Rebranding to OpenTracks (code).

src/main/java/de/dennisguse/opentracks/TabsAdapter.java

@@ -0,0 +1,153 @@
+/*
+ * Copyright 2013q Google Inc.
+ *
+ * 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 de.dennisguse.opentracks;
+
+import android.content.Context;
+import android.os.Bundle;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.TabHost;
+import android.widget.TabHost.TabContentFactory;
+import android.widget.TabWidget;
+
+import androidx.fragment.app.Fragment;
+import androidx.fragment.app.FragmentActivity;
+import androidx.fragment.app.FragmentPagerAdapter;
+import androidx.viewpager.widget.ViewPager;
+
+import java.util.ArrayList;
+
+/**
+ * This is a helper class that implements the management of tabs and all details
+ * of connecting a ViewPager with associated TabHost. It relies on a trick.
+ * Normally a tab host has a simple API for supplying a View or Intent that each
+ * tab will show. This is not sufficient for switching between pages. So instead
+ * we make the content part of the tab host 0dp high (it is not shown) and the
+ * TabsAdapter supplies its own dummy view to show as the tab content. It
+ * listens to changes in tabs, and takes care of switch to the correct paged in
+ * the ViewPager whenever the selected tab changes.
+ * <p>
+ * Copied from the FragmentTabsPager sample in the support library.
+ *
+ * @author Jimmy Shih
+ */
+//TODO Rework or better remove.
+public class TabsAdapter extends FragmentPagerAdapter implements TabHost.OnTabChangeListener, ViewPager.OnPageChangeListener {
+
+    private final Context context;
+    private final TabHost tabHost;
+    private final ViewPager viewPager;
+    private final ArrayList<TabInfo> tabInfos = new ArrayList<>();
+
+    public TabsAdapter(FragmentActivity activity, TabHost tabHost, ViewPager viewPager) {
+        super(activity.getSupportFragmentManager());
+        this.context = activity;
+        this.tabHost = tabHost;
+        this.viewPager = viewPager;
+        this.tabHost.setOnTabChangedListener(this);
+        this.viewPager.setAdapter(this);
+        this.viewPager.setOnPageChangeListener(this);
+    }
+
+    public void addTab(TabHost.TabSpec tabSpec, Class<?> clss, Bundle bundle) {
+        tabSpec.setContent(new DummyTabFactory(context));
+
+        TabInfo info = new TabInfo(clss, bundle);
+
+        tabInfos.add(info);
+        tabHost.addTab(tabSpec);
+        notifyDataSetChanged();
+    }
+
+    @Override
+    public int getCount() {
+        return tabInfos.size();
+    }
+
+    @Override
+    public Fragment getItem(int position) {
+        TabInfo info = tabInfos.get(position);
+        return Fragment.instantiate(context, info.clss.getName(), info.bundle);
+    }
+
+    @Override
+    public void onTabChanged(String tabId) {
+        int position = tabHost.getCurrentTab();
+        viewPager.setCurrentItem(position);
+    }
+
+    @Override
+    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
+    }
+
+    @Override
+    public void onPageSelected(int position) {
+        /*
+         * Unfortunately when TabHost changes the current tab, it kindly also takes
+         * care of putting focus on it when not in touch mode. The jerk. This hack
+         * tries to prevent this from pulling focus out of our ViewPager.
+         */
+        TabWidget tabWidget = tabHost.getTabWidget();
+        int oldFocusability = tabWidget.getDescendantFocusability();
+        tabWidget.setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS);
+        tabHost.setCurrentTab(position);
+        tabWidget.setDescendantFocusability(oldFocusability);
+    }
+
+    @Override
+    public void onPageScrollStateChanged(int state) {
+    }
+
+    /**
+     * An object to hold a tab's info.
+     *
+     * @author Jimmy Shih
+     */
+    private static final class TabInfo {
+
+        private final Class<?> clss;
+        private final Bundle bundle;
+
+        public TabInfo(Class<?> clss, Bundle bunlde) {
+            this.clss = clss;
+            this.bundle = bunlde;
+        }
+    }
+
+    /**
+     * A dummy {@link TabContentFactory} that creates an empty view to satisfy the
+     * {@link TabHost} API.
+     *
+     * @author Jimmy Shih
+     */
+    private static class DummyTabFactory implements TabHost.TabContentFactory {
+
+        private final Context context;
+
+        public DummyTabFactory(Context context) {
+            this.context = context;
+        }
+
+        @Override
+        public View createTabContent(String tag) {
+            View view = new View(context);
+            view.setMinimumWidth(0);
+            view.setMinimumHeight(0);
+            return view;
+        }
+    }
+}