我有一个字符串，其中包含用 package com.example.anonymous.note_taking_app;
import android.app.ActionBar;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.content.Context;
import android.net.Uri;
import android.os.Bundle;
import android.app.Fragment;
import android.support.design.widget.FloatingActionButton;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.EditText;
public class AddingFragment extends Fragment {
public AddingFragment()
{
}
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
View view = inflater.inflate(R.layout.fragment_adding, container, false);
return view;
}
@Override
public void onResume()
{
super.onResume();
FloatingActionButton floating = (FloatingActionButton) getActivity().findViewById(R.id.addingfloatingbutton);
floating.setOnClickListener(new View.OnClickListener()
{
@Override
public void onClick(View view)
{
Log.i("floating_button", "floating button 2 clicked");
EditText title = (EditText) getActivity().findViewById(R.id.firsttextview);
EditText detial = (EditText) getActivity().findViewById(R.id.secondtextview);
DatabaseHelper db = new DatabaseHelper(getActivity().getApplication());
boolean insert = db.insert(title.getText()+"",detial.getText()+"");
if(insert==true)
{
com.example.anonymous.note_taking_app.ListAdapter l = new com.example.anonymous.note_taking_app.ListAdapter();
ListFragment.it.add(new ListItem(title.getText()+"",detial.getText()+""));
l.notifyItemInserted(ListFragment.it.size()-1);//DataSetChanged();
l.notifyDataSetChanged();
for(int i=0;i<ListFragment.it.size();i++)
{
Log.i("List item"+i+"", ListFragment.it.get(i).getNoteTitle());
}
Log.i("insertion", "is added");
}
else
{
Log.i("insertion", "is not added");
}
}
});
FloatingActionButton floatings = (FloatingActionButton) getActivity().findViewById(R.id.addcancelfloatingbutton);
floatings.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view)
{
final FragmentManager fragmentManager = getFragmentManager();
fragmentManager.popBackStackImmediate();
}
});
}
}
//
package com.example.anonymous.note_taking_app;
import android.content.Context;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.ImageButton;
import android.widget.TextView;
import android.widget.Toast;
import android.app.Fragment;
import java.util.ArrayList;
/**
* Created by Anonymous on 12/13/2017.
*/
public class ListAdapter extends RecyclerView.Adapter<ListAdapter.holderclas> implements EditDilogue.EditDilougeinterface
{
static ArrayList<ListItem> i;
Context context;
View view;
ImageButton share;
ImageButton edit;
static int lastposition;
android.app.FragmentManager fm;
public ListAdapter(ArrayList<ListItem> i,android.app.FragmentManager fm)
{
this.i=i;
this.fm=fm;
}
public ListAdapter()
{
}
@Override
public ListAdapter.holderclas onCreateViewHolder(ViewGroup parent, int viewType)
{
view= LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item,parent,false);
holderclas h = new holderclas(view);
share = (ImageButton) view.findViewById(R.id.share);
edit = (ImageButton) view.findViewById(R.id.edit);
return h;
}
@Override
public void onBindViewHolder(ListAdapter.holderclas holder, final int position)
{
final int y= position;
lastposition = position;
final ListItem it = i.get(position);
holder.title.setText(it.getNoteTitle());
holder.details.setText(it.getNoteDetail());
ImageButton b =(ImageButton) view.findViewById(R.id.delete);
b.setOnClickListener(new View.OnClickListener()
{
@Override
public void onClick(View view)
{
Log.i("size", i.size()+"");
i.remove(y);
notifyDataSetChanged();
}
});
share.setOnClickListener(new View.OnClickListener()
{
@Override
public void onClick(View view)
{
Log.i("share", "share");
}
});
edit.setOnClickListener(new View.OnClickListener()
{
@Override
public void onClick(View view)
{
Log.i("edit", i.size()+"edit");
EditDilogue ed = new EditDilogue();
Bundle args = new Bundle();
args.putString("title", it.getNoteTitle());
args.putString("detail", it.getNoteDetail());
ed.setArguments(args);
ed.setTargetFragment(new ListFragment(),1);
ed.show(fm,"fragment");
}
});
}
@Override
public int getItemCount()
{
return i.size();
}
@Override
public void deleteandadd(String titlestring, String detailstring)
{
String oldtitle = i.get(lastposition).getNoteTitle();
String olddetail = i.get(lastposition).getNoteDetail();
Log.i("string", titlestring);
Log.i("string", detailstring);
}
public class holderclas extends RecyclerView.ViewHolder
{
TextView title;
TextView details;
public holderclas(View itemView)
{
super(itemView);
title=(TextView) itemView.findViewById(R.id.title);
details=(TextView) itemView.findViewById(R.id.detail);
}
}
}
//
package com.example.anonymous.note_taking_app;
import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.ListAdapter;
import java.util.ArrayList;
/**
* Created by Anonymous on 12/13/2017.
