在Recyclerview，android中点击项目启动另一个Activity

Question

我正在制作一个笔记应用程序，当我点击Recyclerview中的任何项目时，我想开始一个新的活动并传递一些字符串，我甚至从stackoverflow引用了许多链接，我尝试了它们，仍然无法正常工作。你可以帮助我，因为我刚刚在android中开始。

这是我的NotesAdapter

import android.view.View;

/**
 * Created by Sohail on 9/6/2017.
 */

public interface ItemClickListener {
    void onClick(View view, int position, int i);
}

这是我用来实现onClick

的Itemclick监听器接口

    package org.terna.notes_aap;

import android.content.Intent;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.CardView;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Button;
import android.widget.ImageButton;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.List;

public class ListActivity extends AppCompatActivity implements ItemClickListener{

    int c;
    int get;
    Note note;

    PersonDB db1=new PersonDB(this,"persondb2.db",null,1);

    private List<Note>noteList = new ArrayList<>();
    private RecyclerView recyclerView, listrow;
    private NotesAdapter notesAdapter;
    ImageButton addNote,appIcon;
    Button delete;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_list);

        recyclerView = (RecyclerView)findViewById(R.id.recycler_view);
        recyclerView.setHasFixedSize(true);

        notesAdapter = new NotesAdapter(noteList,this);
        RecyclerView.LayoutManager nLayoutManager = new LinearLayoutManager(getApplicationContext());
        recyclerView.setLayoutManager(nLayoutManager);
        recyclerView.setItemAnimator(new DefaultItemAnimator());
        recyclerView.setAdapter(notesAdapter);
        notesAdapter.setClickListener(this);

        final Intent intent1 = new Intent(this,Add_Update_Activity.class);
        addNote = (ImageButton)(findViewById(R.id.addNote));
        appIcon = (ImageButton)(findViewById(R.id.appIcon));

        addNote.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                intent1.putExtra("check",1);
                startActivity(intent1);
            }
        });
        appIcon.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

            }
        });

       /* db1.insertIntoPerson("Sudhanshu's song","Rock","2017");
        db1.insertIntoPerson("Akshay's song","Pop","2007");*/

        prepareNoteData();
    }

    @Override
    protected void onRestart() {
        super.onRestart();

        ArrayList<PersonModel> persons = db1.getAllPersons();

        for(int i=persons.size()-1;i>=0;i--)
        {
            PersonModel person = persons.get(i);

            String title = person.title;
            int id = person.id;
            String description = person.description;
            String month = person.month;
            String date = person.date;
            String year = person.year;

            note = new Note(id,title,description,month,date,year);
            noteList.add(note);
        }
        notesAdapter.notifyDataSetChanged();
    }

    @Override
    protected void onStop() {
        super.onStop();

        ArrayList<PersonModel> persons = db1.getAllPersons();

        c = persons.size();
        if(c !=0 ){
            for(int j=persons.size()-1;j>=0;j--){              
                noteList.removeAll(persons);
            }
        }
        noteList.clear();
    }


    @Override
    protected void onDestroy() {
        super.onDestroy();
    }


    public void passdata(){    
        NotesAdapter n = null;

       int get = n.getdata();
        Toast.makeText(this, "get = "+get, Toast.LENGTH_SHORT).show();

    }

    private void prepareNoteData() {

        Toast.makeText(this, "i am in preparenote", Toast.LENGTH_SHORT).show();

        ArrayList<PersonModel> persons = db1.getAllPersons();
        for(int i=persons.size()-1;i>=0;i--)
        {
            PersonModel person = persons.get(i);
            String title = person.title;
            int id = person.id;
            String description = person.description;
            String month = person.month;
            String date = person.date;
            String year = person.year;

            Log.e("DB","Initialised");

            note = new Note(id,title,description,month,date,year);
            noteList.add(note);

        }
        notesAdapter.notifyDataSetChanged();
    }

    @Override
    public void onClick(View view, int position, int i) {

        int p = i;    
        Toast.makeText(this, i+" is clicked", Toast.LENGTH_SHORT).show();
        Intent intent2 = new Intent(this,Add_Update_Activity.class);    
        startActivity(intent2);
    }
}

这是我的ListActivity

    package org.terna.notes_aap;

import android.icu.text.DateFormat;
import android.icu.text.SimpleDateFormat;
import android.icu.util.Calendar;
import android.icu.util.TimeZone;
import android.os.Build;
import android.os.Bundle;
import android.support.annotation.RequiresApi;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.text.Editable;
import android.text.TextWatcher;
import android.util.Log;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast; 
import java.util.ArrayList;
import java.util.Date;
import java.util.Formatter;
import java.util.Locale;

@RequiresApi(api = Build.VERSION_CODES.N)
public class Add_Update_Activity extends AppCompatActivity {

    EditText title1, description1;
    TextView label,month1,date1,year1;

    String title,description,month,date,year;
    int check;

    PersonDB db1=new PersonDB(this,"persondb2.db",null,1);

