Question

当我在tableviewcell的文本字段中填写内容时，我想启用视图控制器中的按钮。

我不知道如何解决问题。

对不起。我英文不成熟。

button（viewController）isEnable = false
填充文本字段（在tableviewcell内部）
button（viewController）isEnable = true

1。 ViewController

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="container2">
  <div class="containerr">
    <div class="pic" id="content">
      <div id="container">

        <div class="box" ondrop="drop(event)" ondragover="allowDrop(event)" id="10">
          <p name="values"></p>
        </div>
        <div class="box" ondrop="drop(event)" ondragover="allowDrop(event)" id="11">
          <p name="values"></p>
        </div>
        <div class="box" ondrop="drop(event)" ondragover="allowDrop(event)" id="12">
          <p name="values"></p>
        </div>
        <div class="box" ondrop="drop(event)" ondragover="allowDrop(event)" id="13">
          <p name="values"></p>
        </div>
      </div>
    </div>
  </div>
</div>

<div class="box002" draggable="true" ondragstart="drag(event)" id="2">
  <img src="" draggable="true" id="slide" border="rounded" />
</div>

2。 CustomTableView

import UIKit

class ViewController: UIViewController, UITableViewDataSource, UITableViewDelegate, UITextFieldDelegate {

    @IBOutlet var tableView: UITableView!
    @IBOutlet var viewLabel: UILabel!
    @IBOutlet var clickBtn: UIButton!

    var cell: CustomTableViewCell!

    override func viewDidLoad() {
        super.viewDidLoad()

        self.clickBtn.isEnabled = false
        cell.textFieldCell.addTarget(self, action: #selector(editingChanged), for: .editingChanged)
        cell.textFieldCell2.addTarget(self, action: #selector(editingChanged), for: .editingChanged)
    }

    @objc func editingChanged(sender: UITextField) {

        sender.text = sender.text?.trimmingCharacters(in: .whitespaces)

        guard
            let text1 = cell.textFieldCell.text, !text1.isEmpty,
            let text2 = cell.textFieldCell2.text, !text2.isEmpty
            else
        {
            self.clickBtn.isEnabled = false
            return
        }
        clickBtn.isEnabled = true
    }

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 1
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        cell = tableView.dequeueReusableCell(withIdentifier: "myCell", for: indexPath) as! CustomTableViewCell
        return cell
    }
}

Answer 1

由于表格视图仅包含一个单元格，为什么要完全使用表格视图？
而且，如果您确实需要使用表格视图，为什么不使用静态单元格呢？

一个简单的解决方案是将目标/操作代码从viewDidLoad移到单元格的didSet属性观察器中

var cell: CustomTableViewCell! {
    didSet {
        cell.textFieldCell.addTarget(self, action: #selector(editingChanged), for: .editingChanged)
        cell.textFieldCell2.addTarget(self, action: #selector(editingChanged), for: .editingChanged)
    }
}

override func viewDidLoad() {
    super.viewDidLoad()

    self.clickBtn.isEnabled = false
}

Answer 2

一种选择是使用委托。

/**
 * Text view that auto adjusts text size to fit within the view.
 * If the text size equals the minimum text size and still does not
 * fit, append with an ellipsis.
 */
public class AutoResizeTextView extends android.support.v7.widget.AppCompatTextView {

    // Minimum text size for this text view
    public static final float MIN_TEXT_SIZE = 20;

    // Interface for resize notifications
    public interface OnTextResizeListener {
        public void onTextResize(TextView textView, float oldSize, float newSize);
    }

    // Our ellipse string
    private static final String mEllipsis = "...";

    // Registered resize listener
    private OnTextResizeListener mTextResizeListener;

    // Flag for text and/or size changes to force a resize
    private boolean mNeedsResize = false;

    // Text size that is set from code. This acts as a starting point for resizing
    private float mTextSize;

    // Temporary upper bounds on the starting text size
    private float mMaxTextSize = 0;

    // Lower bounds for text size
    private float mMinTextSize = MIN_TEXT_SIZE;

    // Text view line spacing multiplier
    private float mSpacingMult = 1.0f;

