我是Android Developement的新用户，目前正致力于开发一款应用程序，该应用程序可让我在第一次点击按钮和第二次点击按钮之间的时间，并将其添加到当前选定的客户。
App的当前状态： 我使用Volley和本地Web服务建立了与da mySql数据库的连接。
它可以将我的客户和时间戳插入到表格中，但是当为特定客户加载时间时，我会在一个案例中得到奇怪的结果。我试过调试它但是应用程序在没有消息的情况下继续崩溃。如果不进行调试，它不会崩溃但会显示奇怪的数据。
解决问题：
在我名为“ZeitErfassen”的主要活动中，我有一个按钮，可以了解ListView中显示的所有客户的概况。 我使用自定义ArrayAdapter创建Listview，因为我想将我的对象传递给下一个显示客户的Activity。
所以onCreate的客户概述我创建了一个新的arraylist并填充了我的数据库中的所有客户。我将这个列表传递给我的customadapter，然后将其设置为Listview的适配器。 现在，当我点击一个项目时，我调用一个php脚本并将customer_id传递给查询，以便从customer_id = customer_id的数据库中获取所有时间。
现在我得到“奇怪”数据的部分......
1.（来源：ZeitErfassen;目的地：AddCustomer）我在应用程序中创建了一个新客户，例如xyz，数据被传递到数据库。
2.（来源：ZeitErfassen;目的地：DisplayCustomer）我为ListView充满数据的所有客户打电话给我的概述，如上所述。在列表的最后，我看到了我刚创建的客户，xyz。
3.返回主要活动（ZeitErfassen）
4.（来源：ZeitErfassen;目的地：DisplayCustomer）我再次打开所有客户的概述，它显示我上次创建的用户两次！最后一个条目，xyz，最后一个条目，xyz！
之后，我可以根据需要多次打开视图，客户永远不会再次重复！
调试器在第2步之后停止。
现在，当我点击新客户时，它会调用脚本来获取customer_id的时间。 其中一个xyz entrys从数据库中显示正确的时间。 第二个，我刚刚发现，显示customer_id =“”的时间。在数据库中，“”的值为0。
我不知道第二个客户突然出现在哪里，调试也没有帮助我-.- 当我关闭应用程序并再次打开它时，在关闭应用程序之前，只有一个条目可供用户显示两次。它在打开视图时没有重复...
这是我的代码..
主要活动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;
@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"));
DatabaseHelper.customerFromDatabaseToList(this);
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 onResume() {
super.onResume();
// saveCustomers();
// createDropDown();
}
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);
startActivity(intent);
}
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() {
/*File file = new File(this.getFilesDir(),"kunden.ser"); NOT USED BECAUSE DATABASE WORKS
if(file.exists()) {
Kunde.importFromFile(this);
}*/
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);
}
}
}
DisplayCustomer（所有客户都显示数据库中的数据）
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);
}
});
}
}
我的CustomerAdapter将数据从一个意图传递到另一个意图。
public class CustomerAdapter extends ArrayAdapter<Kunde> {
public CustomerAdapter(Context context, ArrayList<Kunde> customerList) {
super(context,0,customerList);
}
public View getView(int position, View convertView, ViewGroup parent) {
//Data for this position
Kunde kunde = getItem(position);
if (convertView == null) {
convertView = LayoutInflater.from(getContext()).inflate(R.layout.items_customer_layout, parent, false);
}
// Lookup view for data population
TextView tvName = (TextView) convertView.findViewById(R.id.tvCustomerName);
// Populate the data into the template view using the data object
tvName.setText(kunde.getName());
// Return the completed view to render on screen
return convertView;
}
}
DatabaseHelper Class
public class DatabaseHelper {
public static RequestQueue requestQueue;
public static 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) {
showAlert("Fehler in customerFromDatabaseToListn!", "Fehler", context);
}
} else {
showAlert("Fehler in customerFromDatabaseToListn!", "Fehler", context);
}
}
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
error.printStackTrace();
}
});
requestQueue.add(jsonObjectRequest);
}
public static boolean listContainsObject(Kunde cust) {
for(Kunde k : ZeitErfassen.kunden) {
if(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) {
showAlert("Fehler","Fehler bei Verbindung zur Datenbank",context);
}
}) {
@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 void showAlert(String title, String message, Context context) {
// 1. Instantiate an AlertDialog.Builder with its constructor
AlertDialog.Builder builder = new AlertDialog.Builder(context);
// 2. Chain together various setter methods to set the dialog characteristics
builder.setMessage(message)
.setTitle(title);
// 3. Get the AlertDialog from create()
AlertDialog dialog = builder.create();
}
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) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(context,"Fehler beim Holen der Zeiten",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;
};
}
DisplayDetailedCustomer /显示时间
public class DisplayDetailedCustomer extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_display_detailed_customer);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
Intent getCustomerParcable = getIntent();
Kunde customer = getCustomerParcable.getExtras().getParcelable("selectedCustomerObject");
TextView displayCustomerNameDetailed =(TextView) findViewById(R.id.detailedCustomerViewName);
TextView displayCustomerAddressDetailed =(TextView) findViewById(R.id.detailedCustomerAddress);
ListView timeListView = (ListView)findViewById(R.id.detailedTimeListView);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1, DatabaseHelper.timesFromDataBaseToList(this,customer.getId()));
timeListView.setAdapter(adapter);
displayCustomerNameDetailed.setText(customer.getName());
displayCustomerAddressDetailed.setText(customer.getAdresse());
}
}
带有Parcelable接口的Kunde Class / Customer Class
public class Kunde implements Serializable,Parcelable {
private String name;
private String adresse;
private int id;
public LinkedList<String> zeiten;
public Kunde(String name, String adresse) throws Exception{
setName(name);
setAdresse(adresse);
zeiten = new LinkedList<String>();
}
public Kunde(String name, String adresse,int id) throws Exception{
setName(name);
setAdresse(adresse);
setId(id);
zeiten = new LinkedList<String>();
}
public Kunde(){};
public void setId(int id) {
this.id = id;
}
public int getId(){
return id;
}
public void setName(String name) throws Exception {
if(name != null) {
this.name = name;
} else throw new Exception("Name ist ungueltig! in setName");
}
public void setAdresse(String adresse) throws Exception{
if(adresse != null) {
this.adresse = adresse;
}else throw new Exception("Adresse ist ungueltig! in setAdresse");
}
public String getName() {
return name;
}
public String getAdresse() {
return adresse;
}
public void saveZeit(Long totalTime) {
zeiten.add(String.valueOf(totalTime));
}
public void saveTimeToCustomer(Kunde customer,String time){
customer.zeiten.add(time);
}
//------------------------------------Parcelable Methods to pass Daata from one Intent to another----------------------------------------
@Override
public int describeContents() {
return 0;
}
@Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeInt(this.id);
dest.writeString(this.name);
dest.writeString(this.adresse);
// dest.writeList(this.zeiten);
}
// this is used to regenerate your object. All Parcelables must have a CREATOR that implements these two methods
public static final Parcelable.Creator<Kunde> CREATOR = new Parcelable.Creator<Kunde>() {
public Kunde createFromParcel(Parcel in) {
return new Kunde(in);
}
public Kunde[] newArray(int size) {
return new Kunde[size];
}
};
// example constructor that takes a Parcel and gives you an object populated with it's values
private Kunde(Parcel in) {
LinkedList<String> zeiten = null;
id = in.readInt();
name = in.readString();
adresse = in.readString();
}
}
感谢您抽出宝贵的时间!!