八、Android线程与Sqlite

Android线程与Sqlite

• 前言
• 项目目录
• 一、线程
  *
• （1）Handler
• （2）代码ThreadActivity、activity_thread
• 2.Sqlite
  *
• （1）SQLite
• （2）User
• （3）DAO
• （4）Adapter
• （5）Activity
• （6）activity_sqlite
• （7）layout_user_list_item
• （8）layout_user_dialog
• 4.MainActivity
• 5.AndroidManifest.xml

前言

👨‍💻👨‍🌾📝记录学习成果，以便温故而知新

项目目录

; 一、线程

（1）Handler

安卓的线程中有耗时长的操作，在操作完成后需要操作界面，就用到Handler来操作界面，代码如下

               new Thread(() -> {
                    Log.i(getClass().getName(), "Thread start");
                    postMsg("Thread start");
                    try {
                        Thread.sleep(30*1000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    Log.i(getClass().getName(), "Thread end");
                    postMsg("Thread end");
                }).start();

    private void postMsg(String content) {
        Bundle bundle = new Bundle();
        bundle.putString("msg", content);
        Message msg = new Message();
        msg.setData(bundle);
        msgHandler.sendMessage(msg);
    }

    Handler msgHandler = new Handler(Looper.getMainLooper()) {

        public void handleMessage(Message msg) {

            super.handleMessage(msg);

            Bundle bundle = msg.getData();

            String content = bundle.getString("msg");

            Toast.makeText(ThreadActivity.this, content, Toast.LENGTH_SHORT).show();
        }
    };

（2）代码ThreadActivity、activity_thread

package cn.fy.sqlite.activity;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.util.Log;
import android.view.MenuItem;
import android.view.View;
import android.widget.Toast;

import cn.fy.sqlite.databinding.ActivityMainBinding;
import cn.fy.sqlite.databinding.ActivityThreadBinding;

public class ThreadActivity extends AppCompatActivity {

    private ActivityThreadBinding binding;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        binding = ActivityThreadBinding.inflate(getLayoutInflater());
        setContentView(binding.getRoot());

        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        getSupportActionBar().setTitle("线程");

        binding.btnStartThread.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                new Thread(() -> {
                    Log.i(getClass().getName(), "Thread start");
                    postMsg("Thread start");
                    try {
                        Thread.sleep(30*1000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    Log.i(getClass().getName(), "Thread end");
                    postMsg("Thread end");
                }).start();
            }
        });

        binding.btnStartThreadError.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                new Thread(() -> {
                    Log.i(getClass().getName(), "Thread start");
                    Toast.makeText(ThreadActivity.this, "Thread start", Toast.LENGTH_SHORT).show();
                    try {
                        Thread.sleep(30*1000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    Log.i(getClass().getName(), "Thread end");
                    Toast.makeText(ThreadActivity.this, "Thread end", Toast.LENGTH_SHORT).show();
                }).start();
            }
        });
    }

    @Override
    public boolean onOptionsItemSelected(@NonNull MenuItem item) {

        switch (item.getItemId()) {
            case android.R.id.home:
                finish();
                break;
            default:
                break;
        }
        return super.onOptionsItemSelected(item);
    }

    private void postMsg(String content) {
        Bundle bundle = new Bundle();
        bundle.putString("msg", content);
        Message msg = new Message();
        msg.setData(bundle);
        msgHandler.sendMessage(msg);
    }

    Handler msgHandler = new Handler(Looper.getMainLooper()) {

        public void handleMessage(Message msg) {

            super.handleMessage(msg);

            Bundle bundle = msg.getData();

            String content = bundle.getString("msg");

            Toast.makeText(ThreadActivity.this, content, Toast.LENGTH_SHORT).show();
        }
    };
}

<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".activity.ThreadActivity">

    <Button
        android:id="@+id/btn_start_thread"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="60dp"
        android:layout_marginTop="20dp"
        android:layout_marginEnd="60dp"
        android:text="开始线程"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/btn_start_thread_error"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="60dp"
        android:layout_marginTop="20dp"
        android:layout_marginEnd="60dp"
        android:text="线程出错示例"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/btn_start_thread" />
androidx.constraintlayout.widget.ConstraintLayout>

