android - recyclerview 没有到达适配器

Question

我在一个 Activity 中有一个 Recycler View ，它无法访问适配器，我知道这个 bcoz 我已经放置了 Log.e 消息，但没有显示适配器中的任何消息

这是我的代码Phone.java(Activity with the recycler View)

package c.bit.bitscaller;

import android.Manifest;
import android.annotation.SuppressLint;
import android.content.Context;
import android.content.Intent;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.CountDownTimer;
import android.provider.Settings;
import android.support.annotation.NonNull;
import android.support.design.widget.NavigationView;
import android.support.design.widget.TabLayout;
import android.support.v4.view.ViewPager;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.SearchView;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.RelativeLayout;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.widget.Toast;

import com.karumi.dexter.Dexter;
import com.karumi.dexter.MultiplePermissionsReport;
import com.karumi.dexter.PermissionToken;
import com.karumi.dexter.listener.PermissionRequest;
import com.karumi.dexter.listener.multi.MultiplePermissionsListener;

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

import c.bit.bitscaller.Adapters.PhoneRecyclerAdapter;

public class phone extends AppCompatActivity {

private boolean bb;
Toolbar toolbar;
ActionBarDrawerToggle actionBarDrawerToggle;
NavigationView navigationView;
DrawerLayout drawerLayout;

private AppCompatActivity activity = phone.this;
private RecyclerView recyclerViewPhone;
private ArrayList<Pojo> list;
private PhoneRecyclerAdapter phoneRecyclerAdapter;
private DatabaseHelper databaseHelper;
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_phone);

    Dexter.withActivity(this)
            .withPermissions(
                    Manifest.permission.INTERNET, Manifest.permission.ACCESS_NETWORK_STATE, Manifest.permission.WRITE_EXTERNAL_STORAGE, Manifest.permission.READ_PHONE_STATE, Manifest.permission.READ_CONTACTS, Manifest.permission.READ_EXTERNAL_STORAGE, Manifest.permission.WRITE_EXTERNAL_STORAGE, Manifest.permission.READ_CALENDAR, Manifest.permission.INTERNET, Manifest.permission.ACCESS_COARSE_LOCATION, Manifest.permission.ACCESS_FINE_LOCATION)
                            .withListener(new MultiplePermissionsListener() {
                                @Override
                                public void onPermissionsChecked(MultiplePermissionsReport report) {
                                    // check if all permissions are granted
                                    if (report.areAllPermissionsGranted()) {
                                        // do you work now
                                    }

                                    // check for permanent denial of any permission
                                    if (report.isAnyPermissionPermanentlyDenied()) {
                                        Intent intent = new Intent();
                                        intent.setAction(Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
                                        Uri uri = Uri.fromParts("package", getPackageName(), null);
                                        intent.setData(uri);
                                        startActivity(intent);
                                    }
                                }

                                @Override
                                public void onPermissionRationaleShouldBeShown(List<PermissionRequest> permissions, PermissionToken token) {
                                    token.continuePermissionRequest();
                                }
                            })
                            .onSameThread()
                            .check();


    toolbar = (Toolbar) findViewById(R.id.toolbar1);
    setSupportActionBar(toolbar);
    getSupportActionBar().setTitle("PHONE BLACKLIST");

    initAndFillData();

    navigationView = (NavigationView) findViewById(R.id.navigation_menu);
    navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
        @Override
        public boolean onNavigationItemSelected(@NonNull MenuItem item) {
            switch (item.getItemId()) {


                case R.id.phoneblacklist:
                    drawerLayout.closeDrawers();
                    break;

                case R.id.smsblacklist:
                    Intent intent1 = new Intent(phone.this, sms.class);
                    startActivity(intent1);
                    break;

                case R.id.spam_mails:
                    Intent intent2 = new Intent(phone.this, email.class);
                    startActivity(intent2);
                    break;
                case R.id.phonelist:
                    Intent intent3 = new Intent(phone.this, managephonelist.class);
                    startActivity(intent3);
                    break;

                case R.id.smslist:
                    Intent intent4 = new Intent(phone.this, managesmslist.class);
                    startActivity(intent4);
                    break;

                case R.id.about:
                    Intent intent = new Intent(phone.this, about.class);
                    startActivity(intent);
                    break;


            }
            return false;
        }
    });
    setUpToolbar();

}

public void initAndFillData()
{
    recyclerViewPhone = findViewById(R.id.recyclerphone);
    list = new ArrayList<>();
    Log.e("Error1", "Reached Here 1");
    phoneRecyclerAdapter = new PhoneRecyclerAdapter(list, this);
    RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(getApplicationContext());
    recyclerViewPhone.setLayoutManager(mLayoutManager);
    recyclerViewPhone.setItemAnimator(new DefaultItemAnimator());
    recyclerViewPhone.setHasFixedSize(true);
    recyclerViewPhone.setAdapter(phoneRecyclerAdapter);
    databaseHelper = new DatabaseHelper(activity);
    getDataFromSQLite();
}