    // Text view additional line spacing
    private float mSpacingAdd = 0.0f;

    // Add ellipsis to text that overflows at the smallest text size
    private boolean mAddEllipsis = true;

    // Default constructor override
    public AutoResizeTextView(Context context) {
        this(context, null);
    }

    // Default constructor when inflating from XML file
    public AutoResizeTextView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    // Default constructor override
    public AutoResizeTextView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        mTextSize = getTextSize();
    }

    /**
     * When text changes, set the force resize flag to true and reset the text size.
     */
    @Override
    protected void onTextChanged(final CharSequence text, final int start, final int before, final int after) {
        mNeedsResize = true;
        // Since this view may be reused, it is good to reset the text size
        resetTextSize();
    }

    /**
     * If the text view size changed, set the force resize flag to true
     */
    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        if (w != oldw || h != oldh) {
            mNeedsResize = true;
        }
    }

    /**
     * Register listener to receive resize notifications
     *
     * @param listener
     */
    public void setOnResizeListener(AutoResizeTextView.OnTextResizeListener listener) {
        mTextResizeListener = listener;
    }

    /**
     * Override the set text size to update our internal reference values
     */
    @Override
    public void setTextSize(float size) {
        super.setTextSize(size);
        mTextSize = getTextSize();
    }

    /**
     * Override the set text size to update our internal reference values
     */
    @Override
    public void setTextSize(int unit, float size) {
        super.setTextSize(unit, size);
        mTextSize = getTextSize();
    }

    /**
     * Override the set line spacing to update our internal reference values
     */
    @Override
    public void setLineSpacing(float add, float mult) {
        super.setLineSpacing(add, mult);
        mSpacingMult = mult;
        mSpacingAdd = add;
    }

    /**
     * Set the upper text size limit and invalidate the view
     *
     * @param maxTextSize
     */
    public void setMaxTextSize(float maxTextSize) {
        mMaxTextSize = maxTextSize;
        requestLayout();
        invalidate();
    }

    /**
     * Return upper text size limit
     *
     * @return
     */
    public float getMaxTextSize() {
        return mMaxTextSize;
    }

    /**
     * Set the lower text size limit and invalidate the view
     *
     * @param minTextSize
     */
    public void setMinTextSize(float minTextSize) {
        mMinTextSize = minTextSize;
        requestLayout();
        invalidate();
    }

    /**
     * Return lower text size limit
     *
     * @return
     */
    public float getMinTextSize() {
        return mMinTextSize;
    }

    /**
     * Set flag to add ellipsis to text that overflows at the smallest text size
     *
     * @param addEllipsis
     */
    public void setAddEllipsis(boolean addEllipsis) {
        mAddEllipsis = addEllipsis;
    }

    /**
     * Return flag to add ellipsis to text that overflows at the smallest text size
     *
     * @return
     */
    public boolean getAddEllipsis() {
        return mAddEllipsis;
    }

    /**
     * Reset the text to the original size
     */
    public void resetTextSize() {
        if (mTextSize > 0) {
            super.setTextSize(TypedValue.COMPLEX_UNIT_PX, mTextSize);
            mMaxTextSize = mTextSize;
        }
    }

    /**
     * Resize text after measuring
     */
    @Override
    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
        if (changed || mNeedsResize) {
            int widthLimit = (right - left) - getCompoundPaddingLeft() - getCompoundPaddingRight();
            int heightLimit = (bottom - top) - getCompoundPaddingBottom() - getCompoundPaddingTop();
            resizeText(widthLimit, heightLimit);
        }
        super.onLayout(changed, left, top, right, bottom);
    }

    /**
     * Resize the text size with default width and height
     */
    public void resizeText() {
        int heightLimit = getHeight() - getPaddingBottom() - getPaddingTop();
        int widthLimit = getWidth() - getPaddingLeft() - getPaddingRight();
        resizeText(widthLimit, heightLimit);
    }

