我如何修复 java.lang.IndexOutOfBoundsException: Index: 0, Size: 0 in android？我正在尝试学习 ArrayList
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How do i fix java.lang.IndexOutOfBoundsException: Index: 0, Size: 0 in android? I am trying to learn ArrayList
提问by Bokch
What the hell is this thing
这是什么鬼东西
public class MainActivity extends AppCompatActivity {
ArrayList<String> celebrityURL = new ArrayList<>();
int chosenCeleb = 0;
ImageView celebrityImage;
int locationAnswer = 0;
//random answers
ArrayList<String> answers = new ArrayList<>();
//random buttons reference
Button button01;
Button button02;
Button button03;
Button button04;
ArrayList<String> names = new ArrayList<>();
public void selectCeleb(View view) {
if (view.getTag().toString().equals(Integer.toString(locationAnswer))) {
Toast.makeText(getApplicationContext(), "CORRECT ", Toast.LENGTH_LONG).show();
} else {
Toast.makeText(getApplicationContext(), "WRONG, IT WAS: " + names.get(chosenCeleb), Toast.LENGTH_SHORT).show();
}
randomCelebrity();
}
public class imagesGet extends AsyncTask<String, Void, Bitmap> {
@Override
protected Bitmap doInBackground(String... params) {
try {
URL imagesURL = new URL(params[0]);
HttpURLConnection connection = (HttpURLConnection) imagesURL.openConnection();
connection.connect();
InputStream inputStream = connection.getInputStream();
Bitmap bitmap = BitmapFactory.decodeStream(inputStream);
return bitmap;
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
}
public class getData extends AsyncTask<String, Void, String> {
@Override
protected String doInBackground(String... urls) {
String result = "";
URL url;
HttpURLConnection connection = null;
try {
url = new URL(urls[0]);
connection = (HttpURLConnection) url.openConnection();
InputStream inputStream = connection.getInputStream();
InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
int data = inputStreamReader.read();
while (data != -1) {
char current = (char) data;
result += current;
data = inputStreamReader.read();
}
return result;
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
celebrityImage = (ImageView) findViewById(R.id.celebrityID);
button01 = (Button) findViewById(R.id.celebrity01);
button02 = (Button) findViewById(R.id.celebrity02);
button03 = (Button) findViewById(R.id.celebrity03);
button04 = (Button) findViewById(R.id.celebrity04);
getData task = new getData();
String resultData = null;
try {
try {
resultData = task.execute("http://www.posh24.se/kandisar").get();
} catch (InterruptedException e) {
e.printStackTrace();
}
String[] spResult = resultData.split("<div class\"sidebarContainer\">");
//images
Pattern pattern = Pattern.compile("img src=\"(.*?)\"");
Matcher matcher = pattern.matcher(spResult[0]);
while (matcher.find()) {
celebrityURL.add(matcher.group(1));
}
//names of the celebrities
pattern = Pattern.compile("alt=\"(.*?)\"");
matcher = pattern.matcher(spResult[0]);
while (matcher.find()) {
names.add(matcher.group(1));
}
} catch (ExecutionException e) {
e.printStackTrace();
}
randomCelebrity();
}
public void randomCelebrity() {
//random celebrity
Random random = new Random();
chosenCeleb = random.nextInt
//between zero and the size of celebURL
(celebrityURL.size());
//update imageView with new celebrity image
imagesGet imagesGet = new imagesGet();
Bitmap celebBitmap;
try {
celebBitmap = imagesGet.execute(celebrityURL.get(chosenCeleb)).get();
celebrityImage.setImageBitmap(celebBitmap);
int incorrectLocation;
locationAnswer = random.nextInt(4);
for (int i = 0; i < answers.size(); i++) {
if (i == locationAnswer) {
//update answers
answers.get(chosenCeleb);
} else {
//create random celebrity from celebs urls
incorrectLocation = random.nextInt(celebrityURL.size());
//avoid getting the correct and wrong answer in same location
//generate random answer if this condition is met
while (incorrectLocation == chosenCeleb) {
incorrectLocation = random.nextInt(celebrityURL.size());
}
//assign wrong location answer in answers array
answers.get(names.indexOf(incorrectLocation));
}
}
button01.setText(answers.get(0));
button02.setText(answers.get(1));
button03.setText(answers.get(2));
button04.setText(answers.get(3));
} catch (ExecutionException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
I divide the code so you can see it better. I am not idea how to fix this, but i know it is something with the ArrayList answers thing. I am trying to make an app that will random take html data and display it in android app. I am making an app to ques the celebrity name.
