Android-用两个activity实现少女心爆棚的便签（xutil框架实现）

首先上图看效果，由于不能上传视频，多图预警，支持增，删，改，查，搜索。由于篇幅有限，有些xml文件不能上传，想要整个工程可以进行下载，或者私信俺。如果不会xutil数据库操作，可以先进行学习

在这里只贴出，java代码
首先得添加框架依赖

   implementation 'com.facebook.stetho:stetho:1.5.1'
 implementation 'org.xutils:xutils:3.8.5'
    implementation 'com.scwang.smartrefresh:SmartRefreshLayout:1.1.2'  //1.0.5及以前版本的老用户升级需谨慎，API改动过大
    implementation 'com.scwang.smartrefresh:SmartRefreshHeader:1.1.2'  //没有使用特殊Header，可以不加这行

第一个activity.java代码

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.GridLayoutManager;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.telephony.CellSignalStrength;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

import com.facebook.stetho.Stetho;
import com.scwang.smartrefresh.layout.api.RefreshLayout;
import com.scwang.smartrefresh.layout.listener.OnLoadMoreListener;
import com.scwang.smartrefresh.layout.listener.OnRefreshListener;

import org.xutils.DbManager;
import org.xutils.db.Selector;
import org.xutils.ex.DbException;
import org.xutils.x;

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

public class MainActivity extends AppCompatActivity {

   static DbManager.DaoConfig daoConfig;
   //用来增加数据使用,表示id
   static int nums;
   //用来表示是新建还是修改
   static boolean flag=true;
   //切换布局
   static boolean flagRecycle=true;

   static MyAdapter myAdapter;
    static List<Messages> users;
    static List<Messages> userstemp;
    static RecyclerView recyclerView;
    Messages messages;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            Stetho.initializeWithDefaults(this);



            x.Ext.init(getApplication());
            x.Ext.setDebug(BuildConfig.DEBUG);// 是否输出debug日志, 开启debug会影响性能.
            x.view().inject(this);//没有用到view注解可以先不用



            final EditText editText=findViewById(R.id.editText2);

//数据库创建

            daoConfig= new DbManager.DaoConfig()
                    .setDbName("messages.db")
                    // 不设置dbDir时, 默认存储在app的私有目录.
                    // .setDbDir(new File("/sdcard")) // "sdcard"的写法并非最佳实践, 这里为了简单, 先这样写了.
                    .setDbVersion(1)
                    .setDbOpenListener(new DbManager.DbOpenListener() {
                        @Override
                        public void onDbOpened(DbManager db) {
                            // 开启WAL, 对写入加速提升巨大
                            db.getDatabase().enableWriteAheadLogging();
                        }
                    })
                    .setDbUpgradeListener(new DbManager.DbUpgradeListener() {
                        @Override
                        public void onUpgrade(DbManager db, int oldVersion, int newVersion) {
                            // TODO: ...
                            // db.addColumn(...);
                            // db.dropTable(...);
                            // ...
                            // or
                            // db.dropDb();
                        }
                    });
//查询所有的数据,并显示到recycleview
            DbManager db = null;
            try {// 删除1
                db = x.getDb(daoConfig);
                users= new ArrayList<>();
                users= db.selector(Messages.class).orderBy("id", true).limit(1000).findAll();
// users= db.selector(User.class).orderBy("id", true).limit(1000).findAll();
// users= db.selector(User.class).findAll();

                nums=users.size();
            } catch (DbException e) {
                e.printStackTrace();
                return;
            }



            //            搜索
            Button button=findViewById(R.id.button6);
            button.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View v) {
                    EditText seachEdit=findViewById(R.id.editText);
                    String seachContent=seachEdit.getText().toString();
                    DbManager db = null;
                    try {// 删除1
                        db = x.getDb(daoConfig);
                        List<Messages> newMessge = new ArrayList<>();
                        String sql="select * from Messages where content like "+"'%"+seachContent+"%'";
                           Cursor cursor= db.execQuery(sql);


                           while (cursor.moveToNext()){
                               Messages m=new Messages();
                               String seachmess=cursor.getString(1);

                               m.setContent(seachmess);
                               String seachdate=cursor.getString(2);
                               m.setDate(seachdate);
                               int seachid=cursor.getInt(0);
                               m.setId(seachid);
                               newMessge.add(m);
                               Log.i("hhhh", "onClick: sousuo"+m.getContent()+" "+m.getDate()+" "+seachContent);
                           }
                           cursor.close();
//                        newMessge=db.selector(Messages.class).orderBy("id", true).where("content","like","%"+seachContent+"%").findAll();

                        users=newMessge;
                        myAdapter.notifyDataSetChanged();
                        seachEdit.setText("");

// users= db.selector(User.class).orderBy("id", true).limit(1000).findAll();
// users= db.selector(User.class).findAll();


                    } catch (DbException e) {
                        e.printStackTrace();
                        return;
                    }
                }
            });



            //    跳转到编写页面
            Button button2 =findViewById(R.id.button2);
            button2.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    flag=false;
                    Intent intent=new Intent(MainActivity.this,Main2Activity.class);
                    startActivity(intent);
                    Log.i("hhhhh", "onClick: ");
                }
            });

            myAdapter = new MyAdapter();
            recyclerView =findViewById(R.id.recyclerView);
            recyclerView.setAdapter(myAdapter);
//设置边距
             HashMap<String, Integer> stringIntegerHashMap = new HashMap<>();
            stringIntegerHashMap.put(RecyclerViewSpacesItemDecoration.TOP_DECORATION,30);//top间距

            stringIntegerHashMap.put(RecyclerViewSpacesItemDecoration.BOTTOM_DECORATION,50);//底部间距

            stringIntegerHashMap.put(RecyclerViewSpacesItemDecoration.LEFT_DECORATION,50);//左间距

            stringIntegerHashMap.put(RecyclerViewSpacesItemDecoration.RIGHT_DECORATION,50);//右间距

            recyclerView.addItemDecoration(new RecyclerViewSpacesItemDecoration(stringIntegerHashMap));


            recyclerView.setLayoutManager(new LinearLayoutManager(MainActivity.this));



//            刷新
            RefreshLayout refreshLayout = findViewById(R.id.refreshLayout);
            refreshLayout.setOnRefreshListener(new OnRefreshListener() {
                @Override
                public void onRefresh(RefreshLayout refreshlayout) {


                    DbManager db = null;
                    try {// 删除1
                        db = x.getDb(daoConfig);
                        users= new ArrayList<>();
                        users= db.selector(Messages.class).orderBy("id", true).limit(1000).findAll();
// users= db.selector(User.class).orderBy("id", true).limit(1000).findAll();
// users= db.selector(User.class).findAll();

                        nums=users.size();
                    } catch (DbException e) {
                        e.printStackTrace();
                        return;
                    }

                    myAdapter.notifyDataSetChanged();
                    refreshlayout.finishRefresh(2000/*,false*/);//传入false表示刷新失败
                }
            });
            refreshLayout.setOnLoadMoreListener(new OnLoadMoreListener() {
                @Override
                public void onLoadMore(RefreshLayout refreshlayout) {


                    myAdapter.notifyDataSetChanged();
                    refreshlayout.finishLoadMore(2000/*,false*/);//传入false表示加载失败

                }
            });






//            切换布局

            Button button4=findViewById(R.id.button4);
            button4.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    if (flagRecycle) {//如果为真，代表线性布局，设置为网格布局
                        flagRecycle=false;

                        recyclerView.setLayoutManager(new GridLayoutManager(MainActivity.this, 2, LinearLayoutManager.VERTICAL, false));
                }else {
                        flagRecycle=true;

                        recyclerView.setLayoutManager(new LinearLayoutManager(MainActivity.this));
                    }

                }
            });



        }






        public  class MyViewHolder extends  RecyclerView.ViewHolder{//用来包装每个子项的布局信息

            public TextView textView1;
            public TextView textView2;
            public MyViewHolder(@NonNull View itemView) {
                super(itemView);
                textView1=itemView.findViewById(R.id.textView1);
                textView2=itemView.findViewById(R.id.textView2);
            }
        }
        public  class  MyAdapter extends RecyclerView.Adapter<MyViewHolder>{
            //用来配合recycleview进行加载子项以及填充子项的数据

            @Override
            public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, final int viewType) {
                final View view = LayoutInflater.from(MainActivity.this).inflate(R.layout.item1,parent,false);
                final MyViewHolder myViewHolder = new MyViewHolder(view);
//设置子项item监听
                myViewHolder.itemView.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
//                        Messages user=new Messages();
////                        user.setId();
                        Intent intent=new Intent(MainActivity.this,Main2Activity.class);
                        int id=myViewHolder.getAdapterPosition();//得到item的编号，位置
//                        String date=users.get(id).getDate();
//                        String content=users.get(id).getContent();
//跳转页面并实现传递参数
                        intent.putExtra("mess",id);
//                        Log.i("hhhh", "onClick: "+id+"  "+users.get(id).getContent());
                        startActivity(intent);
                    }
                });


