团队冲刺开发第二天

今天花费将近3个多小时的时间，将以前的Android知识回顾了一遍，同时自己针对自己的任务做了一个小Demo。

主要用到的是ViewModel来存储页面数据，Respositry仓库来进行数据的增删改查，还有一个Database数据库，一个Dao和展示数据的Adapter

在数据的增删改查利用的事AsynceTask的副线程，创建singleton单实例数据库。

在实现的过程中，出现的问题有：

对AsynceTask的线程问题不熟悉，一开始的做法是直接在活动中强制在主线程执行增删改查，查了相关操作后才发现可以用AsynceTask的副线程，即安全又可靠。

Word.java

package com.example.roombasic;

import androidx.room.Entity;
import androidx.room.PrimaryKey;

@Entity
public class Word {
    @PrimaryKey(autoGenerate = true)
    private int id;
    private String word;
    private String meaning;

    public Word(String word, String meaning) {
        this.word = word;
        this.meaning = meaning;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getWord() {
        return word;
    }

    public void setWord(String word) {
        this.word = word;
    }

    public String getMeaning() {
        return meaning;
    }

    public void setMeaning(String meaning) {
        this.meaning = meaning;
    }
}

WordDao.java

package com.example.roombasic;

import androidx.lifecycle.LiveData;
import androidx.room.Dao;
import androidx.room.Delete;
import androidx.room.Insert;
import androidx.room.Query;
import androidx.room.Update;

import java.util.List;
import java.util.ListIterator;

@Dao
public interface WordDao {
    @Insert
    void insertWord(Word... words);

    @Update
    void updateWord(Word... words);

    @Delete
    void deleteWord(Word... words);

    @Query("delete from word")
    void deleteALLWord();

    @Query("select * from word order by id desc")
    //List<Word> getAllWord();
    LiveData<List<Word>>getAllWordsLive();
}

WordDataBase.java

package com.example.roombasic;

import android.content.Context;

import androidx.room.Database;
import androidx.room.Room;
import androidx.room.RoomDatabase;
@Database(entities = {Word.class},version=1,exportSchema = false)
//singleton单实例数据库
public abstract class WordDatabase extends RoomDatabase {
    private static WordDatabase INSTANCE;
    static synchronized WordDatabase getDatebase(Context context){
        if(INSTANCE==null){
            INSTANCE= Room.databaseBuilder(context.getApplicationContext(),WordDatabase.class,"word_database")
                    .build();
        }
        return INSTANCE;
    }
    public abstract WordDao getWordDao();
}

WordRepository.java(仓库类)

package com.example.roombasic;

import android.content.Context;
import android.os.AsyncTask;

import androidx.lifecycle.LiveData;

import java.util.List;
//仓库类，用来管理viewmodel的增删改查操作
class WordRepository {
    private LiveData<List<Word>> allWordsLive;
    private WordDao wordDao;

    WordRepository(Context context) {
        WordDatabase wordDatabase = WordDatabase.getDatebase(context.getApplicationContext());
        wordDao = wordDatabase.getWordDao();
        allWordsLive = wordDao.getAllWordsLive();
    }

    LiveData<List<Word>> getAllWordsLive() {
        return allWordsLive;
    }

    void insertWords(Word... words) {
        new InsertAsynceTask(wordDao).execute(words);
    }

    void updateWords(Word... words) {
        new UpdateAsynceTask(wordDao).execute(words);
    }

    void deleteWords(Word... words) {
        new DeleteAsynceTask(wordDao).execute(words);
    }

    void deleteallWords() {
        new DeleteAllAsynceTask(wordDao).execute();
    }

    static class InsertAsynceTask extends AsyncTask<Word, Void, Void> {
        private WordDao wordDao;

        InsertAsynceTask(WordDao wordDao) {
            this.wordDao = wordDao;
        }

        @Override
        protected Void doInBackground(Word... words) {
            wordDao.insertWord(words);
            return null;
        }
    }

    static class UpdateAsynceTask extends AsyncTask<Word, Void, Void> {
        private WordDao wordDao;

        UpdateAsynceTask(WordDao wordDao) {
            this.wordDao = wordDao;
        }

        @Override
        protected Void doInBackground(Word... words) {
            wordDao.updateWord(words);
            return null;
        }
    }

    static class DeleteAsynceTask extends AsyncTask<Word, Void, Void> {
        private WordDao wordDao;

        DeleteAsynceTask(WordDao wordDao) {
            this.wordDao = wordDao;
        }

        @Override
        protected Void doInBackground(Word... words) {
            wordDao.deleteWord(words);
            return null;
        }
    }

    static class DeleteAllAsynceTask extends AsyncTask<Void, Void, Void> {
        private WordDao wordDao;

        DeleteAllAsynceTask(WordDao wordDao) {
            this.wordDao = wordDao;
        }

        @Override
        protected Void doInBackground(Void... voids) {
            wordDao.deleteALLWord();
            return null;
        }
    }
}

WordViewModel（页面数据）

package com.example.roombasic;

import android.app.Application;
import android.os.AsyncTask;

import androidx.annotation.NonNull;
import androidx.lifecycle.AndroidViewModel;
import androidx.lifecycle.LiveData;

import java.util.List;

public class WordViewModel extends AndroidViewModel {
private WordDao wordDao;
private WordRepository wordRepository;
private LiveData<List<Word>> allWordsLive;
    public WordViewModel(@NonNull Application application) {
        super(application);
        wordRepository=new WordRepository(application);
    }

     LiveData<List<Word>> getAllWordsLive() {
        return wordRepository.getAllWordsLive();
    }
    void insertWords(Word...words){
        wordRepository.insertWords(words);
    }
    void updateWords(Word...words){
        wordRepository.updateWords(words);
    }
    void deleteWords(Word...words){
        wordRepository.deleteWords(words);
    }
    void deleteallWords(){
        wordRepository.deleteallWords();
    }


}

MyAdapter（适配器）

package com.example.roombasic;

import android.content.Intent;
import android.net.Uri;
import android.provider.ContactsContract;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

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

public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHoder> {
    List<Word> allwords=new ArrayList<>();
    Boolean aBoolean;

    public MyAdapter(Boolean aBoolean) {
        this.aBoolean = aBoolean;
    }

    public void setAllwords(List<Word> allwords) {
        this.allwords = allwords;
    }

    @NonNull
    @Override
    public MyViewHoder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        LayoutInflater layoutInflater=LayoutInflater.from(parent.getContext());
        View item;
        if(aBoolean){
            item =layoutInflater.inflate(R.layout.cell_card,parent,false);
        }else{
            item =layoutInflater.inflate(R.layout.cell_normal,parent,false);
        }
        return new MyViewHoder(item);
        //return null;
    }

    @Override
    public void onBindViewHolder(@NonNull final MyViewHoder holder, int position) {
            Word word=allwords.get(position);
            holder.textViewNumber.setText(String.valueOf(position+1));
            holder.textViewEnglish.setText(word.getWord());
            holder.textViewChinese.setText(word.getMeaning());
            holder.itemView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Uri uri=Uri.parse("http://m.youdao.com/dict?le=eng&q="+holder.textViewEnglish.getText());
                    Intent intent=new Intent(Intent.ACTION_VIEW);
                    intent.setData(uri);
                    holder.itemView.getContext().startActivity(intent);
                }
            });
    }

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

    static class MyViewHoder extends RecyclerView.ViewHolder{
        TextView textViewNumber,textViewEnglish,textViewChinese;
        public MyViewHoder(@NonNull View itemView) {
            super(itemView);
            textViewNumber=itemView.findViewById(R.id.textViewNumber);
            textViewChinese=itemView.findViewById(R.id.textViewChinese);
            textViewEnglish=itemView.findViewById(R.id.textViewEnglish);

        }
    }

}

MainActivity

package com.example.roombasic;

import androidx.appcompat.app.AppCompatActivity;
import androidx.lifecycle.LiveData;
import androidx.lifecycle.Observer;
import androidx.lifecycle.ViewModelProviders;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.CompoundButton;
import android.widget.Switch;
import android.widget.TextView;

import java.util.List;

public class MainActivity extends AppCompatActivity {
    WordDatabase wordDatabase;
    WordDao wordDao;
    Button insertbutton,clearbutton;
    LiveData<List<Word>>allWordsLive;
    WordViewModel wordViewModel;
    RecyclerView recyclerView;
    Switch aSwitch;
    MyAdapter myAdapter1,myAdapter2;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        wordViewModel= ViewModelProviders.of(this).get(WordViewModel.class);
        recyclerView=findViewById(R.id.recycleview);
        myAdapter1=new MyAdapter(false);
        myAdapter2=new MyAdapter(true);
        //加入线性布局
        recyclerView.setLayoutManager(new LinearLayoutManager(this));
        //默认第一个是适配器为正常格式
        recyclerView.setAdapter(myAdapter1);
        //控件切换展示的格式
        aSwitch=findViewById(R.id.switchButton);

        aSwitch.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                if(isChecked){
                    recyclerView.setAdapter(myAdapter2);
                }else{
                    recyclerView.setAdapter(myAdapter1);
                }
            }
        });
        //监视数据的变化，及时更新
        wordViewModel.getAllWordsLive().observe(this, new Observer<List<Word>>() {
            @Override
            public void onChanged(List<Word> words) {
                    myAdapter1.setAllwords(words);
                    myAdapter2.setAllwords(words);
                    myAdapter1.notifyDataSetChanged();
                    myAdapter2.notifyDataSetChanged();
            }
        });

        insertbutton=findViewById(R.id.addbutton);

        clearbutton=findViewById(R.id.clearbutton);

        insertbutton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String []english={
                        "hello",
                        "world",
                        "apple",
                        "banana",
                        "pear",
                        "watermelon"
                };
                String []chinese={
                        "你好",
                        "世界",
                        "苹果",
                        "香蕉",
                        "梨",
                        "西瓜"
                };
                //副线程插入
                //new InsertAsynceTask(wordDao).execute(w1,w2);
                for(int i=0;i<english.length;i++)
                    wordViewModel.insertWords(new Word(english[i],chinese[i]));
            }
        });

        clearbutton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                wordViewModel.deleteallWords();

            }
        });


    }


}

页面实现：

卡片布局

点击视图切换后，跟换为正常布局：

 点击相应的item，会跳转到有道词典来翻译当前的单词：

例如点击watermelon这个单词后：

就会跳转掉到：

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明天要做的是：利用今天复习的东西，先实现基础的整体轮廓的布局，再将python爬取的新闻信息做成卡片展示