2.Sqlite

; （1）SQLite

工具类

package cn.fy.sqlite.db;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

public class SQLite extends SQLiteOpenHelper {
    public SQLite(Context context) {
        super(context, "SQL.db", null, 1);

    }

    @Override
    public void onCreate(SQLiteDatabase sqLiteDatabase) {
        Log.i(getClass().getName(), "onCreate");

        String sql = "drop table if exists user;";
        sqLiteDatabase.execSQL(sql);

        sql = "create table user(ID INTEGER PRIMARY KEY AUTOINCREMENT, name varchar(30), age Integer )";

        sqLiteDatabase.execSQL(sql);
        Log.i(getClass().getName(), sql);
    }

    @Override
    public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {

    }
}

（2）User

模型

package cn.fy.sqlite.model;

public class User {
    private  Integer id;
    private String name;
    private Integer age;

    public Integer getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }
}

（3）DAO

package cn.fy.sqlite.dao;

import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.widget.Toast;

import java.util.ArrayList;

import cn.fy.sqlite.db.SQLite;
import cn.fy.sqlite.model.User;

public class UserDao {

    private SQLiteDatabase database;

    public UserDao(Context context) {
        SQLite sqLite = new SQLite(context);
        database = sqLite.getWritableDatabase();
    }

    public void addUser(User user) {
        String sql = "insert into user(name, age) values(?, ?)";
        database.execSQL(sql, new Object[]{ user.getName(), user.getAge() });
    }

    public void updateUser(User user) {
        String sql = "update user set name=?, age=? where ID=?";
        database.execSQL(sql, new Object[]{ user.getName(), user.getAge(), user.getId() });
    }

    public void delUser(User user) {
        String sql="delete from user where ID=?";
        database.execSQL(sql, new Object[]{ user.getId() });
    }

    public ArrayList<User> queryUser(User user) {
        ArrayList<User> userList = new ArrayList<>();

        String sql = "select * from user";
        Cursor cursor = database.rawQuery(sql, null);
        while(cursor.moveToNext()) {

            int id = cursor.getInt(cursor.getColumnIndexOrThrow("ID"));
            String name = cursor.getString(cursor.getColumnIndexOrThrow("name"));
            int age = cursor.getInt(cursor.getColumnIndexOrThrow("age"));

            User u = new User();
            u.setId(id);
            u.setName(name);
            u.setAge(age);

            userList.add(u);
        }
        return userList;
    }
}

（4）Adapter

在UserAdapter实现修改与删除

package cn.fy.sqlite.adapter;

import android.content.Context;
import android.content.DialogInterface;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

import androidx.appcompat.app.AlertDialog;

import java.util.ArrayList;

import cn.fy.sqlite.R;
import cn.fy.sqlite.activity.SqliteActivity;
import cn.fy.sqlite.dao.UserDao;
import cn.fy.sqlite.model.User;

public class UserAdapter extends BaseAdapter {
    private Context context;
    private LayoutInflater layoutInflater;

    private UserDao userDao;

    ArrayList<User> userList;
    public UserAdapter(Context context, ArrayList<User> userList) {
        this.context = context;
        layoutInflater = LayoutInflater.from(context);

        this.userList = userList;

        userDao = new UserDao(context);
    }

    @Override
    public int getCount() {
        return userList!=null ? userList.size() : 0;
    }

    @Override
    public Object getItem(int i) {
        return userList.get(i);
    }

    @Override
    public long getItemId(int i) {
        return i;
    }

    @Override
    public View getView(int i, View view, ViewGroup viewGroup) {
        view = layoutInflater.inflate(R.layout.layout_user_list_item, null);

        TextView id = view.findViewById(R.id.txt_id);
        TextView name = view.findViewById(R.id.txt_name);
        TextView age = view.findViewById(R.id.txt_age);

        User user = (User)getItem(i);
        id.setText(user.getId() + "");
        name.setText(user.getName());
        age.setText(user.getAge() + "");

