Error removing object from an ArrayList

Question

Error removing object from an ArrayList

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#1 by (4 votes)

2

When I try to remove a int from arrayList it is simply an error.

Code:

ArrayList<Integer> colors = new ArrayList<>();
colors.add(Color.rgb(119, 103, 141)); colors.add(Color.rgb(33, 10, 208)); colors.add(Color.rgb(203, 100 ,180));
colors.add(Color.rgb(249, 0 ,193)); colors.add(Color.rgb(74, 169, 94)); colors.add(Color.rgb(25, 236, 70));
colors.add(Color.rgb(235, 213, 92)); colors.add(Color.rgb(242, 206, 9)); colors.add(Color.rgb(68, 243, 220));

int teste = colors.get(3);
colors.remove(teste);

Error:

Process: lordlokon.contarapp, PID: 1840
    java.lang.RuntimeException: Unable to start activity ComponentInfo{lordlokon.contarapp/lordlokon.contarapp.MainActivity}: java.lang.ArrayIndexOutOfBoundsException: length=12; index=-458559
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2426)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2490)
        at android.app.ActivityThread.-wrap11(ActivityThread.java)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1354)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:148)
        at android.app.ActivityThread.main(ActivityThread.java:5443)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:728)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
    Caused by: java.lang.ArrayIndexOutOfBoundsException: length=12; index=-458559
        at java.util.ArrayList.remove(ArrayList.java:405)
        at lordlokon.contarapp.MainActivity.randomizar(MainActivity.java:63)
        at lordlokon.contarapp.MainActivity.onCreate(MainActivity.java:52)
        at android.app.Activity.performCreate(Activity.java:6245)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1130)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2379)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2490) 
        at android.app.ActivityThread.-wrap11(ActivityThread.java) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1354) 
        at android.os.Handler.dispatchMessage(Handler.java:102) 
        at android.os.Looper.loop(Looper.java:148) 
        at android.app.ActivityThread.main(ActivityThread.java:5443) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:728) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)

java android arraylist

asked by anonymous 06.08.2016 / 20:57

1 answer

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score 4 · Accepted Answer

The problem is that the remove() method is overloaded:

E remove (int index) - which removes the item based on the index.
boolean remove (Object o) - which removes the item based on the saved object

The get () method returns the Integer in this case) saved in the specified position. Since this object is converted to int ( int teste ) the remove() method to be used is the one that expects an index.

Notice this line of error:

Caused by: java.lang.ArrayIndexOutOfBoundsException: length = 12; index = -458559

You are trying to remove the -458559 index, which is the value ArrayList has in position 3. ( Color.rgb(249, 0 ,193) )

One possible way to resolve this will be as follows:

Integer teste = colors.get(3);
colors.remove(teste);

or

int teste = colors.get(3);
colors.remove(colors.indexOf(teste));