我正在尝试构建一个可设置多个闹钟的应用程序，并且我想使用 SQLite 数据库保存闹钟。已经为此看了很多教程，但在使用数据库时仍然遇到问题。首先，我想通过按下按钮一个一个地保存警报。我也尝试手动插入 2 个警报，但也没有用。我究竟做错了什么？我对此很陌生!
DBHelper 类
public class DBHelper extends SQLiteOpenHelper {
public static final String DATABASE_NAME = "MyDBName.db";
public static final String ALARMS_TABLE_NAME = "alarms";
public static final String ALARMS_COLUMN_ID = "id";
public static final String ALARMS_COLUMN_HOUR = "hour";
public static final String ALARMS_COLUMN_MINUTES = "minutes";
public DBHelper(Context context) {
super(context, DATABASE_NAME, null, 33);
}
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL("CREATE TABLE "+ALARMS_TABLE_NAME+" ("+ALARMS_COLUMN_ID+ " INTEGER PRIMARY KEY , "+
ALARMS_COLUMN_HOUR+ " INTEGER, "+ALARMS_COLUMN_MINUTES+" INTEGER)");
InsertAlarms(db);
}
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
db.execSQL("DROP TABLE IF EXISTS "+ALARMS_TABLE_NAME);
onCreate(db);
}
void AddAlarm(Alarm alarm)
{
SQLiteDatabase db= this.getWritableDatabase();
ContentValues cv=new ContentValues();
cv.put(ALARMS_COLUMN_HOUR, alarm.getHour());
cv.put(ALARMS_COLUMN_MINUTES, alarm.getMinutes());
db.insert(ALARMS_TABLE_NAME, null, cv);
db.close();
}
Cursor getAllAlarms()
{
SQLiteDatabase db=this.getWritableDatabase();
Cursor cur= db.rawQuery("SELECT * FROM "+ALARMS_TABLE_NAME,null);
return cur;
}
void InsertAlarms(SQLiteDatabase db) //insert manually 2 alarms
{
ContentValues cv=new ContentValues();
cv.put(ALARMS_COLUMN_ID, 1);
cv.put(ALARMS_COLUMN_HOUR, 20);
cv.put(ALARMS_COLUMN_MINUTES, 20);
db.insert(ALARMS_TABLE_NAME, null, cv);
cv.put(ALARMS_COLUMN_ID, 2);
cv.put(ALARMS_COLUMN_HOUR, 20);
cv.put(ALARMS_COLUMN_MINUTES, 20);
db.insert(ALARMS_TABLE_NAME, null, cv);
}
int getAlarmCount()
{
SQLiteDatabase db=this.getWritableDatabase();
Cursor cur= db.rawQuery("Select * from "+ALARMS_TABLE_NAME, null);
int x= cur.getCount();
cur.close();
return x;
}
类报警:
public class Alarm {
int _id;
int _hour;
int _minutes;
public Alarm(int Hour, int Minutes)
{
this._hour=Hour;
this._minutes=Minutes;
}
public int getID()
{
return this._id;
}
public void SetID(int ID)
{
this._id=ID;
}
public int getHour()
{
return this._hour;
}
public int getMinutes()
{
return this._minutes;
}
public void setHour(int Hour)
{
this._hour=Hour;
}
public void setMinutes(int Minutes)
{
this._minutes=Minutes;
}
Activity 添加警报
public class AddAlarm extends Activity {
EditText txtHour;
EditText txtMinutes;
DBHelper dbHelper;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_addalarm);
txtHour=(EditText)findViewById(R.id.txtHour);
txtMinutes=(EditText)findViewById(R.id.txtMinutes);
Button button1 = (Button)findViewById(R.id.addalarmbtn);
button1.setOnClickListener(new View.OnClickListener() {
public void onClick(View v){
btnAddAlarm_Click(v);
}
});
}
public void btnAddAlarm_Click(View view)
{
boolean ok=true;
try
{
int hour=Integer.parseInt(txtHour.getText().toString());
int minutes=Integer.parseInt(txtMinutes.getText().toString());
Alarm al=new Alarm(hour,minutes);
Toast.makeText(AddAlarm.this,"ADDED! ", Toast.LENGTH_LONG).show();
dbHelper.AddAlarm(al);
}
catch(Exception ex)
{
Toast.makeText(AddAlarm.this,"ERROR! ", Toast.LENGTH_LONG).show();