        Button b1 = view.findViewById(R.id.btn_update_user);
        b1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                AlertDialog.Builder customizeDialog = new AlertDialog.Builder(context);
                final View dialogView = LayoutInflater.from(context).inflate(R.layout.layout_user_dialog, null);
                EditText name1 = (EditText) dialogView.findViewById(R.id.txt_dialog_name);
                name1.setText(user.getName());
                EditText age1 = (EditText) dialogView.findViewById(R.id.txt_dialog_age);
                age1.setText(user.getAge() + "");

                customizeDialog.setTitle("修改用户");
                customizeDialog.setView(dialogView);
                customizeDialog.setNegativeButton("取消", null);
                customizeDialog.setPositiveButton("确定",new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {

                        EditText name = (EditText) dialogView.findViewById(R.id.txt_dialog_name);
                        EditText age = (EditText) dialogView.findViewById(R.id.txt_dialog_age);

                        User u = new User();
                        u.setId(user.getId());
                        u.setName(name.getText().toString());
                        u.setAge(Integer.parseInt(age.getText().toString()));

                        userDao.updateUser(u);

                        ((SqliteActivity)context).refreshListView();
                        Toast.makeText(context, "修改用户成功", Toast.LENGTH_SHORT).show();
                    }
                });
                customizeDialog.show();
            }
        });

        Button b2 = view.findViewById(R.id.btn_del_user);
        b2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                final AlertDialog.Builder normalDialog =  new AlertDialog.Builder(context);
                normalDialog.setTitle("删除用户");
                normalDialog.setMessage("请确认"  );
                normalDialog.setPositiveButton("确定",  new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        userDao.delUser(user);

                        ((SqliteActivity)context).refreshListView();
                        Toast.makeText(context, "删除用户成功", Toast.LENGTH_SHORT).show();
                    }
                });
                normalDialog.setNegativeButton("取消",  new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                    }
                });

                normalDialog.show();
            }
        });

        return view;
    }
}

（5）Activity

新增在Activity中实现

package cn.fy.sqlite.activity;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;

import android.content.DialogInterface;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

import java.util.ArrayList;

import cn.fy.sqlite.R;
import cn.fy.sqlite.adapter.UserAdapter;
import cn.fy.sqlite.dao.UserDao;
import cn.fy.sqlite.databinding.ActivitySqliteBinding;
import cn.fy.sqlite.databinding.ActivityThreadBinding;
import cn.fy.sqlite.model.User;

public class SqliteActivity extends AppCompatActivity {

    private ActivitySqliteBinding binding;

    private UserDao userDao;

    ArrayList<User> userList;
    UserAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        binding = ActivitySqliteBinding.inflate(getLayoutInflater());
        setContentView(binding.getRoot());

        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        getSupportActionBar().setTitle("Sqlite");

        userDao = new UserDao(SqliteActivity.this);

        userList = userDao.queryUser(new User());
        adapter = new UserAdapter(SqliteActivity.this, userList);
        binding.listView.setAdapter(adapter);

        binding.btnAddUser.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                showAddUserDialog();
            }
        });
    }

    @Override
    public boolean onOptionsItemSelected(@NonNull MenuItem item) {

        switch (item.getItemId()) {
            case android.R.id.home:
                finish();
                break;
            default:
                break;
        }
        return super.onOptionsItemSelected(item);
    }

    private void showAddUserDialog() {
        AlertDialog.Builder customizeDialog = new AlertDialog.Builder(SqliteActivity.this);
        final View dialogView = LayoutInflater.from(SqliteActivity.this).inflate(R.layout.layout_user_dialog, null);

        customizeDialog.setTitle("新增用户");
        customizeDialog.setView(dialogView);
        customizeDialog.setNegativeButton("取消", null);
        customizeDialog.setPositiveButton("确定",new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {

                EditText name = (EditText) dialogView.findViewById(R.id.txt_dialog_name);
                EditText age = (EditText) dialogView.findViewById(R.id.txt_dialog_age);

                User user = new User();
                user.setName(name.getText().toString());
                user.setAge(Integer.parseInt(age.getText().toString()));

                userDao.addUser(user);

                refreshListView();

