使用Android studio写一个简单的记账本代码

好的，下面是一个简单的记账本的Android Studio示例代码：

1. 布局文件：activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <Button
        android:id="@+id/btn_add"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="添加账单"
        android:layout_alignParentBottom="true"
        android:layout_alignParentRight="true"
        android:layout_marginRight="16dp"
        android:layout_marginBottom="16dp"/>

    <ListView
        android:id="@+id/list_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_above="@id/btn_add"
        android:layout_marginBottom="16dp"/>

</RelativeLayout>

2. 账单项布局文件：list_item_bill.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal"
    android:padding="16dp">

    <TextView
        android:id="@+id/tv_name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="18sp"
        android:textStyle="bold"/>

    <TextView
        android:id="@+id/tv_amount"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:gravity="end"
        android:textSize="16sp"/>

</LinearLayout>

3. 账单数据模型类：Bill.java

public class Bill {
    private String name;
    private double amount;

    public Bill(String name, double amount) {
        this.name = name;
        this.amount = amount;
    }

    public String getName() {
        return name;
    }

    public double getAmount() {
        return amount;
    }
}

4. 自定义适配器类：BillAdapter.java

public class BillAdapter extends ArrayAdapter<Bill> {
    private Context mContext;
    private int mResource;

    public BillAdapter(Context context, int resource, List<Bill> objects) {
        super(context, resource, objects);
        mContext = context;
        mResource = resource;
    }

    @NonNull
    @Override
    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
        if (convertView == null) {
            convertView = LayoutInflater.from(mContext).inflate(mResource, parent, false);
        }

        Bill bill = getItem(position);

        TextView tvName = convertView.findViewById(R.id.tv_name);
        TextView tvAmount = convertView.findViewById(R.id.tv_amount);

        tvName.setText(bill.getName());
        tvAmount.setText(String.format(Locale.getDefault(), "%.2f", bill.getAmount()));

        return convertView;
    }
}

5. 主Activity类：MainActivity.java

public class MainActivity extends AppCompatActivity {
    private List<Bill> mBillList = new ArrayList<>();
    private BillAdapter mAdapter;
    private ListView mListView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mListView = findViewById(R.id.list_view);
        mAdapter = new BillAdapter(this, R.layout.list_item_bill, mBillList);
        mListView.setAdapter(mAdapter);

        Button btnAdd = findViewById(R.id.btn_add);
        btnAdd.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                showAddBillDialog();
            }
        });
    }

    private void showAddBillDialog() {
        final EditText etName = new EditText(this);
        final EditText etAmount = new EditText(this);
        etAmount.setInputType(InputType.TYPE_CLASS_NUMBER | InputType.TYPE_NUMBER_FLAG_DECIMAL);

        LinearLayout layout = new LinearLayout(this);
        layout.setOrientation(LinearLayout.VERTICAL);
        layout.addView(etName);
        layout.addView(etAmount);

        AlertDialog dialog = new AlertDialog.Builder(this)
                .setTitle("添加账单")
                .setView(layout)
                .setPositiveButton("保存", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        String name = etName.getText().toString().trim();
                        double amount = Double.parseDouble(etAmount.getText().toString().trim());

                        Bill bill = new Bill(name, amount);
                        mBillList.add(bill);
                        mAdapter.notifyDataSetChanged();
                    }
                })
                .setNegativeButton("取消", null)
                .create();

        dialog.show();
    }
}

这是一个简单的记账本示例代码，当然还有很多其他的实现方式和功能可以添加。希望这可以帮助你开始编写一个记账本应用程序。