    /**
     * Resize the text size with specified width and height
     *
     * @param width
     * @param height
     */
    public void resizeText(int width, int height) {
        CharSequence text = getText();
        // Do not resize if the view does not have dimensions or there is no text
        if (text == null || text.length() == 0 || height <= 0 || width <= 0 || mTextSize == 0) {
            return;
        }

        if (getTransformationMethod() != null) {
            text = getTransformationMethod().getTransformation(text, this);
        }

        // Get the text view's paint object
        TextPaint textPaint = getPaint();

        // Store the current text size
        float oldTextSize = textPaint.getTextSize();
        // If there is a max text size set, use the lesser of that and the default text size
        float targetTextSize = mMaxTextSize > 0 ? Math.min(mTextSize, mMaxTextSize) : mTextSize;

        // Get the required text height
        int textHeight = getTextHeight(text, textPaint, width, targetTextSize);

        // Until we either fit within our text view or we had reached our min text size, incrementally try smaller sizes
        while (textHeight > height && targetTextSize > mMinTextSize) {
            targetTextSize = Math.max(targetTextSize - 2, mMinTextSize);
            textHeight = getTextHeight(text, textPaint, width, targetTextSize);
        }

        // If we had reached our minimum text size and still don't fit, append an ellipsis
        if (mAddEllipsis && targetTextSize == mMinTextSize && textHeight > height) {
            // Draw using a static layout
            // modified: use a copy of TextPaint for measuring
            TextPaint paint = new TextPaint(textPaint);
            // Draw using a static layout
            StaticLayout layout = new StaticLayout(text, paint, width, Layout.Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, false);
            // Check that we have a least one line of rendered text
            if (layout.getLineCount() > 0) {
                // Since the line at the specific vertical position would be cut off,
                // we must trim up to the previous line
                int lastLine = layout.getLineForVertical(height) - 1;
                // If the text would not even fit on a single line, clear it
                if (lastLine < 0) {
                    setText("");
                }
                // Otherwise, trim to the previous line and add an ellipsis
                else {
                    int start = layout.getLineStart(lastLine);
                    int end = layout.getLineEnd(lastLine);
                    float lineWidth = layout.getLineWidth(lastLine);
                    float ellipseWidth = textPaint.measureText(mEllipsis);

                    // Trim characters off until we have enough room to draw the ellipsis
                    while (width < lineWidth + ellipseWidth) {
                        lineWidth = textPaint.measureText(text.subSequence(start, --end + 1).toString());
                    }
                    setText(text.subSequence(0, end) + mEllipsis);
                }
            }
        }

        // Some devices try to auto adjust line spacing, so force default line spacing
        // and invalidate the layout as a side effect
        setTextSize(TypedValue.COMPLEX_UNIT_PX, targetTextSize);
        setLineSpacing(mSpacingAdd, mSpacingMult);

        // Notify the listener if registered
        if (mTextResizeListener != null) {
            mTextResizeListener.onTextResize(this, oldTextSize, targetTextSize);
        }

        // Reset force resize flag
        mNeedsResize = false;
    }

    // Set the text size of the text paint object and use a static layout to render text off screen before measuring
    private int getTextHeight(CharSequence source, TextPaint paint, int width, float textSize) {
        // modified: make a copy of the original TextPaint object for measuring
        // (apparently the object gets modified while measuring, see also the
        // docs for TextView.getPaint() (which states to access it read-only)
        TextPaint paintCopy = new TextPaint(paint);
        // Update the text paint object
        paintCopy.setTextSize(textSize);
        // Measure using a static layout
        StaticLayout layout = new StaticLayout(source, paintCopy, width, Layout.Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, true);
        return layout.getHeight();
    }
}

在表格视图单元格

protocol CustomTableViewCellDelegate  { 
    func editingChanged(_ String: yourString)    
}

用于tableViewController中。首先在indexpath方法中将委托分配给self in cell for row。然后在其中实现委托。

class TableViewCell: UITaleViewCell { 
    // declare the delegate 
    var delegate: CustomTableViewCellDelegate? 
    // and pass it like this from where you want to pass 
    delegate?.editingChanged(cookie) 
}

在所有文本字段填充tableviewcell（SWIFT）时如何启用按钮

2 个答案: