昨天遇到了個Android問題，java.lang.IllegalStateException: Fragment already added. backtrace里邊沒有自己的代碼.(好像是fragment重復(fù)添加)
問題情境大概虱颗，主界面 四個Tab, FragmentTransaction.add() show() commit() 在 onCheckedChangeListener中，來切換四個fragment神帅，有個需要需要在代碼中點擊radiobutton的地方（programmatically），結(jié)果出問題了萌抵，每當(dāng)點擊一個radiobutton處理邏輯大概這樣找御，判端這個指定的FragmentManager.getFragmentByTag(),if null,就 FragmentTransaction.add(fragment...);
上代碼片段
setOnCheckedChangeListener
radioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(RadioGroup group, int checkedId) {
// if(checkedId == radioGroup.getCheckedRadioButtonId()){
// return;
// }
ZLog.d("MainPage setOnCheckedChangeListener now checked " + checkedId + " last checked " + lastCheckId);
fragmentTransaction = fragmentManager.beginTransaction();
switch (checkedId) {
case R.id.one:
hideOtherFragment("one");
addOrShowFragment("one", firstFragment);
break;
case R.id.two:
hideOtherFragment("two");
addOrShowFragment("two", secondFragment);
break;
case R.id.three:
hideOtherFragment("three");
addOrShowFragment("three", thirdFragment);
break;
case R.id.four:
hideOtherFragment("four");
addOrShowFragment("four", fourthFragment);
break;
case R.id.radio_user:
hideOtherFragment("user");
addOrShowFragment("user", userFragment);
break;
}
ZLog.d("radioGroup onCheckedChange");
fragmentTransaction.commit();
fragmentManager.executePendingTransactions(); //重點
currFragment.scrollTop();//在commit前滾動到頂部
markChecked(checkedId);
}
});
radioGroup.check()
touristSubscription1 = RxBroadcast.fromLocalBroadcast(this, touristnotaccess)
.observeOn(AndroidSchedulers.mainThread())
.doOnNext(new Action1<Intent>() {
@Override
public void call(Intent intent) {
// radioGroup.check(R.id.radio_user);//重點
RadioButton b = (RadioButton) findViewById(R.id.radio_user);
b.setChecked(true);
}
})
.doOnError(new Action1<Throwable>() {
@Override
public void call(Throwable throwable) {
throwable.printStackTrace();
}
})
.subscribe(new Action1<Intent>() {
@Override
public void call(Intent intent) {
}
});
fragmentTransaction
private void addOrShowFragment(String tag, BaseFragment fragment) {
ZLog.d("addOrShowFragment " + fragmentManager.getFragments() + " tag " + tag + " isAdd " + fragment.isAdded());
if (fragmentManager.findFragmentByTag(tag) == null) {
fragmentTransaction.add(R.id.fragments_content, fragment, tag);
} else if (!fragment.isAdded()) {
fragmentTransaction.replace(R.id.fragments_content, fragment, tag);
} else {
fragmentTransaction.show(fragment);
}
currFragment = fragment;
}
RadioGroup.check(layoutid) onCheckedChangeListener#onCheckChanged()調(diào)用了 3 次(1 原來的radiobutton，2將要的radiobutton绍填， 3將要的radiobutton)
確實調(diào)用了三次霎桅，stackoverflow上老外看了源碼了，調(diào)用了三次讨永。問題在于滔驶，第三次調(diào)用的時候，判斷 將要顯示的fragment是否存在于FragmentManager.getFragments()中卿闹，明擺著第二次已經(jīng)add了揭糕，已經(jīng)commit了，F(xiàn)ragmentManager.getFragments()還沒有锻霎，原來commit()不會立即產(chǎn)生效果著角。解決方式，radiobutton.setChecked(true）替代旋恼。
FragmentTransaction.commit()不會立即產(chǎn)生效果吏口。解決方式，F(xiàn)ragmentManager.executePendingTransactions(); 立即產(chǎn)生效果
兩種解決方式任選其一即可，都選也沒事锨侯。
Reference (stackoverflow)
