Android api 24+的TabLayout问题处理

API 24的TabLayout更新了一些方法 用着有些问题 比如像我遇到的自定义处理某些tab点击时想要不切换viewPager 而是弹出一个activity
下面是一个简单的懒人处理方式 附带源码分析

ViewPager vp = (ViewPager)findViewById(R.id.viewPager);
TabLayout tabLayout = (TabLayout)findViewById(R.id.tabLayout);
tabLayout.setupWithViewPager(vp);//看看这个方法做了什么

private void setupWithViewPager(@Nullable final ViewPager viewPager, boolean autoRefresh,
            boolean implicitSetup) {
        if (mViewPager != null) {
            // If we've already been setup with a ViewPager, remove us from it
            if (mPageChangeListener != null) {
                mViewPager.removeOnPageChangeListener(mPageChangeListener);
            }
            if (mAdapterChangeListener != null) {
                mViewPager.removeOnAdapterChangeListener(mAdapterChangeListener);
            }
        }


        if (mCurrentVpSelectedListener != null) {
            // If we already have a tab selected listener for the ViewPager, remove it
            removeOnTabSelectedListener(mCurrentVpSelectedListener);
            mCurrentVpSelectedListener = null;
        }


        if (viewPager != null) {
            mViewPager = viewPager;


            // Add our custom OnPageChangeListener to the ViewPager
            if (mPageChangeListener == null) {
                mPageChangeListener = new TabLayoutOnPageChangeListener(this);
            }
            mPageChangeListener.reset();
            viewPager.addOnPageChangeListener(mPageChangeListener);


            // Now we'll add a tab selected listener to set ViewPager's current item
            mCurrentVpSelectedListener = new ViewPagerOnTabSelectedListener(viewPager);
            addOnTabSelectedListener(mCurrentVpSelectedListener);//这里给你添加了一个OnTabSelectedListener


            final PagerAdapter adapter = viewPager.getAdapter();
            if (adapter != null) {
                // Now we'll populate ourselves from the pager adapter, adding an observer if
                // autoRefresh is enabled
                setPagerAdapter(adapter, autoRefresh);
            }


            // Add a listener so that we're notified of any adapter changes
            if (mAdapterChangeListener == null) {
                mAdapterChangeListener = new AdapterChangeListener();
            }
            mAdapterChangeListener.setAutoRefresh(autoRefresh);
            viewPager.addOnAdapterChangeListener(mAdapterChangeListener);


            // Now update the scroll position to match the ViewPager's current item
            setScrollPosition(viewPager.getCurrentItem(), 0f, true);
        } else {
            // We've been given a null ViewPager so we need to clear out the internal state,
            // listeners and observers
            mViewPager = null;
            setPagerAdapter(null, false);
        }


        mSetupViewPagerImplicitly = implicitSetup;
    }

看上面的源码你会发现 这个方法里 TabLayout会帮你add一个OnTabSelectedListener 就是下面这个

class ViewPagerOnTabSelectedListener implements TabLayout.OnTabSelectedListener {
        private final ViewPager mViewPager;


        public ViewPagerOnTabSelectedListener(ViewPager viewPager) {
            mViewPager = viewPager;
        }


        @Override
        public void onTabSelected(TabLayout.Tab tab) {
            mViewPager.setCurrentItem(tab.getPosition());//强行帮你选中你不希望选中的viewPager的某个页面
        }


        @Override
        public void onTabUnselected(TabLayout.Tab tab) {
            // No-op
        }


        @Override
        public void onTabReselected(TabLayout.Tab tab) {
            // No-op
        }
    }

然后罪魁祸首是TabLayout的这个方法 从上面可以看出来 在你addOnTabSelectedListener之前已经有一个OnTabSelectedListener了
所以 执行完你自己加的OnTabSelectedListener的onTabSelected之后 总会执行TabLayout会帮你add那个OnTabSelectedListener的onTabSelected

private void dispatchTabSelected(@NonNull final Tab tab) {
    for (int i = mSelectedListeners.size() - 1; i >= 0; i--) {
        mSelectedListeners.get(i).onTabSelected(tab);
    }
}

所以 我想到的解决方案是强行remove掉它给你加的那个OnTabSelectedListener 可以 这很反射 当然 你要换成github上的一些TabLayout也无妨

Field fields[] = tabLayout.getClass().getDeclaredFields();
String[] name = new String[fields.length];
Object[] value = new Object[fields.length];


try {
    Field.setAccessible(fields, true);
    for (int i = 0; i < name.length; i++) {
        name[i] = fields[i].getName();
        value[i] = fields[i].get(tabLayout);
        if (name[i].equals("mCurrentVpSelectedListener")) {
            tabLayout.removeOnTabSelectedListener((TabLayout.OnTabSelectedListener) value[i]);
        }
    }
} catch (Exception e) {
    e.printStackTrace();
}

然后自定义自己的OnTabSelectedListener

OnTabSelectedListener mTabSelectedListener = new TabLayout.ViewPagerOnTabSelectedListener(vp) {


    @Override
    public void onTabSelected(TabLayout.Tab tab) {
        int position = (int) tab.getTag();
        if (position == 0) {
            vp.setCurrentItem(tab.getPosition());
        }else if (position == 1) {
            if (condition) {//condition：自己写的某些条件
                if (tab != null) {
                    vp.setCurrentItem(tab.getPosition());//手动调用viewPager的setCurrentItem
                }
            } else {
                doSomething();//可以做些其他事情 这里不用调用viewPager的setCurrentItem 就不会切到不想切换的viewPager那个页面了
            }
        }
    }


    @Override
    public void onTabUnselected(TabLayout.Tab tab) {
    }


    @Override
    public void onTabReselected(TabLayout.Tab tab) {
    //之所以要在这里添加reslect的处理 主要是你之前点击tab的时候虽然没选中并切换Viewpager的页面
    //但是 TabLayout的状态其实已经被选中了 再次点击时肯定是不会走onTabSelected方法的
    //但是会走这个onTabReselected 另外 选中时一些UI上的图标、文字切换效果什么的需要自己在onTabSelected中处理 
        int position = (int) tab.getTag();
        L.e(TAG, position + " onTabReselected");
        mTabSelectedListener.onTabSelected(tab);
    }
};

最后addOnTabSelectedListener

tabLayout.addOnTabSelectedListener(mTabSelectedListener);

release版本开了混淆的话在proguard-rules.pro加上

-keepclasseswithmembernames class android.support.design.widget.TabLayout {
    *;
}