android 字体变大 getMeasuredHeight 不变 android实现字体大小调整

一、前言

最近项目添加了一项调整应用字体大小功能，做完后空闲之余总结一下。本功能仿照微信应用“设置” - “通用”  -  “字体大小”功能，又有一点区别。据我所知，常见改变全局字体大小方法有两种，我把这两种分为可控和不可控，为什么这么分呢，当然不是为了方便记忆。那么简单说下两者方式的实现过程：

1、不可控：通过重写Actiivity的getResources()方法更新应用的字体倍数来调整全局字体大小

优点：实现简单

缺点：不可控制(所有字体放大倍数都是一致)，无法跨进程(项目中另一个进程的字体不会改变，需要重新配置)，只对sp字体单位有效果。....

2、可控：通过setTheme()方法，一开始就初始化设置不同风格的字体样式来更改全局字体大小。

优点：随意调节任意位置的字体大小

缺点：实现麻烦

而本文正式采用了第一种方案，主要是中途添加该功能，时间也不充裕，抽取字体大小又太过耗时。

微信字体大小个人猜测使用第二种方案，后者是更好的实现方式也不一定。

二、效果预览

三、实现步骤

1、自定义字体调整控件

网上找了一个相似的控件并加以完善，功能相对简单，就不做介绍了。

/** * TODO 仿微信字体大小调整 * 自定义属性： * lineWidth        线条粗细 * lineColor        线条颜色 * totalCount       线条格数 * circleColor      球型颜色 * circleRadius     球型颜色半径 * textFontColor    文字颜色 * smallSize        小“A” 字体大小 * standerSize      “标准” 字体大小 * bigSize          大“A” 字体大小 * defaultPosition  默认位置 */public class FontSizeView extends View {    private int defaultLineColor = Color.rgb(33, 33, 33);    private int defaultLineWidth;    private int defaultMax = 5;    private int defaultCircleColor = Color.WHITE;    private int defaultCircleRadius;    // 当前所在位置    private int currentProgress;    // 默认位置    private int defaultPosition = 1;    // 一共有多少格    private int max = 7;    // 线条颜色    private int lineColor = Color.BLACK;    // 线条粗细    private int lineWidth;    //字体颜色    private int textColor = Color.BLACK;    //字体大小    private int smallSize = 14;    private int standerSize = 16;    private int bigSize = 28;    // 圆半径    private int circleRadius;    private int circleColor = Color.WHITE;    // 一段的宽度，根据总宽度和总格数计算得来    private int itemWidth;    // 控件的宽高    private int height;    private int width;    // 画笔    private Paint mLinePaint;    private Paint mTextPaint;    private Paint mText1Paint;    private Paint mText2Paint;    private Paint mCirclePaint;    // 滑动过程中x坐标    private float currentX = 0;    // 有效数据点    private List points = new ArrayList<>();    private float circleY;    private float textScaleX;    private float text1ScaleX;    private float text2ScaleX;    public FontSizeView(Context context) {        this(context, null);    }    public FontSizeView(Context context, AttributeSet attrs) {        super(context, attrs);        init(context, attrs);    }    private void init(Context context, AttributeSet attrs) {        // initDefault        defaultLineWidth = DensityUtils.dp2px(context, 2);        defaultCircleRadius = DensityUtils.dp2px(context, 35);        lineWidth = DensityUtils.dp2px(context, 1);        TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.FontSizeView);        final int N = typedArray.getIndexCount();        for (int i = 0; i < N; i++) {            initCustomAttr(typedArray.getIndex(i), typedArray);        }        typedArray.recycle();        // 初始化画笔        mLinePaint = new Paint(Paint.ANTI_ALIAS_FLAG);        mLinePaint.setColor(lineColor);        mLinePaint.setStyle(Paint.Style.FILL_AND_STROKE);        mLinePaint.setStrokeWidth(lineWidth);        //文字画笔        mTextPaint = new Paint(Paint.ANTI_ALIAS_FLAG);        mTextPaint.setColor(textColor);        mTextPaint.setStyle(Paint.Style.FILL_AND_STROKE);//        mTextPaint.setStrokeWidth(DensityUtils.dp2px(context, 1));        mTextPaint.setTextSize(DensityUtils.sp2px(context, smallSize));        textScaleX = mTextPaint.measureText("A");        //文字画笔        mText1Paint = new Paint(Paint.ANTI_ALIAS_FLAG);        mText1Paint.setColor(textColor);        mText1Paint.setStyle(Paint.Style.FILL_AND_STROKE);        mText1Paint.setTextSize(DensityUtils.sp2px(context, bigSize));        text1ScaleX = mText1Paint.measureText("A");        //文字画笔        mText2Paint = new Paint(Paint.ANTI_ALIAS_FLAG);        mText2Paint.setColor(textColor);        mText2Paint.setStyle(Paint.Style.FILL_AND_STROKE);        mText2Paint.setTextSize(DensityUtils.sp2px(context, standerSize));        text2ScaleX = mText2Paint.measureText("标准");        mCirclePaint = new Paint(Paint.ANTI_ALIAS_FLAG);        mCirclePaint.setColor(circleColor);        mCirclePaint.setStyle(Paint.Style.FILL);        // 设置阴影效果        setLayerType(LAYER_TYPE_SOFTWARE, null);        mCirclePaint.setShadowLayer(2, 0, 0, Color.rgb(33, 33, 33));    }    private void initCustomAttr(int attr, TypedArray typedArray) {        if (attr == R.styleable.FontSizeView_lineColor) {            lineColor = typedArray.getColor(attr, defaultLineColor);        } else if (attr == R.styleable.FontSizeView_circleColor) {            circleColor = typedArray.getColor(attr, defaultCircleColor);        } else if (attr == R.styleable.FontSizeView_lineWidth) {            lineWidth = typedArray.getDimensionPixelSize(attr, defaultLineWidth);        } else if (attr == R.styleable.FontSizeView_circleRadius) {            circleRadius = typedArray.getDimensionPixelSize(attr, defaultCircleRadius);        } else if (attr == R.styleable.FontSizeView_totalCount) {            max = typedArray.getInteger(attr, defaultMax);        } else if (attr == R.styleable.FontSizeView_textFontColor) {            textColor = typedArray.getColor(attr, textColor);        } else if (attr == R.styleable.FontSizeView_smallSize) {            smallSize = typedArray.getInteger(attr, smallSize);        } else if (attr == R.styleable.FontSizeView_standerSize) {            standerSize = typedArray.getInteger(attr, standerSize);        } else if (attr == R.styleable.FontSizeView_bigSize) {            bigSize = typedArray.getInteger(attr, bigSize);        }else if (attr == R.styleable.FontSizeView_defaultPosition) {            defaultPosition = typedArray.getInteger(attr, defaultPosition);        }    }    @Override    protected void onSizeChanged(int w, int h, int oldw, int oldh) {        super.onSizeChanged(w, h, oldw, oldh);        height = h;        width = w;        circleY = height / 2;        // 横线宽度是总宽度-2个圆的半径        itemWidth = (w - 2 * circleRadius) / max;        // 把可点击点保存起来        for (int i = 0; i <= max; i++) {            points.add(new Point(circleRadius + i * itemWidth, height / 2));        }        //初始刻度        currentX = points.get(defaultPosition).x;    }    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        //画字        canvas.drawText("A", points.get(0).x - textScaleX / 2, height / 2 - 50, mTextPaint);        //画字        canvas.drawText("标准", points.get(1).x - text2ScaleX / 2, height / 2 - 50, mText2Paint);        //画字        canvas.drawText("A", points.get(points.size() - 1).x - text1ScaleX / 2, height / 2 - 50, mText1Paint);        // 先画中间的横线        canvas.drawLine(points.get(0).x, height / 2, points.get(points.size() - 1).x, height / 2, mLinePaint);        // 绘制刻度        for (Point point : points) {            canvas.drawLine(point.x + 1, height / 2 - 20, point.x + 1, height / 2 + 20, mLinePaint);        }        // 画圆        if (currentX < circleRadius) {            currentX = circleRadius;        }        if (currentX > width - circleRadius) {            currentX = width - circleRadius;        }        // 实体圆        canvas.drawCircle(currentX + 1, circleY, circleRadius, mCirclePaint);    }    @Override    public boolean onTouchEvent(MotionEvent event) {        currentX = event.getX();        switch (event.getAction()) {            case MotionEvent.ACTION_DOWN:                invalidate();                break;            case MotionEvent.ACTION_MOVE:                invalidate();                break;            case MotionEvent.ACTION_UP:                //回到最近的一个刻度点                Point targetPoint = getNearestPoint(currentX);                if (targetPoint != null) {                    // 最终                    currentX = points.get(currentProgress).x;                    invalidate();                }                if (onChangeCallbackListener != null) {                    onChangeCallbackListener.onChangeListener(currentProgress);                }                break;        }        return true;    }    /**     * 获取最近的刻度     */    private Point getNearestPoint(float x) {        for (int i = 0; i < points.size(); i++) {            Point point = points.get(i);            if (Math.abs(point.x - x) < itemWidth / 2) {                currentProgress = i;                return point;            }        }        return null;    }    public void setChangeCallbackListener(OnChangeCallbackListener listener) {        this.onChangeCallbackListener = listener;    }    private OnChangeCallbackListener onChangeCallbackListener;    public interface OnChangeCallbackListener {        void onChangeListener(int position);    }    public void setDefaultPosition(int position){        defaultPosition=position;        if (onChangeCallbackListener != null) {            onChangeCallbackListener.onChangeListener(defaultPosition);        }        invalidate();    }}

xml使用方式：

android:id="@+id/fsv_font_size"        android:layout_width="wrap_content"        android:layout_height="120dp"        android:layout_marginLeft="@dimen/space_line2"        android:layout_marginRight="@dimen/space_line2"        android:background="@color/white"        app:circleRadius="11dp"        app:lineColor="@color/round_corner_progress_bar_progress_default"        app:standerSize="16" />

2、滑动按钮改变当前页面预览字体大小

//备注            14sp        16sp        18sp        20sp        22sp        24sp        26sp        28sp

//滑动返回监听        fsvFontSize.setChangeCallbackListener(new FontSizeView.OnChangeCallbackListener() {            @Override            public void onChangeListener(int position) {                int dimension = getResources().getDimensionPixelSize(R.dimen.sp_stander);                //根据position 获取字体倍数                fontSizeScale = (float) (0.875 + 0.125 * position);                //放大后的sp单位                double v = fontSizeScale * (int) DensityUtils.px2sp(FontSizeActivity.this, dimension);                //改变当前页面大小                changeTextSize((int) v);            }        });

/**     * 改变textsize 大小     */    private void changeTextSize(int dimension) {        tv_font_size1.setTextSize(dimension);        tv_font_size2.setTextSize(dimension);        tv_font_size3.setTextSize(dimension);    }

3、返回时，保存放大倍数并重启应用

public void onClick(View view) {      SPUtils.put(FontSizeActivity.this,Constants.SP_FontScale,fontSizeScale);      //重启应用      AppManager.getAppManager().finishAllActivity();      IntentUtils.toActivity(FontSizeActivity.this, MainActivity.class,true);  }

4、初始化应用时配置字体放大倍数。

改变全局大小的关键  //  res.updateConfiguration(config,res.getDisplayMetrics());

//fontSizeScale = (float) SPUtils.get(this, Constants.SP_FontScale, 0.0f); @Override    public Resources getResources() {        Resources res =super.getResources();        Configuration config = res.getConfiguration();        if(fontSizeScale>0.5){//防止第一次获取SP时得到默认值0            config.fontScale= fontSizeScale;//设置正常字体大小的倍数        }        res.updateConfiguration(config,res.getDisplayMetrics());        return res;    }

源码地址： https://github.com/DayorNight/BLCS 到这里就结束啦