                Toast.makeText(SqliteActivity.this, "新增用户成功", Toast.LENGTH_SHORT).show();
            }
        });
        customizeDialog.show();
    }

    public void refreshListView() {
        userList = userDao.queryUser(new User());
        adapter = new UserAdapter(SqliteActivity.this, userList);
        binding.listView.setAdapter(adapter);
    }
}

（6）activity_sqlite

<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".activity.SqliteActivity">

    <Button
        android:id="@+id/btn_add_user"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="8dp"
        android:text="新增"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <View
        android:id="@+id/divider"
        android:layout_width="0dp"
        android:layout_height="1dp"
        android:layout_marginStart="1dp"
        android:layout_marginTop="2dp"
        android:layout_marginEnd="1dp"
        android:background="?android:attr/listDivider"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/btn_add_user" />

    <ListView
        android:id="@+id/list_view"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:layout_marginStart="2dp"
        android:layout_marginTop="6dp"
        android:layout_marginEnd="2dp"
        android:layout_marginBottom="2dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/divider" />

androidx.constraintlayout.widget.ConstraintLayout>

（7）layout_user_list_item

ListView布局文件

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <TextView
        android:id="@+id/txt_id"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="TextView" />

    <TextView
        android:id="@+id/txt_name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="TextView" />

    <TextView
        android:id="@+id/txt_age"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="TextView" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <Button
            android:id="@+id/btn_update_user"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginStart="20dp"
            android:layout_marginEnd="20dp"
            android:layout_weight="1"
            android:text="修改" />

        <Button
            android:id="@+id/btn_del_user"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginStart="20dp"
            android:layout_marginEnd="20dp"
            android:layout_weight="1"
            android:paddingStart="8dp"
            android:paddingEnd="8dp"
            android:text="删除" />
    LinearLayout>
LinearLayout>

（8）layout_user_dialog

新增修改对话框布局文件

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">

    <EditText
        android:id="@+id/txt_dialog_name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:hint="姓名"
        android:text="" />

    <EditText
        android:id="@+id/txt_dialog_age"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:hint="年龄"
        android:minHeight="48dp" />
LinearLayout>

4.MainActivity

package cn.fy.sqlite;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;

import cn.fy.sqlite.activity.SqliteActivity;
import cn.fy.sqlite.activity.ThreadActivity;
import cn.fy.sqlite.databinding.ActivityMainBinding;

public class MainActivity extends AppCompatActivity {

    private ActivityMainBinding binding;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        binding = ActivityMainBinding.inflate(getLayoutInflater());
        setContentView(binding.getRoot());

        binding.btnThread.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(MainActivity.this, ThreadActivity.class);
                startActivity(intent);
            }
        });

        binding.btnSqlite.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(MainActivity.this, SqliteActivity.class);
                startActivity(intent);
            }
        });
    }
}

<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/btn_thread"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="60dp"
        android:layout_marginTop="20dp"
        android:layout_marginEnd="60dp"
        android:text="线程"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/btn_sqlite"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="60dp"
        android:layout_marginTop="20dp"
        android:layout_marginEnd="60dp"
        android:text="Sqlite"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/btn_thread" />
androidx.constraintlayout.widget.ConstraintLayout>

5.AndroidManifest.xml

<manifest xmlns:android="http://schemas.android.com/apk/res/android">

    <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/Theme.AppCode">
        <activity
            android:name=".activity.SqliteActivity"
            android:exported="false">
            <meta-data
                android:name="android.app.lib_name"
                android:value="" />
        activity>
        <activity
            android:name=".activity.ThreadActivity"
            android:exported="false">
            <meta-data
                android:name="android.app.lib_name"
                android:value="" />
        activity>
        <activity
            android:name=".MainActivity"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            intent-filter>

            <meta-data
                android:name="android.app.lib_name"
                android:value="" />
        activity>
    application>

manifest>

Original: https://blog.csdn.net/mlw519/article/details/127234893
Author: 长铗归来
Title: 八、Android线程与Sqlite