如何在自定义视图组的按钮中垂直居中放置文本

Question

I am building a custom ViewGroup, GridViewGroup, to emulate a simple GridLayout (which I can't use because my target Android version doesn't support it). In the grid, I want an array of GridButton's (a GridButton is a simply extended Button). It's working pretty well: I can build a grid of whatever size I want, and the GridButton's properly resize themselves. However, I cannot make the text vertically center in the GridButton's -- horizontal gravity is honored, but it doesn't appear that vertical gravity is.

I've tried using LayoutParams on the buttons, but the ViewGroup LayoutParams don't support gravity (at least there is no setGravity() method).

I hope I'm missing something obvious.

Here's the code for GridViewGroup...

public class GridViewGroup extends ViewGroup {

    protected int rowCount;
    protected int columnCount;

    public GridViewGroup(Context context) {
        super(context);
        rowCount = 4;
        columnCount = 4;
    }

    public GridViewGroup(Context context, AttributeSet attrs) {
        super(context, attrs);
        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.GridViewGroup);
        rowCount = a.getInt(R.styleable.GridViewGroup_rowCount, 1);
        columnCount = a.getInt(R.styleable.GridViewGroup_columnCount, 1);
        a.recycle();
    }

    @Override
    public void onLayout(boolean changed, int left, int top, int right, int bottom) {

        int pl = getPaddingLeft();
        int pt = getPaddingTop();
        int pr = getPaddingRight();
        int pb = getPaddingBottom();

        int cellSize1 = (right - left + 1 - pl - pr) / rowCount;
        int cellSize2 = (bottom - top + 1 - pt - pb) / columnCount;
        if (cellSize2 < cellSize1)
            cellSize1 = cellSize2;
        Log.i("GridViewGroup", "onLayout: " + String.valueOf(left) + "," + String.valueOf(top) + "," + String.valueOf(right) + "," + String.valueOf(bottom) + "," + String.valueOf(cellSize1));

        for (int i = 0; i < getChildCount(); i++) {
            GridButton gb = (GridButton)getChildAt(i);
            int l = left + pl + gb.layout_column * cellSize1;
            int t = top + pt + gb.layout_row * cellSize1;
            int r = l + gb.layout_columnSpan * cellSize1 - 1;
            int b = t + gb.layout_rowSpan * cellSize1 - 1;
            gb.setTextSize(TypedValue.COMPLEX_UNIT_PX, cellSize1 * 0.25f);
            gb.setGravity(Gravity.CENTER);
            gb.layout(l, t, r, b);
        }

    }

... and here's the code for GridButton ...

public class GridButton extends Button {

    protected int layout_row;
    protected int layout_column;
    protected int layout_rowSpan;
    protected int layout_columnSpan;

    public GridButton(Context context) {
        super(context);
        layout_row = 0;
        layout_column = 0;
        layout_rowSpan = 1;
        layout_rowSpan = 1;
    }

    public GridButton(Context context, AttributeSet attrs) {
        super(context, attrs);
        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.GridButton);
        layout_row = a.getInt(R.styleable.GridButton_layout_row, 0);
        layout_column = a.getInt(R.styleable.GridButton_layout_column, 0);
        layout_rowSpan = a.getInt(R.styleable.GridButton_layout_rowSpan, 1);
        layout_columnSpan = a.getInt(R.styleable.GridButton_layout_columnSpan, 1);
    }
}

Thanks in advance for your help!

Answer 1

I am building a custom ViewGroup, GridViewGroup, to emulate a simple GridLayout (which I can't use because my target Android version doesn't support it).

I haven't used it before, but I read that the most recent version of the Android compatibility library contains a GridLayout.