列表未在UI上显示？

Question

我目前正在构建一个用户界面来支持手机优化的PSO项目。我有一个列表视图，显示用户输入arraylist，但是当我点击我的UI上的“addservice”按钮时，listview没有显示任何内容？以下是我主要活动的代码......

public class MainActivity extends AppCompatActivity {
//declare variables
private EditText name;
private EditText data;
private EditText wlan;
private EditText utility;
private Button addservice;
ListView lv;
ListView lv2;
ListView lv3;
ListView lv4;


public ArrayList<String> servicenames;
public ArrayList<String> dimensions;
private ArrayAdapter<String> namesAdapter;
private ArrayAdapter<Double> dataAdapter;
private ArrayAdapter<Double> wlanAdapter;
private ArrayAdapter<Double> utilityAdapter;
private ArrayList<Double> costDATA;
private ArrayList<Double> costWLAN;
private ArrayList<Double> costUTILITY;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    //map the components to the variables
    name = (EditText) findViewById(R.id.servicename);
    data = (EditText) findViewById(R.id.data);
    wlan = (EditText) findViewById(R.id.wlan);
    utility = (EditText) findViewById(R.id.utility);
    addservice = (Button) findViewById(R.id.addservice);
    lv = (ListView) findViewById(R.id.lv);
    lv2 = (ListView) findViewById(R.id.lv2);
    lv3 = (ListView) findViewById(R.id.lv3);
    lv4 = (ListView) findViewById(R.id.lv4);

    //create arraylists for each component
    Services services = new Services();
    servicenames = services.getServiceNames();
    costDATA = services.getCostData();
    costWLAN = services.getCostWlan();
    costUTILITY = services.getCostUtility();

    //create adapters to pass on the arraylist
    namesAdapter = new ArrayAdapter<>(MainActivity.this, android.R.layout.simple_list_item_1, servicenames);
    dataAdapter = new ArrayAdapter<>(MainActivity.this, android.R.layout.simple_list_item_1, costDATA);
    wlanAdapter = new ArrayAdapter<>(MainActivity.this, android.R.layout.simple_list_item_1, costWLAN);
    utilityAdapter = new ArrayAdapter<>(MainActivity.this, android.R.layout.simple_list_item_1, costUTILITY);

    //display each arraylist in the listviews
    lv.setAdapter(namesAdapter);
    lv2.setAdapter(wlanAdapter);
    lv3.setAdapter(dataAdapter);
    lv4.setAdapter(utilityAdapter);
    namesAdapter.notifyDataSetChanged();
    dataAdapter.notifyDataSetChanged();
    wlanAdapter.notifyDataSetChanged();
    utilityAdapter.notifyDataSetChanged();
    services.addDimensions("DATA");
    services.addDimensions("WLAN");
    onClickBtn();
}

public void onClickBtn() { //when user clicks button, the user input is added to the listview, and cleared for the next service

    addservice.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            String namesOfService = name.getText().toString(); //user input for service names
            String costOfData = data.getText().toString(); //user input for data costs
            String costOfWLAN = wlan.getText().toString(); //user input for wlan costs
            String costOfUtility = utility.getText().toString(); //user input for utility costs
            double doubleWLAN = Double.parseDouble(costOfWLAN); //convert user input into double
            double doubleData = Double.parseDouble(costOfData);
            double doubleUtility = Double.parseDouble(costOfUtility);
            //costDATA.add(doubleData); //add the double costs to each resource arraylist
            //costWLAN.add(doubleWLAN);
            //costUTILITY.add(doubleUtility);

            Services services = new Services();
            services.addDataCost(doubleData);
            services.addWlanCost(doubleWLAN);
            services.addUtilityCost(doubleUtility);
            services.addServiceName(namesOfService);
            services.addDimensions(namesOfService);


            namesAdapter.notifyDataSetChanged();
            dataAdapter.notifyDataSetChanged();
            wlanAdapter.notifyDataSetChanged();
            utilityAdapter.notifyDataSetChanged();
            name.setText(""); //empty the edit text fields when button is clicked
            wlan.setText("");
            data.setText("");
            utility.setText("");
        }
    });

}

public void nextButton(View view) //next button, onto the next activity
{
    Intent intent = new Intent(MainActivity.this, ParticleActivity.class);
    startActivity(intent);
}

更新：

当我尝试输入服务名称时，这是我的日志，以及数据，wlan和实用程序的成本......

