android - 拖放操作栏选项卡(Android 4.0 ICS)？

Question

是否有办法允许用户在 Android 4.0 ICS 上拖放 ActionBar 中的导航选项卡以重新排序？我指的不是已弃用的 TabHost 中的选项卡，而是您添加到在 Honeycomb 及以上版本中使用的 ActionBar 的选项卡。

谢谢!

Answer 1

就使用ActionBar.Tabs而言是的，他们根本不具备实现这一目标的功能。另一方面，创建您自己的模仿 Tabs 的自定义类非常简单，然后您所要做的就是创建并添加一个 OnDragListener 和 用于填充标签栏的 View 的 OnTouchListener。

例如，这是我在一个应用程序中使用的一个类，它模仿 ActionBar.Tabs。

可滚动TabView

    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);
}

连接 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膨胀的 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 Fragment 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

网络上还有一些易于理解的教程。 Android Drag and Drop Tutorial, via Lars Vogel

Or you can always simply use Google to find more