拖放操作栏选项卡（Android 4.0 ICS）？

Question

是否允许用户拖放操作栏中的导航选项卡以在 Android 4.0 ICS 上重新排序？我不是指已弃用的 TabHost 中的选项卡，我指的是您添加到用于 Honeycomb 及更高版本的 ActionBar 中的选项卡。

谢谢！

Answer 1

就使用ActionBar.Tabs 而言，他们根本没有实现这一目标的功能。另一方面，创建您自己的模仿 Tabs 的自定义类很容易，那么您所要做的就是创建并添加一个 OnDragListener 和 OnTouchListener 用于填充您的 View标签栏。

例如，这是我在一个模仿ActionBar.Tabs 的应用程序中使用的类。

ScrollableTabView

    public class ScrollableTabView extends HorizontalScrollView implements OnPageChangeListener {

    private final Context mContext;

    private final LinearLayout mContainer;

    private final ArrayList<View> mTabs = new ArrayList<View>();

    private final int mDividerColor = 0xFF636363;

    private int mDividerMarginTop = 12;

    private int mDividerMarginBottom = 12;

    private int mDividerWidth = 1;

    private ViewPager mPager;

    private TabAdapter mAdapter;

    private Drawable mDividerDrawable;

    public ScrollableTabView(Context context) {
        this(context, null);
    }

    public ScrollableTabView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public ScrollableTabView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs);

        mContext = context;

        final LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
                android.view.ViewGroup.LayoutParams.MATCH_PARENT,
                android.view.ViewGroup.LayoutParams.MATCH_PARENT);

        mDividerMarginTop = (int)(getResources().getDisplayMetrics().density * mDividerMarginTop);
        mDividerMarginBottom = (int)(getResources().getDisplayMetrics().density * mDividerMarginBottom);
        mDividerWidth = (int)(getResources().getDisplayMetrics().density * mDividerWidth);

        setHorizontalScrollBarEnabled(false);
        setHorizontalFadingEdgeEnabled(false);

        mContainer = new LinearLayout(context);
        mContainer.setOrientation(LinearLayout.HORIZONTAL);
        mContainer.setLayoutParams(params);

        addView(mContainer);
    }

    /**
     * Set the tabs Adapter
     * 
     * @param adapter
     */
    public void setAdapter(TabAdapter adapter) {
        mAdapter = adapter;

        if (mPager != null && mAdapter != null) {
            initTabs();
        }
    }

    /**
     * Attach ViewPager
     * 
     * @param pager
     */
    public void setViewPager(ViewPager pager) {
        mPager = pager;
        mPager.setOnPageChangeListener(this);

        if (mPager != null && mAdapter != null) {
            initTabs();
        }
    }

    /**
     * Initiate the tabs
     */
    private void initTabs() {

        mContainer.removeAllViews();
        mTabs.clear();

        if (mAdapter == null) {
            return;
        }

        for (int i = 0; i < mPager.getAdapter().getCount(); i++) {

            final int index = i;

            final View tab = mAdapter.getView(i);
            mContainer.addView(tab);

            tab.setFocusable(true);

            mTabs.add(tab);

            if (i != mPager.getAdapter().getCount() - 1) {
                mContainer.addView(getSeparator());
            }

            tab.setOnClickListener(new OnClickListener() {
                @Override
                public void onClick(View v) {
                    if (mPager.getCurrentItem() == index) {
                        selectTab(index);
                    } else {
                        mPager.setCurrentItem(index, true);
                    }
                }
            });

        }

        selectTab(mPager.getCurrentItem());
    }

    @Override
    public void onPageScrollStateChanged(int state) {
        // Nothing to do
    }

    @Override
    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
        // Nothing to do
    }

    @Override
    public void onPageSelected(int position) {
        selectTab(position);
    }

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        super.onLayout(changed, l, t, r, b);

        if (changed) {
            selectTab(mPager.getCurrentItem());
        }
    }

    /**
     * @return Separates the tabs
     */
    private View getSeparator() {
        final View v = new View(mContext);

        final LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(mDividerWidth,
                android.view.ViewGroup.LayoutParams.MATCH_PARENT);
        params.setMargins(0, mDividerMarginTop, 0, mDividerMarginBottom);
        v.setLayoutParams(params);

        if (mDividerDrawable != null) {
            v.setBackground(mDividerDrawable);
        } else {
            v.setBackgroundColor(mDividerColor);
        }

        return v;
    }

    /**
     * @param position
     */
    private void selectTab(int position) {

        for (int i = 0, pos = 0; i < mContainer.getChildCount(); i += 2, pos++) {
            final View tab = mContainer.getChildAt(i);
            tab.setSelected(pos == position);
        }

        final View selectedTab = mContainer.getChildAt(position * 2);

        final int w = selectedTab.getMeasuredWidth();
        final int l = selectedTab.getLeft();

        final int x = l - this.getWidth() / 2 + w / 2;

        smoothScrollTo(x, this.getScrollY());
    }
}

TabAdapter

    public interface TabAdapter {
    public View getView(int position);
}

附加您的 TabAdapter

    public class ScrollingTabsAdapter implements TabAdapter {

    private final FragmentActivity activity;

    private final LayoutInflater inflater;

    private Button mTabs;

    // Tab titles
    private static final String[] mTitles = {
            "RECENT", "ARTISTS", "ALBUMS", "SONGS", "PLAYLISTS", "GENRES"
    };

    /**
     * @param act
     */
    public ScrollingTabsAdapter(FragmentActivity act) {
        activity = act;
        inflater = activity.getLayoutInflater();
    }

    @Override
    public View getView(int position) {
        mTabs = (Button)inflater.inflate(R.layout.tabs, null);
        if (position < mTitles.length) {
            mTabs.setText(mTitles[position]);
        }
        return mTabs;
    }
}

您可以使用真实ActionBar.Tabs 的默认可绘制对象和属性来设置您充气的Button 的样式。您可以从 SDK 或网络上的某个地方获取它们。要使用它，请将ViewPager 对象附加到ScrollableTabView 并将每个Fragments 添加到FragmentPagerAdapter 中。 This is what they look like, if you're curious about the style after adding the default drawables and attributes

就拖放而言，Android 在其网站上有一些不错的文档。 Drag and Drop

网上也有一些易于学习的教程。 Android Drag and Drop Tutorial, via Lars Vogel

Or you can always simply use Google to find more