我是Android开发人员的新手，目前正在制作我的第一个应用程序，应该给我第一次点击按钮和第二次点击按钮之间的时间并将其保存到当前选定的客户。（我知道已经有很多那些应用程序，但由于我仍在学习并想要一个对我自己有用的应用程序我决定尝试[IMG]）
解决问题：
当我的应用程序启动时，在主活动中我调用一个方法，该方法从数据库中请求我的所有“客户”并将它们存储在列表中。 我用这个列表来显示ListView和微调器中的客户。 微调器也在主要活动onCreate（）中创建。所以在我从数据库中获取数据后，我想用这些数据填充微调器。但它不起作用，在启动应用程序时显示数据。
什么都不起作用：
在应用中添加新客户时，客户将保存到数据库中。 然后我必须打开我的ListView（按钮：Kundenübersicht）两次，直到显示新客户。之后，数据也在微调器中可见。
继承我的代码：
MainActivity（ZeitErfassen）
public class ZeitErfassen extends AppCompatActivity {
public static LinkedList<Kunde> kunden = new LinkedList<Kunde>();
boolean running = false;
long startTime,endTime,totalTime;
private SharedPreferences app_preferences;
private SharedPreferences.Editor editor;
private TextView displayTime;
public Button startEndButton;
private ArrayAdapter<String> adapter;
private Spinner spinner;
public static Kunde selectedCustomer;
private static int numberOfCustomers = -1;
static final int AddCustomer_REQUEST = 1; // REQUEST CODE FOR CALLING list after update
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_zeit_erfassen);
//Einstellungen laden
app_preferences = getApplicationContext().getSharedPreferences("MyPref", MODE_PRIVATE);
startTime= app_preferences.getLong("startTime", 0);
endTime = app_preferences.getLong("endTime", 0);
running = app_preferences.getBoolean("running", false);
displayTime = (TextView)findViewById(R.id.zeit_bei_Kunde);
displayTime.setText((CharSequence) app_preferences.getString("zeitAnzeige", "Zeit bei Kunde"));
startEndButton = (Button)findViewById(R.id.start_Timer);
startEndButton.setText((CharSequence) app_preferences.getString("timerButton", "Start Timer"));
editor = app_preferences.edit();
editor.commit();
}
public void onDestroy() {
super.onDestroy();
editor.putLong("startTime", startTime);
editor.putString("zeitAnzeige", (String) displayTime.getText());
editor.putString("timerButton", (String) startEndButton.getText());
editor.putLong("endTime", endTime);
editor.putLong("totalTime", totalTime);
editor.putBoolean("running", app_preferences.getBoolean("running", false));
editor.commit();
this.finish();
}
public void onStart() {
super.onStart();
DatabaseHelper.customerFromDatabaseToList(this);
createDropDown();
numberOfCustomers= kunden.size();
}
public void onResume() {
super.onResume();
DatabaseHelper.customerFromDatabaseToList(this);
createDropDown();
numberOfCustomers = kunden.size();
}
public void startTimer(View view) {
editor = app_preferences.edit();
if(running == false) {
startTime = getTime();
running = true;
editor.putLong("startTime", startTime);
startEndButton.setText("End Timer");
displayTime.setText("Zeitstoppung läuft");
editor.putString("zeitAnzeige", (String) displayTime.getText());
editor.putString("timerButton", (String) startEndButton.getText());
editor.putBoolean("running", true);
editor.commit();
} else {
setSelectedCustomer();
endTime = getTime();
editor.putLong("endTime",endTime);
totalTime = endTime - startTime;
editor.putLong("totalTime", totalTime);
displayTime.setText(formatTime(totalTime));
editor.putString("zeitAnzeige", (String) displayTime.getText());
startEndButton.setText("Start Timer");
editor.putString("timerButton", (String) startEndButton.getText());
running = false;
editor.putBoolean("running", false);
editor.commit();
DatabaseHelper.timeToDatabase(String.valueOf(selectedCustomer.getId()),formatTime(totalTime),this);
// selectedCustomer.saveTimeToCustomer(selectedCustomer, formatTimeForCustomer(totalTime));
}
}
public String formatTime(Long totalTime) {
int hours = (int) ((totalTime / (1000*60*60)) % 24);
int minutes = (int) ((totalTime / (1000*60)) % 60);
int seconds = (int) (totalTime / 1000) % 60;
String time = (String.valueOf(hours) + ":" + String.valueOf(minutes) + ":" + String.valueOf(seconds));
return time;
}
public String formatTimeForCustomer(Long totalTime) {
StringBuilder time = new StringBuilder();
Calendar cal = Calendar.getInstance();
int year = cal.get(Calendar.YEAR);
int month = cal.get(Calendar.MONTH);
int day = cal.get(Calendar.DAY_OF_MONTH);
time.append((String.valueOf(year) + "." + String.valueOf(month) + "." + String.valueOf(day))).append(formatTime(totalTime));
return time.toString();
}
public void neuerKunde(View view) {
Intent intent = new Intent(this, AddKunde.class);
startActivityForResult(intent, AddCustomer_REQUEST);
}
public void kundenÜbersicht(View view) {
