我使用 ZXing 库创建了一个用于扫描条形码和二维码的应用程序。我还实现了一个database存储扫描产品的方法。我需要实现一个listview来显示存储的产品。有任何想法吗？
这里是类：
条码活动
@Override
public void onCreate (Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.spot_pay);
Button addButton = (Button) findViewById (R.id.addMenuButton);
addButton.setOnClickListener (new OnClickListener(){
public void onClick (View v){
startActivity(new Intent(CodiceBarreActivity.this, AggiungiCodiceActivity.class));
}
});
}
static final class ProductData {
String barcode;
String format;
String title;
BigDecimal price;
}
}
产品数据库：
private SQLiteDatabase db;
private static class ProductDatabaseHelper extends SQLiteOpenHelper {
public ProductDatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
StringBuilder sql = new StringBuilder();
sql.append("create table ").append(PRODUCT_TABLE)
.append("( ")
.append(" _id integer primary key,")
.append(" barcode text,")
.append(" format text,")
.append(" title text,")
.append(" price currency")
.append(") ");
db.execSQL(sql.toString());
Log.d(TAG, PRODUCT_TABLE + "table created");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("drop table if exists " + PRODUCT_TABLE);
Log.d(TAG, PRODUCT_TABLE + "table dropped");
onCreate(db);
}
}
public CodiciDatabase(Context context) {
ProductDatabaseHelper helper = new ProductDatabaseHelper(context);
db = helper.getWritableDatabase();
}
public boolean insert(ProductData product) {
ContentValues vals = new ContentValues();
vals.put("barcode", product.barcode);
vals.put("format", product.format);
vals.put("title", product.title);
vals.put("price", product.price.multiply(ONE_HUNDRED).longValue());
return db.insert(PRODUCT_TABLE, null, vals) != -1;
}
}
添加产品
private static final int REQUEST_BARCODE = 0;
private static final ProductData mProductData = new ProductData();
private EditText mBarcodeEdit;
private EditText mFormatEdit;
private EditText mTitleEdit;
private EditText mPriceEdit;
private Button mScanButton;
private Button mAddButton;
private CodiciDatabase mProductDb;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.add_product);
mBarcodeEdit = (EditText) findViewById(R.id.barcodeEdit);
mFormatEdit = (EditText) findViewById(R.id.codeFormatEdit);
mTitleEdit = (EditText) findViewById(R.id.titleEdit);
mPriceEdit = (EditText) findViewById(R.id.priceEdit);
mScanButton = (Button) findViewById(R.id.scanButton);
mScanButton.setOnClickListener(this);
mAddButton = (Button) findViewById(R.id.addButton);
mAddButton.setOnClickListener(this);
mProductDb = new CodiciDatabase(this); // not yet shown
}
public void onClick(View v) {
switch (v.getId()) {
case R.id.scanButton:
Intent intent = new Intent ("com.google.zxing.client.android.SCAN");
intent.putExtra("SCAN_MODE", "PRODUCT_MODE");
startActivityForResult(intent, REQUEST_BARCODE);
break;
case R.id.addButton:
String barcode = mBarcodeEdit.getText().toString();
String format = mFormatEdit.getText().toString();
String title = mTitleEdit.getText().toString();
String price = mPriceEdit.getText().toString();
String errors = validateFields(barcode, format, title, price);
if (errors.length() > 0) {
showInfoDialog(this, "Please fix errors", errors);
} else {
mProductData.barcode = barcode;
mProductData.format = format;
mProductData.title = title;
mProductData.price = new BigDecimal(price);
mProductDb.insert(mProductData);
showInfoDialog(this, "Success", "Product saved successfully");
resetForm();
}
break;
}
}
}
private void resetForm() {
mBarcodeEdit.getText().clear();
mFormatEdit.getText().clear();
mTitleEdit.getText().clear();
mPriceEdit.getText().clear();
}
private void showInfoDialog(Context context, String title, String information) {
new AlertDialog.Builder (context)
.setMessage(information)
.setTitle(title)
.setPositiveButton("OK", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
}
}).show();
}
public void onActivityResult(int requestCode, int resultCode, Intent intent){
if (requestCode == REQUEST_BARCODE){
if (resultCode == RESULT_OK) {
String barcode = intent.getStringExtra("SCAN_RESULT");
mBarcodeEdit.setText(barcode);
String format = intent.getStringExtra("SCAN_RESULT_FORMAT");
mFormatEdit.setText(format);
} else if (resultCode == RESULT_CANCELED){
finish();
}
}
}
}
private static String validateFields(String barcode, String format,
String title, String price) {
StringBuilder errors = new StringBuilder();
if (barcode.matches("^\\s*$")) {
errors.append("Barcode required\n");
}
if (format.matches("^\\s*$")) {
errors.append("Format required\n");
}
if (title.matches("^\\s*$")) {
errors.append("Title required\n");
}
if (!price.matches("^-?\\d+(.\\d+)?$")) {
errors.append("Need numeric price\n");
}
return errors.toString();
}
}