Develop Reference

How to develop box like Rating bar like zomato android app?

I want to develop Rating bar like zomato android application. In which the rating bar box changes it's color according to selection. if only one box is selected then it's color is Read and gradually we select more box it became Green.
Here I attached snap of zomato android app's screen portion which shows Rating exactly I would like to develop this type of Rating and Review System.

That's a simple horizontal LinearLayout with 9 TextViews, each of them having grey as the default color. Aditionally you can create an array of strings, each string being a color code. This is the quick and dirty solution.
When clicking on a TextView, you can find out its position in the LinearLayout and color each view before it with the corresponding color code in the array, along with the selected view, and the others remain grey.
I had a similar problem once with a progress bar consisting of 10 sections, and instead of looking for a library I made something quick like this and it worked just fine.

I found solution for that we need to make Custom Rating bar Here bellow code shows Custom class of Rating bar. which full fill all requirement which mention in Question.
public class MyCustomRatingBar extends android.support.v7.widget.AppCompatRatingBar {
private int[] iconArrayActive = {
R.drawable.ic_square_sel_1,
R.drawable.ic_square_sel_2,
R.drawable.ic_square_sel_3,
R.drawable.ic_square_sel_4,
R.drawable.ic_square_sel_5,
R.drawable.ic_square_sel_6,
R.drawable.ic_square_sel_7,
R.drawable.ic_square_sel_8,
R.drawable.ic_square_sel_9
};
private int[] iconArrayInactive = {
R.drawable.ic_square_unsel,
R.drawable.ic_square_unsel,
R.drawable.ic_square_unsel,
R.drawable.ic_square_unsel,
R.drawable.ic_square_unsel,
R.drawable.ic_square_unsel,
R.drawable.ic_square_unsel,
R.drawable.ic_square_unsel,
R.drawable.ic_square_unsel
};
public MyCustomRatingBar (Context context) {
super(context);
init();
}
public MyCustomRatingBar (Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public MyCustomRatingBar (Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
this.setMax(9);
this.setNumStars(9);
this.setStepSize(1.0f);
this.setRating(1.0f);
}
private Bitmap getBitmapFromVectorDrawable(Context context, int drawableId) {
Drawable drawable = ContextCompat.getDrawable(context, drawableId);
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
drawable = (DrawableCompat.wrap(drawable)).mutate();
}
Bitmap bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(),
drawable.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
drawable.draw(canvas);
return bitmap;
}
#Override
protected synchronized void onDraw(Canvas canvas) {
int stars = getNumStars();
float rating = getRating();
float x = 0;
Bitmap bitmap;
Paint paint = new Paint();
int W = getWidth();
int H = getHeight();
int icon_size = (W/stars)-0;
int y_pos = (H/2)-icon_size/2;
int delta = ((H > W)?(H):(W))/(stars);
int offset = (W-(icon_size+(stars-1)*delta))/2;
for(int i = 0; i < stars; i++) {
if ((int) rating-1 >= i) {
bitmap = getBitmapFromVectorDrawable(getContext(), iconArrayActive[i]);
} else {
bitmap = getBitmapFromVectorDrawable(getContext(), iconArrayInactive[i]);
}
x = offset+(i*delta);
Bitmap scaled = Bitmap.createScaledBitmap(bitmap, icon_size, icon_size, true);
canvas.drawBitmap(scaled, x, y_pos, paint);
canvas.save();
}
}
}

How to display divider value below seekbar in Android?

I have added a seekbar to one of my activities.
Its max value is 5. Now, I want to display the divider values (with increment 1, like 0, 1, 2, 3, 4 and 5) below my seekbar. How can I do that?
Is there any system method to achieve this which I am not able to put my hands on? Any inputs are welcomed.
NOTE : I want to apply any changes programatically, not from xml. The numbers should be separated at equal intervals. I could not edit it that precisely though.

