Fragment与FragmentActivity通信封装

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

<span style="font-size:14px;">public class BaseChangeFragments extends BaseActivity {

    protected FragmentManager mFragmentManager;
    protected FragmentTransaction mFragmentTransaction;

    protected String mCurrentFragmentTag;
    protected Map<String, BaseFragment> mapFragments = new HashMap<String, BaseFragment>();

    @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();
    }

}</span>

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：

<span style="font-size:14px;">/**
     * 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);
            }
        }
    }</span>

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

<span style="font-size:14px;">@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        startIntent = new Intent();
        beforeCreate();
        LogUtils.customTagPrefix = "IDPoc";
        initView();
        initListener();
        initData();
    }
</span>

回调接口如下：

<span style="font-size:14px;">public interface IFragmentChange {
    void setId(String id, Bundle bundle);
}</span>

在Fragment类中实现：

<span style="font-size:14px;"></span><p style="margin-top: 0px; margin-bottom: 0px; font-family: Menlo;"><span style="font-size:14px;"><span style="color: #bb2ca2">private</span> IFragmentChange mFragmentChange;</span></p><span style="font-size:14px;">@Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        mFragmentChange = (IFragmentChange) activity;
    }

    @Override
    public void onDetach() {
        super.onDetach();
        mFragmentChange = null;
    }
</span>

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。