在项目里面会经常用到Fragment与FragmentActivity，比如Fragment之间的界面切换与Fragment之间的值传递等等，为了方便起见我把Fragment和FragmentActivity进一步封装，那在实际开发中只需要继承父类，然后调用一个方法就可以实现Fragment之间界面切换和值传递

1、FragmentActivity类的封装

public class BaseChangeFragments extends BaseActivity {    protected FragmentManager mFragmentManager;    protected FragmentTransaction mFragmentTransaction;    protected String mCurrentFragmentTag;    protected Map
      
        mapFragments = new HashMap
       
        ();    @Override    protected void beforeCreate() {        super.beforeCreate();        mFragmentManager = getSupportFragmentManager();    }    protected FragmentTransaction ensureTransaction() {        if (mFragmentTransaction == null) {            mFragmentTransaction = mFragmentManager.beginTransaction();            // mFragmentTransaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);            // mFragmentTransaction.addToBackStack(null);            mFragmentTransaction                    .setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);        }        return mFragmentTransaction;    }    protected BaseFragment getFragment(String tag) {        BaseFragment f = (BaseFragment) (mFragmentManager                .findFragmentByTag(tag));        if (f == null) {            // 在这里判断tag,不同则实例化对应的fragment            f = mapFragments.get(tag);        }        return f;    }    protected void attachFragment(int layout, Fragment f, String tag) {        if (f != null) {            if (f.isDetached()) {                ensureTransaction();                mFragmentTransaction.attach(f);            } else if (!f.isAdded()) {                ensureTransaction();                mFragmentTransaction.add(layout, f, tag);            }        }    }    protected void detachFragment(Fragment f) {        if (f != null && !f.isDetached()) {            ensureTransaction();            mFragmentTransaction.detach(f);        }    }    /**     * @param layout     * @param f     * @param tag     */    protected void showFragment(int layout, BaseFragment f, String tag) {        if (f != null) {            if (!f.isAdded()) {                ensureTransaction();                f.updateNet();                mFragmentTransaction.add(layout, f, tag);            } else {                ensureTransaction();                f.updateNet();                mFragmentTransaction.show(f);            }        }    }    /**     * 进行传值     *      * @param layout     * @param f     * @param tag     * @param bundle     */    protected void showFragment(int layout, BaseFragment f, String tag,            Bundle bundle) {        if (f != null) {            if (!f.isAdded()) {                ensureTransaction();                f.updateNet(bundle);                mFragmentTransaction.add(layout, f, tag);            } else {                ensureTransaction();                f.updateNet(bundle);                mFragmentTransaction.show(f);            }        }    }    protected void hideFragment(Fragment f) {        if (f != null) {            if (f.isAdded()) {                ensureTransaction();                mFragmentTransaction.hide(f);            }        }    }    protected void commitTransactions() {        if (mFragmentTransaction != null && !mFragmentTransaction.isEmpty()) {            mFragmentTransaction.commit();            mFragmentTransaction = null;        }    }    /**     * 采用attach和detach来实现fragment的切换，每一次都会进入onCreateView     *      * @param tag     */    protected void switchFragmenCreate(String tag) {        if (TextUtils.equals(mCurrentFragmentTag, tag))            return;        if (mCurrentFragmentTag != null)            detachFragment(getFragment(mCurrentFragmentTag));        attachFragment(R.id.container, getFragment(tag), tag);        mCurrentFragmentTag = tag;        commitTransactions();    }    /**     * 采用show和hide来实现fragment的切换，只有第一次都会进入onCreateView     *      * @param tag     */    protected void switchFragmen(String tag) {        if (TextUtils.equals(mCurrentFragmentTag, tag))            return;        if (mCurrentFragmentTag != null)            hideFragment(getFragment(mCurrentFragmentTag));        showFragment(R.id.container, getFragment(tag), tag);        mCurrentFragmentTag = tag;        commitTransactions();    }        /**     * 切换界面，通过bundle来传值     * @param tag     * @param bundle     */    protected void switchFragmen(String tag, Bundle bundle) {        if (TextUtils.equals(mCurrentFragmentTag, tag))            return;        if (mCurrentFragmentTag != null)            hideFragment(getFragment(mCurrentFragmentTag));        showFragment(R.id.container, getFragment(tag), tag, bundle);        mCurrentFragmentTag = tag;        commitTransactions();    }}
       
      

上面包含了三种切换方式分别是：（1）attach和detach （2）show和hide -- 不传值（3）show和hide--传值

 其中传值方式采用接口回调的方式实现，比如下面这个方法：

/**     * 进行传值     *      * @param layout     * @param f     * @param tag     * @param bundle     */    protected void showFragment(int layout, BaseFragment f, String tag,            Bundle bundle) {        if (f != null) {            if (!f.isAdded()) {                ensureTransaction();                f.updateNet(bundle);  --采用接口回调告知fragment显示以及更新数据两个功能                mFragmentTransaction.add(layout, f, tag);            } else {                ensureTransaction();                f.updateNet(bundle);                mFragmentTransaction.show(f);            }        }    }

其中里面BaseActivity这个类是在我的项目的基础类，我把onCreate里面的添加的空方法写出来

@Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        startIntent = new Intent();        beforeCreate();        LogUtils.customTagPrefix = "IDPoc";        initView();        initListener();        initData();    }

回调接口如下：

public interface IFragmentChange {    void setId(String id, Bundle bundle);}

在Fragment类中实现：

private IFragmentChange mFragmentChange;
@Override    public void onAttach(Activity activity) {        super.onAttach(activity);        mFragmentChange = (IFragmentChange) activity;    }    @Override    public void onDetach() {        super.onDetach();        mFragmentChange = null;    }

这样的话，切换fragment界面的时候，只需要调用那三个中的一个就可以了。