從RecyclerView適配器調用片段

Question

我有一個recyclerView，顯示c​​ardView中的列表。此recyclerview位於viewPager選項卡中顯示的一個片段中。點擊卡片視圖中的縮略圖時，我想要去新的片段。

我執行下列操作，以便onBindViewHolder有這樣的功能：

holder.thumbnail.setOnClickListener(new View.OnClickListener() { 
 
@Override 
 
    public void onClick(View v) { 
 

 
    Fragment productDetailFragment = new ProductDetailFragment(); 
 
    (FragmentActivity)mContext).getSupportFragmentManager().beginTransaction() 
 
    .replace(R.id.grid_page_recycler_view, productDetailFragment).commit(); 
 
       } 
 
      });

但運行後，它會返回：

E/AndroidRuntime: FATAL EXCEPTION: main 
       java.lang.NullPointerException 
        at android.support.v7.widget.RecyclerView.findMinMaxChildLayoutPositions(RecyclerView.java:3757) 
        at android.support.v7.widget.RecyclerView.dispatchLayoutStep1(RecyclerView.java:3494) 
        at android.support.v7.widget.RecyclerView.onMeasure(RecyclerView.java:3019) 
        at android.view.View.measure(View.java:15819) 
        at android.widget.RelativeLayout.measureChild(RelativeLayout.java:666) 
        at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:477) 
        at android.view.View.measure(View.java:15819) 
        at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1658) 
        at android.view.View.measure(View.java:15819) 
        at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:681) 
        at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:461) 
        at android.view.View.measure(View.java:15819) 
        at android.support.v4.widget.DrawerLayout.onMeasure(DrawerLayout.java:1081) 
        at android.view.View.measure(View.java:15819) 
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4890) 
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) 
        at android.view.View.measure(View.java:15819) 
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4890) 
        at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404) 
        at android.widget.LinearLayout.measureVertical(LinearLayout.java:695) 
        at android.widget.LinearLayout.onMeasure(LinearLayout.java:588) 
        at android.view.View.measure(View.java:15819) 
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4890) 
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) 
        at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2176) 
        at android.view.View.measure(View.java:15819) 
        at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1965) 
        at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1146) 
        at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1356) 
        at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1046) 
        at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4603) 
        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749) 
        at android.view.Choreographer.doCallbacks(Choreographer.java:562) 
        at android.view.Choreographer.doFrame(Choreographer.java:532) 
        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735) 
        at android.os.Handler.handleCallback(Handler.java:725) 
        at android.os.Handler.dispatchMessage(Handler.java:92) 
        at android.os.Looper.loop(Looper.java:137) 
        at android.app.ActivityThread.main(ActivityThread.java:5086) 
        at java.lang.reflect.Method.invokeNative(Native Method) 
        at java.lang.reflect.Method.invoke(Method.java:511) 
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 
        at dalvik.system.NativeStart.main(Native Method) 

是什麼原因？值得注意的是，如果我想調用其他活動，則很容易實現。

謝謝。

我必須說，這裏有幾個類似的問題，但我不能使用它們。

Answer 1

• 在您的MAinActivity中創建一個替換片段的方法。
• 將ViewPager放入片段並從MainActivity推送它。
• 現在調用您的recyclerView適配器中的replace方法。

公共無效replaceFragment（片段片段）{

String backStateName = fragment.getClass().getName(); 
    FragmentManager manager = getSupportFragmentManager(); 
    boolean fragmentPopped = manager.popBackStackImmediate(backStateName, 0); 

    if (!fragmentPopped && manager.findFragmentByTag(backStateName) == null) { 
     FragmentTransaction ft = manager.beginTransaction(); 
     ft.replace(R.id.frame_container, fragment, backStateName); 
     ft.addToBackStack(backStateName); 
     ft.commit(); 
    } 
}