Paint.setStrokeJoin doesn't work with canvas.drawLines - android

I am trying to draw a line chart using canvas.drawLines(...), but it seems that the lines are not properly connected. As I understand using Paint.setStrokeJoin should use the miter join:
chartLinePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
chartLinePaint.setStyle(Paint.Style.STROKE);
chartLinePaint.setStrokeJoin(Paint.Join.MITER);
chartLinePaint.setStrokeWidth(6.0f);
How do I fix this problem and make the lines properly joined?

As I told you in the comment, Paint objects are fully applied only when you draw them with Path.
In drawLine documentation there is a paragraph with: 'the Style is ignored in the paint' and the same thing is applied to drawLines method.
To test this, I created a simple custom view:
class CanvasTestView #JvmOverloads constructor(
context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0
) : View(context, attrs, defStyleAttr) {
private val textPaint1 = Paint(ANTI_ALIAS_FLAG).apply {
style = Paint.Style.STROKE
strokeJoin = Paint.Join.MITER
strokeWidth = 12.0f
color = Color.RED
}
private val textPaint2 = Paint(ANTI_ALIAS_FLAG).apply {
style = Paint.Style.STROKE
strokeJoin = Paint.Join.MITER
strokeWidth = 12.0f
color = Color.BLUE
}
#SuppressLint("DrawAllocation")
override fun onDraw(canvas: Canvas?) {
super.onDraw(canvas)
canvas?.apply {
val floatArray = floatArrayOf(250f, 550f, 450f, 200f, 450f, 200f, 650f, 700f)
drawLines(floatArray, textPaint2)
val path = Path()
path.moveTo(200f, 500f)
path.lineTo(400f, 200f)
path.lineTo(600f, 700f)
drawPath(path, textPaint1)
}
}
}
And the result is this:
So using drawLines partially apply the styles of Paint obj, like colours, but is not applying strokeJoin like properties. drawPath seems to apply all of them instead.
If you have a performance problem maybe you can try to cache the result somewhere, pre-compute the animation or try with a simpler one.
Remember that if you don't have particular requirements there is this
awesome library: MPAndroidChart which already has some built-in animations

Problem
As you may have noticed in the Android documentation, you can’t apply
a style to a drawLine.
ref
From the Canvas documentation
drawLine:
public void drawLine (float startX, float startY, float stopX, float stopY, Paint paint)
Draw a line segment with the specified start and stop x,y coordinates,
using the specified paint.
Note that since a line is always "framed", the Style is ignored in the
paint.
Degenerate lines (length is 0) will not be drawn.
drawLines:
public void drawLines (float[] pts, int offset, int count, Paint paint)
Draw a series of lines. Each line is taken from 4 consecutive values
in the pts array. Thus to draw 1 line, the array must contain at least
4 values. This is logically the same as drawing the array as
follows:
drawLine(pts[0], pts[1], pts[2], pts[3])
followed by:
drawLine(pts[4], pts[5], pts[6], pts[7])
and so on.
Solution
If you need to apply a style, the solution is to use drawPath instead.
It will apply the style set in the paint object.

For anyone else looking for to use the StrokeJoin or StrokeCap with DrawPath(), you can try SkPathEffect such as CreateCorner():
MS Docs, SkiaSharp, but kind of the same.

Related

Android: Canvas Animate Path

Good morning
I have created custom view where I draw a line based on input like this:
override fun onDraw(canvas: Canvas) {
super.onDraw(canvas)
val width = dpToPixels(context.resources, 300);
if (_value != null) {
val calculatedPath = createPath(_value !!, width.toFloat());
canvas.drawPath(calculatedPath !!, _paint)
} else {
canvas.drawPath(defaultPath, _paint)
}
}
The both calculatedPath and defaultPath are simply curved line similar to function
f(x) = x^( - 2).
As I am not Android programmer I am looking for an easy way to draw these lines with animation. I have tried something with ValueAnimator with listener like:
animator.addUpdateListener { valueAnimator ->
paint.pathEffect = DashPathEffect(dashes, (valueAnimator.animatedValue as Int).toFloat())
invalidate()
}
However I am not interested in Dashed path effect but rather Solid which I couldn't find.
Is there simply way to draw these lines with animation like
canvas.drawPath(path, paint, animation)?

TextView as a Progress Bar in Kotlin

I am trying to replicate the TextView as progress bar described in this question using Kotlin, overriding the TextView class and using the canvas clipping trick in Zielony's comment.
The code almost works: I can see the text change color at the specified percentage (fixed, for now) but the background stays the same (yellow, the last background color I set).
Here's my code:
class ProgressTextView(context: Context): TextView(context) {
override fun onDraw(canvas: Canvas) {
val color1 = ContextCompat.getColor(context, R.color.primaryColor)
val color2 = ContextCompat.getColor(context, R.color.secondaryColor)
var percent = 0.3 // Fixed progress % at 30%, for testing
// first half
canvas.save()
setTextColor(Color.RED)
setBackgroundColor(Color.GREEN)
canvas.clipRect(Rect(0, 0, (width * percent).toInt(), height))
super.onDraw(canvas)
canvas.restore()
// second half
canvas.save()
setTextColor(Color.BLACK)
setBackgroundColor(Color.YELLOW)
canvas.clipRect(Rect((width * percent).toInt(), 0, width, height))
super.onDraw(canvas)
canvas.restore()
}
}
What am I missing?
I managed to get it to work painting a rectangle instead of clipping for the first half, but I am still curious about how it should be done "properly", as this solution seems more elegant.

