Vertical (rotated) label in Android
I need 2 ways of showing vertical label in Android:
- Horizontal label turned 90 degrees counterclockwise (letters on the side)
- Horizontal label with letters one under the other (like a store sign)
Do I need to develop custom widgets for both cases (one case), can I make TextView to render that way, and what would be a good way to do something like that if I need to go completely custom?
Here is my elegant and simple vertical text implementation, extending TextView. This means that all standard styles of TextView may be used, because it is extended TextView.
public class VerticalTextView extends TextView{
final boolean topDown;
public VerticalTextView(Context context, AttributeSet attrs){
super(context, attrs);
final int gravity = getGravity();
if(Gravity.isVertical(gravity) && (gravity&Gravity.VERTICAL_GRAVITY_MASK) == Gravity.BOTTOM) {
setGravity((gravity&Gravity.HORIZONTAL_GRAVITY_MASK) | Gravity.TOP);
topDown = false;
}else
topDown = true;
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec){
super.onMeasure(heightMeasureSpec, widthMeasureSpec);
setMeasuredDimension(getMeasuredHeight(), getMeasuredWidth());
}
@Override
protected boolean setFrame(int l, int t, int r, int b){
return super.setFrame(l, t, l+(b-t), t+(r-l));
}
@Override
public void draw(Canvas canvas){
if(topDown){
canvas.translate(getHeight(), 0);
canvas.rotate(90);
}else {
canvas.translate(0, getWidth());
canvas.rotate(-90);
}
canvas.clipRect(0, 0, getWidth(), getHeight(), android.graphics.Region.Op.REPLACE);
super.draw(canvas);
}
}
By default, rotated text is from top to bottom. If you set android:gravity="bottom", then it's drawn from bottom to top.
Technically, it fools underlying TextView to think that it's normal rotation (swapping width/height in few places), while drawing it rotated. It works fine also when used in an xml layout.
EDIT: posting another version, above has problems with animations. This new version works better, but loses some TextView features, such as marquee and similar specialties.
public class VerticalTextView extends TextView{
final boolean topDown;
public VerticalTextView(Context context, AttributeSet attrs){
super(context, attrs);
final int gravity = getGravity();
if(Gravity.isVertical(gravity) && (gravity&Gravity.VERTICAL_GRAVITY_MASK) == Gravity.BOTTOM) {
setGravity((gravity&Gravity.HORIZONTAL_GRAVITY_MASK) | Gravity.TOP);
topDown = false;
}else
topDown = true;
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec){
super.onMeasure(heightMeasureSpec, widthMeasureSpec);
setMeasuredDimension(getMeasuredHeight(), getMeasuredWidth());
}
@Override
protected void onDraw(Canvas canvas){
TextPaint textPaint = getPaint();
textPaint.setColor(getCurrentTextColor());
textPaint.drawableState = getDrawableState();
canvas.save();
if(topDown){
canvas.translate(getWidth(), 0);
canvas.rotate(90);
}else {
canvas.translate(0, getHeight());
canvas.rotate(-90);
}
canvas.translate(getCompoundPaddingLeft(), getExtendedPaddingTop());
getLayout().draw(canvas);
canvas.restore();
}
}
EDIT Kotlin version:
import android.content.Context
import android.graphics.Canvas
import android.text.BoringLayout
import android.text.Layout
import android.text.TextUtils.TruncateAt
import android.util.AttributeSet
import android.view.Gravity
import androidx.appcompat.widget.AppCompatTextView
import androidx.core.graphics.withSave
class VerticalTextView(context: Context, attrs: AttributeSet) : AppCompatTextView(context, attrs) {
private val topDown = gravity.let { g ->
!(Gravity.isVertical(g) && g.and(Gravity.VERTICAL_GRAVITY_MASK) == Gravity.BOTTOM)
}
private val metrics = BoringLayout.Metrics()
private var padLeft = 0
private var padTop = 0
private var layout1: Layout? = null
override fun setText(text: CharSequence, type: BufferType) {
super.setText(text, type)
layout1 = null
}
private fun makeLayout(): Layout {
if (layout1 == null) {
metrics.width = height
paint.color = currentTextColor
paint.drawableState = drawableState
layout1 = BoringLayout.make(text, paint, metrics.width, Layout.Alignment.ALIGN_NORMAL, 2f, 0f, metrics, false, TruncateAt.END, height - compoundPaddingLeft - compoundPaddingRight)
padLeft = compoundPaddingLeft
padTop = extendedPaddingTop
}
return layout1!!
