Display multiple arrays to JTable

Question

I'm doing a very basic Java GUI app. but I don't know what I'm doing wrong in here.

This is what I have done so far:

 String[] colNames = { "QTY", "Item Code", "Amount" };

 model = new DefaultTableModel(colNames, 0);  
 JTable table = new JTable(model);

 String[] arrQty = {"2", "3", "10"};
 String[] arrItemCode = {"Item 1", "Item 2", "Item 3"};
 String[] arrAmount = {"100", "200", "80"};
 String f_qty, f_itemcode, f_amount;    

 for(String arrAmt: arrAmount){
    f_amount = arrAmt;
 }

 for(String arrQt : arrQty){
    f_qty = arrQt;
 }

 for(String arrItem : arrItemCode){
    f_itemcode = arrItem;
 }

 model.addRow(new Object[]{ f_qty, f_itemcode, f_amount });

But it won't allow me because compiler needs to initialize first the strings, how can I fix this issue? Any ideas?

sanbhat · Accepted Answer · 2014-01-09 08:16:15Z

2

Fix is initializing String with null OR empty string or any string

String f_qty= null, f_itemcode =null, f_amount =null;

Second point is, your logic seems to be wrong. You are setting the value to the table after iteration is finished. Should it be?

for(int i=0; i< arrQty.length; i++) {
    model.addRow(new Object[]{ arrQty[i], arrItemCode[i], arrAmount[i});
}

answered Jan 9, 2014 at 8:16

sanbhat

17.6k6 gold badges52 silver badges65 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

StoopidDonut Over a year ago

+1 removing my answer, this would suffice per OPs requirement :)

Dunkey Over a year ago

@sanbhat thanks. but let me ask is this efficient? If arrqty has only 2 elements while other arrays have more than 2 elements?

alex2410 · Accepted Answer · 2014-01-09 08:17:09Z

2

For initializing this variables you can use next line:

String f_qty="", f_itemcode="", f_amount="";

But seems for me, you just need to do next:

DefaultTableModel model = new DefaultTableModel(colNames, 0);  
JTable table = new JTable(model);

String[] arrQty = {"2", "3", "10"};
String[] arrItemCode = {"Item 1", "Item 2", "Item 3"};
String[] arrAmount = {"100", "200", "80"};

for(int i=0;i<arrQty.length;i++){
    model.addRow(new Object[]{ arrQty[i], arrItemCode[i], arrAmount[i] });
}

and result will be:

enter image description here

answered Jan 9, 2014 at 8:17

alex2410

11k3 gold badges29 silver badges41 bronze badges

2 Comments

Dunkey Over a year ago

thank you! This solves my problem. But is this method efficient? I mean what if the qty has only 2 elements and the other arrays have 5 elements?

alex2410 Over a year ago

I think you need to manage that by yourself, because only you know what need to display if arrays have different length.

René Link · Accepted Answer · 2014-01-09 08:25:45Z

In order to loop over the values of all arrays the arrays must have the same length or you might get an ArrayIndexOutOfBoundsException or miss some values.

Thus I would first introduce a check that makes it easier to find a problem in different array length.

String[] arrQty = { "2", "3", "10" };
String[] arrItemCode = { "Item 1", "Item 2", "Item 3" };
String[] arrAmount = { "100", "200", "80" };

if (arrQty.length != arrItemCode.length || arrQty.length != arrAmount.length) {
    throw new IllegalStateException("All arrays must have the same length." 
                                  + "arrQty[" + arrQty.length 
                                  + "], arritemCode[" + arrItemCode.length 
                                  + "], arrAmount[" + arrAmount.length + "]");
}

after that you can safely loop over the string arrays and add the rows to the table model.

for (int i = 0; i < arrQty.length; i++) {
    model.addRow(new Object[] { arrQty[i], arrItemCode[i], arrAmount[i]});
}

Qadir Hussain · Accepted Answer · 2014-01-09 08:17:25Z

0

Initialize your String variables with null.

answered Jan 9, 2014 at 8:17

Qadir Hussain

1,2611 gold badge10 silver badges26 bronze badges

Comments

Rahul · Accepted Answer · 2014-01-09 08:18:16Z

0

Use as below:

Create a initial empty 2D array of object:

Object[ ][ ] rowData = { };

Create Datamodel as below:

model = new DefaultTableModel(rowData,colNames);

Fill the table as your need.

answered Jan 9, 2014 at 8:18

Rahul

3,5193 gold badges19 silver badges29 bronze badges

Collectives™ on Stack Overflow

Display multiple arrays to JTable

5 Answers 5

2 Comments

2 Comments

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

5 Answers 5

2 Comments

2 Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related