Android: Black outline around text [duplicate]

Is there a simple way to have text be able to have a black outline? I have textviews that will be different colors, but some of the colors don't show up on my background so well, so I was wondering if there's an easy way to get a black outline or something else that will do the job? I'd prefer not to have to create a custom view and make a canvas and such.
outline effect can be achieved using shadow in TextView:
android:shadowColor="#000000"
android:shadowDx="1.5"
android:shadowDy="1.3"
android:shadowRadius="1.6"
android:text="CCC"
android:textAllCaps="true"
android:textColor="#android:color/white"
So, little late, but MagicTextView will do text outlines, amongst other things.
<com.qwerjk.better_text.MagicTextView
xmlns:qwerjk="http://schemas.android.com/apk/res/com.qwerjk.better_text"
android:textSize="78dp"
android:textColor="#ff333333"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
qwerjk:strokeColor="#FFff0000"
qwerjk:strokeJoinStyle="miter"
qwerjk:strokeWidth="5"
android:text="Magic" />
Note: I made this, and am posting more for the sake of future travelers than the OP.
It's borderline spam, but being on-topic, perhaps acceptable?
You can put a shadow behind the text, which can often help readability. Try experimenting with 50% translucent black shadows on your green text. Details on how to do this are over here: Android - shadow on text?
To really add a stroke around the text, you need to do something a bit more involved, like this:
How do you draw text with a border on a MapView in Android?
It is quite an old question but still I don't see any complete answers. So I am posting this solution, hoping that someone struggling with this problem might find it useful. The simplest and most effective solution is to override TextView class' onDraw method. Most implementations I have seen use drawText method to draw the stroke but that approach doesn't account for all the formatting alignment and text wrapping that goes in. And as a result often the stroke and text end up at different places. Following approach uses super.onDraw to draw both the stroke and fill parts of the text so you don't have to bother about rest of the stuff. Here are the steps
Extend TextView class
Override onDraw method
Set paint style to FILL
call parent class on Draw to render text in fill
mode.
save current text color.
Set current text color to your stroke color
Set paint style to Stroke
Set stroke width
And call parent class onDraw again to draw the stroke over the
previously rendered text.
package com.example.widgets;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Typeface;
import android.util.AttributeSet;
import android.widget.Button;
public class StrokedTextView extends Button {
private static final int DEFAULT_STROKE_WIDTH = 0;
// fields
private int _strokeColor;
private float _strokeWidth;
// constructors
public StrokedTextView(Context context) {
this(context, null, 0);
}
public StrokedTextView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public StrokedTextView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
if(attrs != null) {
TypedArray a = context.obtainStyledAttributes(attrs,R.styleable.StrokedTextAttrs);
_strokeColor = a.getColor(R.styleable.StrokedTextAttrs_textStrokeColor,
getCurrentTextColor());
_strokeWidth = a.getFloat(R.styleable.StrokedTextAttrs_textStrokeWidth,
DEFAULT_STROKE_WIDTH);
a.recycle();
}
else {
_strokeColor = getCurrentTextColor();
_strokeWidth = DEFAULT_STROKE_WIDTH;
}
//convert values specified in dp in XML layout to
//px, otherwise stroke width would appear different
//on different screens
_strokeWidth = dpToPx(context, _strokeWidth);
}
// getters + setters
public void setStrokeColor(int color) {
_strokeColor = color;
}
public void setStrokeWidth(int width) {
_strokeWidth = width;
}
// overridden methods
#Override
protected void onDraw(Canvas canvas) {
if(_strokeWidth > 0) {
//set paint to fill mode
Paint p = getPaint();
p.setStyle(Paint.Style.FILL);
//draw the fill part of text
super.onDraw(canvas);
//save the text color
int currentTextColor = getCurrentTextColor();
//set paint to stroke mode and specify
//stroke color and width
p.setStyle(Paint.Style.STROKE);
p.setStrokeWidth(_strokeWidth);
setTextColor(_strokeColor);
//draw text stroke
super.onDraw(canvas);
//revert the color back to the one
//initially specified
setTextColor(currentTextColor);
} else {
super.onDraw(canvas);
}
}
/**
* Convenience method to convert density independent pixel(dp) value
* into device display specific pixel value.
* #param context Context to access device specific display metrics
* #param dp density independent pixel value
* #return device specific pixel value.
*/
public static int dpToPx(Context context, float dp)
{
final float scale= context.getResources().getDisplayMetrics().density;
return (int) (dp * scale + 0.5f);
}
}
That is all. This class uses custom XML attributes to enable specifying stroke color and width from the XML layout files. Therefore, you need to add these attributes in your attr.xml file in subfolder 'values' under folder 'res'. Copy and paste the following in your attr.xml file.
<?xml version="1.0" encoding="utf-8"?>
<resources>
<declare-styleable name="StrokedTextAttrs">
<attr name="textStrokeColor" format="color"/>
<attr name="textStrokeWidth" format="float"/>
</declare-styleable>
</resources>
Once you are done with that, you can use the custom StrokedTextView class in your XML layout files and specify stroke color and width as well. Here is an example
<com.example.widgets.StrokedTextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Stroked text sample"
android:textColor="#android:color/white"
android:textSize="25sp"
strokeAttrs:textStrokeColor="#android:color/black"
strokeAttrs:textStrokeWidth="1.7" />
Remember to replace package name with your project's package name. Also add the xmlns namespace in the layout file in order to use custom XML attributes. You can add the following line in your layout file's root node.
xmlns:strokeAttrs="http://schemas.android.com/apk/res-auto"
The framework supports text-shadow but does not support text-outline. But there is a trick: shadow is something that is translucent and fades. Redraw the shadow a couple of times and all the alpha gets summed up and the result is an outline.
A very simple implementation extends TextView and overrides the draw(..) method. Every time a draw is requested our subclass does 5-10 drawings.
public class OutlineTextView extends TextView {
// Constructors
#Override
public void draw(Canvas canvas) {
for (int i = 0; i < 5; i++) {
super.draw(canvas);
}
}
}
<OutlineTextView
android:shadowColor="#000"
android:shadowRadius="3.0" />
I've just been trying to figure out how to do this and couldn't find a good guide online but eventually figured it out. As Steve Pomeroy suggested, you do have to do something more involved. In order to get the outlined text effect, you draw the text twice: once with a thick outline and then the second time we draw the main text over the outline. But, the task is made easier because you can very easily adapt one of the code samples provided with the SDK, namely the one under this name in your SDK directory: "/samples/android-/ApiDemos/src/com/example/android/apis/view/LabelView.java". Which can also found on the Android developer website here.
Depending on what you're doing, it's very easy to see you will only need to make minor modifications to that code, such as changing it to extend from TextView, etc. Before I discovered this sample I forgot to override onMeasure() (which you must do in addition to overriding onDraw() as is mentioned in the "Building Custom Components" guide on the Android Developer website), which is part of why I was having trouble.
Once you've done that, you can do what I did:
public class TextViewOutline extends TextView {
private Paint mTextPaint;
private Paint mTextPaintOutline; //add another paint attribute for your outline
...
//modify initTextViewOutline to setup the outline style
private void initTextViewOutline() {
mTextPaint = new Paint();
mTextPaint.setAntiAlias(true);
mTextPaint.setTextSize(16);
mTextPaint.setColor(0xFF000000);
mTextPaint.setStyle(Paint.Style.FILL);
mTextPaintOutline = new Paint();
mTextPaintOutline.setAntiAlias(true);
mTextPaintOutline.setTextSize(16);
mTextPaintOutline.setColor(0xFF000000);
mTextPaintOutline.setStyle(Paint.Style.STROKE);
mTextPaintOutline.setStrokeWidth(4);
setPadding(3, 3, 3, 3);
}
...
//make sure to update other methods you've overridden to handle your new paint object
...
//and finally draw the text, mAscent refers to a member attribute which had
//a value assigned to it in the measureHeight and Width methods
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawText(mText, getPaddingLeft(), getPaddingTop() - mAscent,
mTextPaintOutline);
canvas.drawText(mText, getPaddingLeft(), getPaddingTop() - mAscent, mTextPaint);
}
So, in order to get the outlined text effect, you draw the text twice: once with a thick outline and then the second time we draw the main text over the outline.
credit to #YGHM add shadow support
package com.megvii.demo;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
public class TextViewOutline extends android.support.v7.widget.AppCompatTextView {
// constants
private static final int DEFAULT_OUTLINE_SIZE = 0;
private static final int DEFAULT_OUTLINE_COLOR = Color.TRANSPARENT;
// data
private int mOutlineSize;
private int mOutlineColor;
private int mTextColor;
private float mShadowRadius;
private float mShadowDx;
private float mShadowDy;
private int mShadowColor;
public TextViewOutline(Context context) {
this(context, null);
}
public TextViewOutline(Context context, AttributeSet attrs) {
super(context, attrs);
setAttributes(attrs);
}
private void setAttributes(AttributeSet attrs) {
// set defaults
mOutlineSize = DEFAULT_OUTLINE_SIZE;
mOutlineColor = DEFAULT_OUTLINE_COLOR;
// text color
mTextColor = getCurrentTextColor();
if (attrs != null) {
TypedArray a = getContext().obtainStyledAttributes(attrs, R.styleable.TextViewOutline);
// outline size
if (a.hasValue(R.styleable.TextViewOutline_outlineSize)) {
mOutlineSize = (int) a.getDimension(R.styleable.TextViewOutline_outlineSize, DEFAULT_OUTLINE_SIZE);
}
// outline color
if (a.hasValue(R.styleable.TextViewOutline_outlineColor)) {
mOutlineColor = a.getColor(R.styleable.TextViewOutline_outlineColor, DEFAULT_OUTLINE_COLOR);
}
// shadow (the reason we take shadow from attributes is because we use API level 15 and only from 16 we have the get methods for the shadow attributes)
if (a.hasValue(R.styleable.TextViewOutline_android_shadowRadius)
|| a.hasValue(R.styleable.TextViewOutline_android_shadowDx)
|| a.hasValue(R.styleable.TextViewOutline_android_shadowDy)
|| a.hasValue(R.styleable.TextViewOutline_android_shadowColor)) {
mShadowRadius = a.getFloat(R.styleable.TextViewOutline_android_shadowRadius, 0);
mShadowDx = a.getFloat(R.styleable.TextViewOutline_android_shadowDx, 0);
