如何为 android 键盘上的每个键设置背景。 KeyboardView android:keyBackground 为所有按键提供一个背景。但是我想为每个键设置不同的背景。

最佳答案

我自定义 MyKeyBoradView 扩展 KeyBoardView 并覆盖 onDraw 方法。

public class MyKeyBoardView extends KeyboardView {
    private Context  mContext;
    private Keyboard mKeyBoard;

    public MyKeyBoardView(Context context, AttributeSet attrs) {
        super(context, attrs);
        this.mContext = context;
    }

    public MyKeyBoardView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        this.mContext = context;
    }

    /**
     * ov
     */
    @Override
    public void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        mKeyBoard = this.getKeyboard();
        List<Key> keys = null;
        if (mKeyBoard != null) {
            keys = mKeyBoard.getKeys();
        }

        if (keys != null) {
            for (Key key : keys) {
                // TODO: 16/8/23  different key set the different background
                if (key.codes[0] == -4) {
                    drawKeyBackground(R.drawable.bg_keyboardview_yes, canvas, key);
                    drawText(canvas, key);
                }
            }
        }
    }

    private void drawKeyBackground(int drawableId, Canvas canvas, Key key) {
        Drawable npd = mContext.getResources().getDrawable(
                drawableId);
        int[] drawableState = key.getCurrentDrawableState();
        if (key.codes[0] != 0) {
            npd.setState(drawableState);
        }
        npd.setBounds(key.x, key.y, key.x + key.width, key.y
                + key.height);
        npd.draw(canvas);
    }

    private void drawText(Canvas canvas, Key key) {
        Rect bounds = new Rect();
        Paint paint = new Paint();
        paint.setTextAlign(Paint.Align.CENTER);


        paint.setAntiAlias(true);

        paint.setColor(Color.WHITE);
        if (key.label != null) {
            String label = key.label.toString();

            Field field;

            if (label.length() > 1 && key.codes.length < 2) {
                int labelTextSize = 0;
                try {
                    field = KeyboardView.class.getDeclaredField("mLabelTextSize");
                    field.setAccessible(true);
                    labelTextSize = spToPx((int) field.get(this));
                } catch (NoSuchFieldException e) {
                    e.printStackTrace();
                } catch (IllegalAccessException e) {
                    e.printStackTrace();
                }
                paint.setTextSize(labelTextSize);
                paint.setTypeface(Typeface.DEFAULT_BOLD);
            } else {
                int keyTextSize = 0;
                try {
                    field = KeyboardView.class.getDeclaredField("mLabelTextSize");
                    field.setAccessible(true);
                    keyTextSize = spToPx((int) field.get(this));
                } catch (NoSuchFieldException e) {
                    e.printStackTrace();
                } catch (IllegalAccessException e) {
                    e.printStackTrace();
                }
                paint.setTextSize(keyTextSize);
                paint.setTypeface(Typeface.DEFAULT);
            }

            paint.getTextBounds(key.label.toString(), 0, key.label.toString()
                    .length(), bounds);
            canvas.drawText(key.label.toString(), key.x + (key.width / 2),
                    (key.y + key.height / 2) + bounds.height() / 2, paint);
        } else if (key.icon != null) {
            key.icon.setBounds(key.x + (key.width - key.icon.getIntrinsicWidth()) / 2, key.y + (key.height - key.icon.getIntrinsicHeight()) / 2,
                    key.x + (key.width - key.icon.getIntrinsicWidth()) / 2 + key.icon.getIntrinsicWidth(), key.y + (key.height - key.icon.getIntrinsicHeight()) / 2 + key.icon.getIntrinsicHeight());
            key.icon.draw(canvas);
        }

    }
    public int spToPx(float sp) {
        return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, sp, getContext().getResources().getDisplayMetrics());
    }
}

实现效果如下

此链接:https://github.com/xuejinwei/NumberKeyboard

关于安卓键盘。 key 的背景，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/3185237/