IllegalAccessException when reading values with reflection

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IllegalAccessException when reading values with reflection

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#1 by (1 votes)

1

I can not read the values of the class attributes with reflection:

    ContentValues values = new ContentValues();

    Field[] fields = this.getClass().getDeclaredFields();

    for (Field field: fields ) {
        field.setAccessible(true);
        values.put(field.getName(), field.get(this.getClass()));
    }

I have the exception: IllegalAccessException in the get method: field.get(this.getClass()) I also tried field.get(this) and still passing the instance of object field.get(model)

The attributes of the model object are not private. If you do not use the field.setAccessible(true); method, the exception is the same.

At the request of your friend Ramaral, follow the whole class:

public class GenericModel {

    public Long id;

    public ContentValues GetContentValues()
    {
        ContentValues values = new ContentValues();

        Field[] fields = this.getClass().getDeclaredFields();

        for (Field field: fields ) {
            field.setAccessible(true);

            try {
                values.put(field.getName(), field.get(this.getClass()));
            } catch (IllegalAccessException e) {

            }
        }

        return values;
    }
}

java android

asked by anonymous 04.03.2017 / 20:22

1 answer

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score 1 · Accepted Answer

You have 3 things wrong with your code:

The Field # get () method returns an object, it is necessary to cast to a type that the ContentValues # put () accepts and this type must be compatible with the type of attribute in question.

(Long)field.get(...)

The Field # get () method must be passed to the object containing the attribute represented by this field and whose value is to be obtained.

(Long)field.get(this)

The id attribute must be initialized.

public Long id = 3l;

The changes will look like this:

public class GenericModel {

    public Long id = 3l;

    public ContentValues GetContentValues()
    {
        ContentValues values = new ContentValues();

        Field[] fields = this.getClass().getDeclaredFields();

        for (Field field: fields ) {
            field.setAccessible(true);

            try {
                values.put(field.getName(), (Long)field.get(this));
            } catch (IllegalAccessException e) {
                //Faça algo aqui, nem que seja apenas um log
            }
        }

        return values;
    }
}

Note:
If GenericModel has more attributes and they are not all of type Long you will need to change the GetContentValues() method to handle this situation.