MainActivity类。
公共类MainActivity扩展了Activity {
EditText etName, etEmail, etPhone, etDesignation;
DatabaseHelper dbHelper;
// declare view
ListView lvEmployees;
// declare adapter
CustomizedAdapter adapter;
Employee employee;
// datasource
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
etName = (EditText) findViewById(R.id.etName);
lvEmployees = (ListView) findViewById(R.id.lvEmployees);
dbHelper = new DatabaseHelper(this);
Employee employee;
}
public void save(View v) {
String name = etName.getText().toString();
SimpleDateFormat sm = new SimpleDateFormat("dd/MM/yyyy hh:mm:ss a");
Date today = Calendar.getInstance().getTime();
String reportDate = sm.format(today);
Employee employee = new Employee(name, reportDate);
Toast.makeText(getApplicationContext(), employee.toString(),
Toast.LENGTH_LONG).show();
long inserted = dbHelper.insertEmployee(employee);
if (inserted >= 0) {
Toast.makeText(getApplicationContext(), "Data inserted",
Toast.LENGTH_LONG).show();
} else {
Toast.makeText(getApplicationContext(), "Data insertion failed...",
Toast.LENGTH_LONG).show();
}
}
public void view(View v) {
ArrayList<Employee> employees = dbHelper.getAllEmployees();
if (employees != null && employees.size() > 0) {
adapter = new CustomizedAdapter(this, employees);
lvEmployees.setAdapter(adapter);
}
}
}
这是我的DataBasehelper
公共类DatabaseHelper扩展了SQLiteOpenHelper {
public static final String DB_NAME = "task_management";
public static final int DB_VERSION = 1;
public static final String EMPLOYEE_TABLE = "employee";
public static final String ID_FIELD = "_id";
public static final String NAME_FIELD = "name";
public static final String TIME_DATE = "time_date";
public static final String EMPLOYEE_TABLE_SQL = "CREATE TABLE "
+ EMPLOYEE_TABLE + " (" + ID_FIELD + " INTEGER PRIMARY KEY, "
+ NAME_FIELD + " TEXT, " + TIME_DATE + " DATETIME);";
public DatabaseHelper(Context context) {
super(context, DB_NAME, null, DB_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
// create tables
db.execSQL(EMPLOYEE_TABLE_SQL);
Log.e("TABLE CREATE", EMPLOYEE_TABLE_SQL);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// upgrade logic
}
// insert
public long insertEmployee(Employee emp) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(NAME_FIELD, emp.getName());
SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy hh:mm:ss a");
String date = sdf.format(emp.getDate());
values.put(TIME_DATE, date);
long inserted = db.insert(EMPLOYEE_TABLE, null, values);
db.close();
return inserted;
}
// query
public ArrayList<Employee> getAllEmployees() {
ArrayList<Employee> allEmployees = new ArrayList<Employee>();
SQLiteDatabase db = this.getReadableDatabase();
// String[] columns={NAME_FIELD, EMAIL_FIELD, PHONE_FIELD};
// SELECT * FROM EMPLOYEE;
Cursor cursor = db.query(EMPLOYEE_TABLE, null, null, null, null, null,
null);
// Cursor cursor = db.rawQuery("SELECT * FROM EMPLOYEE", null);
if (cursor != null && cursor.getCount() > 0) {
cursor.moveToFirst();
for (int i = 0; i < cursor.getCount(); i++) {
//
int id = cursor.getInt(cursor.getColumnIndex(ID_FIELD));
String name = cursor.getString(cursor
.getColumnIndex(NAME_FIELD));
String datetime = cursor.getString(cursor
.getColumnIndex(TIME_DATE));
Employee e = new Employee(name, datetime);
allEmployees.add(e);
cursor.moveToNext();
}
}
cursor.close();
db.close();
return allEmployees;
}
}
自定义适配器..
