问题：
Android Studio：我正在尝试更改共享首选项，并希望将数据存储在SQLite数据库中
安建木
我是Java编程的新手。
现在，我面临的问题是，我想要更改共享的首选项，并且想要使用SQLite数据库来存储这些数据。我已经创建了一个表来存储这些数据，名称为Register table，但我不知道如何更改。
我该怎么办？有人能帮我吗？？？？
这是我的代码：
public class Login extends AppCompatActivity {
InputStream inputStream;
ACDatabase db;
SharedPreferences prefs;
ActivityLoginBinding binding;
AC_Class.Connection connection;
AC_Class.Register reg;
String versionNo;
String url;
String urlStr;
String id;
String pwd;
private static String uniqueID = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
binding = DataBindingUtil.setContentView(this, R.layout.activity_login);
getSupportActionBar().hide();
// Placeholder
versionNo = "3.1.6";
reg = new AC_Class.Register();
connection = new AC_Class.Connection();
binding.setConSettings(connection);
db = new ACDatabase(this);
// Check preferences/create if nonexistent
prefs = this.getSharedPreferences("com.presoft.androidmobilestock", Context.MODE_PRIVATE);
uniqueID = prefs.getString("UUID", null);
if (uniqueID == null)
{
uniqueID = UUID.randomUUID().toString();
//uniqueID = "3FDE9813F93A47CBA6CD4F5DAAECEE01";
prefs.edit().putString("UUID", uniqueID).commit();
}
binding.lblUUID.setText(uniqueID);
binding.lblVersion.setText(versionNo);
if (prefs.getString("ID", id) != null) {
binding.rmbCheckBox.setChecked(true);
url = prefs.getString("URL", url);
binding.txtURL.setText(prefs.getString("URLstr", urlStr));
binding.txtID.setText(prefs.getString("ID", id));
binding.txtpw.setText(prefs.getString("pwd", pwd));
}
if (prefs.getString("Default_curr", null) == null) {
prefs.edit().putString("Default_curr", "RM").apply();
}
if (prefs.getString("Default_loc", null) == null) {
Cursor tempCursor = db.getLocation();
if (tempCursor.moveToNext()) {
prefs.edit().putString("Default_loc", tempCursor
.getString(tempCursor.getColumnIndex("Location"))).apply();
}
}
// Version number
if (prefs.getString("Version ", null) == null) {
prefs.edit().putString("Version", versionNo).apply();
}
// Tax Inclusive
if (!prefs.getBoolean("taxInclusive", false)) {
prefs.edit().putBoolean("taxInclusive", false).apply();
}
if (Build.MODEL.equals("HC720"))
{
Snackbar.make(findViewById(android.R.id.content), "RFID Detected.", Snackbar.LENGTH_SHORT).show();
}
}
@Override
public void onBackPressed() {
finish();
}
//On return of intent
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == 7) {
url = data.getStringExtra("URLKey");
urlStr = data.getStringExtra("URLStr");
Log.i("custDebug", url + ", " + urlStr);
binding.txtURL.setText(urlStr);
if (!TextUtils.isEmpty(binding.txtURL.getText().toString())) {
new GetModules(Login.this).execute(url);
new GetLoginList(Login.this).execute(url);
new SetDevice(Login.this).execute(url);
}
}
}
//Open connection settings
public void btnSetClicked(View view) {
Intent intent = new Intent(Login.this, ConnectionSettings.class);
startActivityForResult(intent, 7);
}
//Reset Database
public void btnResetDbClicked(final View view) {
final AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("Reset DB");
builder.setMessage("Are you sure you want to reset the Database?");
final EditText input = new EditText(this);
input.setInputType(InputType.TYPE_CLASS_TEXT | InputType.TYPE_TEXT_VARIATION_PASSWORD);
builder.setView(input);
builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
if (input.getText().toString().equals("presoftmobile")) {
db.close();
deleteDatabase("AutoCountDatabase");
} else {
// Toast.makeText(getApplicationContext(), "Incorrect Password", Toast.LENGTH_SHORT);
}
}
});
builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
builder.show();
}
//Login button
public void btnLoginBtnClicked(View view) {
if (TextUtils.isEmpty(binding.txtURL.getText().toString())) {
binding.txtURL.setError("This field can't be blank.");
//return;
}
if (TextUtils.isEmpty(binding.txtID.getText().toString())) {
binding.txtID.setError("This field can't be blank.");
//return;
}
if (TextUtils.isEmpty(binding.txtpw.getText().toString())) {
binding.txtpw.setError("This field can't be blank.");
//return;
}
//Non-empty fields
else {
Cursor checkData = db.loginValidate(binding.txtID.getText().toString(),
binding.txtpw.getText().toString().toUpperCase());
if (checkData.getCount() > 0) {
checkData.moveToNext();
//Shared Preferences
prefs.edit().putString("URL", url).apply();
prefs.edit().putString("URLstr", binding.txtURL.getText().toString()).apply();
if (binding.rmbCheckBox.isChecked()) {
prefs.edit().putString("ID", binding.txtID.getText().toString()).apply();
prefs.edit().putString("pwd", binding.txtpw.getText().toString()).apply();
}
prefs.edit().putInt("EnableSetting", checkData.getInt(checkData.getColumnIndex("EnableSetting"))).apply();
prefs.edit().putInt("FilterByAgent", checkData.getInt(checkData.getColumnIndex("FilterByAgent"))).apply();
prefs.edit().putInt("Sales", checkData.getInt(checkData.getColumnIndex("Sales"))).apply();
prefs.edit().putInt("Purchase", checkData.getInt(checkData.getColumnIndex("Purchase"))).apply();
prefs.edit().putInt("Transfer", checkData.getInt(checkData.getColumnIndex("Transfer"))).apply();
if (url != null) {
try {
// Check Connection
new SetDevice(Login.this).execute(url);
// Go to main
Intent intent = new Intent(Login.this, Dashboard.class);
intent.putExtra("URLKey", url);
intent.putExtra("URLStr", binding.txtURL.getText().toString());
startActivity(intent);
finish();
} catch (Exception e) {
Log.i("custDebug", e.getMessage());
Toast.makeText(this, "Unable to connect to server", Toast.LENGTH_SHORT).show();
}
}
} else {
Toast.makeText(this, "Invalid login credentials", Toast.LENGTH_SHORT).show();
binding.txtpw.setText(null);
}
checkData.close();
}
}
共有1个答案
陆浩博
下面是一个工作示例，它的操作与共享偏好非常相似，但将偏好存储在SQLite数据库中。
该表非常简单，有2列。键（存储值的名称）和值本身。可以是String、boolean、int、long或float。
它包括以下方法；插入（添加）键/值对，更新键/值对，根据键获取值，并返回传递的默认值（使其易于检测是否检索到值）。
DatabaseHelper（SQLiteOpenHelper的子类）拥有大部分代码，它是：-
class DBHelper extends SQLiteOpenHelper {
private static volatile DBHelper instance = null;
private SQLiteDatabase db = null;
public static final String DBNAME = "sharedpreferences.db";
public static final int DBVERSION = 1;
public static final String TBLNAME_SP = "_shared_preferences";
public static final String COLNAME_SP_KEY = "_key";
public static final String COLNAME_SP_VALUE = "_value";
private DBHelper(@Nullable Context context) {
super(context, DBNAME, null, DBVERSION);
db = this.getWritableDatabase();
}
public static DBHelper getInstance(Context context) {
if (instance == null) {
instance = new DBHelper(context);
}
return instance;
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE IF NOT EXISTS " + TBLNAME_SP +
"(" +
COLNAME_SP_KEY + " PRIMARY KEY," +
COLNAME_SP_VALUE + " TEXT" +
")");
}
@Override
public void onUpgrade(SQLiteDatabase db, int i, int i1) {
}
private long insertPrefsRow(ContentValues cv, String key) {
cv.put(COLNAME_SP_KEY,key);
return db.insertWithOnConflict(TBLNAME_SP,null,cv, SQLiteDatabase.CONFLICT_IGNORE);
}
public long insertPrefsValue (String key, int value) {
ContentValues cv = new ContentValues();
cv.put(COLNAME_SP_VALUE,value);
return insertPrefsRow(cv,key);
}
public long insertPrefsValue (String key, String value) {
ContentValues cv = new ContentValues();
cv.put(COLNAME_SP_VALUE,value);
return insertPrefsRow(cv,key);
}
public long insertPrefsValue (String key, long value) {
ContentValues cv = new ContentValues();
cv.put(COLNAME_SP_VALUE,value);
return insertPrefsRow(cv,key);
}
public long insertPrefsValue (String key, boolean value) {
ContentValues cv = new ContentValues();
cv.put(COLNAME_SP_VALUE,value);
return insertPrefsRow(cv,key);
}
public long insertPrefsValue (String key, float value) {
ContentValues cv = new ContentValues();
cv.put(COLNAME_SP_VALUE,value);
return insertPrefsRow(cv,key);
}
private long updatePrefs(String key, ContentValues cv) {
return db.update(TBLNAME_SP,cv,COLNAME_SP_KEY + "=?",new String[]{key} );
}
public long updatePrefsStringValue(String key, String newValue) {
ContentValues cv = new ContentValues();