    @RequiresApi(api = Build.VERSION_CODES.N)
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_add__update_);

        title1 = (EditText)(findViewById(R.id.title1));
        description1 = (EditText)(findViewById(R.id.description1));
        label = (TextView) (findViewById(R.id.label));
        month1 = (TextView) (findViewById(R.id.month));
        date1 = (TextView) (findViewById(R.id.date));
        year1 = (TextView) (findViewById(R.id.year));

        check = getIntent().getIntExtra("check",0);

        /*if(check == 1)
        {
            // Code for Creating new Note

            *//*Formatter mon = new Formatter();
            Calendar cal = Calendar.getInstance();
            mon = new Formatter();
            mon.format("%tb",cal);

            Calendar calendar = Calendar.getInstance();
            int y = calendar.get(Calendar.YEAR);

            year = String.valueOf(y);
            date = new SimpleDateFormat("EE", Locale.ENGLISH).format(cal.getTime());
            month = mon.toString();

            month = new SimpleDateFormat("MMM").format(new Date());
            date = new SimpleDateFormat("dd").format(new Date());
            year = new SimpleDateFormat("yyyy").format(new Date());
        }
        else
        {
            //  Code for Updating a Note
        }
        */
        month = new SimpleDateFormat("MMM").format(new Date());
        date = new SimpleDateFormat("dd").format(new Date());
        year = new SimpleDateFormat("yyyy").format(new Date());

        month1.setText(month);
        date1.setText(date);
        year1.setText(year);

        Toast.makeText(this, "month"+month+"  date"+date+"  year"+year, Toast.LENGTH_SHORT).show();    

    }

    @Override
    protected void onRestart() {
        super.onRestart();
        Toast.makeText(this, "add activity restarted", Toast.LENGTH_SHORT).show();
    }

    @Override
    protected void onResume() {
        super.onResume();

        Toast.makeText(this, "add activity resumed", Toast.LENGTH_SHORT).show();
    }

    @Override
    protected void onPause() {
        super.onPause();
        title = title1.getText().toString();
        description = description1.getText().toString();

        if(title.equals(""))
        {
            if(description.equals(""))
            {

            }
            else
            {
                Toast.makeText(this, "desc inserted", Toast.LENGTH_SHORT).show();
                db1.insertIntoPerson(title, description,month, date, year);

                onBackPressed();
            }
        }
        else
        {
            Toast.makeText(this, "title inserted", Toast.LENGTH_SHORT).show();
            db1.insertIntoPerson(title, description,month, date, year);
            onBackPressed();
        }
    }

    @Override
    protected void onStop() {
        super.onStop();
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
    }
}

这是我的Add_Update_Activity

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="org.terna.notes_aap">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name=".SplashActivity" />
        <activity
            android:name=".ListActivity"
            android:label="@string/title_activity_list"
            android:theme="@style/AppTheme.NoActionBar" />
        <activity
            android:name=".Add_Update_Activity"
            android:label="@string/title_activity_add__update_"
            android:theme="@style/AppTheme.NoActionBar" />
        <activity
            android:name=".Edit_Update_Activity"
            android:label="@string/title_activity_edit__update_"
            android:theme="@style/AppTheme.NoActionBar"></activity>
    </application>

</manifest>

这是我的清单文件

09-06 06:05:14.596 6726-6726/? E/FirebaseInstanceId: Failed to resolve target intent service, skipping classname enforcement
09-06 06:05:14.598 6726-6726/? E/FirebaseInstanceId: Error while delivering the message: ServiceIntent not found.
09-06 06:16:46.851 6726-6726/? E/FirebaseInstanceId: Failed to resolve target intent service, skipping classname enforcement
09-06 06:16:46.854 6726-6726/? E/FirebaseInstanceId: Error while delivering the message: ServiceIntent not found.

这一切都显示在我的日志中

{{1}}

Answer 1

您已使用构造函数将上下文传递给适配器：

series_params

所以在onClickListener中你可以使用那个，不需要再次调用上下文，如下所示：

def new
  @series = Series.new
  #build objects of nested
  @season = @series.seasons.build  
  @episod = @season.episods.build
end

def series_params 
  params.require(:series).permit(:title, 
   seasons_attributes: [:id, :title, episodes_attributes: [:id, :title]]) 
end

虽然你使用它的方式不应该导致问题，但是没有必要两次做同样的事情。

<强> SOLUTION：

在Add_Update_Activity中而不是

public NotesAdapter(List<Note> noteList, Context context) { this.noteList = noteList; this.context = context; mInflater = LayoutInflater.from(context); viewBinderHelper.setOpenOnlyOne(true); }

使用

holder.relativeLayout.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { Intent i=new Intent(context1,Add_Update_Activity.class); Toast.makeText(context1, "i am clicked", Toast.LENGTH_SHORT).show(); // When I comment it, my app works fine, I think something is missing here. context.startActivity(i); } });

因为当你不发送任何额外内容时，适配器中的getExtras方法将返回null。