我实现了 AsyncTask 来执行结果。这是我得到的错误...
FATAL EXCEPTION: AsyncTask #1
Process: ai69.psoui, PID: 3287
java.lang.RuntimeException: An error occurred while executing doInBackground()
at android.os.AsyncTask$3.done(AsyncTask.java:309)
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:354)
at java.util.concurrent.FutureTask.setException(FutureTask.java:223)
at java.util.concurrent.FutureTask.run(FutureTask.java:242)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:234)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588)
at java.lang.Thread.run(Thread.java:818)
Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
at android.os.Handler.<init>(Handler.java:200)
at android.os.Handler.<init>(Handler.java:114)
at android.app.Activity.<init>(Activity.java:754)
at android.support.v4.app.SupportActivity.<init>(SupportActivity.java:31)
at android.support.v4.app.BaseFragmentActivityGingerbread.<init>(BaseFragmentActivityGingerbread.java:37)
at android.support.v4.app.BaseFragmentActivityHoneycomb.<init>(BaseFragmentActivityHoneycomb.java:29)
at android.support.v4.app.BaseFragmentActivityJB.<init>(BaseFragmentActivityJB.java:30)
at android.support.v4.app.FragmentActivity.<init>(FragmentActivity.java:79)
at android.support.v7.app.AppCompatActivity.<init>(AppCompatActivity.java:61)
at ai69.psoui.MainActivity.<init>(MainActivity.java:0)
at android_tests.CustomUseCase.<init>(CustomUseCase.java:19)
at android_tests.TestFactory.getTest(TestFactory.java:15)
at ai69.psoui.ParticleActivity.runTest(ParticleActivity.java:91)
at ai69.psoui.ParticleActivity$runTests.doInBackground(ParticleActivity.java:53)
at ai69.psoui.ParticleActivity$runTests.doInBackground(ParticleActivity.java:50)
at android.os.AsyncTask$2.call(AsyncTask.java:295)
我查看了有关“Looper.prepare()”的不同 SOF 帖子，但问题是，在将静态变量更改为 getter/setter 方法的一些更改之前，我的 UI 工作正常。
这是我的代码...
public class ParticleActivity extends AppCompatActivity {
public final static String EXTRA_MESSAGE = "PSOUI.MESSAGE";
private ProgressDialog pd;
private double[] results = {-1.0, -1.0, -1.0};
EditText particles;
EditText iterations;
EditText userSol;
EditText userBatt;
private double battery;
private double solution;
//int numberOfDimensions = MainActivity.dimensions.size();
//public ArrayList<Double> costData = MainActivity.costDATA; //costs that
the user enters for each resource
//public ArrayList<Double> costWlan = MainActivity.costWLAN;
//public ArrayList<Double> costUtilities = MainActivity.costUTILITY;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_particle);
particles = (EditText) findViewById(R.id.particles);
iterations = (EditText) findViewById(R.id.iterations);
userSol = (EditText) findViewById(R.id.solution);
userBatt = (EditText) findViewById(R.id.battery);
pd = null;
runPSOButton();
}
@Override
public void onPause(){
super.onPause();
if(pd != null)
pd.dismiss();
}
public class runTests extends AsyncTask<Void, Void, Void> {
@Override
protected Void doInBackground(Void... params) { //sort this out
results = runTest("CustomUseCase"); //i only want to run this one!!!