@SuppressLint("StaticFieldLeak")
private void getDataFromSQLite()    {
    // AsyncTask is used that SQLite operation not blocks the UI Thread.
    new AsyncTask<Void, Void, Void>() {
        @Override
        protected Void doInBackground(Void... params) {
            list.clear();
            list.addAll(databaseHelper.getAllPhoneList());
            Log.e("Error3", "Reached Here 3");
            return null;
        }

        @Override
        protected void onPostExecute(Void aVoid) {
            super.onPostExecute(aVoid);
            phoneRecyclerAdapter.notifyDataSetChanged();
        }
    }.execute();
}

private void setUpToolbar() {
    drawerLayout = (DrawerLayout) findViewById(R.id.drawerlayout);
    toolbar = (Toolbar) findViewById(R.id.toolbar1);
    setSupportActionBar(toolbar);
    getSupportActionBar().setTitle("PHONE BLACKLIST");
    actionBarDrawerToggle = new ActionBarDrawerToggle(this, drawerLayout, toolbar, R.string.app_name, R.string.app_name);
    drawerLayout.addDrawerListener(actionBarDrawerToggle);
    actionBarDrawerToggle.syncState();


}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.phone_menu, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    int id = item.getItemId();
    if (id == R.id.phone_clearlog) {
        //code for phone clear log


    }
    return super.onOptionsItemSelected(item);
}

@Override
//pressing back button twice to exit
public void onBackPressed() {
    if (!bb) {
        Toast.makeText(this, "press back again to exit", Toast.LENGTH_LONG).show();
        bb = true;
    } else {
        super.onBackPressed();
    }
    new CountDownTimer(3000, 1000) {
        @Override
        public void onTick(long millisUntilFinished) {
        }

        @Override
        public void onFinish() {
            bb = false;
        }
    }.start();
}

}

这是我的手机 Activity xml 文件

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout 
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/drawerlayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true">

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#ffffff"
    android:orientation="vertical">

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar1"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="#00bcd4"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar" />

    <android.support.v7.widget.RecyclerView
        android:id="@+id/recyclerphone"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</LinearLayout>

<android.support.design.widget.NavigationView
    android:id="@+id/navigation_menu"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="start"
    android:background="#00bcd4"
    app:headerLayout="@layout/header"
    app:menu="@menu/drawer_phone"/>
</android.support.v4.widget.DrawerLayout>

这是我的适配器

package c.bit.bitscaller.Adapters;

import android.content.Context;
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.TextView;

import java.util.ArrayList;

import c.bit.bitscaller.Pojo;
import c.bit.bitscaller.R;

public class PhoneRecyclerAdapter extends 
RecyclerView.Adapter<PhoneRecyclerAdapter.PhoneViewHolder> {

private ArrayList<Pojo> listPhone;
Context context;

public PhoneRecyclerAdapter(ArrayList<Pojo> listPhone, Context context) {
    this.listPhone = listPhone;
    this.context = context;

}


public class PhoneViewHolder extends RecyclerView.ViewHolder {

    public TextView name;
    public TextView number;
    public TextView lati;
    public TextView longi;
    public TextView time;
    public TextView date;

    public PhoneViewHolder(View view) {
        super(view);
        name = view.findViewById(R.id.name);
        number = view.findViewById(R.id.number);
        lati = view.findViewById(R.id.lati);
        longi = view.findViewById(R.id.longi);
        time = view.findViewById(R.id.time);
        date = view.findViewById(R.id.date);
        Log.e("Error 4", "Reached Here  4");
    }
}

@Override
public PhoneViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.recycler_item, parent, false);
    return new PhoneViewHolder(itemView);
}

@Override
public void onBindViewHolder(final PhoneViewHolder holder, int position) {
    holder.name.setText(listPhone.get(position).getName());
    holder.number.setText(listPhone.get(position).getNumber());
    holder.lati.setText("" + listPhone.get(position).getLati());
    holder.longi.setText("" + listPhone.get(position).getLongi());
    holder.time.setText(listPhone.get(position).getTime());
    Log.e("Error5 ", "Reached Here 5");
    holder.date.setText(listPhone.get(position).getDate());
}

@Override
public int getItemCount() {
    return listPhone.size();
}
}

这是我要获取的数据库函数

 public List<Pojo> getAllPhoneList() {
    List<Pojo> list = new ArrayList<>();
    SQLiteDatabase db = this.getReadableDatabase();
    Cursor cursor = db.rawQuery("SELECT * FROM PhoneTable where BPhone=1 ORDER BY rid DESC", null);
    if (cursor.moveToFirst()) {
        do {
            Pojo listRecord = new Pojo();
          listRecord.setNumber(cursor.getString(cursor.getColumnIndex(DatabaseHelper.number)));
            listRecord.setLati(cursor.getFloat(cursor.getColumnIndex(DatabaseHelper.lati)));
            listRecord.setLongi(cursor.getFloat(cursor.getColumnIndex(DatabaseHelper.longi)));
            listRecord.setDate(cursor.getString(cursor.getColumnIndex(DatabaseHelper.date)));
            listRecord.setTime(cursor.getString(cursor.getColumnIndex(DatabaseHelper.time)));
        } while (cursor.moveToNext());
    }
    cursor.close();
    db.close();
    Log.e("Error 2 ", "Reached Here 2");
    return list;
}

在我的 logcat 中错误是

04-13 23:11:56.855 6416-6416/c.bit.bitscaller E/Error1: Reached Here 1
04-13 23:11:56.885 6416-6485/c.bit.bitscaller E/Error 2: Reached Here 2
04-13 23:11:56.885 6416-6485/c.bit.bitscaller E/Error3: Reached Here 3

错误 2 和 3 来自数据库，这意味着它们也可以正常工作来自适配器的错误 4 和 5 丢失，这意味着适配器无法访问(以某种方式)

请帮助(我也通过 sqlite 浏览器检查了 sqlite 中是否有数据及其存在)

现在已经做了一天，非常感谢任何帮助。

(我已经发布了代码，但由于我的项目负责人通知的版权问题而不得不删除)

Answer 1

在您的代码中发现了一些错误。此方法 getAllPhoneList() 返回 Pojo 对象的空列表，因为您错过了将 pojo 对象添加到 do while 迭代器中的列表。

list.add(listRecord);

并且我已经进行了修改，希望它能正常工作，请像我下面的代码一样进行更改。

从 onCreate() 方法调用此 initAndFillData() 就像您在代码中所做的那样，并粘贴下面的代码代替您的代码

public void initAndFillData()
    {
        Log.e("Error1", "Reached Here 1");
        recyclerViewPhone = findViewById(R.id.recyclerphone);
        list = new ArrayList<>();
        recyclerViewPhone.setLayoutManager(new LinearLayoutManager(this));
    recyclerViewPhone.setItemAnimator(new DefaultItemAnimator());
        recyclerViewPhone.setHasFixedSize(true);
        new LoadDataFromSqlite().execute();
    }

现在将这个异步任务方法粘贴到您的 Activity 中

class LoadDataFromSqlite extends AsyncTask<Void, Void, Void>
{
    DataBaseHelper dataBaseHelper = new DataBaseHelper(context);

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

       //Show porgressbar if needed.
    }

    @Override
    protected Void doInBackground(Void... voids)
    {

       //           Get the list of pojo objects by calling this below method of databasehelper
        list = dataBaseHelper.getAllPhoneList();
        return null;
    }

    @Override
    protected void onPostExecute(Void aVoid)
    {
        super.onPostExecute(aVoid);

     //         Check if obtained list of pojo size is null, if its null then you have no data in db.
        if (list.size() > 0)
        {

          //                pass dataset (list of pojo object) to adapter and set adapter to recylerview
            phoneRecyclerAdapter = new PhoneRecyclerAdapter(list, this);
            recyclerViewPhone.setAdapter(phoneRecyclerAdapter);
        }
    }
}

最后，像这样在 databasehelper 中为您的 getAllPhoneList() 方法粘贴此代码

    public List<Pojo> getAllPhoneList()
{
    List<Pojo> list = new ArrayList<>();
    SQLiteDatabase db = this.getReadableDatabase();
    Cursor cursor = db.rawQuery("SELECT * FROM PhoneTable where BPhone=1 ORDER BY rid DESC", null);
    if (cursor.moveToFirst())
    {
        do
        {
            Pojo listRecord = new Pojo();
            listRecord.setNumber(cursor.getString(cursor.getColumnIndex(DatabaseHelper.number)));
            listRecord.setLati(cursor.getFloat(cursor.getColumnIndex(DatabaseHelper.lati)));
            listRecord.setLongi(cursor.getFloat(cursor.getColumnIndex(DatabaseHelper.longi)));
            listRecord.setDate(cursor.getString(cursor.getColumnIndex(DatabaseHelper.date)));
            listRecord.setTime(cursor.getString(cursor.getColumnIndex(DatabaseHelper.time)));


            //You have missed to add pojo object to List<Pojo> list
            list.add(listRecord);
        } while (cursor.moveToNext());
    }
    cursor.close();
    db.close();
    Log.e("Error 2 ", "Reached Here 2");
    return list;
}

这一定能正常工作。希望对您有所帮助。