android-calculatorpp/android-app/src/main/java/org/solovyev/android/calculator/matrix/MatrixView.java

package org.solovyev.android.calculator.matrix;

import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import android.widget.EditText;
import android.widget.TableLayout;
import android.widget.TableRow;
import android.widget.TextView;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

/**
 * User: Solovyev_S
 * Date: 12.10.12
 * Time: 15:41
 */
public class MatrixView extends TableLayout {

    /*
    **********************************************************************
    *
    *                           CONSTANTS
    *
    **********************************************************************
    */

    private static final CharSequence DEFAULT_CELL_TEXT = "0";
    private static final int NUMBER_INDEX = -1;


    /*
    **********************************************************************
    *
    *                           FIELDS
    *
    **********************************************************************
    */

    private int rows = 0;
    private int cols = 0;

    @Nullable
    private CharSequence defaultCellText = DEFAULT_CELL_TEXT;

    private boolean initialized = false;

    /*
    **********************************************************************
    *
    *                           CONSTRUCTORS
    *
    **********************************************************************
    */

    public MatrixView(Context context) {
        super(context);
    }

    public MatrixView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    /*
    **********************************************************************
    *
    *                           METHODS
    *
    **********************************************************************
    */

    public int getRows() {
        return rows;
    }

    public int getCols() {
        return cols;
    }

    public void setMatrixCols(int newCols) {
        setMatrixDimensions(rows, newCols);
    }

    public void setMatrixRows(int newRows) {
        setMatrixDimensions(newRows, cols);
    }

    public void setMatrixDimensions(int newRows, int newCols) {
        if (newRows <= 1) {
            throw new IllegalArgumentException("Number of rows must be more than 1: " + newRows);
        }

        if (newCols <= 1) {
            throw new IllegalArgumentException("Number of columns must be more than 1: " + newCols);
        }

        boolean rowsChanged = this.rows != newRows;
        boolean colsChanged = this.cols != newCols;

        if (rowsChanged || colsChanged) {
            if (!initialized) {
                addRow(NUMBER_INDEX, 0);
                initialized = true;
            }

            if (this.cols > newCols) {
                removeCols(newCols);
            } else if (this.cols < newCols) {
                addCols(newCols);
            }

            this.cols = newCols;

            if (this.rows > newRows) {
                removeRows(newRows);
            } else if (this.rows < newRows) {
                addRows(newRows);
            }

            this.rows = newRows;
        }
    }

    public void setMatrix(@NotNull Object[][] matrix) {
        final int rows = matrix.length;
        final int cols = matrix[0].length;

        setMatrixDimensions(rows, cols);
        for (int row = 0; row < rows; row++) {
            for (int col = 0; col < cols; col++) {
                setCell(row, col, matrix[row][col]);
            }
        }
    }

    @NotNull
    public String[][] toMatrix() {
        final String[][] result = new String[rows][cols];

        for (int row = 0; row < rows; row++) {
            for (int col = 0; col < cols; col++) {
                final TextView cellTextView = (TextView) getCell(this, row, col);
                if (cellTextView != null) {
                    result[row][col] = cellTextView.getText().toString();
                }
            }
        }

        return result;
    }

    private void setCell(int row, int col, @Nullable Object o) {
        final TextView cellTextView = (TextView) getCell(this, row, col);
        if (cellTextView != null) {
            if (o == null) {
                cellTextView.setText(null);
            } else {
                cellTextView.setText(String.valueOf(o));
            }
        }
    }

    /*
    **********************************************************************
    *
    *                           PRIVATE METHODS
    *
    **********************************************************************
    */

    private void addRows(int newRows) {
        for (int row = this.rows; row < newRows; row++) {
            addRow(row, cols);
        }
    }

    private void removeRows(int newRows) {
        for (int row = this.rows - 1; row >= newRows; row--) {
            removeRow(row);
        }
    }

    private void addCols(int newCols) {
        for (int row = NUMBER_INDEX; row < rows; row++) {
            final ViewGroup rowView = getRow(row);
            if (rowView != null) {
                for (int col = this.cols; col < newCols; col++) {
                    rowView.addView(createCellView(row, col));
                }
            }
        }
    }

    private void removeCols(int newCols) {
        for (int row = NUMBER_INDEX; row < rows; row++) {
            final ViewGroup rowView = getRow(row);
            if (rowView != null) {
                for (int col = this.cols - 1; col >= newCols; col--) {
                    final View cellView = getCell(rowView, row, col);
                    if (cellView != null) {
                        rowView.removeView(cellView);
                    }
                }
            }
        }
    }

    private void addRow(int row, int newCols) {
        this.addView(createRowView(row, newCols));
    }

    private void removeRow(int row) {
        final View rowView = getRow(row);
        if (rowView != null) {
            this.removeView(rowView);
        }
    }

    @Nullable
    private TableRow getRow(int row) {
        return (TableRow) this.findViewWithTag(getRowTag(row));
    }

    @Nullable
    private View getCell(@NotNull View view, int row, int col) {
        return view.findViewWithTag(getCellTag(row, col));
    }

    @NotNull
    private String getRowTag(int row) {
        if (row != NUMBER_INDEX) {
            return "row_" + row;
        } else {
            return "row_index";
        }
    }

    @NotNull
    private View createRowView(int row, int cols) {
        final ViewGroup rowView = new TableRow(this.getContext());

        rowView.setTag(getRowTag(row));

        if (row != NUMBER_INDEX) {
            rowView.addView(createCellView(row, NUMBER_INDEX));
        } else {
            // empty cell
            rowView.addView(new View(this.getContext()));
        }

        for (int col = 0; col < cols; col++) {
            rowView.addView(createCellView(row, col));
        }
        return rowView;
    }

    @NotNull
    private View createCellView(int row, int col) {
        final TextView result;

        if (row != NUMBER_INDEX && col != NUMBER_INDEX) {
            result = new EditText(this.getContext());
            result.setText(defaultCellText);
        } else {
            result = new TextView(this.getContext());
            if (row == NUMBER_INDEX) {
                result.setText(String.valueOf(col + 1));
            } else {
                result.setText(String.valueOf(row + 1));
            }
        }

        result.setTag(getCellTag(row, col));

        return result;

    }

    @NotNull
    private String getCellTag(int row, int col) {
        if (row != NUMBER_INDEX) {
            return "cell_" + row + "_" + col;
        } else {
            return "cell_index_" + col;
        }
    }

}