在TableLayout中动态加载按钮

Question

I am trying to create buttons dynamically in my Android code. I have a string array defnied based on which I figure out how many buttons to load and the text for every button is picked from that string array. I have written the code below for the same on my Activity onCreate() . The code is not working. There are no errors but I don't see the buttons when my activity loads. I do see some space being taken up on the screen but buttons are not there. Can someone spot any issues here to help.

Code below

TableLayout table = (TableLayout) findViewById(R.id.tableLayoutCategoryButtons);
int buttonsInRow = 3;//number of buttons in each row
String[] itemNames = getResources().getStringArray(R.array.categories_array);
int numRows = (itemNames.length / buttonsInRow);
//round off numRows to next integer. e.g. for 10 items in array there will be (10/3) +1=4 rows
if (itemNames.length % buttonsInRow != 0)
    numRows++;
TableRow[] tr = new TableRow[numRows];
Button[] buttons = new Button[itemNames.length];
int rowcount = 0;
for (int i = 0; i < itemNames.length; i++) {
    buttons[i] = new Button(table.getContext(), null, android.R.attr.buttonStyleSmall);
    buttons[i].setText(itemNames[i]);
    buttons[i].setTextColor(Color.BLACK);
    buttons[i].setVisibility(View.VISIBLE);
    buttons[i].setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
    tr[rowcount] = new TableRow(table.getContext());
    tr[rowcount].setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT));
    tr[rowcount].addView(buttons[i]);

    //change of tablerow, once a multiple of 3 reached. 
    if (((i + 1) % buttonsInRow == 0) && (i != 0)) {
        tr[rowcount].setVisibility(View.VISIBLE);
        table.addView(tr[rowcount]);

        rowcount++;
    }
}

As you can see I am creating a TableRows with three buttons each in a row. And then adding the tablerow to TableLayout view. And my activity xml below

<RelativeLayout
    android:id="@+id/relativeLayoutCategoryHeader"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal" >
    <TableLayout 
        android:id="@+id/tableLayoutCategoryButtons"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:stretchColumns="0,1,2">
    </TableLayout>
 </RelativeLayout>

Answer 1

I made a few changes. Hope it works for you.

        LinearLayout[] tablerowLayout = new LinearLayout[numRows];
        tablerowLayout[0] = new LinearLayout(table.getContext());
        int rowcount=0;
        for (int i=0; i<itemNames.length; i++){
            buttons[i]= new Button(table.getContext(), null, android.R.attr.buttonStyleSmall);
            buttons[i].setText(itemNames[i]);
            buttons[i].setTextColor(Color.BLACK);
            buttons[i].setVisibility(View.VISIBLE);

            LinearLayout.LayoutParams buttonLayoutParams = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
            tablerowLayout[rowcount].addView(buttons[i], buttonLayoutParams);

            if (((i+1)%buttonsInRow==0)&&(i!=0)){
                table.addView(tablerowLayout[rowcount++]);
                if(rowcount<numRows)
                    tablerowLayout[rowcount] = new LinearLayout(table.getContext());
            }
        }
        if(rowcount<numRows)
            table.addView(tablerowLayout[rowcount]);

Answer 2

I think your loop may be a bit off here.

Looking at your original code -> you are adding a row for every button (so each button has it's own row). You also then reset the tr[rowcount] ie tr[0] gets set about 4 times, each time only having 1 button added to it.

Below I did a quick fix, it might not work, but it sort of shows how you would only want to add a row when necessary (and not rewrite it evertime). (Gotta catch a bus)

rowCount = 0;
int lastRowAdded = 0;
for (int i=0; i<itemNames.length; i++){

    if (i % buttonsInRow == 0){
        tr[rowcount] = new TableRow(table.getContext());
        tr[rowcount].setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.WRAP_CONTENT));

        tr[rowcount].setVisibility(View.VISIBLE);

        table.addView(tr[rowcount]);
        lastRowAdded = rowCount;
        rowcount++;
    }

    buttons[i]= new Button(table.getContext(),null,android.R.attr.buttonStyleSmall);
    buttons[i].setText(itemNames[i]);
    buttons[i].setTextColor(Color.BLACK);
    buttons[i].setVisibility(View.VISIBLE);
    buttons[i].setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT));
    tr[lastRowAdded].addView(buttons[i]);