Android-用两个activity实现少女心爆棚的便签（xutil框架实现）移动开发qq43520913的博客-

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; } }