调用 FragmentPagerAdapter.notifyDataSetChanged() 并不能更新其 Fragment之我的解决方法

http://www.526net.com/blog/mobile/335.html

private class ViewPagerAdapter extends FragmentPagerAdapter {

FragmentManager mFragmentManager;

FragmentTransaction mCurTransaction;

public ViewPagerAdapter(FragmentManager fragmentManager) {

super(fragmentManager);

this.mFragmentManager = fragmentManager;

}

@Override

public Fragment getItem(int position) {

final String mimeType = mSortedActionMimeTypes.get(position);

Log.d("lyl", "getItem-->mimeType: " + mimeType + " position: " + position);

QuickContactListFragment fragment = new QuickContactListFragment(mimeType);

return fragment;

}

@Override

public Object instantiateItem(ViewGroup container, int position) {

removeFragment(container,position);

QuickContactListFragment fragment =

(QuickContactListFragment) super.instantiateItem(container,position);

final String mimeType = mSortedActionMimeTypes.get(position);

final List<Action> actions = mActions.get(mimeType);

Log.d("lyl", "instantiateItem-->mimeType: " + mimeType + " position: " + position

+ " container.id: " + container.getId());

Log.d("lyl", "actions: " + actions);

fragment.setActions(actions);

return fragment;

}

private void removeFragment(ViewGroup container, int position){

if (mCurTransaction == null) {

mCurTransaction = mFragmentManager.beginTransaction();

}

String name = getFragmentName(container.getId(), position);

Fragment fragment = mFragmentManager.findFragmentByTag(name);

mCurTransaction.remove(fragment);

mCurTransaction.commit();

mCurTransaction = null;

mFragmentManager.executePendingTransactions();

}

private String getFragmentName(int viewId, int index) {

return "android:switcher:" + viewId + ":" + index;

}

@Override

public int getCount() {

return mSortedActionMimeTypes.size();

}

@Override

public int getItemPosition(Object object) {

final QuickContactListFragment fragment = (QuickContactListFragment) object;

final String mimeType = fragment.getMimeType();

for (int i = 0; i < mSortedActionMimeTypes.size(); i++) {

if (mimeType.equals(mSortedActionMimeTypes.get(i))) {

return i;

}

}

return PagerAdapter.POSITION_NONE;

}

}

贴出源码FragmentPagerAdapter中关于instantiateItem方法的机制

@Override

public Object instantiateItem(View container, int position) {

if (mCurTransaction == null) {

mCurTransaction = mFragmentManager.beginTransaction();

}

// Do we already have this fragment?

String name = makeFragmentName(container.getId(), position);

Fragment fragment = mFragmentManager.findFragmentByTag(name);

if (fragment != null) {

if (DEBUG) Log.v(TAG, "Attaching item #" + position + ": f=" + fragment){

mCurTransaction.attach(fragment);

} else {

fragment = getItem(position);

if (DEBUG) Log.v(TAG, "Adding item #" + position + ": f=" + fragment);

mCurTransaction.add(container.getId(), fragment,

makeFragmentName(container.getId(), position));

}

if (fragment != mCurrentPrimaryItem) {

fragment.setMenuVisibility(false);

}

return fragment;

}

在继承fragmentpagerAdapter的类中，重载instantiateItem后，首先清除掉缓存内的fragment，这样保证了调用父类的instantiateItem后，会每次从geiItem()里获得最新的fragment.就解决了使用的是缓存内的fragment，而数据却不是最新的问题。