Android开发库VUtils之文字大小自适应TextView

来源：互联网发布：东京大学医学部知乎编辑：程序博客网时间：2024/06/03 16:37

很多时候我们需要文字大小随控件的宽变小，以保证文字能完整显示，现自定义控件如下：

package com.v.vutils.views;import android.content.Context;import android.graphics.Paint;import android.text.TextPaint;import android.util.AttributeSet;import android.view.Gravity;import android.widget.TextView;public class FitTextView extends TextView {    private Paint mTextPaint;    private float mMaxTextSize; // 获取当前所设置文字大小作为最大文字大小    private float mMinTextSize = 8;    public FitTextView(Context context) {        this(context, null);    }    public FitTextView(Context context, AttributeSet attrs) {        super(context, attrs);        setGravity(getGravity() | Gravity.CENTER_VERTICAL); // 默认水平居中        setLines(1);        initialise();    }    @Override    protected void onTextChanged(CharSequence text, int start, int lengthBefore, int lengthAfter) {        refitText(text.toString(), this.getWidth());        super.onTextChanged(text, start, lengthBefore, lengthAfter);    }    private void initialise() {        mTextPaint = new TextPaint();        mTextPaint.set(this.getPaint());        // max size defaults to the intially specified text size unless it is too small        mMaxTextSize = this.getTextSize();//        mMinTextSize = 8;    }    @Override    protected void onSizeChanged(int w, int h, int oldw, int oldh) {        if (w != oldw) {            refitText(this.getText().toString(), w);        }    }    /**     * Resize the font so the specified text fits in the text box     * assuming the text box is the specified width.     *         */    private void refitText(String text, int textWidth) {        if (textWidth > 0) {            int availableWidth = textWidth - this.getPaddingLeft() - this.getPaddingRight();            float trySize = mMaxTextSize;            mTextPaint.setTextSize(trySize);            while (mTextPaint.measureText(text) > availableWidth) {                trySize -= 1;                if (trySize <= mMinTextSize) {                    trySize = mMinTextSize;                    break;                }                mTextPaint.setTextSize(trySize);            }            // setTextSize参数值为sp值            setTextSize(px2sp(getContext(), trySize));        }    }    /**     * 将px值转换为sp值，保证文字大小不变     */    public static float px2sp(Context context, float pxValue) {        float fontScale = context.getResources().getDisplayMetrics().scaledDensity;        return (pxValue / fontScale);    }}

xml中使用，同TextView使用完全一样：

    <com.v.vutils.views.FitTextView        android:layout_width="200dp"        android:layout_height="wrap_content"        android:text="80000000"        android:textSize="36sp" />

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