如何将2D数组从一个活动传递到另一个活动（包括该数组包含的所有信息）

Question

I have a 2D array setup in Activity A which I would then like to use in activity B. I have looked at varying examples online but cant get any to work properly.

The code below compiles OK but I get an error with my Toast of java.lang.nullpointerexception. so it looks to me as if my array structure is being passed through but the contents are null . Any help is greatly appreciated.

Here is what I have so far.:

Activity A

String[][] Question=new String[100][100];

Bundle b = new Bundle();
b.putSerializable("questionset", Question);
Intent intent = new Intent(this, QuizActivity.class);
startActivity(intent);

Activity B

    try{

        Bundle b=this.getIntent().getExtras();
        String[][] Questions = (String[][]) b.getSerializable("questionset");        
        Toast.makeText(this, Questions[2][1].toString(), Toast.LENGTH_SHORT).show();
    }

    catch(Exception e){
    Toast.makeText(this, e.toString(), Toast.LENGTH_SHORT).show();

    }

Answer 1

I solve those problems always with a storage object class which is a singleton and where i can save such objects.

public class Model
{
    private static Model instance;

    private Model()
    {
        // singleton implementation
    }

    /**
     * Returns a valid instance of the model.
     * 
     * @return THE instance of the model.
     */
    public static Model getInstance()
    {

        if (instance == null)
        {
            instance = new Model();
        }

        return instance;
    }

    private String[][] arr;
    // + getter and setter methods for arr
}

Answer 2

String[][] Question=new String[100][100]; 
Question[2][1]="sample";    // here
Bundle b = new Bundle(); 
b.putSerializable("questionset", Question); 
Intent intent = new Intent(this, QuizActivity.class); 
intent.putExtras(b);    // here
startActivity(intent); 

Your code lacks initialization of array contents and passing it to intent. Is it intentional? For me the above code works pretty well.