cv.put(COLNAME_SP_VALUE,newValue);
return updatePrefs(key,cv);
}
public long updatePrefsStringValue(String key, boolean newValue) {
ContentValues cv = new ContentValues();
cv.put(COLNAME_SP_VALUE,newValue);
return updatePrefs(key,cv);
}
public long updatePrefsStringValue(String key, int newValue) {
ContentValues cv = new ContentValues();
cv.put(COLNAME_SP_VALUE,newValue);
return updatePrefs(key,cv);
}
public long updatePrefsStringValue(String key, long newValue) {
ContentValues cv = new ContentValues();
cv.put(COLNAME_SP_VALUE,newValue);
return updatePrefs(key,cv);
}
public long updatePrefsStringValue(String key, Float newValue) {
ContentValues cv = new ContentValues();
cv.put(COLNAME_SP_VALUE,newValue);
return updatePrefs(key,cv);
}
private Cursor getPrefsValue(String key) {
return db.query(TBLNAME_SP,new String[]{COLNAME_SP_VALUE},COLNAME_SP_KEY + "=?",new String[]{key},null,null,null);
}
public String getPrefsStringValue(String key, String default_value) {
String rv = default_value;
Cursor csr;
if ((csr = getPrefsValue(key)).moveToFirst()) {
rv = csr.getString(csr.getColumnIndex(COLNAME_SP_VALUE));
csr.close();
}
return rv;
}
public Boolean getPrefsBooleanValue(String key, boolean default_value ) {
Boolean rv = default_value;
Cursor csr;
if ((csr = getPrefsValue(key)).moveToFirst()) {
rv = csr.getInt(csr.getColumnIndex(COLNAME_SP_VALUE)) != 0;
csr.close();
}
return rv;
}
public int getPrefsIntValue(String key, int default_value) {
int rv = default_value;
Cursor csr;
if ((csr = getPrefsValue(key)).moveToFirst()) {
rv = csr.getInt(csr.getColumnIndex(COLNAME_SP_VALUE));
csr.close();
}
return rv;
}
public long getPrefsLongValue(String key, long default_value) {
long rv = default_value;
Cursor csr;
if ((csr = getPrefsValue(key)).moveToFirst()) {
rv = csr.getLong(csr.getColumnIndex(COLNAME_SP_VALUE));
csr.close();
}
return rv;
}
public Float getPrefsFLoatValue(String key, Float default_value) {
Float rv = default_value;
Cursor csr;
if ((csr = getPrefsValue(key)).moveToFirst()) {
rv = csr.getFloat(csr.getColumnIndex(COLNAME_SP_VALUE));
csr.close();
}
return rv;
}
}
下面是演示用法的活动：-
public class MainActivity extends AppCompatActivity {
DBHelper db;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
db = DBHelper.getInstance(this);
db.insertPrefsValue("UUID","3FDE9813F93A47CBA6CD4F5DAAECEE01");
db.insertPrefsValue("taxInclusive",false);
db.insertPrefsValue("myprefs_int",100);
db.insertPrefsValue("myprefs_long",100L);
db.insertPrefsValue("myprefs_float",10.567F);
Log.d("PREFSINFO",
"Stored UUID is " + db.getPrefsStringValue("UUID","000000000000000000000000") +
" Stored taxinclusive is " + db.getPrefsBooleanValue("taxInclusive",true) +
" Stored mpint is " + db.getPrefsIntValue("myprefs_int",-99) +
" Stored mplong is " + db.getPrefsLongValue("myprefs_long",-99999999) +
" Stored mpfloat is " + db.getPrefsFLoatValue("myprefs_float",-999999.999999F) +
" NOT STORED is " + db.getPrefsFLoatValue("NOT A SET KEY",-3333.3333F)
);
db.updatePrefsStringValue("UUID","FFFF9813F93A47CBA6CD4F5DAAECEE01");
Log.d("PREFSINFO",
"Stored UUID is " + db.getPrefsStringValue("UUID","000000000000000000000000") +
" Stored taxinclusive is " + db.getPrefsBooleanValue("taxInclusive",true) +
" Stored mpint is " + db.getPrefsIntValue("myprefs_int",-99) +
" Stored mplong is " + db.getPrefsLongValue("myprefs_long",-99999999) +
" Stored mpfloat is " + db.getPrefsFLoatValue("myprefs_float",-999999.999999F) +
" NOT STORED is " + db.getPrefsFLoatValue("NOT A SET KEY",-3333.3333F)
);
}
}
运行时（或重新运行，但重新运行时检索的是更新的UUID，而不是原始的UUID)，日志包含：-
D/PREFSINFO: Stored UUID is 3FDE9813F93A47CBA6CD4F5DAAECEE01 Stored taxinclusive is false Stored mpint is 100 Stored mplong is 100 Stored mpfloat is 10.567 NOT STORED is -3333.3333
D/PREFSINFO: Stored UUID is FFFF9813F93A47CBA6CD4F5DAAECEE01 Stored taxinclusive is false Stored mpint is 100 Stored mplong is 100 Stored mpfloat is 10.567 NOT STORED is -3333.3333
-
null
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