E/AndroidRuntime: FATAL EXCEPTION: main
              Process: ai69.psoui, PID: 2926
              java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.util.ArrayList.add(java.lang.Object)' on a null object reference
                  at test_classes.Services.addDimensions(Services.java:30)
                  at ai69.psoui.MainActivity$1.onClick(MainActivity.java:103)
                  at android.view.View.performClick(View.java:5198)
                  at android.view.View.onKeyUp(View.java:9879)
                  at android.widget.TextView.onKeyUp(TextView.java:6248)
                  at android.view.KeyEvent.dispatch(KeyEvent.java:2664)
                  at android.view.View.dispatchKeyEvent(View.java:9234)
                  at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1640)
                  at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1640)
                  at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1640)
                  at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1640)
                  at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1640)
                  at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1640)
                  at com.android.internal.policy.PhoneWindow$DecorView.superDispatchKeyEvent(PhoneWindow.java:2395)
                  at com.android.internal.policy.PhoneWindow.superDispatchKeyEvent(PhoneWindow.java:1727)
                  at android.app.Activity.dispatchKeyEvent(Activity.java:2725)
                  at android.support.v7.app.AppCompatActivity.dispatchKeyEvent(AppCompatActivity.java:541)
                  at android.support.v7.view.WindowCallbackWrapper.dispatchKeyEvent(WindowCallbackWrapper.java:59)
                  at android.support.v7.app.AppCompatDelegateImplBase$AppCompatWindowCallbackBase.dispatchKeyEvent(AppCompatDelegateImplBase.java:319)
                  at com.android.internal.policy.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:2310)
                  at android.view.ViewRootImpl$ViewPostImeInputStage.processKeyEvent(ViewRootImpl.java:4127)
                  at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:4089)
                  at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3642)
                  at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3695)
                  at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3661)
                  at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:3787)
                  at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3669)
                  at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:3844)
                  at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3642)
                  at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3695)
                  at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3661)
                  at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3669)
                  at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3642)
                  at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3695)
                  at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3661)
                  at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:3820)
                  at android.view.ViewRootImpl$ImeInputStage.onFinishedInputEvent(ViewRootImpl.java:3981)
                  at android.view.inputmethod.InputMethodManager$PendingEvent.run(InputMethodManager.java:2253)
                  at android.view.inputmethod.InputMethodManager.invokeFinishedInputEventCallback(InputMethodManager.java:1874)
                  at android.view.inputmethod.InputMethodManager.finishedInputEvent(InputMethodManager.java:1865)
                  at android.view.inputmethod.InputMethodManager$ImeInputEventSender.onInputEventFinished(InputMethodManager.java:2230)
                  at android.view.InputEventSender.dispatchInputEventFinished(InputEventSender.java:141)
                  at android.os.MessageQueue.nativePollOnce(Native Method)
                  at android.os.MessageQueue.next(MessageQueue.java:323)
                  at android.os.Looper.loop(Looper.java:135)
                  at android.app.ActivityThread.main(ActivityThread.java:5417)
                  at java.lang.reflect.Method.invoke(Native Method)
                  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
I/Process: Sending signal. PID: 2926 SIG: 9
Application terminated.

这也是我的服务类。这个课程是为了保存用户输入的所有信息，我在这里做错了什么？当用户为其添加值时，为什么我的arraylist不会更新？我是android studio / java的新手（3个月），我正试图以最OO的方式实现我的UI。

public class Services {

private ArrayList<Double> costDATA = new ArrayList<>();
private ArrayList<Double> costWLAN = new ArrayList<>();
private ArrayList<Double> costUTILITY = new ArrayList<>();
private ArrayList<String> dimensions = new ArrayList<>();
private ArrayList<String> serviceNames = new ArrayList<>();
private int numOfDimensions = dimensions.size();
private double solution;
private double battery;


public ArrayList<String> getServiceNames(){
    return this.serviceNames;
}

public void addServiceName(String services) {
    this.serviceNames.add(services);
}

public void addDimensions(String services) {
    this.dimensions.add(services);
}

public int getNumDimensions(){
    return this.numOfDimensions;
}

public ArrayList<String> getDimensions(){
    return this.dimensions;
}

public void addDataCost(double dataCost){
    this.costDATA.add(dataCost);
}


public void addWlanCost(double wlanCost){
    this.costWLAN.add(wlanCost);
}


public void addUtilityCost(double utilityCost){
    this.costUTILITY.add(utilityCost);
}

public ArrayList<Double> getCostData(){
    return this.costDATA;
}

public ArrayList<Double> getData(ArrayList<Double> Data){
    this.costDATA = Data;
    return Data;
}
public ArrayList<Double> getWlan(ArrayList<Double> Wlan){
    this.costWLAN = Wlan;
    return Wlan;
}
public ArrayList<Double> getUtility(ArrayList<Double> Utility){
    this.costUTILITY = Utility;
    return Utility;
}

public ArrayList<String> getDim(ArrayList<String> dimensions){
    this.dimensions = dimensions;
    return dimensions;
}

public ArrayList<Double> getCostWlan(){
    return this.costWLAN;
}
public ArrayList<Double> getCostUtility(){
    return this.costUTILITY;
}

public void setSolution(double solution){
    this.solution = solution;
}

public double getSolution(){
    return this.solution;
}

public void setBattery(double battery){
    this.battery = battery;
}

public double getBattery(){
    return this.battery;
}

}