}
override fun onDraw(c: Canvas) {
// c.drawColor(0xffffff80); // TEST
if (layout == null)
return
c.withSave {
if (topDown) {
val fm = paint.fontMetrics
translate(textSize - (fm.bottom + fm.descent), 0f)
rotate(90f)
} else {
translate(textSize, height.toFloat())
rotate(-90f)
}
translate(padLeft.toFloat(), padTop.toFloat())
makeLayout().draw(this)
}
}
}
I implemented this for my ChartDroid project. Create VerticalLabelView.java:
public class VerticalLabelView extends View {
private TextPaint mTextPaint;
private String mText;
private int mAscent;
private Rect text_bounds = new Rect();
final static int DEFAULT_TEXT_SIZE = 15;
public VerticalLabelView(Context context) {
super(context);
initLabelView();
}
public VerticalLabelView(Context context, AttributeSet attrs) {
super(context, attrs);
initLabelView();
TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.VerticalLabelView);
CharSequence s = a.getString(R.styleable.VerticalLabelView_text);
if (s != null) setText(s.toString());
setTextColor(a.getColor(R.styleable.VerticalLabelView_textColor, 0xFF000000));
int textSize = a.getDimensionPixelOffset(R.styleable.VerticalLabelView_textSize, 0);
if (textSize > 0) setTextSize(textSize);
a.recycle();
}
private final void initLabelView() {
mTextPaint = new TextPaint();
mTextPaint.setAntiAlias(true);
mTextPaint.setTextSize(DEFAULT_TEXT_SIZE);
mTextPaint.setColor(0xFF000000);
mTextPaint.setTextAlign(Align.CENTER);
setPadding(3, 3, 3, 3);
}
public void setText(String text) {
mText = text;
requestLayout();
invalidate();
}
public void setTextSize(int size) {
mTextPaint.setTextSize(size);
requestLayout();
invalidate();
}
public void setTextColor(int color) {
mTextPaint.setColor(color);
invalidate();
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
mTextPaint.getTextBounds(mText, 0, mText.length(), text_bounds);
setMeasuredDimension(
measureWidth(widthMeasureSpec),
measureHeight(heightMeasureSpec));
}
private int measureWidth(int measureSpec) {
int result = 0;
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);
if (specMode == MeasureSpec.EXACTLY) {
// We were told how big to be
result = specSize;
} else {
// Measure the text
result = text_bounds.height() + getPaddingLeft() + getPaddingRight();
if (specMode == MeasureSpec.AT_MOST) {
// Respect AT_MOST value if that was what is called for by measureSpec
result = Math.min(result, specSize);
}
}
return result;
}
private int measureHeight(int measureSpec) {
int result = 0;
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);
mAscent = (int) mTextPaint.ascent();
if (specMode == MeasureSpec.EXACTLY) {
// We were told how big to be
result = specSize;
} else {
// Measure the text
result = text_bounds.width() + getPaddingTop() + getPaddingBottom();
if (specMode == MeasureSpec.AT_MOST) {
// Respect AT_MOST value if that was what is called for by measureSpec
result = Math.min(result, specSize);
}
}
return result;
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
float text_horizontally_centered_origin_x = getPaddingLeft() + text_bounds.width()/2f;
float text_horizontally_centered_origin_y = getPaddingTop() - mAscent;
canvas.translate(text_horizontally_centered_origin_y, text_horizontally_centered_origin_x);
canvas.rotate(-90);
canvas.drawText(mText, 0, 0, mTextPaint);
}
}And in attrs.xml:
<resources>
<declare-styleable name="VerticalLabelView">
<attr name="text" format="string" />
<attr name="textColor" format="color" />
<attr name="textSize" format="dimension" />
</declare-styleable>
</resources>