private void initFragment() { mRecommendFragment = new RecommendFragment(); mInvestFragment = new InvestFragment(); mCla***oomFragment = new Cla***oomFragment(); mMineFragment = new MineFragment(); mBaseFragments = new BaseFragment[] { mRecommendFragment, mInvestFragment, mCla***oomFragment, mMineFragment }; } @Override public void onClick(View v) { // TODO Auto-generated method stub switch (v.getId()) { case R.id.llrecommend: btStatuas(mRecommendFragment, 0); switchContent(mRecommendFragment); if(mRecommendFragment.getActivity() != null){ mRecommendFragment.NetFragment(); } break; case R.id.llinvest: btStatuas(mInvestFragment, 1); switchContent(mInvestFragment); break; case R.id.llcla***oom: btStatuas(mCla***oomFragment, 2); switchContent(mCla***oomFragment); break; case R.id.llmine: if (MyApplication.getInstance().getLoginInfo() != null) { btStatuas(mMineFragment, 3); switchContent(mMineFragment); if(mMineFragment.getActivity() != null){ mMineFragment.refreshTitleData(); } } else { Intent intent = new Intent(MainActivity.this, LoginActivity.class); intent.putExtra("fromact", Constant.FROM_ACT_MAIN); startActivityForResult(intent, 0); } break; } } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { // TODO Auto-generated method stub super.onActivityResult(requestCode, resultCode, data); switch (resultCode) { case 1: if (MyApplication.getInstance().getLoginInfo() == null) { btStatuas(mCurrentContent, mCurrentLockIndex); switchContent(mCurrentContent); } else { btStatuas(mMineFragment, 3); switchContent(mMineFragment); } break; case 2: if (MyApplication.getInstance().getLoginInfo() == null) { btStatuas(mRecommendFragment, 0); switchContent(mRecommendFragment); } break; } } public void switchContent(Fragment to) { if (mContent != null && mContent != to) { FragmentTransaction transaction = fragmentManager .beginTransaction().setCustomAnimations( android.R.anim.fade_in, android.R.anim.fade_out); if (!to.isAdded()) { // 先判斷是否被add過 transaction.hide(mContent).add(R.id.llfrag, to).commitAllowingStateLoss(); // 隱藏當前的fragment,add下一個到Activity中 } else { transaction.hide(mContent).show(to).commitAllowingStateLoss(); // 隱藏當前的fragment,顯示下一個 } mContent = to; } }
1、上面代碼是多個fragment之間進行切換顯示,未添加到activity中的需要add、commit,已添加的需要hide,show。
在FragmentActivity啓動時,會加載在Fragment1,當Fragment1--->Activity2----->Activity3---->FragmentActivity(Fragment1)---->Fragment2,時此時Fragmnet屬於未被Add入FragmentActivity中,僅僅通過new創建了實例,內部生命週期不跑,其中getActivity == null,isAdded() == false;commit並沒有立即執行,而是走正常生命週期,所以不能再activity中不能調用fragment內部方法,ui未加載都爲空,不能進行ui刷新。當add過後commit執行完,內部方法可以調用。
2、關於show,hiden時fragment在別的activity中fc後返回會出現fragment顯示show異常
protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); if (savedInstanceState == null) { initView(); initClick(); initFragment(); initFragmentContent(); //版本檢測 // initData(); } else { initView(); initClick(); initFragment(); fragmentManager = getSupportFragmentManager(); FragmentTransaction beginTransaction = fragmentManager .beginTransaction(); btStatuas(mRecommendFragment, 0); // findViewById(R.id.llfrag) beginTransaction.replace(R.id.llfrag, mRecommendFragment); // beginTransaction.add(R.id.llfrag, mRecommendFragment); mContent = mBaseFragments[0]; beginTransaction.commitAllowingStateLoss(); // Toast.makeText(MainActivity.this, "", Toast.LENGTH_SHORT).show(); } @Override protected void onSaveInstanceState(Bundle outState) { // TODO Auto-generated method stub super.onSaveInstanceState(outState); outState.putInt("index", 0); }
onSaveInstanceState(Bundle outState)保存狀態,當異常重新加載會走onCreate方法,通過保存狀態的參數來判斷