mShadowDy = a.getFloat(R.styleable.TextViewOutline_android_shadowDy, 0);
mShadowColor = a.getColor(R.styleable.TextViewOutline_android_shadowColor, Color.TRANSPARENT);
}
a.recycle();
}
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
setPaintToOutline();
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
private void setPaintToOutline() {
Paint paint = getPaint();
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeWidth(mOutlineSize);
super.setTextColor(mOutlineColor);
super.setShadowLayer(0, 0, 0, Color.TRANSPARENT);
}
private void setPaintToRegular() {
Paint paint = getPaint();
paint.setStyle(Paint.Style.FILL);
paint.setStrokeWidth(0);
super.setTextColor(mTextColor);
super.setShadowLayer(mShadowRadius, mShadowDx, mShadowDy, mShadowColor);
}
#Override
public void setTextColor(int color) {
super.setTextColor(color);
mTextColor = color;
}
public void setOutlineSize(int size) {
mOutlineSize = size;
}
public void setOutlineColor(int color) {
mOutlineColor = color;
}
#Override
protected void onDraw(Canvas canvas) {
setPaintToOutline();
super.onDraw(canvas);
setPaintToRegular();
super.onDraw(canvas);
}
}
attr define
<declare-styleable name="TextViewOutline">
<attr name="outlineSize" format="dimension"/>
<attr name="outlineColor" format="color|reference"/>
<attr name="android:shadowRadius"/>
<attr name="android:shadowDx"/>
<attr name="android:shadowDy"/>
<attr name="android:shadowColor"/>
</declare-styleable>
xml code below
<com.megvii.demo.TextViewOutline
android:id="#+id/product_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:layout_marginTop="110dp"
android:background="#f4b222"
android:fontFamily="#font/kidsmagazine"
android:padding="10dp"
android:shadowColor="#d7713200"
android:shadowDx="0"
android:shadowDy="8"
android:shadowRadius="1"
android:text="LIPSTICK SET"
android:textColor="#android:color/white"
android:textSize="30sp"
app:outlineColor="#cb7800"
app:outlineSize="3dp" />
You can do this programmatically with the below snippet.
That provides white letters with black background:
textView.setTextColor(Color.WHITE);
textView.setShadowLayer(1.6f,1.5f,1.3f,Color.BLACK);
The parameters of the method are radius,dx,dy,color. You can change them for you specific needs.
I hope I will help someone that creates TextView programmatically and not having it inside xml.
Cheers to the stackOverflow community!
I want to add a solution in order to solve the performance issue. For example, the answer of #YGHM and a few others does the job, but it causes infinite call of onDraw because setTextColor calls invalidate(). So in order to solve it, you also need to override invalidate() and add a variable isDrawing that you will set to true, when onDraw() is in progress and drawing with a stroke. invalidate will return if the variable is true.
override fun invalidate() {
if (isDrawing) return
super.invalidate()
}
Your onDraw will look like this:
override fun onDraw(canvas: Canvas) {
if (strokeWidth > 0) {
isDrawing = true
val textColor = textColors.defaultColor
setTextColor(strokeColor)
paint.strokeWidth = strokeWidth
paint.style = Paint.Style.STROKE
super.onDraw(canvas)
setTextColor(textColor)
paint.strokeWidth = 0f
paint.style = Paint.Style.FILL
isDrawing = false
super.onDraw(canvas)
} else {
super.onDraw(canvas)
}
}
Here's the trick I found that works better than MagicTextView's stroke IMO
#Override
protected void onDraw(Canvas pCanvas) {
int textColor = getTextColors().getDefaultColor();
setTextColor(mOutlineColor); // your stroke's color
getPaint().setStrokeWidth(10);
getPaint().setStyle(Paint.Style.STROKE);
super.onDraw(pCanvas);
setTextColor(textColor);
getPaint().setStrokeWidth(0);
getPaint().setStyle(Paint.Style.FILL);
super.onDraw(pCanvas);
}
I've written a class to perform text with outline and still support all the other attributes and drawing of a normal text view.
it basically uses the super.onDraw(Canves canvas) on the TextView but draws twice with different styles.
hope this helps.
public class TextViewOutline extends TextView {
// constants
private static final int DEFAULT_OUTLINE_SIZE = 0;
private static final int DEFAULT_OUTLINE_COLOR = Color.TRANSPARENT;
// data
private int mOutlineSize;
private int mOutlineColor;
private int mTextColor;
private float mShadowRadius;
private float mShadowDx;
private float mShadowDy;
private int mShadowColor;
public TextViewOutline(Context context) {
this(context, null);
}
public TextViewOutline(Context context, AttributeSet attrs) {
super(context, attrs);
setAttributes(attrs);
}
private void setAttributes(AttributeSet attrs){
// set defaults
mOutlineSize = DEFAULT_OUTLINE_SIZE;
mOutlineColor = DEFAULT_OUTLINE_COLOR;
// text color
mTextColor = getCurrentTextColor();
if(attrs != null) {
TypedArray a = getContext().obtainStyledAttributes(attrs,R.styleable.TextViewOutline);
// outline size
if (a.hasValue(R.styleable.TextViewOutline_outlineSize)) {
mOutlineSize = (int) a.getDimension(R.styleable.TextViewOutline_outlineSize, DEFAULT_OUTLINE_SIZE);
}
// outline color
if (a.hasValue(R.styleable.TextViewOutline_outlineColor)) {
mOutlineColor = a.getColor(R.styleable.TextViewOutline_outlineColor, DEFAULT_OUTLINE_COLOR);
}
// shadow (the reason we take shadow from attributes is because we use API level 15 and only from 16 we have the get methods for the shadow attributes)
if (a.hasValue(R.styleable.TextViewOutline_android_shadowRadius)
|| a.hasValue(R.styleable.TextViewOutline_android_shadowDx)
|| a.hasValue(R.styleable.TextViewOutline_android_shadowDy)
