android TabLayout实现京东详情效果

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:appcompat-v7:24.2.0'
    compile 'com.android.support:design:24.2.0'
    compile 'com.android.support:recyclerview-v7:24.2.0'
    compile 'com.android.support:cardview-v7:24.2.0'
}

我们来看一下实现的布局：

这布局文件最关键的一点就是android.support.design.widget.TabLayout 标签中的app:tabMode=”scrollable”，他设置tab的模式为“可滑动的”。

其他的用法和Indicator的用法差不多，都需要设置适配器，然后通过数据实现页面的适配。直接上代码

Adapter

public class ProductDetailPagerAdapter extends FragmentPagerAdapter {

    private List mFragments=null;
    private List mTitles=null;

    public ProductDetailPagerAdapter(FragmentManager fm, List mFragments,List mTitles) {
        super(fm);
        this.mFragments =mFragments;
        this.mTitles=mTitles;
    }

    public ProductDetailPagerAdapter(FragmentManager fm, Fragment... fragments) {
        super(fm);
        this.mFragments = Arrays.asList(fragments);
    }

    @Override
    public Fragment getItem(int position) {
        return mFragments.get(position);
    }

    @Override
    public int getCount() {
        return mFragments.size();
    }

    @Override
    public CharSequence getPageTitle(int position) {
        return mTitles.get(position);
    }
}

主页面的相关逻辑，这里的Fragment就是简单的Fragment。

public class ProductDetailsActivity extends BaseActivity {

    @BindView(R.id.viewPager)
    ViewPager viewPager;
    @BindView(R.id.toolbar_more)
    ImageView toolbarMore;
    @BindView(R.id.tabLayout)
    TabLayout tabLayout;

    private List mFragments;
    private String[] titles = new String[]{"商品", "详情"};
    private ProductDetailPagerAdapter productPagerAdapter = null;
    private MorePopupWindow popupWindow = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_product_details);
        ButterKnife.bind(this);
        init();
    }

    private void init() {
        initViewPager();
    }

    private void initViewPager() {
        mFragments = new ArrayList();
        mFragments.add(new ProductFragment());
        mFragments.add(new ProductDetailFragment());

        productPagerAdapter = new ProductDetailPagerAdapter(getSupportFragmentManager(), mFragments, Arrays.asList(titles));
        viewPager.setOffscreenPageLimit(2);
        viewPager.setAdapter(productPagerAdapter);
        viewPager.setCurrentItem(1);
        tabLayout.setupWithViewPager(viewPager);
    }


    @OnClick(R.id.back)
    public void backClick() {
        finish();
    }

    @OnClick(R.id.toolbar_more)
    public void moreClick() {
       
    }

    private AdapterView.OnItemClickListener onItemClickListener = new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView parent, View view, int position,
                                long id) {
            popupWindow.dismiss();
        }
    };


    public static void open(Context context) {
        Intent intent = new Intent(context, ProductDetailsActivity.class);
        context.startActivity(intent);
    }
}

上面的代码都比较简单不做过多的解释，在使用TabLayout的时候需要注意一点：

tabmode有两个属性值：

MODE_FIXED:Fixed tabs display all tabs concurrently and are best used with content that benefits from quick pivots between tabs. MODE_SCROLLABLE:Scrollable tabs display a subset of tabs at any given moment, and can contain longer tab labels and a larger number of tabs. MODE_SCROLLABLE适合很多tabs的情况,是可以滚动的，如果你要实现京东的那种挤在一起的效果就需要MODE_FIXED了。

为了更好的满足开发需要，TabLayout实现了自定义TabLayout的样式，然后通过引入

app:tabTextAppearance=""

自定义icon添加到tab

private int[] imageResId = {
        R.drawable.ic_one,
        R.drawable.ic_two,
        R.drawable.ic_three
};
 
// ...
 
@Override
public CharSequence getPageTitle(int position) {
    // Generate title based on item position
    // return tabTitles[position];
    Drawable image = context.getResources().getDrawable(imageResId[position]);
    image.setBounds(0, 0, image.getIntrinsicWidth(), image.getIntrinsicHeight());
    SpannableString sb = new SpannableString(" ");
    ImageSpan imageSpan = new ImageSpan(image, ImageSpan.ALIGN_BOTTOM);
    sb.setSpan(imageSpan, 0, 1, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
    return sb;
}

运行，发现没有显示，这是因为TabLayout创建的tab默认设置textAllCaps属性为true，这阻止了ImageSpan被渲染出来，可以通过下面的样式文件定义来改变：

      @style/MyCustomTextAppearance

 

      false

然后在getPageTitle方法中设置上有标题的tab

@Override
public CharSequence getPageTitle(int position) {
    // Generate title based on item position
    Drawable image = context.getResources().getDrawable(imageResId[position]);
    image.setBounds(0, 0, image.getIntrinsicWidth(), image.getIntrinsicHeight());
    // Replace blank spaces with image icon
    SpannableString sb = new SpannableString("   " + tabTitles[position]);
    ImageSpan imageSpan = new ImageSpan(image, ImageSpan.ALIGN_BOTTOM);
    sb.setSpan(imageSpan, 0, 1, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
    return sb;
}

TabLayout还支持自定义View，通过getTabView来设置，这里就不讲怎么实现了，有兴趣的可以自行研究。