android ellipsize multiline textview

Question

I need to ellipsize a multi-line textview. My component is large enough to display at least 4 lines with the ellipse, but only 2 lines are displayed. I tried to change the minimum and maximum number of rows of the component but it changes nothing.

Answer 1

Here is a solution to the problem. It is a subclass of TextView that actually works for ellipsizing. The android-textview-multiline-ellipse code listed in an earlier answer I have found to be buggy in certain circumstances, as well as being under GPL, which doesn't really work for most of us. Feel free to use this code freely and without attribution, or under the Apache license if you would prefer. Note that there is a listener to notify you when the text becomes ellipsized, which I found quite useful myself.

import java.util.ArrayList;
import java.util.List;

import android.content.Context;
import android.graphics.Canvas;
import android.text.Layout;
import android.text.Layout.Alignment;
import android.text.StaticLayout;
import android.text.TextUtils.TruncateAt;
import android.util.AttributeSet;
import android.widget.TextView;

public class EllipsizingTextView extends TextView {
    private static final String ELLIPSIS = "...";

    public interface EllipsizeListener {
        void ellipsizeStateChanged(boolean ellipsized);
    }

    private final List<EllipsizeListener> ellipsizeListeners = new ArrayList<EllipsizeListener>();
    private boolean isEllipsized;
    private boolean isStale;
    private boolean programmaticChange;
    private String fullText;
    private int maxLines = -1;
    private float lineSpacingMultiplier = 1.0f;
    private float lineAdditionalVerticalPadding = 0.0f;

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

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

    public EllipsizingTextView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    public void addEllipsizeListener(EllipsizeListener listener) {
        if (listener == null) {
            throw new NullPointerException();
        }
        ellipsizeListeners.add(listener);
    }

    public void removeEllipsizeListener(EllipsizeListener listener) {
        ellipsizeListeners.remove(listener);
    }

    public boolean isEllipsized() {
        return isEllipsized;
    }

    @Override
    public void setMaxLines(int maxLines) {
        super.setMaxLines(maxLines);
        this.maxLines = maxLines;
        isStale = true;
    }

    public int getMaxLines() {
        return maxLines;
    }

    @Override
    public void setLineSpacing(float add, float mult) {
        this.lineAdditionalVerticalPadding = add;
        this.lineSpacingMultiplier = mult;
        super.setLineSpacing(add, mult);
    }

    @Override
    protected void onTextChanged(CharSequence text, int start, int before, int after) {
        super.onTextChanged(text, start, before, after);
        if (!programmaticChange) {
            fullText = text.toString();
            isStale = true;
        }
    }

    @Override
    protected void onDraw(Canvas canvas) {
        if (isStale) {
            super.setEllipsize(null);
            resetText();
        }
        super.onDraw(canvas);
    }

    private void resetText() {
        int maxLines = getMaxLines();
        String workingText = fullText;
        boolean ellipsized = false;
        if (maxLines != -1) {
            Layout layout = createWorkingLayout(workingText);
            if (layout.getLineCount() > maxLines) {
                workingText = fullText.substring(0, layout.getLineEnd(maxLines - 1)).trim();
                while (createWorkingLayout(workingText + ELLIPSIS).getLineCount() > maxLines) {
                    int lastSpace = workingText.lastIndexOf(' ');
                    if (lastSpace == -1) {
                        break;
                    }
                    workingText = workingText.substring(0, lastSpace);
                }
                workingText = workingText + ELLIPSIS;
                ellipsized = true;
            }
        }
        if (!workingText.equals(getText())) {
            programmaticChange = true;
            try {
                setText(workingText);
            } finally {
                programmaticChange = false;
            }
        }
        isStale = false;
        if (ellipsized != isEllipsized) {
            isEllipsized = ellipsized;
            for (EllipsizeListener listener : ellipsizeListeners) {
                listener.ellipsizeStateChanged(ellipsized);
            }
        }
    }

    private Layout createWorkingLayout(String workingText) {
        return new StaticLayout(workingText, getPaint(), getWidth() - getPaddingLeft() - getPaddingRight(),
                Alignment.ALIGN_NORMAL, lineSpacingMultiplier, lineAdditionalVerticalPadding, false);
    }

    @Override
    public void setEllipsize(TruncateAt where) {
        // Ellipsize settings are not respected
    }
}