|| a.hasValue(R.styleable.TextViewOutline_android_shadowColor)) {
mShadowRadius = a.getFloat(R.styleable.TextViewOutline_android_shadowRadius, 0);
mShadowDx = a.getFloat(R.styleable.TextViewOutline_android_shadowDx, 0);
mShadowDy = a.getFloat(R.styleable.TextViewOutline_android_shadowDy, 0);
mShadowColor = a.getColor(R.styleable.TextViewOutline_android_shadowColor, Color.TRANSPARENT);
}
a.recycle();
}
PFLog.d("mOutlineSize = " + mOutlineSize);
PFLog.d("mOutlineColor = " + mOutlineColor);
}
private void setPaintToOutline(){
Paint paint = getPaint();
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeWidth(mOutlineSize);
super.setTextColor(mOutlineColor);
super.setShadowLayer(mShadowRadius, mShadowDx, mShadowDy, mShadowColor);
}
private void setPaintToRegular() {
Paint paint = getPaint();
paint.setStyle(Paint.Style.FILL);
paint.setStrokeWidth(0);
super.setTextColor(mTextColor);
super.setShadowLayer(0, 0, 0, Color.TRANSPARENT);
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
setPaintToOutline();
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
#Override
public void setTextColor(int color) {
super.setTextColor(color);
mTextColor = color;
}
#Override
public void setShadowLayer(float radius, float dx, float dy, int color) {
super.setShadowLayer(radius, dx, dy, color);
mShadowRadius = radius;
mShadowDx = dx;
mShadowDy = dy;
mShadowColor = color;
}
public void setOutlineSize(int size){
mOutlineSize = size;
}
public void setOutlineColor(int color){
mOutlineColor = color;
}
#Override
protected void onDraw(Canvas canvas) {
setPaintToOutline();
super.onDraw(canvas);
setPaintToRegular();
super.onDraw(canvas);
}
}
attr.xml
<declare-styleable name="TextViewOutline">
<attr name="outlineSize" format="dimension"/>
<attr name="outlineColor" format="color|reference"/>
<attr name="android:shadowRadius"/>
<attr name="android:shadowDx"/>
<attr name="android:shadowDy"/>
<attr name="android:shadowColor"/>
</declare-styleable>
I have created a library based on Nouman Hanif's answer with some additions. For example, fixing a bug that caused an indirect infinite loop on View.invalidate() calls.
OTOH, the library also supports outlined text in EditText widgets, as it was my real goal and it needed a bit more work than TextView.
Here is the link to my library: https://github.com/biomorgoth/android-outline-textview
Thanks to Nouman Hanif for the initial idea on the solution!
I found simple way to outline view without inheritance from TextView.
I had wrote simple library that use Android's Spannable for outlining text.
This solution gives possibility to outline only part of text.
I already had answered on same question (answer)
Class:
class OutlineSpan(
#ColorInt private val strokeColor: Int,
#Dimension private val strokeWidth: Float
): ReplacementSpan() {
override fun getSize(
paint: Paint,
text: CharSequence,
start: Int,
end: Int,
fm: Paint.FontMetricsInt?
): Int {
return paint.measureText(text.toString().substring(start until end)).toInt()
}
override fun draw(
canvas: Canvas,
text: CharSequence,
start: Int,
end: Int,
x: Float,
top: Int,
y: Int,
bottom: Int,
paint: Paint
) {
val originTextColor = paint.color
paint.apply {
color = strokeColor
style = Paint.Style.STROKE
this.strokeWidth = this#OutlineSpan.strokeWidth
}
canvas.drawText(text, start, end, x, y.toFloat(), paint)
paint.apply {
color = originTextColor
style = Paint.Style.FILL
}
canvas.drawText(text, start, end, x, y.toFloat(), paint)
}
}
Library: OutlineSpan
MagicTextView is very useful to make stroke font, but in my case, it cause error like
this
this error caused by duplication background attributes which set by MagicTextView
so you need to edit attrs.xml and MagicTextView.java
attrs.xml
<attr name="background" format="reference|color" />
↓
<attr name="mBackground" format="reference|color" />
MagicTextView.java 88:95
if (a.hasValue(R.styleable.MagicTextView_mBackground)) {
Drawable background = a.getDrawable(R.styleable.MagicTextView_mBackground);
if (background != null) {
this.setBackgroundDrawable(background);
} else {
this.setBackgroundColor(a.getColor(R.styleable.MagicTextView_mBackground, 0xff000000));
}
}
So you want a stroke around the textview? Unfortunately there is no simple way to do it with the styling. You'll have to create another view and place your textview over-top, making the parent view (the one it's on top of) just a few pixels bigger - this should create an outline.
Here is the simplest way I could find by extending TextView
public class CustomTextView extends androidx.appcompat.widget.AppCompatTextView {
float mStroke;
public CustomTextView(Context context, #Nullable AttributeSet attrs) {
super(context, attrs);
TypedArray a = context.obtainStyledAttributes(attrs,
R.styleable.CustomTextView);
mStroke=a.getFloat(R.styleable.CustomTextView_stroke,1.0f);
a.recycle();
}
#Override
protected void onDraw(Canvas canvas) {
TextPaint paint = this.getPaint();
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeWidth(mStroke);
super.onDraw(canvas);
}
}
then you only need to add the following to the attrs.xml file
<declare-styleable name="CustomTextView">
<attr name="stroke" format="float"/>
</declare-styleable>
and now you will be able to set the stroke widht by app:stroke while retaining all other desirable properties of TextView. my solution only draws the stroke w/o a fill. this makes it a bit simpler than the others. bellow a screencapture with the result while setting a custom font to my customtextview.

