从另一个

Question

调用FragmentDialog在我的Android项目中，我需要从第一个对话框调用第二个对话框，两者都是Dialog Fragment。我的代码似乎是正确的，因为我从我的活动做同样的事情来调用第一个对话框，但对于第二个对话框它不这样工作。

代码：

public class ProjectDialogFragment extends DialogFragment { 

    public FragmentManager fManager = getFragmentManager(); 
    public CPDialogFragment cpDF = new CPDialogFragment(); 
    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup  container, Bundle savedInstanceState) { 

     View view =  inflater.inflate(R.layout.project_dialogfragment,container,false); 
     getDialog().requestWindowFeature(Window.FEATURE_NO_TITLE); 
     Button btn_CreateProject =  (Button)view.findViewById(R.id.btn_CreateProject); 
     btn_CreateProject.setOnClickListener(PFOnClickListener); 
     Button btn_ProjectsList =  (Button)view.findViewById(R.id.btn_ProjectsList); 
     btn_ProjectsList.setOnClickListener(PFOnClickListener); 
     return view; 
    } 

    private final View.OnClickListener PFOnClickListener = new  View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      switch (v.getId()) 
      { 
       case R.id.btn_CreateProject: 
        Log.e("CP","CreateProject Clicked"); 

        cpDF.show(fManager,"Create Project Dialog Fragment"); 
        break; 
       case R.id.btn_ProjectsList: 
         Log.e("CP","ProjectList Clicked"); 
        break; 
       default: 
        break; 
      } 
     } 
    }; 
} 

但在这行其抛出零点例外：

cpDF.show(fManager,"Create Project Dialog Fragment"); 

Answer 1

通过移动全局参数到本地，我的问题解决了：

首先，我尝试创建方法：

//prepare to open create project dialog fragment 
    public void openCreateProjectDialogFragment() { 
     FragmentManager fManager = getFragmentManager(); 
     CPDialogFragment cpDF = new CPDialogFragment(); 
     cpDF.show(fManager,"Create Project Dialog Fragment"); 
    } 

然后用它在：

private final View.OnClickListener PFOnClickListener = new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      switch (v.getId()) 
      { 
       case R.id.btn_CreateProject: 
        openCreateProjectDialogFragment(); 
        dismiss(); 
       break; 
       case R.id.btn_ProjectsList: 
        openProjectsListDialogFragment(); 
        dismiss(); 
        break; 
       default: 
        break; 
      } 
     } 
    }; 
}