我正在关注本教程 http://anujarosha.wordpress.com/2011/12/12/how-to-insert-data-in-to-a-sqlite-database-in-android/ ， 然而， 当我尝试时，我无法在 DDMS 中找到我的数据库。 为什么会这样？
不知道是不是代码问题，但是没有eror log。 这是我的代码
AndroidDBHelper.java
public class AndroidOpenDbHelper extends SQLiteOpenHelper {
// Database attributes
public static final String DB_NAME = "myDB";
public static final int DB_VERSION = 2;
// Table attributes
public static final String TABLE_NAME_LOG = "fuelLog";
public static final String KEY_ROWID = "_id";
public static final String KEY_DATE = "date";
public static final String KEY_PRICE = "fuelprice";
public static final String KEY_FUEL = "fuelpump";
public static final String KEY_COST = "tcost";
public static final String KEY_ODM = "odometer";
public static final String KEY_CON = "fcon";
public AndroidOpenDbHelper(Context context) {
super(context, DB_NAME, null, DB_VERSION);
}
// Called when the database is created for the first time.
//This is where the creation of tables and the initial population of the tables should happen.
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
// We need to check whether table that we are going to create is already exists.
//Because this method get executed every time we created an object of this class.
//"create table if not exists TABLE_NAME ( BaseColumns._ID integer primary key autoincrement, FIRST_COLUMN_NAME text not null, SECOND_COLUMN_NAME integer not null);"
String SQL_createTable = "create table if not exists " + TABLE_NAME_LOG + " ( " + BaseColumns._ID + " integer primary key autoincrement, "
+ KEY_DATE + " text not null, "
+ KEY_PRICE + " text not null, "
+ KEY_FUEL + " text not null, "
+ KEY_COST + " text not null, "
+ KEY_ODM + " text not null, "
+ KEY_CON + " text not null);";
// Execute a single SQL statement that is NOT a SELECT or any other SQL statement that returns data.
db.execSQL(SQL_createTable);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
if(oldVersion == 1 && newVersion == 2){
// Upgrade the database
}
}
}
fuelLogPojo.java
public class fuelLogPojo {
private String date;
private String price;
private String pump;
private String cost;
private String odometer;
private String fcon;
public String getdate() {
return date;
}
public void setdate(String date) {
this.date = date;
}
public String getprice() {
return price;
}
public void setprice(String price) {
this.price = price;
}
public String getpump() {
return pump;
}
public void setpump(String pump) {
this.pump = pump;
}
public String getcost() {
return cost;
}
public void setcost(String cost) {
this.cost = cost;
}
public String getodometer() {
return odometer;
}
public void setodometer(String odometer) {
this.odometer = odometer;
}
public String getfcon() {
return fcon;
}
public void setfcon(String fcon) {
this.fcon = fcon;
}
}
主要 Activity .java
public class MainActivity extends Activity {
// TableLayout tablelayout_Log = null;
Button saveButton = null;
Button cancelButton = null;
// Button searchButton = null;
static EditText dateEdit;
EditText priceEdit;
EditText pumpEdit;
TextView costView;
EditText odometerEdit;
TextView fconView;
TextWatcher textWatcher;
String priceEditStr ="",pumpEditStr="";
String odmEditStr = "";
String lastOdm = "";
double result;
double resultCon;
private int mYear;
private int mMonth;
private int mDay;
static final int DATE_DIALOG_ID = 0;
private ArrayList fuelLogArrayList;
public boolean isNumeric(String str)
{
return str.matches("-?\\d+(\\.\\d+)?");
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
costView = (TextView)findViewById(R.id.tcost);
dateEdit = (EditText)findViewById(R.id.date);
priceEdit = (EditText)findViewById(R.id.fuelprice);
pumpEdit = (EditText)findViewById(R.id.fuelpump);
odometerEdit = (EditText)findViewById(R.id.odometer);
fconView = (TextView)findViewById(R.id.fcon);
fuelLogArrayList = new ArrayList();
// DBAdapter dbAdaptor = new DBAdapter(getApplicationContext());
// lastOdm = dbAdaptor.getLastOdometer();
//Check that your database is enable to fetch the value or not?
