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私はすでに新しいプロジェクトで自分のBMIアプリケーションのSQLiteデータベースを作成しました。
問題は、データベースへの接続方法がわかりません。SQLiteデータベースに接続
private string file = "mydata";は他のものに変更されるか、それとも正しいですか？
CalculatorActivity。 java
public class CalculatorActivity extends AppCompatActivity {
private EditText etWeight, etHeight;
private TextView tvDisplayResult, tvResultStatus;
Button bSave, bRead;
TextView tvStored;
String data;
private String file = "mydata";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_calculator);
etWeight = (EditText) findViewById(R.id.weight);
etHeight = (EditText) findViewById(R.id.height);
tvDisplayResult = (TextView) findViewById(R.id.display_result);
tvResultStatus = (TextView) findViewById(R.id.result_status);
tvResultStatus = (TextView) findViewById(R.id.result_status);
bSave = (Button) findViewById(R.id.savebutton);
bRead = (Button) findViewById(R.id.readbutton);
tvStored = (TextView) findViewById(R.id.displaysaveditem);
bSave.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
data = tvDisplayResult.getText().toString() + "\n";
try {
FileOutputStream fOut = openFileOutput(file, Context.MODE_APPEND);
fOut.write(data.getBytes());
fOut.close();
Toast.makeText(getBaseContext(), "file saved", Toast.LENGTH_SHORT).show();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
//Read
bRead.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
startActivity(new Intent(CalculatorActivity.this, RecordActivity.class));
finish();
}
});
}
public void onClick(View v) {
switch (v.getId()) {
case R.id.button_calculate:
Log.d("check", "Button Clicked!");
calculate();
break;
case R.id.button_reset:
reset();
break;
}
}
private void calculate() {
String weight = etWeight.getText().toString();
String height = etHeight.getText().toString();
double bmiResult = Double.parseDouble(weight)/(Double.parseDouble(height) * Double.parseDouble(height));
tvDisplayResult.setText(String.valueOf(bmiResult));
if (bmiResult < 18.5) {
tvResultStatus.setText(R.string.under);
tvResultStatus.setBackgroundColor(Color.parseColor("#F1C40F"));
tvResultStatus.setTextColor(Color.parseColor("#FFFFFF"));
} else if (bmiResult >= 18.5 && bmiResult <= 24.9) {
tvResultStatus.setText(R.string.normal);
tvResultStatus.setBackgroundColor(Color.parseColor("#2ECC71"));
tvResultStatus.setTextColor(Color.parseColor("#FFFFFF"));
} else if (bmiResult >= 24.9 && bmiResult <= 29.9) {
tvResultStatus.setText(R.string.over);
tvResultStatus.setBackgroundColor(Color.parseColor("#E57E22"));
tvResultStatus.setTextColor(Color.parseColor("#FFFFFF"));
} else if (bmiResult >= 30) {
tvResultStatus.setText(R.string.obes);
tvResultStatus.setBackgroundColor(Color.parseColor("#C0392B"));
tvResultStatus.setTextColor(Color.parseColor("#FFFFFF"));
}
}
private void reset() {
etWeight.setText("");
etHeight.setText("");
tvDisplayResult.setText(R.string.default_result);
tvResultStatus.setText(R.string.na);
tvResultStatus.setBackgroundColor(0);
tvResultStatus.setTextColor(0);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.menu_options, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle item selection
switch (item.getItemId()) {
case R.id.menu_home:
startActivity(new Intent(CalculatorActivity.this, CalculatorActivity.class));
finish();
break;
case R.id.menu_info:
startActivity(new Intent(CalculatorActivity.this, InformationActivity.class));
finish();
break;
}
return true;
}
}
DBHandler Javaの
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import java.util.ArrayList;
import java.util.List;
public class DBHandler extends SQLiteOpenHelper {
// Database Version
public static final int DATABASE_VERSION = 1;
// Database Name
public static final String DATABASE_NAME = "RecordDB";
// Record table name
public static final String TABLE_RECORD = "recordtable";
// Record Table Columns names
public static final String KEY_ID = "id";
public static final String KEY_BMI = "bmi";
public DBHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
String CREATE_RECORD_TABLE = "CREATE TABLE " + TABLE_RECORD + "(" + KEY_ID + " INTEGER PRIMARY KEY," + KEY_BMI + " TEXT " + ")";
db.execSQL(CREATE_RECORD_TABLE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Drop older table if existed
db.execSQL("DROP TABLE IF EXISTS " + TABLE_RECORD);
// Creating tables again
onCreate(db);
}
public void addBmi(Record record) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_BMI, record.getBmi()); // BMI value
// Inserting Row
db.insert(TABLE_RECORD, null, values);
db.close(); // Closing database connection
}
public List<Record> getAllRecords() {
List<Record> recordList = new ArrayList<Record>();
// Select All Query
String selectQuery = "SELECT * FROM " + TABLE_RECORD;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
Record record = new Record();
record.setId(Integer.parseInt(cursor.getString(0)));
record.setBmi(cursor.getString(1));
// Adding record to list
recordList.add(record);
} while (cursor.moveToNext());
}
// return record list
return recordList;
}
}
あなたは決して 'DBHandler'を作成しません。プライベート文字列はデータベースとは無関係です –
申し訳ありませんが、私はDBハンドルを作成することによって何を意味するのですか？ – nabskim
を参照してください。 https://developer.android.com/training/basics/data-storage/databases.html –