// setSelectedCustomer();
Intent intent = new Intent(this, DisplayCustomer.class);
startActivity(intent);
}
public long getTime() {
long millis = System.currentTimeMillis();
return millis;
}
public void setSelectedCustomer() {
if(kunden.size() > 0) {
if (spinner.getSelectedItem().toString() != null) {
String tempCustomer = spinner.getSelectedItem().toString();
for (Kunde k : kunden) {
if (k.getName().equals(tempCustomer)) {
selectedCustomer = k;
}
}
}
}
}
public void createDropDown() {
if (kunden.size() > 0) {
spinner = (Spinner) findViewById(R.id.chooseCustomer);
// Create an ArrayAdapter using the string array and a default spinner layout
adapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, DisplayCustomer.namesOfCustomers());
// Specify the layout to use when the list of choices appears
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
// Apply the adapter to the spinner
spinner.setAdapter(adapter);
}
}
public void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == AddCustomer_REQUEST) {
if(resultCode == Activity.RESULT_OK){
DatabaseHelper.customerFromDatabaseToList(getApplicationContext());
//adapter.notifyDataSetChanged();
}
if (resultCode == Activity.RESULT_CANCELED) {
//Write your code if there's no result
}
}
}//onActivityResult
}
DatabaseHelper Class
public class DatabaseHelper {
public static RequestQueue requestQueue;
public static final String host = "http://192.168.150.238/";
public static final String insertUrl = host+"insertCustomer.php";
public static final String showUrl = host+"showCustomer.php";
public static final String insertTimeUrl = host+"insertTime.php";
public static final String showTimeUrl = host+"showTimes.php";
public static void customerFromDatabaseToList(final Context context) {
//Display customer from database
requestQueue = Volley.newRequestQueue(context);
final ArrayList<String> customerNames = new ArrayList<>();
JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.POST, showUrl, new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
try {
JSONArray customers = response.getJSONArray("customers");
if(customers.length() > 0) {
for (int i = 0; i < customers.length(); i++) {
JSONObject customer = customers.getJSONObject(i);
String customerName = customer.getString("cus_name");
String customerAddress = customer.getString("cus_address");
int customerID = Integer.valueOf(customer.getString("cus_id"));
if (customerName != null && customerAddress != null) {
try {
Kunde k = new Kunde(customerName, customerAddress, customerID);
if (!listContainsObject(k)) {
ZeitErfassen.kunden.add(k);
}
} catch (Exception e) {
Toast.makeText(context, "Fehler in customerFromDatabaseToListn!Code:X1", Toast.LENGTH_SHORT).show();
}
} else {
Toast.makeText(context,"Fehler in customerFromDatabaseToListn!Code:X2", Toast.LENGTH_SHORT).show();
}
}
}
} catch (JSONException e) {
Toast.makeText(context,"Fehler bei holen der Daten!Code:X3",Toast.LENGTH_SHORT).show();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(context,"Fehler beim holen der Daten!Code:X4",Toast.LENGTH_SHORT).show();
}
});
requestQueue.add(jsonObjectRequest);
}
public static boolean listContainsObject(Kunde cust) {
for(Kunde k : ZeitErfassen.kunden) {
if((k.getId() >0 )&& (k.getId() == cust.getId())) {
return true;
}
}
return false;
}
public static void timeToDatabase(final String customer_id, final String time_value, final Context context) {
requestQueue = Volley.newRequestQueue(context);
StringRequest request = new StringRequest(Request.Method.POST, DatabaseHelper.insertTimeUrl, new Response.Listener<String>() {
@Override
public void onResponse(String response) {
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(context,"Fehler beim holen der Daten!Code:X5",Toast.LENGTH_SHORT).show();
}
}) {
@Override
protected Map<String, String> getParams() throws AuthFailureError {
Map<String,String> parameters = new HashMap<String,String>();
parameters.put("customerid",customer_id);
parameters.put("timevalue",time_value);
return parameters;
}
};
requestQueue.add(request);
};
public static ArrayList<String> timesFromDataBaseToList(final Context context,final int customer_id) {
requestQueue = Volley.newRequestQueue(context);
final String cus_id = String.valueOf(customer_id) ;
final ArrayList<String> customerTimes = new ArrayList<>();
