使用ViewPager切换Fragment，我原先使用系统自带的适配器FragmentPagerAdapter。
切换fragment时，频繁调用oncreatview()。
查看FragmentPagerAdapter的源码，发现两个关键的地方
1 @Override 2 public Object instantiateItem(ViewGroup container, int position) { 3 if (mCurTransaction == null) { 4 mCurTransaction = mFragmentManager.beginTransaction(); 5 } 6 7 final long itemId = getItemId(position); 8 9 // Do we already have this fragment? 10 String name = makeFragmentName(container.getId(), itemId); 11 Fragment fragment = mFragmentManager.findFragmentByTag(name); 12 if (fragment != null) { 13 if (DEBUG) Log.v(TAG, "Attaching item #" + itemId + ": f=" + fragment); 14 //该处使用attach导致频繁调用oncreatview 15 mCurTransaction.attach(fragment); 16 17 } else { 18 fragment = getItem(position); 19 if (DEBUG) Log.v(TAG, "Adding item #" + itemId + ": f=" + fragment); 20 mCurTransaction.add(container.getId(), fragment, 21 makeFragmentName(container.getId(), itemId)); 22 } 23 if (fragment != mCurrentPrimaryItem) { 24 fragment.setMenuVisibility(false); 25 fragment.setUserVisibleHint(false); 26 } 27 28 return fragment; 29 } 30 31 @Override 32 public void destroyItem(ViewGroup container, int position, Object object) { 33 if (mCurTransaction == null) { 34 mCurTransaction = mFragmentManager.beginTransaction(); 35 } 36 if (DEBUG) Log.v(TAG, "Detaching item #" + getItemId(position) + ": f=" + object 37 + " v=" + ((Fragment)object).getView()); 38 //该处使用detach导致频繁调用oncreatview 39 mCurTransaction.detach((Fragment)object); 40 }
attach和detach的频繁使用导致了fragment频繁调用oncreatview。
找到元凶了，接下来就好办了。
自定义一个适配器，将attach改为show，将detach改为hide。
完美解决问题。
@Override public Object instantiateItem(ViewGroup container, int position) { if (mCurTransaction == null) { mCurTransaction = mFragmentManager.beginTransaction(); } final long itemId = getItemId(position); // Do we already have this fragment? String name = makeFragmentName(container.getId(), itemId); Fragment fragment = mFragmentManager.findFragmentByTag(name); if (fragment != null) { if (DEBUG) Log.v(TAG, "Attaching item #" + itemId + ": f=" + fragment); //用show而不用attach，防止频繁调用oncreatview mCurTransaction.show(fragment); } else { fragment = getItem(position); if (DEBUG) Log.v(TAG, "Adding item #" + itemId + ": f=" + fragment); mCurTransaction.add(container.getId(), fragment, makeFragmentName(container.getId(), itemId)); } if (fragment != mCurrentPrimaryItem) { fragment.setMenuVisibility(false); fragment.setUserVisibleHint(false); } return fragment; } @Override public void destroyItem(ViewGroup container, int position, Object object) { if (mCurTransaction == null) { mCurTransaction = mFragmentManager.beginTransaction(); } if (DEBUG) Log.v(TAG, "Detaching item #" + getItemId(position) + ": f=" + object + " v=" + ((Fragment) object).getView()); //用hide而不用detach，防止频繁调用oncreatview mCurTransaction.hide((Fragment) object); }