公共类CustomizedAdapter扩展了ArrayAdapter {
Activity con;
ArrayList<Employee> employeeList;
Employee employee;
public CustomizedAdapter(Context context, ArrayList<Employee> employees) {
super(context, R.layout.list_item, employees);
this.con = (Activity) context;
this.employeeList = employees;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View v = null;
if (convertView == null) {
// generate a view and return
LayoutInflater inflater = con.getLayoutInflater();
v = inflater.inflate(R.layout.list_item, null);
TextView txtName = (TextView) v.findViewById(R.id.txtName);
TextView datee = (TextView) v.findViewById(R.id.txtEmail);
Employee e = employeeList.get(position);
Date date = e.getDate();
// Date date = e.get(position).getWishDate();
datee.setText(DateFormat.format("dd/MM/yyyy hh:mm:ss a", date));
txtName.setText(e.getName());
datee.setText(e.getDatetime());
} else {
v = convertView;
}
return v;
}
}
这是LogCat：
09-27 16:11:35.374: E/AndroidRuntime(32300): FATAL EXCEPTION: main
09-27 16:11:35.374: E/AndroidRuntime(32300): java.lang.IllegalStateException: Could not execute method of the activity
09-27 16:11:35.374: E/AndroidRuntime(32300): at android.view.View$1.onClick(View.java:3609)
09-27 16:11:35.374: E/AndroidRuntime(32300): at android.view.View.performClick(View.java:4102)
09-27 16:11:35.374: E/AndroidRuntime(32300): at android.view.View$PerformClick.run(View.java:17085)
09-27 16:11:35.374: E/AndroidRuntime(32300): at android.os.Handler.handleCallback(Handler.java:615)
09-27 16:11:35.374: E/AndroidRuntime(32300): at android.os.Handler.dispatchMessage(Handler.java:92)
09-27 16:11:35.374: E/AndroidRuntime(32300): at android.os.Looper.loop(Looper.java:155)
09-27 16:11:35.374: E/AndroidRuntime(32300): at
android.app.ActivityThread.main(ActivityThread.java:5511)
09-27 16:11:35.374: E/AndroidRuntime(32300): at java.lang.reflect.Method.invokeNative(Native Method)
09-27 16:11:35.374: E/AndroidRuntime(32300): at java.lang.reflect.Method.i
nvoke(Method.java:511)
09-27 16:11:35.374: E/AndroidRuntime(32300): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1029)
09-27 16:11:35.374: E/AndroidRuntime(32300): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:796)
09-27 16:11:35.374: E/AndroidRuntime(32300): at dalvik.system.NativeStart.main(Native Method)
09-27 16:11:35.374: E/AndroidRuntime(32300): Caused by: java.lang.reflect.InvocationTargetException
09-27 16:11:35.374: E/AndroidRuntime(32300): at java.lang.reflect.Method.invokeNative(Native Method)
09-27 16:11:35.374: E/AndroidRuntime(32300): at java.lang.reflect.Method.invoke(Method.java:511)
09-27 16:11:35.374: E/AndroidRuntime(32300): at android.view.View$1.onClick(View.java:3604)
09-27 16:11:35.374: E/AndroidRuntime(32300): ... 11 more
09-27 16:11:35.374: E/AndroidRuntime(32300): Caused by: java.lang.NullPointerException
09-27 16:11:35.374: E/AndroidRuntime(32300): at java.util.Calendar.setTime(Calendar.java:1324)
09-27 16:11:35.374: E/AndroidRuntime(32300): at
java.text.SimpleDateFormat.formatImpl(SimpleDateFormat.java:536)
09-27 16:11:35.374: E/AndroidRuntime(32300): at java.text.SimpleDateFormat.format(SimpleDateFormat.java:821)
09-27 16:11:35.374: E/AndroidRuntime(32300): at java.text.DateFormat.format(DateFormat.java:376)
09-27 16:11:35.374: E/AndroidRuntime(32300): at
com.shikkhok.taskmanagement.DatabaseHelper.insertEmployee(DatabaseHelper.java:51)
09-27 16:11:35.374: E/AndroidRuntime(32300): at
com.shikkhok.taskmanagement.MainActivity.save(MainActivity.java:48)
09-27 16:11:35.374: E/AndroidRuntime(32300): ... 14 more
09-27 16:11:35.394: E/EmbeddedLogger(426): App crashed! Process: com.shikkhok.taskmanagement
09-27 16:11:35.394: E/EmbeddedLogger(426): App crashed! Package: com.shikkhok.taskmanagement v1 (1.0)
09-27 16:11:35.394: E/EmbeddedLogger(426): Application Label: My Task Management
09-27 16:11:36.124: E/Trace(32345): error opening trace file: No such file or directory (2)
我想将当前时间和日期显示在ListView中，并希望将其保存到数据库中。 我想选择日期和时间，并希望将其保存为我的Sqlite数据库中的String。 当我想保存我的约会时，应用程序就会停止。 那怎么解决呢？
答案 0 :(得分：0)
format()类中的方法SimpleDateFromat获取Date值并返回一个字符串。就像你在这里一样：
Date today = Calendar.getInstance().getTime();
String reportDate = sm.format(today);
Employee employee = new Employee(name, reportDate);
所以emp.getDate()返回一个字符串，当你说：
String date = sdf.format(emp.getDate());
实际上，您正在转换的字符串值不是Date值。
你有两种方法。如果您想真正将Date值添加到您的表格中（我不确定Sqlite支持此项），您应该使用此：
values.put(NAME_FIELD, emp.getName());
SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy hh:mm:ss a");
Date date = sdf.parse(emp.getDate());
values.put(TIME_DATE, date);
long inserted = db.insert(EMPLOYEE_TABLE, null, values);
另一种方法是将列类型从DATETIME更改为TEXT：
public static final String EMPLOYEE_TABLE_SQL = "CREATE TABLE "
+ EMPLOYEE_TABLE + " (" + ID_FIELD + " INTEGER PRIMARY KEY, "
+ NAME_FIELD + " TEXT, " + TIME_DATE + " TEXT);";
完成此更改后，您可以轻松使用此功能：
values.put(NAME_FIELD, emp.getName());
values.put(TIME_DATE, emp.getDate());
long inserted = db.insert(EMPLOYEE_TABLE, null, values);
我希望这可以帮到你。