I am supposing you want to display view like below in picture.
if that is the case you have to create your own customSeekbar like give code.
CustomSeekBar.java
public class CustomSeekBar extends SeekBar {
private Paint textPaint;
private Rect textBounds = new Rect();
private String text = "";
public CustomSeekBar(Context context) {
super(context);
textPaint = new Paint();
textPaint.setColor(Color.WHITE);
}
public CustomSeekBar(Context context, AttributeSet attrs) {
super(context, attrs);
textPaint = new Paint();
textPaint.setTypeface(Typeface.SANS_SERIF);
textPaint.setColor(Color.BLACK);
}
public CustomSeekBar(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
textPaint = new Paint();
textPaint.setColor(Color.BLACK);
}
#Override
protected synchronized void onDraw(Canvas canvas) {
// First draw the regular progress bar, then custom draw our text
super.onDraw(canvas);
int progress = getProgress();
text = progress + "";
// Now get size of seek bar.
float width = getWidth();
float height = getHeight();
// Set text size.
textPaint.setTypeface(Typeface.create(Typeface.DEFAULT, Typeface.BOLD));
textPaint.setTextSize(40);
// Get size of text.
textPaint.getTextBounds(text, 0, text.length(), textBounds);
// Calculate where to start printing text.
float position = (width / getMax()) * getProgress();
// Get start and end points of where text will be printed.
float textXStart = position - textBounds.centerX();
float textXEnd = position + textBounds.centerX();
// Check does not start drawing outside seek bar.
if (textXStart <= 1) textXStart = 20;
if (textXEnd > width) {
textXStart -= (textXEnd - width + 30);
}
// Calculate y text print position.
float yPosition = height;
canvas.drawText(text, textXStart, yPosition, textPaint);
}
public synchronized void setTextColor(int color) {
super.drawableStateChanged();
textPaint.setColor(color);
drawableStateChanged();
}
}
In your Xml file use your custom file like below
<com.waleedsarwar.customseekbar.CustomSeekBar
android:id="#+id/seekbar"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:max="5"
android:paddingBottom="16dp" />

This is another approach. I am extending a linearlayout. I put seekbar and another linearlayout(layout_5) which contains 6 textviews with 0-1-2-3-4-5. Better option would be creating a dynamic image(get width from seekBar) which has these numbers according to segment count.
I force seekbar's indicator to stop at specific points(6 points in your case). Instead of doing this, it is possible to set seekBar's maximum progress value to 5. It will work, but it will not give a good user experience.
public class SegmentedSeekBar extends LinearLayout {
private int[] preDefinedValues;
private int currentProgressIndex;
private SeekBar seekBar;
private int segmentCount = 5:
public SegmentedSeekBar(Context context) {
this(context, null, 0);
}
public SegmentedSeekBar(Context context, AttributeSet attrs) {
this(context, attrs, android.R.attr.seekBarStyle);
}
public SegmentedSeekBar(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
TypedArray a = context.getTheme().obtainStyledAttributes(
attrs,
R.styleable.SegmentedSeekBar,
0, 0);
try {
segmentCount =
a.getInt(R.styleable.SegmentedSeekBar_segmentCount, -1);
} finally {
a.recycle();
}
init();
}
public void init() {
//this values will be used when you need to set progress
preDefinedValues = new int[segmentCount];
for(int i = 0; i < preDefinedValues.length; i++) {
preDefinedValues[i] = (100/(segmentCount-1)) * i;
}
//Get layout_5
//which is linearlayout with 6 textviews
LayoutInflater inflater = (LayoutInflater) getContext()
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View sliderView = inflater.inflate(
getSliderId(segmentCount), null);
//seekbar already inside the linearlayout
seekBar = (SeekBar)sliderView.findViewById(R.id.seek_bar);
//linear layout is vertically align
//so add your 6 textview linearlayout
addView(sliderView);
seekBar.setOnTouchListener(seekBarTouchListener);
}
private int getSliderId(int size) {
return R.layout.layout_5;
}
//this method sets progress which is seen in UI not actual progress
//It uses the conversion that we did in beginning
public synchronized void setProgress(int progress) {
if(preDefinedValues != null && progress < preDefinedValues.length && progress >= 0) {
seekBar.setProgress(preDefinedValues[progress]);
currentProgressIndex = progress;
}
}
//this listener make sure the right progress is seen in ui
//take action when user finish with changing progress
SeekBar.OnSeekBarChangeListener onSeekBarChangeListener = new SeekBar.OnSeekBarChangeListener() {
#Override
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
}
#Override
public void onStartTrackingTouch(SeekBar seekBar) {
}
#Override
public void onStopTrackingTouch(SeekBar seekBar) {
int index = 0;
for(int i = 0; i < preDefinedValues.length; i++) {
//try to find closest preDefinedvalues by comparing with latest value
if(Math.abs(seekBar.getProgress() - preDefinedValues[i]) < Math.abs(seekBar.getProgress() - preDefinedValues[index])) {
index = i;
}
}
setProgress(index);
}
};
}

putting 2 textViews on top of each other

I want to have something where half of the text in a textView or any other kind of text display is highlighted while the other half is not. For example
in "textView". the "text" would be in a red font and "view" would be in black.
I was thinking about doing this by putting 2 textViews directly on top of each other but I am not exactly sure how to do this. (What kind of parameters, etc?) Any ideas?
Thank you

You can stack multiple textViews by using a Layout that supports this, such as a FrameLayout or RelativeLayout. That said, I think the better approach (which would provide better control over the appearance) would be to create a custom view, and draw the text to the canvas yourself. You can do this with something like this (I have not tested this, but it should work - might need a few tweaks though):
public class TwoPartTextView extends View
{
private CharSequence part1 = "", part2 = "";
private Paint mPaint;
private int color1 = Color.BLACK, color2 = Color.BLACK;
private Context context;
private float part1Size = 12f, part2Size = 12f;
private int strokeWidth = 2;
public TwoPartTextView(Context context) {
super(context);
init(context);
}
public TwoPartTextView(Context context, AttributeSet attrs) {
super(context, attrs);
init(context);
}
public TwoPartTextView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init(context);
}
private void init(context) {
this.context = context;
mPaint = new Paint();
}
public void setText(CharSequence part1, int color1, part1Size, CharSequence part2, int color2, part2Size, strokeWidth) {
this.part1 = part1;
this.color1 = color1;
this.part1Size = part1Size;
this.part2 = part2;
this.color2 = color2;
this.part2Size = part2Size;
this.strokeWidth = strokeWidth;
mPaint.setStrokeWidth(strokeWidth);
}
#Override
public void onDraw(Canvas canvas) {
super.onDraw(canvas);
mPaint.setColor(color1);
mPaint.setTextSize(part1Size);
canvas.drawText(part1.toString(), 0, paint.getTextSize(), paint);
mPaint.setColor(color2);
mPaint.setTextSize(part2Size);
canvas.drawText(part2.toString(), getWidth()/2 /* tweak as needed*/, paint.getTextSize(), paint);
}
}
Then to use it, add it to XML or create it in code, then call:
myTwoPartTextView.setText("text", Color.RED, 12f, "View", Color.BLACK, 14f, 2);
myTwoPartTextView.setText.invalidate();

onDraw doesn't get called on custom view?

I'm trying to draw a rounded rect with a specific color, but i'm getting nothing.
I've already done lots of googling, and found some questions like this and read them all. However, none of them solved my problem. Why my onDraw method is never called?
Any help is appreciated.
public class RoundedTagItem extends RelativeLayout {
Context ctx;
String colorString;
int color;
public RoundedTagItem(Context context) {
super(context);
this.ctx = context;
color = Color.WHITE;
this.setWillNotDraw(false);
this.setPadding(10, 0, 10, 0);
}
public RoundedTagItem(Context context, String color) {
super(context);
this.ctx = context;
this.colorString = color;
this.setWillNotDraw(false);
this.setPadding(10, 0, 10, 0);
}
#Override
protected void onDraw(Canvas canvas) {
if(colorString != null)
color = Color.parseColor("#" + colorString);
int rectValue = 35;
Log.d("Rounded", "rectValue: " + rectValue);
RectF rect1 = new RectF(0, 0, rectValue, rectValue);
Paint paint = new Paint();
paint.setStrokeWidth(1);
paint.setStrokeCap(Paint.Cap.ROUND);
paint.setStyle(Paint.Style.FILL);
paint.setAntiAlias(true);
paint.setColor(color);
canvas.save();
canvas.drawRoundRect(rect1, 10, 10, paint);
canvas.restore();
super.onDraw(canvas);
}
public void ChangeBackgroundColor(String colorString) {
color = Color.parseColor(colorString);
invalidate();
}
}
And then I put icons on this custom view on my main class:
// add category items to view
LinearLayout categories = (LinearLayout) findViewById(R.id.detailTagImagesLayout);
for(int i = 0; i < item.getCategoryItems().size(); i++) {
RoundedTagItem v = null;
if(i == 0)
v = new RoundedTagItem(DetailActivity.this,
item.getCategoryItems().get(i).getColorCode());
else
v = new RoundedTagItem(DetailActivity.this);
ImageView img = new ImageView(DetailActivity.this);
img.setImageDrawable(Drawable.createFromPath(
item.getCategoryItems().get(i).getLightIconUrl()));
v.addView(img);
v.setTag(i);
v.setOnClickListener(new TagClickListener());
categories.addView(v);
}

Some improvements/problems you can make/fix...
You can move these lines to your constructor:
if(colorString != null)
color = Color.parseColor("#" + colorString);
Since this colorString never changes and the way you are doing it now you are calculating it every time onDraw is called (and he will be called a lot of times).
Second please move your super.onDraw(canvas) to your first line.
Third you need to define your LayoutParams on your constructor. If a View has 0 width/height its draw will never be called!
this.setLayoutParams(new LayoutParams(150, 150));
At last please make sure you are using your RoundTagItem. You can add this view to your xml using a tag like this: <your.package.RoundTagItem> where your.package is the package that you are using (com.something.blabla). If you use it like this please be sure you define the layout_width and the layout_height.
You can also add your view programmatcly by adding to your root view (you get it by using findViewById(R.layout.your_root)) or by setting your view as the main content.
RoundedTagItem myView = new RoundedTagItem(this);
setContentView(myView);

Try to create a simple single RelativeLayout XML (rounded_tag_item.xml), and inflate the custom view:
public class RoundedTagItem extends RelativeLayout {
public RoundedTagItem(Context context, AttributeSet attrs) {
super(context, attrs);
init(context);
}
public RoundedTagItem(Context context) {
super(context);
init(context);
}
private void init(Context context) {
LayoutInflater inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
if (inflater != null) {
RelativeLayout layout = (RelativeLayout) inflater.inflate(R.layout.rounded_tag_item, new RelativeLayout(context));
// rest of stuff...
}
}
}

Is it possible to write vertically in a textview in android?

Let's say you have a normal TextView, with "Stackoverflow" written in it, Is it possible to rotate the TextView by -90°, to have the S at the bottom and the W at the top of the screen?
Of course I could write my text as an image, rotate it and use it that way, but I am interested in the text right now.
Thanks.

You can set your textview as you would normally do
for example:
<TextView android:id="#+id/txtview"
android:layout_height="fill_parent"
android:layout_width="wrap_content" />
and write a function in your activity to
reverse the characters in your text
insert \n after every characters
and then set the text to the TextView.
If you dont want to insert the \n, you will have to set the size of android:layout_width and play with font size not to have 2 characters fitting on the same line and no truncation
Edit
If I have understood you correctly, you can get what you want by using animation.
For example
Under res/anim/myanim.xml:
<rotate xmlns:android="http://schemas.android.com/apk/res/android"
android:fromDegrees="0"
android:toDegrees="-90"
android:pivotX="50%"
android:duration="0" />
You will have to play with this file to define where you want your text view to be placed.
In your activity:
TextView t = (TextView)findViewById(R.id.txtview);
String txt = "Stackoverflow";
t.setText(txt);
RotateAnimation ranim = (RotateAnimation)AnimationUtils.loadAnimation(this, R.anim.myanim);
ranim.setFillAfter(true); //For the textview to remain at the same place after the rotation
t.setAnimation(ranim);

Worked for me:
public class VerticalTextView extends TextView {
private int _width, _height;
private final Rect _bounds = new Rect();
public VerticalTextView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
public VerticalTextView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public VerticalTextView(Context context) {
super(context);
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
// vise versa
_height = getMeasuredWidth();
_width = getMeasuredHeight();
setMeasuredDimension(_width, _height);
}
#Override
protected void onDraw(Canvas canvas) {
canvas.save();
canvas.translate(_width, _height);
canvas.rotate(-90);
TextPaint paint = getPaint();
paint.setColor(getTextColors().getDefaultColor());
String text = text();
paint.getTextBounds(text, 0, text.length(), _bounds);
canvas.drawText(text, getCompoundPaddingLeft(), (_bounds.height() - _width) / 2, paint);
canvas.restore();
}
private String text() {
return super.getText().toString();
}
}
xml:
<VerticalTextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="left|center_vertical"
android:background="#color/feedback_background"
android:padding="4dip"
android:text="#string/feedback"
android:textColor="#color/feedback_text_color"
android:textSize="#dimen/text_xlarge" />

<TextView
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:text="xyz"
android:rotation="-90"
android:gravity="fill_vertical"/>

Try this. It works fine for me. It can display one line of text vertically, but just one line. colors, size, paddings, margins and background all work fine.
public class VerticalTextView extends TextView {
public VerticalTextView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
public VerticalTextView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public VerticalTextView(Context context) {
super(context);
}
#Override
protected void onDraw(Canvas canvas) {
final ColorStateList csl = getTextColors();
final int color = csl.getDefaultColor();
final int paddingBottom = getPaddingBottom();
final int paddingTop = getPaddingTop();
final int viewWidth = getWidth();
final int viewHeight = getHeight();
final TextPaint paint = getPaint();
paint.setColor(color);
final float bottom = viewWidth * 9.0f / 11.0f;
Path p = new Path();
p.moveTo(bottom, viewHeight - paddingBottom - paddingTop);
p.lineTo(bottom, paddingTop);
canvas.drawTextOnPath(getText().toString(), p, 0, 0, paint);
}
}

If you are using API 11 or later, you may try:
TextView t = (TextView) findViewById(R.id.txtview);
String txt = "Stackoverflow";
t.setText(txt);
t.setRotation(90); // 90 degree rotation

I'll show for you guys my example of custom vertical button with the rotated TextView in it:
<!--Undo button-->
<LinearLayout
android:id="#+id/undo_points_pr_a"
android:layout_width="#dimen/zero_dp"
android:gravity="center"
android:layout_height="match_parent"
android:orientation="vertical"
android:layout_weight="1"
android:background="#color/timerUndoButton">
<ImageView
android:layout_width="#dimen/large"
android:layout_height="#dimen/large"
android:src="#drawable/undo_icon"
android:rotation="-90"
android:layout_marginBottom="#dimen/medium"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/undo"
android:textSize="#dimen/small_medium_text"
android:rotation="-90"/>
</LinearLayout>
And this is how it looks in Android Studio:
And of course you have to modify this code to make it works for you. (in attributes like android:layout_width, android:layout_height, etc.)

I provided a solution in another StackOverflow question. You can get vertical TextView by extending from View and overriding its onMeasure() and onDraw() methods. However, it will not support all TextView features, rather its main ones like padding, size, color and font.
import android.annotation.TargetApi;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.Typeface;
import android.os.Build;
import android.text.TextPaint;
import android.util.AttributeSet;
import android.util.Log;
import android.util.TypedValue;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
public class VerticalLabelView extends View
{
private final String LOG_TAG = "VerticalLabelView";
private final int DEFAULT_TEXT_SIZE = 30;
private int _ascent = 0;
private int _leftPadding = 0;
private int _topPadding = 0;
private int _rightPadding = 0;
private int _bottomPadding = 0;
private int _textSize = 0;
private int _measuredWidth;
private int _measuredHeight;
private Rect _textBounds;
private TextPaint _textPaint;
private String _text = "";
private TextView _tempView;
private Typeface _typeface = null;
private boolean _topToDown = false;
public VerticalLabelView(Context context)
{
super(context);
initLabelView();
}
public VerticalLabelView(Context context, AttributeSet attrs)
{
super(context, attrs);
initLabelView();
}
public VerticalLabelView(Context context, AttributeSet attrs, int defStyleAttr)
{
super(context, attrs, defStyleAttr);
initLabelView();
}
#TargetApi(Build.VERSION_CODES.LOLLIPOP)
public VerticalLabelView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes)
{
super(context, attrs, defStyleAttr, defStyleRes);
initLabelView();
}
private final void initLabelView()
{
this._textBounds = new Rect();
this._textPaint = new TextPaint();
this._textPaint.setAntiAlias(true);
this._textPaint.setTextAlign(Paint.Align.CENTER);
this._textPaint.setTextSize(DEFAULT_TEXT_SIZE);
this._textSize = DEFAULT_TEXT_SIZE;
}
public void setText(String text)
{
this._text = text;
requestLayout();
invalidate();
}
public void topToDown(boolean topToDown)
{
this._topToDown = topToDown;
}
public void setPadding(int padding)
{
setPadding(padding, padding, padding, padding);
}
public void setPadding(int left, int top, int right, int bottom)
{
this._leftPadding = left;
this._topPadding = top;
this._rightPadding = right;
this._bottomPadding = bottom;
requestLayout();
invalidate();
}
public void setTextSize(int size)
{
this._textSize = size;
this._textPaint.setTextSize(size);
requestLayout();
invalidate();
}
public void setTextColor(int color)
{
this._textPaint.setColor(color);
invalidate();
}
public void setTypeFace(Typeface typeface)
{
this._typeface = typeface;
this._textPaint.setTypeface(typeface);
requestLayout();
invalidate();
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
{
try
{
this._textPaint.getTextBounds(this._text, 0, this._text.length(), this._textBounds);
this._tempView = new TextView(getContext());
this._tempView.setPadding(this._leftPadding, this._topPadding, this._rightPadding, this._bottomPadding);
this._tempView.setText(this._text);
this._tempView.setTextSize(TypedValue.COMPLEX_UNIT_PX, this._textSize);
this._tempView.setTypeface(this._typeface);
this._tempView.measure(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
this._measuredWidth = this._tempView.getMeasuredHeight();
this._measuredHeight = this._tempView.getMeasuredWidth();
this._ascent = this._textBounds.height() / 2 + this._measuredWidth / 2;
setMeasuredDimension(this._measuredWidth, this._measuredHeight);
}
catch (Exception e)
{
setMeasuredDimension(widthMeasureSpec, heightMeasureSpec);
Log.e(LOG_TAG, Log.getStackTraceString(e));
}
}
#Override
protected void onDraw(Canvas canvas)
{
super.onDraw(canvas);
if (!this._text.isEmpty())
{
float textHorizontallyCenteredOriginX = this._measuredHeight / 2f;
float textHorizontallyCenteredOriginY = this._ascent;
canvas.translate(textHorizontallyCenteredOriginY, textHorizontallyCenteredOriginX);
float rotateDegree = -90;
float y = 0;
if (this._topToDown)
{
rotateDegree = 90;
y = this._measuredWidth / 2;
}
canvas.rotate(rotateDegree);
canvas.drawText(this._text, 0, y, this._textPaint);
}
}
}

I think the simplest answer to your question to write "Stackoverflow" vertically is to use an ordinary TextView, and since the text will wrap to the next line when narrowed, play around with the width of the TextView so there is one letter is on each line and if you need more space on the edge as a buffer increase the "padding" and/or "margin" of the TextView.

My initial approach to rendering vertical text inside a vertical LinearLayout was as follows (this is Kotlin, in Java use setRoatation etc.):
val tv = TextView(context)
tv.gravity = Gravity.CENTER
tv.rotation = 90F
tv.height = calcHeight(...)
linearLabels.addView(tv)
As you can see the problem is that the TextView goes vertically but still treats its width as if it were oriented horizontally! =/
Thus approach #2 consisted of additionally switching width and height manually to account for this:
tv.measure(0, 0)
// tv.setSingleLine()
tv.width = tv.measuredHeight
tv.height = calcHeight(...)
This however resulted in the labels wrapping around to the next line (or being cropped if you setSingleLine) after the relatively short width. Again, this boils down to confusing x with y.
My approach #3 was thus to wrap the TextView in a RelativeLayout. The idea is to allow the TextView any width it wants by extending it far to the left and the right (here, 200 pixels in both directions). But then I give the RelativeLayout negative margins to ensure it is drawn as a narrow column. Here is my full code for this screenshot:
val tv = TextView(context)
tv.text = getLabel(...)
tv.gravity = Gravity.CENTER
tv.rotation = 90F
tv.measure(0, 0)
tv.width = tv.measuredHeight + 400 // 400 IQ
tv.height = calcHeight(...)
val tvHolder = RelativeLayout(context)
val lp = LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,
LinearLayout.LayoutParams.WRAP_CONTENT)
lp.setMargins(-200, 0, -200, 0)
tvHolder.layoutParams = lp
tvHolder.addView(tv)
linearLabels.addView(tvHolder)
val iv = ImageView(context)
iv.setImageResource(R.drawable.divider)
linearLabels.addView(iv)
As a general tip, this strategy of having a view "hold" another view has been really useful for me in positioning things in Android! For example, the info window below the ActionBar uses the same tactic!
For text starting at the bottom just rotate it by -90F instead of 90F degrees.

public class VerticalTextView extends AppCompatTextView {
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();
}
}