我正在寻找一种最佳的方法来调整包装文本在一个TextView,使它将适合它的getHeight和getWidth界限。我不是简单地寻找一种方法来包装文本-我想确保它既包装,又足够小,完全适合在屏幕上。

我在StackOverflow上看到了一些需要自动调整大小的情况,但它们要么是非常特殊的情况下的hack解决方案,没有解决方案,或涉及重新绘制TextView递归直到它足够小(这是内存紧张,迫使用户观看文本收缩一步一步与每次递归)。

但我相信有人已经找到了一个很好的解决方案,它不涉及我正在做的事情:编写几个繁重的例程来解析和测量文本,调整文本的大小,然后重复,直到找到一个合适的小尺寸。

TextView使用什么例程来包装文本?难道这些不能用来预测文本是否足够小吗?

是否有一个最佳实践的方法来自动调整TextView的大小,以适应,包装,在它的getHeight和getWidth边界?


当前回答

感谢Chase和onoelle,对于懒惰的程序员,让我在这里发布一个他们神奇的合并代码的工作版本,在一个按钮上改编,而不是一个TextView。

用AutoResizeTextButtons替换所有的按钮(不是ImageButtons),同样无聊的问题也得到了解决。

这是代码。我只是删除了导入。

/**
 *            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
 *                    Version 2, December 2004
 * 
 * Copyright (C) 2004 Sam Hocevar <sam@hocevar.net>
 * 
 * Everyone is permitted to copy and distribute verbatim or modified
 * copies of this license document, and changing it is allowed as long
 * as the name is changed.
 * 
 *            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
 *   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
 * 
 *  0. You just DO WHAT THE FUCK YOU WANT TO.
 *  made better by onoelle
 *  adapted for button by beppi
 */

/**
 * Text Button 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.
 * 
 * @author Chase Colburn
 * @since Apr 4, 2011
 */
public class AutoResizeTextButton extends Button {

    // 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(Button 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 AutoResizeTextButton(Context context) {
        this(context, null);
    }

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

    // Default constructor override
    public AutoResizeTextButton(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(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;
        }

        // 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);
            StaticLayout layout = new StaticLayout(text, paint, width, 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
//      textPaint.setTextSize(targetTextSize);
     // modified: setting text size via this.setTextSize (instead of textPaint.setTextSize(targetTextSize))
        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 originalPaint, 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)
        // Update the text paint object
          TextPaint paint = new TextPaint(originalPaint);
        paint.setTextSize(textSize);
        // Measure using a static layout
        StaticLayout layout = new StaticLayout(source, paint, width, Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, true);
        return layout.getHeight();
    }

}

用法:

把一个AutoResizeTextButton在你的xml中代替一个正常的按钮,没有改变 一切。 在onCreate()中放置(例如):

    myButton = (AutoResizeTextButton)getView().findViewById(id.myButton);
    myButton.setMinTextSize(8f);
    myButton.resizeText();

其他回答

因为我一直在寻找这个,而我刚刚找到了一个解决方案,但这里没有,我将把它写在这里,以供将来参考。

注意:这段代码是直接从谷歌Android棒棒糖拨号器一段时间后,我不记得如果改变在当时。此外,我不知道这是在哪个许可证下,但我有理由认为它是Apache 2.0。

类ResizeTextView,实际的视图

public class ResizeTextView extends TextView {

private final int mOriginalTextSize;
private final int mMinTextSize;
private final static int sMinSize = 20;
public ResizeTextView(Context context, AttributeSet attrs) {
    super(context, attrs);
    mOriginalTextSize = (int) getTextSize();
    mMinTextSize = (int) sMinSize;
}
@Override
protected void onTextChanged(CharSequence text, int start, int lengthBefore, int lengthAfter) {
    super.onTextChanged(text, start, lengthBefore, lengthAfter);
    ViewUtil.resizeText(this, mOriginalTextSize, mMinTextSize);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    super.onSizeChanged(w, h, oldw, oldh);
    ViewUtil.resizeText(this, mOriginalTextSize, mMinTextSize);
}

这个ResizeTextView类可以扩展TextView和它所有的孩子,我的理解,所以EditText以及。

ViewUtil类带有resizeText方法(…)

/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*      http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

import android.graphics.Paint;
import android.util.TypedValue;
import android.widget.TextView;

public class ViewUtil {

    private ViewUtil() {}

    public static void resizeText(TextView textView, int originalTextSize, int minTextSize) {
        final Paint paint = textView.getPaint();
        final int width = textView.getWidth();
        if (width == 0) return;
        textView.setTextSize(TypedValue.COMPLEX_UNIT_PX, originalTextSize);
        float ratio = width / paint.measureText(textView.getText().toString());
        if (ratio <= 1.0f) {
            textView.setTextSize(TypedValue.COMPLEX_UNIT_PX,
                    Math.max(minTextSize, originalTextSize * ratio));
        }
    }
}

您应该将您的视图设置为

<yourpackage.yourapp.ResizeTextView
            android:layout_width="match_parent"
            android:layout_height="64dp"
            android:gravity="center"
            android:maxLines="1"/>

希望能有所帮助!

我为此写了一篇博客。

我根据Kirill Grouchnikov关于在新的android market应用中使用的自定义组件的博客文章创建了一个名为ResizableButton的组件。我把src代码放在这里。

另一方面,mosabua读了我的文章,并告诉我他将开源他的实现,这比我的更快。我希望他能尽快发布:)

这是一个简单的解决方案,使用TextView本身和textchangedlistens添加到它:

expressionView = (TextView) findViewById(R.id.expressionView);
expressionView.addTextChangedListener(textAutoResizeWatcher(expressionView, 25, 55));

private TextWatcher textAutoResizeWatcher(final TextView view, final int MIN_SP, final int MAX_SP) {
    return new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {}

        @Override
        public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {}

        @Override
        public void afterTextChanged(Editable editable) {

            final int widthLimitPixels = view.getWidth() - view.getPaddingRight() - view.getPaddingLeft();
            Paint paint = new Paint();
            float fontSizeSP = pixelsToSp(view.getTextSize());
            paint.setTextSize(spToPixels(fontSizeSP));

            String viewText = view.getText().toString();

            float widthPixels = paint.measureText(viewText);

            // Increase font size if necessary.
            if (widthPixels < widthLimitPixels){
                while (widthPixels < widthLimitPixels && fontSizeSP <= MAX_SP){
                    ++fontSizeSP;
                    paint.setTextSize(spToPixels(fontSizeSP));
                    widthPixels = paint.measureText(viewText);
                }
                --fontSizeSP;
            }
            // Decrease font size if necessary.
            else {
                while (widthPixels > widthLimitPixels || fontSizeSP > MAX_SP) {
                    if (fontSizeSP < MIN_SP) {
                        fontSizeSP = MIN_SP;
                        break;
                    }
                    --fontSizeSP;
                    paint.setTextSize(spToPixels(fontSizeSP));
                    widthPixels = paint.measureText(viewText);
                }
            }

            view.setTextSize(fontSizeSP);
        }
    };
}

private float pixelsToSp(float px) {
    float scaledDensity = getResources().getDisplayMetrics().scaledDensity;
    return px/scaledDensity;
}

private float spToPixels(float sp) {
    float scaledDensity = getResources().getDisplayMetrics().scaledDensity;
    return sp * scaledDensity;
}

这种方法将根据需要增加或减少字体大小以适应文本,尊重作为参数接收的MIN_SP和MAX_SP边界。

我从Chase的解决方案开始,但在我的设备(Galaxy Nexus, Android 4.1)上正常工作之前,我必须调整两件事:

using a copy of TextPaint for measuring layout The documentation for TextView.getPaint() states that it should be used read-only, so I made a copy in both places where we use the paint object for measuring: // 1. in resizeText() if (mAddEllipsis && targetTextSize == mMinTextSize && textHeight > height) { // Draw using a static layout // modified: use a copy of TextPaint for measuring TextPaint paint = new TextPaint(textPaint); // 2. in getTextHeight() private int getTextHeight(CharSequence source, TextPaint originalPaint, 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 paint = new TextPaint(originalPaint); // Update the text paint object paint.setTextSize(textSize); ... adding a unit to setting the text size // modified: setting text size via this.setTextSize (instead of textPaint.setTextSize(targetTextSize)) setTextSize(TypedValue.COMPLEX_UNIT_PX, targetTextSize); setLineSpacing(mSpacingAdd, mSpacingMult);

With these two modifications the solution is working perfectly for me, thanks Chase! I don't know whether it is due to Android 4.x that the original solution was not working. In case you want to see it in action or test whether it really works on your device, you can have a look at my flashcard app Flashcards ToGo where I use this solution to scale the text of a flashcard. The text can have arbitrary length, and the flashcards are displayed in different activities, sometimes smaller sometimes bigger, plus in landscape + portrait mode, and I haven't found any corner case where the solution would not work properly...

在2017年谷歌IO大会上,谷歌介绍了TextView的autoSize属性

https://youtu.be/fjUdJ2aVqE4

<android.support.v7.widget.AppCompatTextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="@string/my_text"
        app:autoSizeTextType="uniform"
        app:autoSizeMaxTextSize="10sp"
        app:autoSizeMinTextSize="6sp"
        app:autoSizeStepGranularity="1sp"/>