Xamarin - Radial Progress Component Issue

I 've been trying to implement the RadialProgress component (https://components.xamarin.com/view/radialprogress) on my app.
I managed to get it on the screen, and change the progress colour but I can't find a way to change the inner colour of the circle.
The RadialProgressView object itself has a BackgroundTintMode field which takes a DuffPorter.Mode but whenever I try to set the background tint mode the app breaks with this message (Message = "no method with name='setBackgroundTintMode' signature='(Landroid/graphics/PorterDuff$Mode;))
Is there even a way to do what I want?
Thanks!
Yes, it can be done. Although not in a very straight-forward way or even maintainable way.
Firstly, let's dig a little into RadialProgressView's drawing code (as exposed by Xamarin Studio Assembly Browser):
protected override void OnDraw(Canvas canvas)
{
// ... there's more stuff here, but you get the idea
canvas.DrawCircle(this.bgCx, this.bgCy, this.radius, this.bgCirclePaint);
canvas.DrawCircle(this.bgCx, this.bgCy, this.innerLineRadius, this.bgBorderPaint);
canvas.DrawText(this.valueText, this.textX, this.textY, this.textPaint);
}
We notice some colors here, like bgCirclePaintand bgBorderPaint. If we are able to change the value of these variables, we will be able to change the color with which the ProgressView is painted.
The problem is that RadialProgressView does not expose the fields – they are all private, so simply inheriting from RadialProgressView will not allow us to set them to a new value.
However, we can make use of reflection to change these private fields, like so:
var textPaintMember = typeof(RadialProgressView).GetField("textPaint", BindingFlags.Instance | BindingFlags.NonPublic);
textPaintMember.SetValue(Instance, MyNewSuperCoolColorPaint);
By combining the two, we can come up with a new, customizable class like this:
public class CustomizableRadialProgressView : RadialProgressView
{
public CustomizableRadialProgressView(Context context) : base(context)
{
}
public void SetTextColor(Color color)
{
var paint = new Paint();
paint.SetTypeface(Typeface.DefaultBold);
paint.Color = color;
paint.AntiAlias = true;
var textPaintMember = typeof(RadialProgressView).GetField("textPaint", BindingFlags.Instance | BindingFlags.NonPublic);
textPaintMember.SetValue(this, paint);
}
public void SetCircleColor(Color color)
{
var paint = new Paint();
paint.SetStyle(Paint.Style.Fill);
paint.Color = color;
paint.AntiAlias = true;
var circlePaintMember = typeof(RadialProgressView).GetField("bgCirclePaint", BindingFlags.Instance | BindingFlags.NonPublic);
circlePaintMember.SetValue(this, paint);
}
public void SetBorderColor(Color color)
{
var paint = new Paint();
paint.SetStyle(Paint.Style.Stroke);
paint.Color = color;
paint.AntiAlias = true;
var circlePaintMember = typeof(RadialProgressView).GetField("bgBorderPaint", BindingFlags.Instance | BindingFlags.NonPublic);
circlePaintMember.SetValue(this, paint);
}
public void SetProgressPackgroundColor(Color color)
{
var paint = new Paint();
paint.SetStyle(Paint.Style.Stroke);
paint.Color = color;
paint.AntiAlias = true;
var circlePaintMember = typeof(RadialProgressView).GetField("bgProgressPaint", BindingFlags.Instance | BindingFlags.NonPublic);
circlePaintMember.SetValue(this, paint);
}
}
This will get us the result we're after:
Note: It is probably wise to notice that we are making improper use of private fields: We're manipulating them from outside of the class they live in. If Xamarin ever decides to change the way RadialProgressViewis implemented, or even only renames one of the private variables, our code will fail at runtime. The better way to approach this problem would probably be to just ask Xamarin to provide the getters/setters you need. But, hey, it's SO much cooler this way ;)
You can try implementing a custom ViewRenderer and access the underlying native Android views to modify them as you want.
https://blog.xamarin.com/using-custom-controls-in-xamarin.forms-on-android/
The error you have regarding the "setBackgroundTintMode" method indicates that you may need to update your Xamarin platform to make sure that the latest APIs are available

Android textview outline text

Is there a simple way to have text be able to have a black outline? I have textviews that will be different colors, but some of the colors don't show up on my background so well, so I was wondering if there's an easy way to get a black outline or something else that will do the job? I'd prefer not to have to create a custom view and make a canvas and such.
outline effect can be achieved using shadow in TextView:
android:shadowColor="#000000"
android:shadowDx="1.5"
android:shadowDy="1.3"
android:shadowRadius="1.6"
android:text="CCC"
android:textAllCaps="true"
android:textColor="#android:color/white"
So, little late, but MagicTextView will do text outlines, amongst other things.
<com.qwerjk.better_text.MagicTextView
xmlns:qwerjk="http://schemas.android.com/apk/res/com.qwerjk.better_text"
android:textSize="78dp"
android:textColor="#ff333333"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
qwerjk:strokeColor="#FFff0000"
qwerjk:strokeJoinStyle="miter"
qwerjk:strokeWidth="5"
android:text="Magic" />
Note: I made this, and am posting more for the sake of future travelers than the OP.
It's borderline spam, but being on-topic, perhaps acceptable?
You can put a shadow behind the text, which can often help readability. Try experimenting with 50% translucent black shadows on your green text. Details on how to do this are over here: Android - shadow on text?
To really add a stroke around the text, you need to do something a bit more involved, like this:
How do you draw text with a border on a MapView in Android?
It is quite an old question but still I don't see any complete answers. So I am posting this solution, hoping that someone struggling with this problem might find it useful. The simplest and most effective solution is to override TextView class' onDraw method. Most implementations I have seen use drawText method to draw the stroke but that approach doesn't account for all the formatting alignment and text wrapping that goes in. And as a result often the stroke and text end up at different places. Following approach uses super.onDraw to draw both the stroke and fill parts of the text so you don't have to bother about rest of the stuff. Here are the steps
Extend TextView class
Override onDraw method
Set paint style to FILL
call parent class on Draw to render text in fill
mode.
save current text color.
Set current text color to your stroke color
Set paint style to Stroke
Set stroke width
And call parent class onDraw again to draw the stroke over the
previously rendered text.
package com.example.widgets;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Typeface;
import android.util.AttributeSet;
import android.widget.Button;
public class StrokedTextView extends Button {
private static final int DEFAULT_STROKE_WIDTH = 0;
// fields
private int _strokeColor;
private float _strokeWidth;
// constructors
public StrokedTextView(Context context) {
this(context, null, 0);
}
public StrokedTextView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public StrokedTextView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
if(attrs != null) {
TypedArray a = context.obtainStyledAttributes(attrs,R.styleable.StrokedTextAttrs);
_strokeColor = a.getColor(R.styleable.StrokedTextAttrs_textStrokeColor,
getCurrentTextColor());
_strokeWidth = a.getFloat(R.styleable.StrokedTextAttrs_textStrokeWidth,
DEFAULT_STROKE_WIDTH);
a.recycle();
}
else {
_strokeColor = getCurrentTextColor();
_strokeWidth = DEFAULT_STROKE_WIDTH;
}
//convert values specified in dp in XML layout to
//px, otherwise stroke width would appear different
//on different screens
_strokeWidth = dpToPx(context, _strokeWidth);
}
// getters + setters
public void setStrokeColor(int color) {
_strokeColor = color;
}
public void setStrokeWidth(int width) {
_strokeWidth = width;
}
// overridden methods
#Override
protected void onDraw(Canvas canvas) {
if(_strokeWidth > 0) {
//set paint to fill mode
Paint p = getPaint();
p.setStyle(Paint.Style.FILL);
//draw the fill part of text
super.onDraw(canvas);
//save the text color
int currentTextColor = getCurrentTextColor();
//set paint to stroke mode and specify
//stroke color and width
p.setStyle(Paint.Style.STROKE);
p.setStrokeWidth(_strokeWidth);
setTextColor(_strokeColor);
//draw text stroke
super.onDraw(canvas);
//revert the color back to the one
//initially specified
setTextColor(currentTextColor);
} else {
super.onDraw(canvas);
}
}
/**
* Convenience method to convert density independent pixel(dp) value
* into device display specific pixel value.
* #param context Context to access device specific display metrics
* #param dp density independent pixel value
* #return device specific pixel value.
*/
public static int dpToPx(Context context, float dp)
{
final float scale= context.getResources().getDisplayMetrics().density;
return (int) (dp * scale + 0.5f);
}
}
That is all. This class uses custom XML attributes to enable specifying stroke color and width from the XML layout files. Therefore, you need to add these attributes in your attr.xml file in subfolder 'values' under folder 'res'. Copy and paste the following in your attr.xml file.
<?xml version="1.0" encoding="utf-8"?>
<resources>
<declare-styleable name="StrokedTextAttrs">
<attr name="textStrokeColor" format="color"/>
<attr name="textStrokeWidth" format="float"/>
</declare-styleable>
</resources>
Once you are done with that, you can use the custom StrokedTextView class in your XML layout files and specify stroke color and width as well. Here is an example
<com.example.widgets.StrokedTextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Stroked text sample"
android:textColor="#android:color/white"
android:textSize="25sp"
strokeAttrs:textStrokeColor="#android:color/black"
strokeAttrs:textStrokeWidth="1.7" />
Remember to replace package name with your project's package name. Also add the xmlns namespace in the layout file in order to use custom XML attributes. You can add the following line in your layout file's root node.
xmlns:strokeAttrs="http://schemas.android.com/apk/res-auto"
The framework supports text-shadow but does not support text-outline. But there is a trick: shadow is something that is translucent and fades. Redraw the shadow a couple of times and all the alpha gets summed up and the result is an outline.
A very simple implementation extends TextView and overrides the draw(..) method. Every time a draw is requested our subclass does 5-10 drawings.
public class OutlineTextView extends TextView {
// Constructors
#Override
public void draw(Canvas canvas) {
for (int i = 0; i < 5; i++) {
super.draw(canvas);
}
}
}
<OutlineTextView
android:shadowColor="#000"
android:shadowRadius="3.0" />
I've just been trying to figure out how to do this and couldn't find a good guide online but eventually figured it out. As Steve Pomeroy suggested, you do have to do something more involved. In order to get the outlined text effect, you draw the text twice: once with a thick outline and then the second time we draw the main text over the outline. But, the task is made easier because you can very easily adapt one of the code samples provided with the SDK, namely the one under this name in your SDK directory: "/samples/android-/ApiDemos/src/com/example/android/apis/view/LabelView.java". Which can also found on the Android developer website here.
