Sudoku (Keypad.java)

package org.example.sudoku;
 
import android.app.Dialog;
import android.content.Context;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.View;
 
public class Keypad extends Dialog {
    protected static final String TAG = "Sudoku";
 
    private final View keys[] = new View[9];
    private View keypad;
 
    private final int useds[];
    private final PuzzleView puzzleView;
 
    public Keypad(Context context, int useds[], PuzzleView puzzleView) {
        super(context);
        this.useds = useds;
        this.puzzleView = puzzleView;
    }
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
 
        setTitle(R.string.keypad_title);
        setContentView(R.layout.keypad);
        findViews();
        for(int element : useds) {
            if(element != 0)
                keys[element - 1].setVisibility(View.INVISIBLE);
        }
        setListeners();
    }
 
    private void findViews() {
        keypad = findViewById(R.id.keypad);
        keys[0] = findViewById(R.id.keypad_1);
        keys[1] = findViewById(R.id.keypad_2);
        keys[2] = findViewById(R.id.keypad_3);
        keys[3] = findViewById(R.id.keypad_4);
        keys[4] = findViewById(R.id.keypad_5);
        keys[5] = findViewById(R.id.keypad_6);
        keys[6] = findViewById(R.id.keypad_7);
        keys[7] = findViewById(R.id.keypad_8);
        keys[8] = findViewById(R.id.keypad_9);
    }
 
    private void setListeners() {
        for(int i = 0; i < keys.length; i++) {
            final int t = i + 1;
            keys[i].setOnClickListener(new View.OnClickListener() {
                public void onClick(View v) {
                    returnResult(t);
                }});
        }
        keypad.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                returnResult(0);
            }});
    }
 
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        int tile = 0;
        switch(keyCode) {
        case KeyEvent.KEYCODE_0:
        case KeyEvent.KEYCODE_SPACE: tile = 0; break;
        case KeyEvent.KEYCODE_1:     tile = 1; break;
        case KeyEvent.KEYCODE_2:     tile = 2; break;
        case KeyEvent.KEYCODE_3:     tile = 3; break;
        case KeyEvent.KEYCODE_4:     tile = 4; break;
        case KeyEvent.KEYCODE_5:     tile = 5; break;
        case KeyEvent.KEYCODE_6:     tile = 6; break;
        case KeyEvent.KEYCODE_7:     tile = 7; break;
        case KeyEvent.KEYCODE_8:     tile = 8; break;
        case KeyEvent.KEYCODE_9:     tile = 9; break;
        default:
            return super.onKeyDown(keyCode, event);
        }
        if(isValid(tile)) {
            returnResult(tile);
        }
        return true;
    }
 
    private boolean isValid(int tile) {
        for(int t : useds) {
            if(tile == t) return false;
        }
        return true;
    }
 
    /** Return the chosen tile to the caller */
    private void returnResult(int tile) {
        puzzleView.setSelectedTile(tile);
        dismiss();
    }
}