记账本

今天了解了安卓程序开发的内容，根据示例练习理解安卓与以往学习的内容的不同之处，也尝试编程了记账本的内容。

在content_main.xml中添加

  <ListView
        android:id="@+id/lv_main"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

listview适配器

public class CostListAdapter extends BaseAdapter {
    private List<CostBean> mList;
    private Context mContext;
    private LayoutInflater mLayoutInflater;
 
    public CostListAdapter(Context context, List<CostBean> list){
        mContext=context;
        mList=list;
        mLayoutInflater=LayoutInflater.from(context);
 
    }
 
    @Override
    public int getCount() {
        return mList.size();
    }
 
    @Override
    public Object getItem(int position) {
        return mList.get(position);
    }
 
    @Override
    public long getItemId(int position) {
        return position;
    }
 
    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder viewHolder;
        if (convertView==null){
            viewHolder=new ViewHolder();
            convertView=mLayoutInflater.inflate(R.layout.list_item,null);
            viewHolder.mTvCostTitle= (TextView) convertView.findViewById(R.id.tv_title);
            viewHolder.mTvCostDate= (TextView) convertView.findViewById(R.id.tv_date);
            viewHolder.mTvCostMoney= (TextView) convertView.findViewById(R.id.tv_cost);
            convertView.setTag(viewHolder);
        }else {
            viewHolder= (ViewHolder) convertView.getTag();
        }
 
        CostBean bean=mList.get(position);
        viewHolder.mTvCostTitle.setText(bean.costTitle);
        viewHolder.mTvCostDate.setText(bean.costDate);
        viewHolder.mTvCostMoney.setText(bean.costMoney);
 
        return convertView;
    }
 
    private static class ViewHolder{
        public TextView mTvCostTitle;
        public TextView mTvCostDate;
        public TextView mTvCostMoney;
    }
}

list_item的布局代码

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="80dp">
 
    <TextView
        android:id="@+id/tv_title"
        android:layout_width="150dp"
        android:layout_height="80dp"
        android:layout_marginLeft="10dp"
        android:layout_alignParentLeft="true"
        android:singleLine="true"
        android:ellipsize="marquee"
        android:textSize="35sp"
        android:gravity="center"
        android:text="costTitle"/>
 
    <TextView
        android:id="@+id/tv_date"
        android:layout_width="wrap_content"
        android:layout_height="80dp"
        android:gravity="center"
        android:textSize="20sp"
        android:layout_marginLeft="15dp"
        android:layout_toRightOf="@+id/tv_title"
        android:text="costDate"/>
 
    <TextView
        android:id="@+id/tv_cost"
        android:layout_width="wrap_content"
        android:layout_height="80dp"
        android:gravity="center"
        android:layout_alignParentRight="true"
        android:textSize="30sp"
        android:layout_marginRight="20dp"
        android:text="30"/>
 
 
</RelativeLayout>

实体Bean对象

public class CostBean implements Serializable {
    public String costTitle;
    public String costDate;
    public String costMoney;
}

数据库中的增删改查

public class DatabaseHelper extends SQLiteOpenHelper {
 
    public static final String COST_DATE = "cost_date";
    public static final String COST_TITLE = "cost_title";
    public static final String COST_MONEY = "cost_money";
    public static final String COST = "cost";
 
    public DatabaseHelper(Context context) {
        super(context, "daily", null, 1);
    }
 
    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("create table if not exists cost("+
                "id integer primary key, "+
                "cost_title varchar, "+
                "cost_date varchar, "+
                "cost_money varchar)");
    }
 
    public void insertCost(CostBean costBean){
        SQLiteDatabase database=getWritableDatabase();
        ContentValues cv=new ContentValues();
        cv.put(COST_TITLE,costBean.costTitle);
        cv.put(COST_DATE,costBean.costDate);
        cv.put(COST_MONEY,costBean.costMoney);
        database.insert(COST,null,cv);
    }
 
    public  void deleteAllData(){
        SQLiteDatabase database=getWritableDatabase();
        database.delete(COST,null,null);
    }
 
 
    public Cursor getAllCostData(){
        SQLiteDatabase database=getWritableDatabase();
        return database.query(COST,null,null,null,null,null,COST_DATE + " ASC");
 
    }
 
 
 
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
 
    }
}

先根据了已有的代码进行了解，记账本的具体实现方法还在学习中。