return null;
}
@Override
protected void onPostExecute(Void v) {
if (results != null && results.length > 0 && results[0] != -1) {
loadIntent(results);
} //otherwise it will evaluate the next logic statement results[0] != -1 with no chance of NulLPointerException
}
@Override
protected void onPreExecute() {
pd = ProgressDialog.show(ParticleActivity.this, "Busy", "Algorithm is currently executing");
pd.setCancelable(true);
pd.show();
}
}
public void runPSOButton() {
final Button runPSO = (Button) findViewById(R.id.runpso);
runPSO.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(final View v) {
new runTests().execute();
}
});
}
public double[] runTest(String test) {
int noPart = Integer.parseInt(particles.getText().toString());
int noIter = Integer.parseInt(iterations.getText().toString());
return new TestFactory(noPart, noIter).getTest(test).test();
}
public void loadIntent(double[] result) {
double[] results = result;
Intent intent = new Intent(this, SolutionActivity.class);
intent.putExtra(EXTRA_MESSAGE, results);
startActivity(intent);
}
public double setBatteryCost(){
battery = Double.parseDouble(userBatt.getText().toString());
return battery;
}
public double getBatteryCost(){return setBatteryCost();}
public double setUserSolution(){
solution = Double.parseDouble(userSol.getText().toString());
return solution;
}
public double getUserSolution(){return setUserSolution();}
}
有人可以解释发生了什么吗？刚接触 Android Studio 并且只用 Java 开发了 3 个月，所以对于任何解决方案，我也可以请求解释一下吗？非常感谢谢谢
更新：
这是我的主要活动...
public class MainActivity extends AppCompatActivity {
//declare variables
EditText name;
EditText data;
EditText wlan;
EditText utility;
Button addservice;
ListView lv;
ListView lv2;
ListView lv3;
ListView lv4;
public ArrayList<String> servicenames;
public ArrayList<String> dimensions;
public ArrayList<Double> costDATA;
public ArrayList<Double> costWLAN;
public ArrayList<Double> costUTILITY;
ArrayAdapter<String> namesAdapter;
ArrayAdapter<Double> dataAdapter;
ArrayAdapter<Double> wlanAdapter;
ArrayAdapter<Double> utilityAdapter;
@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
servicenames = new ArrayList<String>();
dimensions = new ArrayList<String>();
costDATA = new ArrayList<Double>();
costWLAN = new ArrayList<Double>();
costUTILITY = new ArrayList<Double>();
//create adapters to pass on the arraylist
namesAdapter = new ArrayAdapter<String>(MainActivity.this, android.R.layout.simple_list_item_1, servicenames);
dataAdapter = new ArrayAdapter<Double>(MainActivity.this, android.R.layout.simple_list_item_1, costDATA);
wlanAdapter = new ArrayAdapter<Double>(MainActivity.this, android.R.layout.simple_list_item_1, costWLAN);
utilityAdapter = new ArrayAdapter<Double>(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();
dimensions.add("DATA");
dimensions.add("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);
servicenames.add(namesOfService);
dimensions.add(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);
}
public int getDimensions(){ return dimensions.size();}
public ArrayList<String> getElements(){ return servicenames;}
public ArrayList<Double> getCostDATA(){;return costDATA;}
public ArrayList<Double> getCostWLAN(){return costUTILITY;}
public ArrayList<Double> getCostUTILITY(){return costUTILITY;}
}
如您所见，可以使用 getter 和 setter 访问存储用户输入的数组列表，而不是将数组列表设置为静态（我之前这样做过）。我在另一个名为 CustomUseCase 和 CustomService 的类中访问这些数组列表。这是 customUseCase 的代码：
public class CustomUseCase extends Test {
MainActivity mainActivity = new MainActivity();
ParticleActivity particleActivity = new ParticleActivity();
private int numberOfDimensions = mainActivity.getDimensions();
private ArrayList<Double> costData = mainActivity.getCostDATA(); //costs that the user enters for each resource
private ArrayList<Double> costWlan = mainActivity.getCostWLAN();
private ArrayList<Double> costUtilities = mainActivity.getCostUTILITY();
private double batteryCost = particleActivity.getBatteryCost();
private int maxIter;
private int noParticles;
public CustomUseCase(int noParticles, int maxIterations) {
this.noParticles = noParticles;
this.maxIter = maxIterations;
}
@Override
public double[] test() {