我将代码分开，以便您可以更好地看到它。我不知道如何解决这个问题，但我知道它与 ArrayList 答案有关。我正在尝试制作一个应用程序，它会随机获取 html 数据并将其显示在 android 应用程序中。我正在制作一个应用程序来查询名人的名字。
Edit: Sorry i forgot to include the error
编辑：对不起，我忘了包括错误
FATAL EXCEPTION: main
Process: com.stringmanipulation.stringmanipulation, PID: 24397
java.lang.IllegalStateException: Could not execute method for android:onClick
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:293)
at android.view.View.performClick(View.java:5610)
at android.view.View$PerformClick.run(View.java:22265)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6077)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invoke(Native Method)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
at android.view.View.performClick(View.java:5610)?
at android.view.View$PerformClick.run(View.java:22265)?
at android.os.Handler.handleCallback(Handler.java:751)?
at android.os.Handler.dispatchMessage(Handler.java:95)?
at android.os.Looper.loop(Looper.java:154)?
at android.app.ActivityThread.main(ActivityThread.java:6077)?
at java.lang.reflect.Method.invoke(Native Method)?
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)?
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)?
Caused by: java.lang.IndexOutOfBoundsException: Index: 103, Size: 100
at java.util.ArrayList.get(ArrayList.java:411)
at com.stringmanipulation.stringmanipulation.MainActivity.randomCelebrity(MainActivity.java:183)
at com.stringmanipulation.stringmanipulation.MainActivity.selectCeleb(MainActivity.java:53)
at java.lang.reflect.Method.invoke(Native Method)?
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)?
at android.view.View.performClick(View.java:5610)?
at android.view.View$PerformClick.run(View.java:22265)?
at android.os.Handler.handleCallback(Handler.java:751)?
at android.os.Handler.dispatchMessage(Handler.java:95)?
at android.os.Looper.loop(Looper.java:154)?
回答by Zoe
Until you highlight what line causes the problem, I will not be able to help you solve it accurately
除非您突出显示是哪条线导致问题，否则我将无法帮您准确解决
IndexOutOfBoundsException is an exception thrown when you try to access an array and request an index that is too high. Example:(this goes for ArrayList and other types of array)
IndexOutOfBoundsException 是当您尝试访问数组并请求太高的索引时抛出的异常。示例：（这适用于 ArrayList 和其他类型的数组）
ArrayList<Integer> ex = new ArrayList<>();
int exceptionThrownHere = ex.get(0);
The exception is thrown when you try to get an object from the list whose index is out of bounds. Another example:
当您尝试从索引超出范围的列表中获取对象时，将引发异常。另一个例子：
int[] ex = new int[10];
//initialize for this example to be valid
int exceptionThrownHere = ex[10];
The max index in this case is 9(0-9) and in the event you try to get 10 or more, you get the exception.
在这种情况下，最大索引为 9(0-9)，如果您尝试获得 10 或更多，则会出现异常。
The solution:(need the line where the exception is thrown for accurate answer)
解决办法：（需要抛出异常的那一行才能准确回答）
Make sure you don't try to get an object whose index is bigger than the amount of objects in the list. Another solution is to check how many objects are in the ArrayList(using .size()) and make sure you aren't trying to access an index that is bigger than the amount of objects in the list.
确保您不要尝试获取索引大于列表中对象数量的对象。另一种解决方案是检查 ArrayList 中有多少对象（使用.size()）并确保您没有尝试访问大于列表中对象数量的索引。
From analyzing your code, I see(assuming all the code is in the question) that you never add anything to the array "answers" - thus there are no objects in the list and it causes the exception. Make sure to add objects to the list by:
通过分析您的代码，我看到（假设所有代码都在问题中）您从不向数组“答案”中添加任何内容 - 因此列表中没有对象并导致异常。确保通过以下方式将对象添加到列表中：
answers.add("whatever string you need here");
Also see
另见
Java Documentation - IndexOutOfBoundsException
Java 文档 - IndexOutOfBoundsException
