我使用的api将根据用户输入的文本返回音调列表，具体取决于文本，如果api可以从用户输入中检测到某些音调，则该应用程序将显示结果列表，但是， api有时会崩溃，我猜是因为它返回空结果？
我无法控制api服务器，我尝试通过检查列表的大小来避免此问题，如果列表为空或不是空的，但是没有用，则该应用程序仍然崩溃。
是否有防止应用崩溃的方法？我认为没有确定方法来检查用户输入是否会从api返回某些信息，这取决于该api本身。非常感谢您的帮助。
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.os.StrictMode;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import com.ibm.cloud.sdk.core.security.IamAuthenticator;
import com.ibm.cloud.sdk.core.service.exception.NotFoundException;
import com.ibm.cloud.sdk.core.service.exception.RequestTooLargeException;
import com.ibm.cloud.sdk.core.service.exception.ServiceResponseException;
import com.ibm.watson.tone_analyzer.v3.ToneAnalyzer;
import com.ibm.watson.tone_analyzer.v3.model.SentenceAnalysis;
import com.ibm.watson.tone_analyzer.v3.model.ToneAnalysis;
import com.ibm.watson.tone_analyzer.v3.model.ToneOptions;
import com.ibm.watson.tone_analyzer.v3.model.ToneScore;
import java.util.List;
public class Main2Activity extends AppCompatActivity {
private TextView textmain1, textmain2;
private EditText editText;
private Button submitBtn;
private ToneAnalysis toneAnalysis;
private List<ToneScore> documentToneScores;
private List<SentenceAnalysis> sentenceDetectedTones;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
textmain1 = (TextView) findViewById(R.id.textmain1);
textmain2 = (TextView) findViewById(R.id.textmain2);
editText = (EditText) findViewById(R.id.edittext);
submitBtn = (Button) findViewById(R.id.submitBtn);
submitBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int SDK_INT = android.os.Build.VERSION.SDK_INT;
if (SDK_INT > 8) {
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
String userInputText = editText.getText().toString();
try {
IamAuthenticator authenticator = new IamAuthenticator(authenticatorString);
ToneAnalyzer toneAnalyzer = new ToneAnalyzer("2020-02-22", authenticator);
toneAnalyzer.setServiceUrl(url);
ToneOptions toneOptions = new ToneOptions.Builder().text(userInputText).build();
toneAnalysis = toneAnalyzer.tone(toneOptions).execute().getResult();
documentToneScores = toneAnalysis.getDocumentTone().getTones();
int toneSizelist = documentToneScores.size();
if (toneSizelist == 0) {
Toast.makeText(Main2Activity.this, "No tones", Toast.LENGTH_SHORT).show();
} else {
StringBuilder detectedTones = new StringBuilder();
for (ToneScore score : documentToneScores) {
if (score.getScore() > 0.5f) {
detectedTones.append(score.getToneName()).append(" \n").append(score.getScore()).append("\n\n");
}
}
textmain1.setText(detectedTones.toString());
}
sentenceDetectedTones = toneAnalysis.getSentencesTone();
int listSize = sentenceDetectedTones.size();
if (listSize == 0) {
Toast.makeText(Main2Activity.this, "Oops!", Toast.LENGTH_SHORT).show();
} else {
StringBuilder sentenceTones = new StringBuilder();
for (SentenceAnalysis sentenceAnalysis : sentenceDetectedTones) {
List<ToneScore> singleScoreBlock = sentenceAnalysis.getTones();
for (ToneScore toneScore : singleScoreBlock) {
if (toneScore.getScore() > 0.5) {
sentenceTones.append("\"" + sentenceAnalysis.getText() + "\"");
sentenceTones.append("\n").append(toneScore.getToneName()).append(": ").append(toneScore.getScore()).append("\n\n");
}
}
}
textmain2.setText(sentenceTones);
}
} catch (NotFoundException e) {
// Handle Not Found (404) exception
Toast.makeText(Main2Activity.this, e.getMessage(), Toast.LENGTH_LONG).show();
} catch (RequestTooLargeException e) {
// Handle Request Too Large (413) exception
} catch (ServiceResponseException e) {
// Base class for all exceptions caused by error responses from the service
System.out.println("Service returned status code " + e.getStatusCode() + ": " + e.getMessage());
} catch (ArrayIndexOutOfBoundsException e){
Toast.makeText(Main2Activity.this, e.getMessage(), Toast.LENGTH_SHORT).show();
}
editText.setText("");
}
}
});
}
}
由于返回结果为空而导致应用程序崩溃时，错误nullpointerexception
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.amethyst.toneanalyzer, PID: 3492
java.lang.NullPointerException: Attempt to invoke interface method 'int java.util.List.size()' on a null object reference
at com.amethyst.toneanalyzer.Main2Activity$1.onClick(Main2Activity.java:82)
at android.view.View.performClick(View.java:6724)
at android.view.View.performClickInternal(View.java:6682)
at android.view.View.access$3400(View.java:799)
at android.view.View$PerformClick.run(View.java:26355)
at android.os.Handler.handleCallback(Handler.java:873)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:226)
at android.app.ActivityThread.main(ActivityThread.java:7231)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:500)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:913)
I/Process: Sending signal. PID: 3492 SIG: 9
谢谢你。
这些方法中的一个或多个正在返回null：
toneAnalysis.getDocumentTone()
toneAnalysis.getDocumentTone().getTones();
toneAnalysis.getSentencesTone();
您必须纠正它们
java.lang。
NullPointerException：尝试调用接口方法空对象引用上的'int java.util.List.size（）'
应用程序应抛出此类的实例，以指示对null对象的其他非法使用。您应该初始化ArrayList
NullPointerException