
63        }
64        if (mTabHost.getCurrentTab() < 0) {
65            if (mDefaultTab != null) {
66                mTabHost.setCurrentTabByTag(mDefaultTab);
67            } else if (mDefaultTabIndex >= 0) {
68                mTabHost.setCurrentTab(mDefaultTabIndex);
69            }
70        }
71    }
72
73    @Override
74    protected void onPostCreate(Bundle icicle) {
75        super.onPostCreate(icicle);
76
77        ensureTabHost();
78
79        if (mTabHost.getCurrentTab() == -1) {
80            mTabHost.setCurrentTab(0);
81        }
82    }
83
84    @Override
85    protected void onSaveInstanceState(Bundle outState) {
86        super.onSaveInstanceState(outState);
87        String currentTabTag = mTabHost.getCurrentTabTag();
88        if (currentTabTag != null) {
89            outState.putString("currentTab", currentTabTag);
90        }
91    }
92
93    /**
94     * Updates the screen state (current list and other views) when the
95     * content changes.
96     *
97     *@see Activity#onContentChanged()
98     */
99    @Override
100    public void onContentChanged() {
101        super.onContentChanged();
102        mTabHost = (TabHost) findViewById(com.android.internal.R.id.tabhost);
103
104        if (mTabHost == null) {
105            throw new RuntimeException(
106                    "Your content must have a TabHost whose id attribute is " +
107                    "'android.R.id.tabhost'");
108        }
109        mTabHost.setup(getLocalActivityManager());
110    }
111
112    private void ensureTabHost() {
113        if (mTabHost == null) {
114            this.setContentView(com.android.internal.R.layout.tab_content);
115        }
116    }
117
118    @Override
119    protected void
120    onChildTitleChanged(Activity childActivity, CharSequence title) {
121        // Dorky implementation until we can have multiple activities running.
122        if (getLocalActivityManager().getCurrentActivity() == childActivity) {
123            View tabView = mTabHost.getCurrentTabView();
124            if (tabView != null && tabView instanceof TextView) {
125                ((TextView) tabView).setText(title);
126            }
127        }
128    }
129
130    /**
131     * Returns the {@link TabHost} the activity is using to host its tabs.
132     *
133     * @return the {@link TabHost} the activity is using to host its tabs.
134     */
135    public TabHost getTabHost() {
136        ensureTabHost();
137        return mTabHost;
138    }
139
140    /**
141     * Returns the {@link TabWidget} the activity is using to draw the actual tabs.
142     *
143     * @return the {@link TabWidget} the activity is using to draw the actual tabs.
144     */
145    public TabWidget getTabWidget() {
146        return mTabHost.getTabWidget();
147    }
148}
149