//              设置监听
//                view.setOnClickListener(new View.OnClickListener() {
//                    @Override
//                    public void onClick(View v) {
////                        Messages user=new Messages();
////                        user.setId();
//                        Intent intent=new Intent(MainActivity.this,Main2Activity.class);
////                        intent.putExtra("user",users.get())
//                        Log.i("hhhh", "onClick: "+view.getTag());
//                        startActivity(intent);
//                    }
//                });
                return myViewHolder;
            }

            @Override
            public void onBindViewHolder(@NonNull MyViewHolder holder, int position) {//在这里进行子项的文本图片数据填充
                holder.textView1.setText(users.get(position).getContent());
                holder.textView2.setText(users.get(position).getDate());
            }

            @Override
            public int getItemCount() {//返回子项的数目，即加载多少列表项
                return users.size();
            }
        }
    }

第二个activity.java代码

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.TextView;

import com.facebook.stetho.Stetho;

import org.xutils.DbManager;
import org.xutils.common.util.KeyValue;
import org.xutils.db.sqlite.WhereBuilder;
import org.xutils.ex.DbException;
import org.xutils.x;

import java.text.SimpleDateFormat;
import java.util.Date;

import static com.c201801020217.tangbo.MainActivity.daoConfig;
import static com.c201801020217.tangbo.MainActivity.flag;
import static com.c201801020217.tangbo.MainActivity.myAdapter;
import static com.c201801020217.tangbo.MainActivity.nums;
import static com.c201801020217.tangbo.MainActivity.users;

public class Main2Activity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
        Stetho.initializeWithDefaults(this);
//        返回
        final Button button=findViewById(R.id.button);
//        保存
        Button button2=findViewById(R.id.button7);
//        删除
        final Button button3=findViewById(R.id.button5);

        final TextView textViewDate=findViewById(R.id.textView);
        final TextView textContent=findViewById(R.id.editText2);
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy年MM月dd日 HH:mm:ss");// HH:mm:ss
//获取当前时间
        Date date = new Date(System.currentTimeMillis());
        final String time= simpleDateFormat.format(date);

        textViewDate.setText(time);
//        Messages messages= (Messages) getIntent().getSerializableExtra("mess");

            final int id = getIntent().getIntExtra("mess", 0);
            final int itemid = users.get(id).getId();
            if(flag) {
            String dates = users.get(id).getDate();
            String content = users.get(id).getContent();
            textViewDate.setText(dates);
            textContent.setText(content);
        }
        //        保存
        button2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                DbManager db = null;

                try {
                    if (flag) {//如果为真，代表是点击item进来的，要用更新语句而不是插入语句
//条件更新
                        String newcontent=textContent.getText().toString();
                        db = x.getDb(daoConfig);
                        db.update(Messages.class, WhereBuilder.b("id", "=", itemid),
// WhereBuilder.b("id", "=", 1).and("isAdmin", "=", true).,
                                new KeyValue("content",newcontent), new KeyValue("date", time));
                        users.get(id).setDate(time);
                        users.get(id).setContent(newcontent);

                    } else {


                        db = x.getDb(daoConfig);
                        Messages user = new Messages();//new 一个对象，相当于是表中的一行，相当于一条记录
                        //相当于插入数据
                        user.setId(nums + 1);
                        nums++;
                        user.setDate(time);
                        user.setContent(textContent.getText().toString());
                        db.save(user);//写入数据，保存到数据库
                        flag=true;
                        users.add(user);
//                       myAdapter.notifyDataSetChanged();

                    }
                    finish();
                } catch (DbException e) {
                    e.printStackTrace();
                    return;
                }
            }
            });
//        删除

            button3.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {

//条件删除
                    DbManager db = null;
                    try {
                        db = x.getDb(daoConfig);
                        db.delete(Messages.class,
                                WhereBuilder.b("id", "=", itemid));
                        users.remove(id);

                    } catch (DbException e) {
                        e.printStackTrace();
                        return;
                    }
                    finish();
                }

            });
//返回
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                finish();
            }
        });



    }
}

数据库使用的java类

import org.xutils.db.annotation.Column;
import org.xutils.db.annotation.Table;

import java.util.Date;

@Table(name = "Messages")
public class Messages {

    @Column(name = "id",isId=true)
    private int id;
    @Column(name = "date")
    private String date;
    @Column(name = "content")
    private String content;

    public String getDate() {
        return date;
    }

    public void setDate(String date) {
        this.date = date;
    }

    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }

    public int getId() {
        return id;
    }

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