java - 在适配器中返回相同的 fragment

Question

我想使用相同的 fragment 并用重置功能替换内容但是当为每个选项卡返回相同的 fragment 时，我收到以下错误:

无法更改 fragment FragmentRank 的标签

这是我的代码:

class pagerAdapter extends FragmentPagerAdapter {

String[] tabs = {"1", "2", "3"};
FragmentRank rank;

public pagerAdapter(FragmentManager fm) {
    super(fm);
    rank = FragmentRank.newInstance();
}

@Override
public CharSequence getPageTitle(int position) {
    return tabs[position];
}

@Override
public int getCount() {
    return 3;
}

@Override
public Fragment getItem(int position) {

    return rank;


}


}

有什么想法吗？

日志猫:

java.lang.IllegalStateException: Can't change tag of fragment FragmentRank{529c3b00 id=0x7f080044 android:switcher:2131230788:0}: was android:switcher:2131230788:0 now android:switcher:2131230788:1
                    at android.support.v4.app.BackStackRecord.doAddOp(BackStackRecord.java:398)
                    at android.support.v4.app.BackStackRecord.add(BackStackRecord.java:389)
                    at android.support.v4.app.FragmentPagerAdapter.instantiateItem(FragmentPagerAdapter.java:99)
                    at android.support.v4.view.ViewPager.addNewItem(ViewPager.java:832)
                    at android.support.v4.view.ViewPager.populate(ViewPager.java:1048)
                    at android.support.v4.view.ViewPager.populate(ViewPager.java:914)
                    at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1436)
                    at android.view.View.measure(View.java:16497)
                    at android.widget.LinearLayout.measureVertical(LinearLayout.java:847)
                    at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
                    at android.view.View.measure(View.java:16497)
                    at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
                    at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
                    at android.view.View.measure(View.java:16497)
                    at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
                    at com.android.internal.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:327)
                    at android.view.View.measure(View.java:16497)
                    at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
                    at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
                    at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2291)
                    at android.view.View.measure(View.java:16497)
                    at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1912)
                    at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1109)
                    at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1291)
                    at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:996)
                    at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5600)
                    at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761)
                    at android.view.Choreographer.doCallbacks(Choreographer.java:574)
                    at android.view.Choreographer.doFrame(Choreographer.java:544)
                    at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747)
                    at android.os.Handler.handleCallback(Handler.java:733)
                    at android.os.Handler.dispatchMessage(Handler.java:95)
                    at android.os.Looper.loop(Looper.java:136)
                    at android.app.ActivityThread.main(ActivityThread.java:5001)
                    at java.lang.reflect.Method.invokeNative(Native Method)
                    at java.lang.reflect.Method.invoke(Method.java:515)
                    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
                    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
                    at dalvik.system.NativeStart.main(Native Method)

Answer 1

FragmentPager 中的每个页面都需要有一个不同的 Fragment，否则无法在配置更改时重新创建它。它使用内部命名约定来识别每个 fragment 并重新创建它。因此，每次调用 getItem() 时都会返回 FragmentRank.newInstance()。

如果您想更好地控制适配器内的 fragment ，请使用以下方法:https://stackoverflow.com/a/15261142/535762

通过此功能，您可以重新附加您可能拥有的任何状态信息。最好在 fragment 的 onResume() 内执行此操作