//Toast.makeText(getApplicationContext()," "+lastOdm,Toast.LENGTH_LONG).show();
dateEdit.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// showDialog(DATE_DIALOG_ID);
DialogFragment newFragment = new DatePickerFragment();
newFragment.show(getFragmentManager(), "datePicker");
}
});
priceEdit.addTextChangedListener(new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
}
@Override
public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
}
@Override
public void afterTextChanged(Editable editable) {
//here, after we introduced something in the EditText we get the string from it
if(!priceEdit.getText().toString().trim().equalsIgnoreCase("") && !priceEdit.getText().toString().trim().equalsIgnoreCase(null))
priceEditStr = priceEdit.getText().toString().trim();
if(!pumpEdit.getText().toString().trim().equalsIgnoreCase("") && !pumpEdit.getText().toString().trim().equalsIgnoreCase(null))
pumpEditStr = pumpEdit.getText().toString().trim();
if(!priceEdit.getText().toString().trim().equalsIgnoreCase("") && !pumpEdit.getText().toString().trim().equalsIgnoreCase(""))
{
result = Double.parseDouble(priceEditStr) * Double.parseDouble(pumpEditStr);
costView.setText(" "+result);
}
}
});
pumpEdit.addTextChangedListener(new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
}
@Override
public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
}
@Override
public void afterTextChanged(Editable editable) {
//here, after we introduced something in the EditText we get the string from it
if(!priceEdit.getText().toString().trim().equalsIgnoreCase(""))
priceEditStr = priceEdit.getText().toString().trim();
if(!pumpEdit.getText().toString().trim().equalsIgnoreCase(""))
pumpEditStr = pumpEdit.getText().toString().trim();
if(!priceEdit.getText().toString().trim().equalsIgnoreCase("") && !pumpEdit.getText().toString().trim().equalsIgnoreCase(""))
{
result = Double.parseDouble(priceEditStr) * Double.parseDouble(pumpEditStr);
costView.setText(" "+result);
}
}
});
odometerEdit.addTextChangedListener(new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
}
@Override
public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
}
@Override
public void afterTextChanged(Editable editable) {
//here, after we introduced something in the EditText we get the string from it
if(!odometerEdit.getText().toString().trim().equalsIgnoreCase(""))
odmEditStr = odometerEdit.getText().toString().trim();
if(!odometerEdit.getText().toString().trim().equalsIgnoreCase("") && !pumpEdit.getText().toString().trim().equalsIgnoreCase("") && !lastOdm.trim().equalsIgnoreCase(null) && !lastOdm.trim().equalsIgnoreCase(" "))
{
resultCon = Double.parseDouble(odmEditStr) / Double.parseDouble(pumpEditStr);
fconView.setText(" "+resultCon);
}
}
});
}
public void onClick(View v) {
if(v.getId() == R.id.cancelBTN){
finish();
}else if(v.getId() == R.id.saveBTN){
// Get the values provided by the user via the UI
String date = dateEdit.getText().toString();
String price = priceEdit.getText().toString();
String pump = pumpEdit.getText().toString();
String tcost = costView.getText().toString();
String odometer = odometerEdit.getText().toString();
String fcon = fconView.getText().toString();
// Pass above values to the setter methods in POJO class
fuelLogPojo fuelLogPojoObj = new fuelLogPojo();
fuelLogPojoObj.setdate(date);
fuelLogPojoObj.setprice(price);
fuelLogPojoObj.setpump(pump);
fuelLogPojoObj.setcost(tcost);
fuelLogPojoObj.setodometer(odometer);
fuelLogPojoObj.setfcon(fcon);
// Add an undergraduate with his all details to a ArrayList
fuelLogArrayList.add(fuelLogPojoObj);
// Inserting undergraduate details to the database is doing in a separate method
insertLog(fuelLogPojoObj);
// Release from the existing UI and go back to the previous UI
finish();
}
}
private void insertLog(fuelLogPojo fuelLogPojoObj) {
// TODO Auto-generated method stub
// First we have to open our DbHelper class by creating a new object of that
AndroidOpenDbHelper androidOpenDbHelperObj = new AndroidOpenDbHelper(this);
// Then we need to get a writable SQLite database, because we are going to insert some values
// SQLiteDatabase has methods to create, delete, execute SQL commands, and perform other common database management tasks.
SQLiteDatabase sqliteDatabase = androidOpenDbHelperObj.getWritableDatabase();
// ContentValues class is used to store a set of values that the ContentResolver can process.
ContentValues contentValues = new ContentValues();
// Get values from the POJO class and passing them to the ContentValues class
contentValues.put(AndroidOpenDbHelper.KEY_DATE, fuelLogPojoObj.getdate());
contentValues.put(AndroidOpenDbHelper.KEY_PRICE, fuelLogPojoObj.getprice());
contentValues.put(AndroidOpenDbHelper.KEY_FUEL, fuelLogPojoObj.getpump());
contentValues.put(AndroidOpenDbHelper.KEY_COST, fuelLogPojoObj.getcost());
contentValues.put(AndroidOpenDbHelper.KEY_ODM, fuelLogPojoObj.getodometer());
contentValues.put(AndroidOpenDbHelper.KEY_CON, fuelLogPojoObj.getfcon());
// Now we can insert the data in to relevant table
// I am going pass the id value, which is going to change because of our insert method, to a long variable to show in Toast
long affectedColumnId = sqliteDatabase.insert(AndroidOpenDbHelper.TABLE_NAME_LOG, null, contentValues);
// It is a good practice to close the database connections after you have done with it
sqliteDatabase.close();
// I am not going to do the retrieve part in this post. So this is just a notification for satisfaction ;-)
Toast.makeText(this, "Values inserted column ID is :" + affectedColumnId, Toast.LENGTH_SHORT).show();
}
public static class DatePickerFragment extends DialogFragment
implements DatePickerDialog.OnDateSetListener {
public EditText editText;
DatePicker dpResult;
public Dialog onCreateDialog(Bundle savedInstanceState) {
// Use the current date as the default date in the picker
final Calendar c = Calendar.getInstance();
int year = c.get(Calendar.YEAR);
int month = c.get(Calendar.MONTH);
int day = c.get(Calendar.DAY_OF_MONTH);
//return new DatePickerDialog(getActivity(), (EditSessionActivity)getActivity(), year, month, day);
// Create a new instance of DatePickerDialog and return it
return new DatePickerDialog(getActivity(), this, year, month, day);
}
public void onDateSet(DatePicker view, int year, int month, int day) {
dateEdit.setText(String.valueOf(day) + "/"
+ String.valueOf(month + 1) + "/" + String.valueOf(year));
// set selected date into datepicker also
}}}
最佳答案
你还没有初始化你的按钮，你只在你的 Activity 中声明了它们
Button saveButton = null;
Button cancelButton = null;
稍后您需要在 onCreate() 方法中初始化它们，如下所示，
saveButton = (Button) findViewById ( your ID );
cancelButton = (Button) findViewById ( you ID );
然后需要添加OnClickListener
saveButton.setOnClickListener(this);
cancelButton.setOnClickListener(this);
关于android - 在 DDMS 中找不到数据库，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/21308632/