*/
public class ListFragment extends Fragment implements EditDilogue.EditDilougeinterface
{
RecyclerView recyClerView;
RecyclerView.Adapter adapter;
RecyclerView.LayoutManager layoutManager;
public static ArrayList<ListItem> it;
public View onCreateView(LayoutInflater inflater, ViewGroup parent, Bundle savedInstanceState)
{
it = new ArrayList<>();
View view = inflater.inflate(R.layout.fragment_list, parent, false);
FloatingActionButton floating = (FloatingActionButton) view.findViewById(R.id.listfloatingbutton);
floating.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view)
{
Fragment frg = new AddingFragment();
FragmentManager manager = getFragmentManager();
FragmentTransaction trans = manager.beginTransaction();
trans.replace(R.id.placeholder,frg);
trans.addToBackStack("addingfragment");
trans.commit();
AddingFragment()).addToBackStack("addingfragment").commit();
}
});
for(int i=0;i<5;i++)
{
ListItem t = new ListItem("Time Bank",
"Bank should contain atleast $2000 rupees then i will leave this matter") ;
it.add(t);
}
recyClerView=(RecyclerView) view.findViewById(R.id.recycle);
FragmentManager fm = getFragmentManager();
com.example.anonymous.note_taking_app.ListAdapter l = new com.example.anonymous.note_taking_app.ListAdapter(it,fm);
recyClerView.setAdapter(l);
layoutManager = new LinearLayoutManager(getActivity());
recyClerView.setLayoutManager(layoutManager);
return view;
}
@Override
public void onResume()
{
super.onResume();
if(adapter!=null)
{
adapter.notifyDataSetChanged();
adapter.notifyItemInserted(ListFragment.it.size()-1);
}
}
@Override
public void deleteandadd(String titlestring, String detailstring)
{
String oldtitle = com.example.anonymous.note_taking_app.ListAdapter.i.get(com.example.anonymous.note_taking_app.ListAdapter.lastposition).getNoteTitle();
String olddetail = com.example.anonymous.note_taking_app.ListAdapter.i.get(com.example.anonymous.note_taking_app.ListAdapter.lastposition).getNoteDetail();
Log.i("string", titlestring);
Log.i("string", detailstring);
}
}
分隔的数字。我想删除第一个字符前的,。
输入为,，此代码无效：
,1,2,3,4,5,6,7,8,9,10答案 0 :(得分：7)
字符串在Java中是不可变的。在字符串上调用方法不会修改字符串本身，而是返回一个新字符串。
为了捕获这个新字符串，您需要将操作结果分配回变量：
results = results.replaceFirst(",", "");
答案 1 :(得分：0)
试试这个
String str = ",1,2,3,4,5,6,7,8,9,10";
if(Objects.nonNull(str) && str.startsWith(",")){
str = str.substring(1, str.length());
}
它将删除第一个位置的,
答案 2 :(得分：0)
你也可以这样做..
String str = ",1,2,3,4,5,6,7,8,9,10";
String stre = str.replaceFirst("^,", "");
Log.e("abd",stre);
答案 3 :(得分：0)
试试这个
String str = ",1,2,3,4,5,6,7,8,9,10";
str = str .startsWith(",") ? str .substring(1) : str ;
System.out.println("output"+str); // 1,2,3,4,5,6,7,8,9,10