}
}
主要 Activity :
public class MainActivity extends AppCompatActivity {
Intent intent=getIntent();
DBHelper mydb;
TextView xupnitiria;
String hour;
public static boolean flag = false;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button button = (Button)findViewById(R.id.set_alarm_button);
//Bundle extras=intent.getExtras();
mydb=new DBHelper(this);
xupnitiria =(TextView)findViewById(R.id.xupnitiria);
xupnitiria.setText(xupnitiria.getText()+String.valueOf(mydb.getAlarmCount()));
button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v){
Intent a= new Intent(MainActivity.this, AddAlarm.class);
startActivity(a);
}
});
}
android Monitor 上的错误
10-04 15:07:26.592 2625-2625/com.google.android.gms E/ActivityThread: Service com.google.android.gms.chimera.GmsIntentOperationService has leaked ServiceConnection csk@8709fba that was originally bound here
android.app.ServiceConnectionLeaked: Service com.google.android.gms.chimera.GmsIntentOperationService has leaked ServiceConnection csk@8709fba that was originally bound here
at android.app.LoadedApk$ServiceDispatcher.<init>(LoadedApk.java:1336)
at android.app.LoadedApk.getServiceDispatcher(LoadedApk.java:1231)
at android.app.ContextImpl.bindServiceCommon(ContextImpl.java:1450)
at android.app.ContextImpl.bindService(ContextImpl.java:1422)
at android.content.ContextWrapper.bindService(ContextWrapper.java:636)
at android.content.ContextWrapper.bindService(ContextWrapper.java:636)
at android.content.ContextWrapper.bindService(ContextWrapper.java:636)
at android.content.ContextWrapper.bindService(ContextWrapper.java:636)
at com.google.android.gms.chimera.container.zapp.ZappLogOperation.onHandleIntent(:com.google.android.gms:0)
at com.google.android.chimera.IntentOperation.onHandleIntent(:com.google.android.gms:1)
at bvq.run(:com.google.android.gms:9)
at bvn.run(:com.google.android.gms:10)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
at java.lang.Thread.run(Thread.java:761)
最佳答案
在 AddAlarm.java 的 onCreate() 中添加:
dbHelper=new DBHelper(this);
还要在 logcat 中查看错误日志，在 try-catch block 中添加以下内容:
ex.printStackTrace();
添加警报 Activity :
public class AddAlarm extends Activity {
EditText txtHour;
EditText txtMinutes;
DBHelper dbHelper;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_addalarm);
txtHour = (EditText) findViewById(R.id.txtHour);
txtMinutes = (EditText) findViewById(R.id.txtMinutes);
dbHelper=new DBHelper(this);
Button button1 = (Button) findViewById(R.id.addalarmbtn);
button1.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
btnAddAlarm_Click(v);
}
});
}
public void btnAddAlarm_Click(View view) {
boolean ok = true;
try {
int hour = Integer.parseInt(txtHour.getText().toString());
int minutes = Integer.parseInt(txtMinutes.getText().toString());
Alarm al = new Alarm(hour, minutes);
Toast.makeText(AddAlarm.this, "ADDED! ", Toast.LENGTH_LONG).show();
dbHelper.AddAlarm(al);
} catch (Exception ex) {
Toast.makeText(AddAlarm.this, "ERROR! ", Toast.LENGTH_LONG).show();
ex.printStackTrace();
}
}
}
关于java - Android 应用程序上的 SQLite 错误，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/46568105/