家庭记账本APP（7）

目前APP还存在很多问题，只实现了最基本的添加，查看，删除功能，

如有机会以后打算再进行功能的扩充。

涉及哪些知识：

页面的基本布局、ListView的使用、SQLite数据库的基本操作、Dialog对话框、按钮的点击事件、单选框的使用、自动获取系统时间等

主要代码

package com.JIN;

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

import androidx.annotation.Nullable;

public class SQL extends SQLiteOpenHelper {
    final String add="create table jizhangben (money varchar(20),time varchar(20),driction varchar(10),info varchar(50))";
    public SQL(@Nullable Context context, @Nullable String name, @Nullable SQLiteDatabase.CursorFactory factory, int version) {
        super(context, name, null, version);
    }
    @Override

package com.JIN;

import androidx.appcompat.app.AppCompatActivity;

import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.GestureDetector;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    private long exitTime=0;
    private SQL sqL;
    private SQLiteDatabase sqliteDatabase;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        makeview();
    }
    public void makeview() {
        String a="";
        final LinearLayout linearLayout=findViewById(R.id.linearlayout);
        sqL = new SQL(MainActivity.this, "Jizhangben", null, 1);
        sqliteDatabase = sqL.getReadableDatabase();
        Cursor c = sqliteDatabase.rawQuery("select * from jizhangben order by time desc", null);
        if(c.moveToNext()) {
            c.moveToFirst();
            do {
                a=c.getString(c.getColumnIndex("driction"))+ ":" + c.getString(c.getColumnIndex("money")) +"元"+","+"备注:" + c.getString(c.getColumnIndex("info"))+ ","+ "时间:" + c.getString(c.getColumnIndex("time"));
                TextView t = new TextView(this);
                t.setText(a);
                t.setTextSize(20);
               t.setPadding(0, 0, 0, 15);
                LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
                t.setLayoutParams(params);
                linearLayout.addView(t);
            } while (c.moveToNext());
        }else{
            final TextView textView = new TextView(this);
            textView.setText("无记录");
            textView.setTextSize(19);
            textView.setPadding(0, 0, 0, 10);
            LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
            textView.setLayoutParams(params);
            linearLayout.addView(textView);
        }
    }
    @Override
    public boolean onCreatePanelMenu(int featureId, Menu menu) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.menu, menu);
        MenuItem deleteItem = menu.findItem(R.id.delete);
        deleteItem.setOnMenuItemClickListener(new MenuItem.OnMenuItemClickListener() {
            @Override
            public boolean onMenuItemClick(MenuItem item) {
                deleteall();
                return false;
            }
        });
        return super.onCreatePanelMenu(featureId, menu);
    }
    public void deleteall(){
        LinearLayout b=findViewById(R.id.linearlayout);
        AlertDialog alertDialog=new AlertDialog.Builder(MainActivity.this).create();
        alertDialog.setTitle("提示");
        alertDialog.setMessage("清空数据？");
        alertDialog.setButton(DialogInterface.BUTTON_POSITIVE, "是", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                sqL.getWritableDatabase().execSQL("delete from jizhangben");
                Toast.makeText(MainActivity.this,"清空成功",Toast.LENGTH_SHORT).show();
                finish();
                Intent intent = new Intent(MainActivity.this, MainActivity.class);
                startActivity(intent);
            }
        });
        alertDialog.setButton(DialogInterface.BUTTON_NEGATIVE, "否", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {

            }
        });
        alertDialog.show();
    }
}

package com.JIN;

import androidx.appcompat.app.AppCompatActivity;

import android.app.AlertDialog;
import android.content.ContentValues;
import android.content.Context;
import android.content.DialogInterface;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Toast;

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

public class add_Activity extends AppCompatActivity {
    private String driction="";
    private SQL sqL;
    private SQLiteDatabase sqliteDatabase;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_add);
        TextView textView =findViewById(R.id.commit);
        RadioGroup radioGroup=findViewById(R.id.driction);
        radioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(RadioGroup group, int checkedId) {
                RadioButton r=findViewById(checkedId);
                driction=r.getText().toString();
            }
        });
        textView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String time = new SimpleDateFormat("yyyy/MM/dd,HH:mm:ss").format(new Date());
                EditText money=findViewById(R.id.money);
                EditText info=findViewById(R.id.info);
                if(money.getText().toString().equals("")||money.getText().toString().equals(""))
                {
                    Toast.makeText(add_Activity.this,"填写完整即可提交",Toast.LENGTH_SHORT).show();
                }else{
                    sqL=new SQL(add_Activity.this,"Jizhangben",null,1);
                    sqliteDatabase = sqL.getWritableDatabase();
                    ContentValues values = new ContentValues();
                    values.put("money", money.getText().toString());
                    values.put("time", time);
                    values.put("driction", driction);
                    values.put("info", info.getText().toString());
                    sqliteDatabase.insert("jizhangben", null, values);
                    sqliteDatabase.close();
                    money.setText("");
                    info.setText("");
                    Toast.makeText(add_Activity.this,"添加成功！",Toast.LENGTH_SHORT).show();
                }
            }
        });
    }
}

package com.JIN;

import androidx.appcompat.app.ActionBar;
import androidx.appcompat.app.AppCompatActivity;

import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.View;
import android.widget.TextView;

public class firstActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        ActionBar actionBar=getSupportActionBar();
        actionBar.hide();
        setContentView(R.layout.activity_first);
        TextView t1=findViewById(R.id.add);
        TextView t2=findViewById(R.id.look);
        t2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent();
                intent.setClass(firstActivity.this, MainActivity.class);
                startActivity(intent);
            }
        });
        t1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent();
                intent.setClass(firstActivity.this, add_Activity.class);
                startActivity(intent);
            }
        });
    }
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (((keyCode == KeyEvent.KEYCODE_BACK) ||
                (keyCode == KeyEvent.KEYCODE_HOME))
                && event.getRepeatCount() == 0) {

            dialog_Exit(firstActivity.this);

        }
        return false;


    }
    private void dialog_Exit(Context context) {
        AlertDialog.Builder builder = new AlertDialog.Builder(context);
        builder.setMessage("确定要退出吗?");
        builder.setTitle("提示");
        builder.setIcon(android.R.drawable.ic_dialog_alert);
        builder.setPositiveButton("确认",
                new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.dismiss();
                        System.exit(0);
                        finish();
                    }
                });

        builder.setNegativeButton("取消",
                new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.dismiss();
                    }
                });

        builder.create().show();
    }
}

public void onCreate(SQLiteDatabase db) {
        db.execSQL(add);
    }
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        Log.i("记账本","--版本更新"+oldVersion+"-->"+newVersion);
        String sql = "alter table tally add sex varchar(8)";
        db.execSQL(sql);
    }
}