Question

我正在尝试将Strings动态地添加到ArrayList中以及索引位置，然后在Intent中将Arraylist作为额外内容传递。该过程第一次运行良好，并且在下次调用此活动时最终会在Index中退出边界异常。请参阅下面的代码，并建议这是否是代码中的缺陷。

 private ArrayList<String> imagesUriArray=new ArrayList<>();
 static int imageIndex=-1;
 @Override
 protected void onActivityResult(int requestCode, int resultCode, Intent data) {  
    // Some standard code goes here to capture the image and store it...
        image = new SimpleDateFormat("yyyy.MM.dd.HH.mm.ss").format(new Date());
        photo = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES), image);
        selectedImage = Uri.fromFile(photo);
        final String UriString = new String(selectedImage.toString());
        imageIndex++;

 195:   imagesUriArray.add(imageIndex,UriString);
        Intent email = new Intent(ScanActivity.this, EmailActivity.class);
        email.putExtra("picture", imageInByte);
        email.putStringArrayListExtra("Uri", imagesUriArray);
        startActivity(email);


Logcat says:
    20320-20320/com.example.kittu.ClientLync E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=1, result=-1, data=Intent { act=inline-data (has extras) }} to activity {com.example.kittu.ClientLync/com.example.kittu.ClientLync.ScanActivity}: java.lang.IndexOutOfBoundsException: Invalid index 1, size is 0
        at android.app.ActivityThread.deliverResults(ActivityThread.java:2536)
        at android.app.ActivityThread.handleSendResult(ActivityThread.java:2578)
        at android.app.ActivityThread.access$2000(ActivityThread.java:117)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:965)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:130)
        at android.app.ActivityThread.main(ActivityThread.java:3689)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:507)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:842)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
        at dalvik.system.NativeStart.main(Native Method)
 Caused by: java.lang.IndexOutOfBoundsException: Invalid index 1, size is 0
        at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:257)
        at java.util.ArrayList.add(ArrayList.java:152)
        at com.example.kittu.ClientLync.ScanActivity.onActivityResult(ScanActivity.java:195)
        at android.app.Activity.dispatchActivityResult(Activity.java:3908)
        at android.app.ActivityThread.deliverResults(ActivityThread.java:2532)
        at android.app.ActivityThread.handleSendResult(ActivityThread.java:2578 
        at android.app.ActivityThread.access$2000(ActivityThread.java:117)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:965)

Answer 1

您正在访问arraylist中的无效索引，例如，如果您的arraylist为空并且您尝试在index = 1中插入，则会向您抛出IndexOutOfBoundsException

Answer 2

根据您的堆栈跟踪，您看到的是IndexOutOfBoundsException，而不是NPE。

引起：java.lang.IndexOutOfBoundsException：索引1无效，大小为0

你看到了这个，因为你试图在允许范围之外的列表中插入。允许的范围为列表长度的零，包括端点。在这种情况下，您尝试在索引1处添加元素，但列表中没有元素。

来自ArrayList.add(int index, E element)的文档：

public void add（int index，         E元素）

...

<强>抛出：

IndexOutOfBoundsException - 如果索引超出范围（索引＆lt; 0 || index＆gt; size（））

Answer 3

试试这个，你在插入

时访问错误的索引

 private ArrayList<String> imagesUriArray=new ArrayList<>();
     @Override
     protected void onActivityResult(int requestCode, int resultCode, Intent data) {  
        imagesUriArray.add(imageIndex,UriString);
        Intent email = new Intent(ScanActivity.this, EmailActivity.class);
        email.putExtra("picture", imageInByte);
        email.putStringArrayListExtra("Uri", imagesUriArray);
        startActivity(email);
    }

Answer 4

https://docs.oracle.com/javase/7/docs/api/java/util/ArrayList.html#add(int,%20E) 阅读文档。显式地写道，add（int，E）方法抛出IndexOutOfBoundsException - 如果索引超出范围（索引＆lt; 0 || index＆gt; size（））

多个字符串进入Arraylist

4 个答案: