Question

我应该在活动中创建每个片段的成员变量吗？

像：

private DemoFragment1 frag1;
private DemoFragment2 frag2;
private DemoFragment3 frag3;
private DemoFragment4 frag4;
private DemoFragment5 frag5;

然后在Activity.onCreate（）中我应该实例化所有这些，以便我知道它们都已经启动并且只启动了一次？或者当我去创建它们时，我应该这样做吗？

createFrag1(){
        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        fragmentTransaction.replace(R.id.frame_holder, new DemoFragment1());
        fragmentTransaction.commit();
}

Answer 1

在我的一项活动中，我在WindowsFocusChanged上添加了所有片段（所以我有适当的屏幕测量值）：

 private void addFragments() {
    if(mPassedMachine.getMachineType() == MachineType.ZR7)
        addZeroFragment(ANIMATION_TYPE_NONE, false);
    else 
        addLevelFragment(ANIMATION_TYPE_NONE, false);
    addHeartRateFragment(ANIMATION_TYPE_NONE, false);
    addMaxMinAvgFragment(ANIMATION_TYPE_NONE, false);
    addExtraFragment(ANIMATION_TYPE_NONE, false);
 }

当我添加片段时，我确保将其添加到片段堆栈中。然后，当我检索片段时，我要么获得现有片段，要么创建一个新片段：

 private void addLevelFragment(int animationType, boolean shouldShow) {
    String fragmentTag = getFragmentTag();
    FragmentTransaction fragmentTransaction = getFragmentTransactionWithAnimation(animationType);
    mLevelFragment = (SupplementLevelFragment) getFragmentManager().findFragmentByTag(fragmentTag);

    if(mLevelFragment == null) {
        mLevelFragment = new SupplementLevelFragment();
        Bundle levelBundle = getSupplementBundle(false);
        levelBundle.putBoolean(WorkoutSupplementBaseFragment.SUPPLEMENT_CLOCK_COUNT_DOWN, mTimerCountingDown);
        levelBundle.putInt(WorkoutSupplementBaseFragment.FRAGMENT_ORIGINAL_TIME, mTotalMinutes);
        levelBundle.putInt(SupplementLevelFragment.FRAGMENT_LEVEL, mCurrentLevel);
        mLevelFragment.setArguments(levelBundle);
        fragmentTransaction.addToBackStack(null);
    }

    fragmentTransaction.replace(R.id.workout_supplement_fragment_middle_layout, mLevelFragment, fragmentTag);

    if(shouldShow == true) 
        fragmentTransaction.show(mLevelFragment);
    else
        fragmentTransaction.hide(mLevelFragment);

    fragmentTransaction.commit();
    fragmentTransaction = null;
}

我这样做是因为我滚动片段并向他们添加数据，即使他们当前没有焦点。

我的活动可能包含很多片段（5+）我应该如何创建它们？

1 个答案: