最近项目里面RecyclerView做4列显示文字标签，但是按UI给的标注设置后，标签还是可能不止占一行，一些小屏手机时就不是预期效果了，于是自己摸索了一个view来根据宽高调节textSize：

image.png

代码贴出来，可能还不是很完善，一个思路：

/**

* use to do 如果限定textView的宽度，则根据宽度显示文字,字体大小改变

* 绘制只在居中绘制的样式，其他样式需要自己完善

*

* @author zhangdong on 2018/2/11 0011.

* @version 1.0

* @see .

* @since 1.0

*/

public class WrapContentTextView extends AppCompatTextView {

private static final String TAG = "WrapContentTextView";

private Paint mPaint;

private Boolean isWrapContent = false;//是否开启根据view的宽高调节字体大小

public void setWrapContent(Boolean wrapContent) {

isWrapContent = wrapContent;

invalidate();

}

public Boolean getWrapContent() {

return isWrapContent;

}

public WrapContentTextView(Context context) {

super(context);

init();

}

public WrapContentTextView(Context context, AttributeSet attrs) {

super(context, attrs);

TypedArray typedArray = context.getTheme()

.obtainStyledAttributes(attrs, R.styleable.WrapContentTextView, 0, 0);

isWrapContent = typedArray.getBoolean(R.styleable.WrapContentTextView_isWrapContent, false);

typedArray.recycle();

init();

}

public WrapContentTextView(Context context, AttributeSet attrs, int defStyleAttr) {

super(context, attrs, defStyleAttr);

init();

}

private void init() {

mPaint = new Paint();

mPaint.setAntiAlias(true);

float density = getResources().getDisplayMetrics().density;

Log.d(TAG, "onDraw: ------- 屏幕密度系数density = " + density);

}

@Override

protected void onDraw(Canvas canvas) {

if (isWrapContent) {

int width = getWidth();

int height = getHeight();

Log.d(TAG, "onDraw: ------- View的width = " + width + "; View的height = " + height);

CharSequence text = getText();

if (!TextUtils.isEmpty(text)) {

//文字的字数

int length = text.length();

//view的内边距

int paddingLeft = getPaddingLeft();

int paddingRight = getPaddingRight();

int paddingTop = getPaddingTop();

int paddingBottom = getPaddingBottom();

Log.d(TAG, "onDraw: ------- paddingLeft = " + paddingLeft +

"; paddingTop = " + paddingTop +

"; paddingRight = " + paddingRight +

"; paddingBottom = " + paddingBottom);

//文字可绘制的宽高

int textWidth = width - paddingLeft - paddingRight;

int textHeight = height - paddingTop - paddingBottom;

//一个字可绘制的宽度

int oneWidth = textWidth / length;

//一个字可绘制的宽度与可绘制的高度取最小的值

int textSize = Math.min(oneWidth, textHeight);

Log.d(TAG, "onDraw: ------- 文字长度：" + length +

"; 可绘制的textWidth = " + textWidth +

"; oneWidth = " + oneWidth +

"; 可绘制的textHeight = " + textHeight);

//当前文字的size

float size = getTextSize();

float measureText = getPaint().measureText(text, 0, length);

Log.d(TAG, "onDraw: ------- 初始文字的size = " + size +

"; 初始文字的宽measureText = " + measureText);

//获取当前文字的高度

Paint.FontMetrics fontMetrics = getPaint().getFontMetrics();

float tHeight = fontMetrics.bottom - fontMetrics.top;

Log.d(TAG, "onDraw: ------- 初始文字的fontMetrics.bottom= " + fontMetrics.bottom +

"; 初始文字的fontMetrics.top= " + fontMetrics.top +

"; 初始文字的高度tHeight= " + tHeight);

float newSize = 0;

//新的文字大小根据宽度比例关系得到

float newSizeW = size * textSize * length / measureText;

//新的文字大小根据高度比例关系得到

float newSizeH = size * textHeight / tHeight;

Log.d(TAG, "onDraw: ------- 根据宽度比例关系得到newSizeW= " + newSizeW +

"; 根据高度比例关系得到newSizeH= " + newSizeH);

newSize = Math.min(newSizeW, newSizeH);

Log.d(TAG, "onDraw: ------- 取最小的文字大小设置给画笔newSize : " + newSize);

mPaint.setTextSize(newSize);

mPaint.setColor(getCurrentTextColor());

Rect textRect = new Rect();

mPaint.getTextBounds(text.toString(), 0, length, textRect);

Paint.FontMetrics mPaintFontMetrics = mPaint.getFontMetrics();

float top = mPaintFontMetrics.top;

float bottom = mPaintFontMetrics.bottom;

//文字绘制的x轴起点

int startX = (width - textRect.width() + paddingLeft - paddingRight) / 2;

//文字绘制的中心

int textCenterY = textHeight + paddingTop - textHeight / 2;

//文字绘制的基线 BaseLine

int startY = (int) (textCenterY - (bottom - top) / 2 - top);

Log.d(TAG, "onDraw: ------- textRect.width()= " + textRect.width() +

"; textRect.height()= " + textRect.height());

Log.d(TAG, "onDraw: ------- 绘制的起点：X = " + startX + "; Y = " + startY);

canvas.drawText(text, 0, length, startX, startY, mPaint);

}

} else super.onDraw(canvas);

}

}

需要的自定义属性：是否需要view根据宽高改变textSize

使用：

android:id="@+id/tv_test"

android:layout_width="160dp"

android:layout_height="60dp"

android:layout_marginTop="100dp"

android:background="#70000000"

android:textColor="#ff0000"

app:isWrapContent="true"

app:layout_constraintLeft_toLeftOf="parent"

app:layout_constraintRight_toRightOf="parent"

app:layout_constraintTop_toTopOf="parent"

tools:text="this is test text" />

这一句代码是控制的：

app:isWrapContent="true"

当然也可以在代码里面动态设置，调用方法：

public void setWrapContent(Boolean wrapContent) {

isWrapContent = wrapContent;

invalidate();

}

eg：

wrapContentTextView.setText("好的的一个家，哎呀我大中华");

wrapContentTextView.setWrapContent(true);

运行效果还不错：

image.png