Fragment切换返回

1.开发中遇到需要在Fragment之间切换,保存状态

(1).初始化Fragment:

1 public void initFragment(){
2         FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
3         ft.replace(R.id.fl_container,onCreteFragment());
4         ft.commitAllowingStateLoss();//允许丢失,一般可以不用这个采用commit()替代
5 }

(2).切换Fragment算法:

1 public void switchFragment(Fragment from, Fragment to) {
2         FragmentTransaction mFragmentTransaction = getSupportFragmentManager().beginTransaction();
3         if (!to.isAdded()) { // 先判断是否被add过
4             mFragmentTransaction.hide(from).add(R.id.fl_container, to)
5                     .commit(); // 隐藏当前的fragment，add下一个到Activity中
6         } else {
7             mFragmentTransaction.hide(from).show(to).commit(); // 隐藏当前的fragment，显示下一个
8         }
9 }

(3).封装返回监听,采用弱引用和静态内部类,避免内存泄漏

 1 public static class MyOnBackListener implements BaseFragment.OnBackListener {
 2         private final WeakReference<BaseFragment> mBaseFragment;//目的Fragment
 3         private final WeakReference<BaseFragmentActivity> mBaseActivity;
 4         /**
 5          * @param toFragment 跳转目的Fragment
 6          * @param baseActivit 当前BaseActivity
 7          */
 8         public MyOnBackListener(BaseFragment toFragment,BaseFragmentActivity baseActivit) {
 9             mBaseFragment =new WeakReference<>(toFragment);
10             mBaseActivity =new WeakReference<>(baseActivit);
11         }
12 
13         @Override
14         public void back(BaseFragment baseFragment) {
15             BaseFragmentActivity baseActivity = mBaseActivity.get();
16             BaseFragment baseFragment2 = mBaseFragment.get();
17             if (baseActivity !=null&& baseFragment2 !=null&&baseFragment!=null){
18                 baseActivity.switchFragment(baseFragment,baseFragment2);
19             }
20         }
21     }

(4).Activity中简单使用:

private void initLocalFragment() {
        mRfbf = new RecyclerFabBehaviorFragment();
        mRfbf.setOnBackListener(new MyOnBackListener(mStartRecycFragment,this));
 }

1 @Override
2 public void click(View view, int position) {
3         switch (position){
4             case 0:
5                 switchFragment(mStartRecycFragment, mRfbf);
6                 break;
7         }
8  }

(5).子类Fragment中记得调用back:eg

TabyoutViewPagerFragment extends BaseFragment

private void initToolbar() {
        mToolbar.setNavigationOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (mOnBackListener!=null){
                    mOnBackListener.back(TabyoutViewPagerFragment.this);
                }
            }
        });
}

(6).可以采用鸿阳的FABridge来简化Fragment中定义接口在Activity中回调

annotationProcessor 'com.zhy.fabridge:fabridge-compiler:1.0.0'
implementation 'com.zhy.fabridge:fabridge-api:1.0.0'

Fragment中定义

Fabridge.call(getActivity(), EVENT_CLICK, "来了");

Activity中使用

@FCallbackId(id = FabrigeSampleFragment.EVENT_CLICK)
public void menuItemClick(String title)
{
    Toast.makeText(this, ""+title+","+Thread.currentThread().getName(), Toast.LENGTH_SHORT).show();
}

Fragment切换返回

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