long max = 10000; //maximum number of iterations, override //2 bits for the WLAN/DATA and the rest for the amount of services the user inputs
double[] results = new double[numberOfDimensions]; //new array of results with numOfBits as number of elements
for (int i = 1; i <= max; i++) {
BinaryPso bpso = new BinaryPso(noParticles,
numberOfDimensions);
ParticleActivity getUserInput = new ParticleActivity();
CustomService customService =
new CustomService(batteryCost, costData, costWlan, costUtilities);
long start = System.currentTimeMillis(); //start time
bpso.setSolution(getUserInput.getUserSolution()); //changed this to user selection
bpso.optimize(maxIter, customService, true);
this.found += (bpso.getFound() ? 1 : 0);
this.iterations += bpso.getSolIterations(); //use the method in bpso to get number of iterations taken
long end = System.currentTimeMillis() - start; //end time minus start time
this.sumTimes += end; //override the time spent variable
System.out.println("P-value: " + Particle.getValue(Particle.bestGlobal()));
System.out.println("P-bitCombo: " + Arrays.toString(Particle.bestGlobal()));
System.out.println("P-goodness: " + customService.getGoodness(Particle.bestGlobal()));
}
System.out.println("Time: " + sumTimes / max);
System.out.println("Iterations: " + iterations / max);
System.out.println("Success Rate: " + found);
boolean[] bestCombo = Particle.bestGlobal();
for (Boolean b : bestCombo) {
System.out.print(b + " ");
}
System.out.println();
results[0] = sumTimes / max;
results[1] = iterations / max;
results[2] = found;
return results;
}
public static List<Boolean> getBestComboArray() { //method to get best global array
boolean[] bestCombo = Particle.bestGlobal(); //calculate best global
List<Boolean> bestCombi = new ArrayList<>(bestCombo.length);
for (int x = 0; x < bestCombo.length; x++) {
bestCombi.add(bestCombo[x]);
}
return bestCombi;
}
}
这是我的 CustomService 类：
public class CustomService implements Goodness {
MainActivity mainActivity = new MainActivity();
private int numOfDimensions = mainActivity.getDimensions();
private ArrayList<String> serviceNames = mainActivity.getElements();
private ArrayList<Double> costData = mainActivity.getCostDATA();
private ArrayList<Double> costWlan = mainActivity.getCostWLAN();
private ArrayList<Double> costUtilities = mainActivity.getCostUTILITY();
private double batteryCost;
public void setBatteryCost(double batteryCost) {
this.batteryCost = batteryCost;
}
public CustomService(double batteryCost, ArrayList<Double> costData, ArrayList<Double> costWlan,
ArrayList<Double> costUtilities) {
if (costUtilities == null || costUtilities.size() < 1 || costData.size() < 1 || costWlan.size() < 1) {
throw new RuntimeException("Please add atleast 1 cost to Data, WLAN and Utility");
}
this.batteryCost = batteryCost; //make sure you add battery field to UI, user enters battery level
this.costData = costData;
this.costWlan = costWlan;
this.costUtilities = costUtilities;
}
public double getGoodness(boolean[] bits) {
double utility = 0.0;
double rcost = 0.0;
ArrayList<Double> resourceCost = new ArrayList<Double>();
Collections.sort(costUtilities); //sort the costUtilities arraylist
double maxValue = Collections.max(costUtilities); //get the maximum value from the costUtilities arraylist
if(bits[0] && bits[1]){
return -500;
}
if(!bits[0] || bits[1]){
return -1000;
}
for(int x = 1; x < numOfDimensions; x++){
if(bits[x] == costUtilities.contains(maxValue)){
return -1900;
}
}
if (bits[0]) {
resourceCost = costData;
} else if (bits[1]) {
resourceCost = costWlan;
}
for (int i = 2; i <= serviceNames.size(); i++) { //if i = 2, 2<=4
if (bits[i]) {
utility += costUtilities.get(i-2);
rcost += resourceCost.get(i-2);
}
}
if (rcost < batteryCost) {
return utility;
}
return utility * 0.50;
}
}
您不能在 nonUIThread 上更新 UI 项目。在谷歌上搜索 runOnUiThread 的用法。在 runOnUiThread() 中调用您的方法。
@Override
protected Void doInBackground(Void... params) { //sort this out
runOnUiThread (new Runnable() {
public void run() {
results = runTest("CustomUseCase");
}
}
return null;
}
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