StringRequest jsonObjectRequest = new StringRequest(Request.Method.POST, showTimeUrl, new Response.Listener<String>() {
@Override
public void onResponse(String response) {
try {
JSONObject object = new JSONObject(response.toString());
JSONArray times = object.getJSONArray("customertimes");
if (times.length() > 0) {
for (int i = 0; i < times.length(); i++) {
JSONObject jsonObject = times.getJSONObject(i);
String timeValue = jsonObject.getString("time_value");
if (timeValue != null) {
customerTimes.add(timeValue);
}
}
}
} catch (JSONException e) {
Toast.makeText(context,"Fehler beim holen der Daten!Code:X6",Toast.LENGTH_SHORT).show();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(context,"Fehler beim Holen der Zeiten, keine Verbindung zur Datenbank!Code: X7",Toast.LENGTH_LONG).show();
error.printStackTrace();
}
}){
protected Map<String, String> getParams() throws AuthFailureError {
Map<String,String> parameters = new HashMap<String,String>();
parameters.put("cus_id",cus_id);
return parameters;
}
};
requestQueue.add(jsonObjectRequest);
return customerTimes;
};
}
DisplayCustomers /我在列表中显示客户的位置
public class DisplayCustomer extends AppCompatActivity {
CustomerAdapter customerAdapter;
public ArrayAdapter<String> adapterCustomerView;
private ListView listCustomerView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_display_customer);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
ArrayList<Kunde> customerList = getCustomerObjects();
customerAdapter = new CustomerAdapter(this,customerList);
listCustomerView = (ListView)findViewById(R.id.list_View_Customers);
// adapterCustomerView = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, namesOfCustomers());
listCustomerView.setAdapter(customerAdapter);
openCustomerDetails();
}
public static ArrayList<String> namesOfCustomers() {
ArrayList<String> customerNames = new ArrayList<>();
if(ZeitErfassen.kunden.size() > 0 ) {
for (Kunde k : ZeitErfassen.kunden) {
customerNames.add(k.getName());
}
}
return customerNames;
}
public static ArrayList<Kunde> getCustomerObjects() {
ArrayList<Kunde> customerList = new ArrayList<>();
if(ZeitErfassen.kunden.size() > 0 ) {
for (Kunde k : ZeitErfassen.kunden) {
customerList.add(k);
}
}
return customerList;
}
public void openCustomerDetails() {
listCustomerView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Kunde kunde = new Kunde();
kunde = (Kunde)listCustomerView.getItemAtPosition(position);
Intent intent = new Intent(DisplayCustomer.this, DisplayDetailedCustomer.class);
intent.putExtra("selectedCustomerObject",(Parcelable)kunde);
startActivity(intent);
}
});
}
}
AddKunde / Class用于添加客户
public class AddKunde extends AppCompatActivity {
public RequestQueue requestQueue;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add_kunde);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
}
public void addKunde(View view) throws Exception {
try {
EditText nameField = (EditText) findViewById(R.id.customerName);
String name = nameField.getText().toString();
EditText addressField = (EditText) findViewById(R.id.addressField);
String address = addressField.getText().toString();
if(TextUtils.isEmpty(name)){
nameField.setError("Ungültiger Name!");
return;
} else if(TextUtils.isEmpty(address)){
addressField.setError("Ungültige Adresse");
return;
} else {
try {
customerToDatabase(name, address);
Kunde customer = new Kunde(name, address);
Intent returnIntent = new Intent();
returnIntent.putExtra("kunde",customer);
setResult(Activity.RESULT_OK, returnIntent);
} catch (VolleyError e) {
Toast.makeText(this,"Fehler: Keine Verbindung zur Datenbank!",Toast.LENGTH_SHORT).show();
}
}
} catch (Exception e) {
throw new Exception("Fehler in addKunde!");
}
finish();
}
public void customerToDatabase(final String name, final String address) {
requestQueue = Volley.newRequestQueue(getApplicationContext());
StringRequest request = new StringRequest(Request.Method.POST, DatabaseHelper.insertUrl, new Response.Listener<String>() {
@Override
public void onResponse(String response) {
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
error.printStackTrace();
}
}) {
@Override
protected Map<String, String> getParams() throws AuthFailureError {
Map<String,String> parameters = new HashMap<String,String>();
parameters.put("customername",name);
parameters.put("customeraddress",address);
return parameters;
}
};
requestQueue.add(request);
};
}