Depending on what you're doing, it's very easy to see you will only need to make minor modifications to that code, such as changing it to extend from TextView, etc. Before I discovered this sample I forgot to override onMeasure() (which you must do in addition to overriding onDraw() as is mentioned in the "Building Custom Components" guide on the Android Developer website), which is part of why I was having trouble.
Once you've done that, you can do what I did:
public class TextViewOutline extends TextView {
private Paint mTextPaint;
private Paint mTextPaintOutline; //add another paint attribute for your outline
...
//modify initTextViewOutline to setup the outline style
private void initTextViewOutline() {
mTextPaint = new Paint();
mTextPaint.setAntiAlias(true);
mTextPaint.setTextSize(16);
mTextPaint.setColor(0xFF000000);
mTextPaint.setStyle(Paint.Style.FILL);
mTextPaintOutline = new Paint();
mTextPaintOutline.setAntiAlias(true);
mTextPaintOutline.setTextSize(16);
mTextPaintOutline.setColor(0xFF000000);
mTextPaintOutline.setStyle(Paint.Style.STROKE);
mTextPaintOutline.setStrokeWidth(4);
setPadding(3, 3, 3, 3);
}
...
//make sure to update other methods you've overridden to handle your new paint object
...
//and finally draw the text, mAscent refers to a member attribute which had
//a value assigned to it in the measureHeight and Width methods
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawText(mText, getPaddingLeft(), getPaddingTop() - mAscent,
mTextPaintOutline);
canvas.drawText(mText, getPaddingLeft(), getPaddingTop() - mAscent, mTextPaint);
}
So, in order to get the outlined text effect, you draw the text twice: once with a thick outline and then the second time we draw the main text over the outline.
credit to #YGHM add shadow support
package com.megvii.demo;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
public class TextViewOutline extends android.support.v7.widget.AppCompatTextView {
// constants
private static final int DEFAULT_OUTLINE_SIZE = 0;
private static final int DEFAULT_OUTLINE_COLOR = Color.TRANSPARENT;
// data
private int mOutlineSize;
private int mOutlineColor;
private int mTextColor;
private float mShadowRadius;
private float mShadowDx;
private float mShadowDy;
private int mShadowColor;
public TextViewOutline(Context context) {
this(context, null);
}
public TextViewOutline(Context context, AttributeSet attrs) {
super(context, attrs);
setAttributes(attrs);
}
private void setAttributes(AttributeSet attrs) {
// set defaults
mOutlineSize = DEFAULT_OUTLINE_SIZE;
mOutlineColor = DEFAULT_OUTLINE_COLOR;
// text color
mTextColor = getCurrentTextColor();
if (attrs != null) {
TypedArray a = getContext().obtainStyledAttributes(attrs, R.styleable.TextViewOutline);
// outline size
if (a.hasValue(R.styleable.TextViewOutline_outlineSize)) {
mOutlineSize = (int) a.getDimension(R.styleable.TextViewOutline_outlineSize, DEFAULT_OUTLINE_SIZE);
}
// outline color
if (a.hasValue(R.styleable.TextViewOutline_outlineColor)) {
mOutlineColor = a.getColor(R.styleable.TextViewOutline_outlineColor, DEFAULT_OUTLINE_COLOR);
}
// shadow (the reason we take shadow from attributes is because we use API level 15 and only from 16 we have the get methods for the shadow attributes)
if (a.hasValue(R.styleable.TextViewOutline_android_shadowRadius)
|| a.hasValue(R.styleable.TextViewOutline_android_shadowDx)
|| a.hasValue(R.styleable.TextViewOutline_android_shadowDy)
|| a.hasValue(R.styleable.TextViewOutline_android_shadowColor)) {
mShadowRadius = a.getFloat(R.styleable.TextViewOutline_android_shadowRadius, 0);
mShadowDx = a.getFloat(R.styleable.TextViewOutline_android_shadowDx, 0);
mShadowDy = a.getFloat(R.styleable.TextViewOutline_android_shadowDy, 0);
mShadowColor = a.getColor(R.styleable.TextViewOutline_android_shadowColor, Color.TRANSPARENT);
}
a.recycle();
}
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
setPaintToOutline();
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
private void setPaintToOutline() {
Paint paint = getPaint();
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeWidth(mOutlineSize);
super.setTextColor(mOutlineColor);
super.setShadowLayer(0, 0, 0, Color.TRANSPARENT);
}
private void setPaintToRegular() {
Paint paint = getPaint();
paint.setStyle(Paint.Style.FILL);
paint.setStrokeWidth(0);
super.setTextColor(mTextColor);
super.setShadowLayer(mShadowRadius, mShadowDx, mShadowDy, mShadowColor);
}
#Override
public void setTextColor(int color) {
super.setTextColor(color);
mTextColor = color;
}
public void setOutlineSize(int size) {
mOutlineSize = size;
}
public void setOutlineColor(int color) {
mOutlineColor = color;
}
#Override
protected void onDraw(Canvas canvas) {
setPaintToOutline();
super.onDraw(canvas);
setPaintToRegular();
super.onDraw(canvas);
}
}
attr define
<declare-styleable name="TextViewOutline">
<attr name="outlineSize" format="dimension"/>
<attr name="outlineColor" format="color|reference"/>
<attr name="android:shadowRadius"/>
<attr name="android:shadowDx"/>
<attr name="android:shadowDy"/>
<attr name="android:shadowColor"/>
</declare-styleable>
xml code below
<com.megvii.demo.TextViewOutline
android:id="#+id/product_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:layout_marginTop="110dp"
android:background="#f4b222"
android:fontFamily="#font/kidsmagazine"
android:padding="10dp"
android:shadowColor="#d7713200"
android:shadowDx="0"
android:shadowDy="8"
android:shadowRadius="1"
android:text="LIPSTICK SET"
android:textColor="#android:color/white"
android:textSize="30sp"
app:outlineColor="#cb7800"
app:outlineSize="3dp" />
You can do this programmatically with the below snippet.
That provides white letters with black background:
textView.setTextColor(Color.WHITE);
textView.setShadowLayer(1.6f,1.5f,1.3f,Color.BLACK);
The parameters of the method are radius,dx,dy,color. You can change them for you specific needs.
I hope I will help someone that creates TextView programmatically and not having it inside xml.
Cheers to the stackOverflow community!
I want to add a solution in order to solve the performance issue. For example, the answer of #YGHM and a few others does the job, but it causes infinite call of onDraw because setTextColor calls invalidate(). So in order to solve it, you also need to override invalidate() and add a variable isDrawing that you will set to true, when onDraw() is in progress and drawing with a stroke. invalidate will return if the variable is true.
override fun invalidate() {
if (isDrawing) return
super.invalidate()
}
Your onDraw will look like this:
override fun onDraw(canvas: Canvas) {
if (strokeWidth > 0) {
isDrawing = true
val textColor = textColors.defaultColor
setTextColor(strokeColor)
paint.strokeWidth = strokeWidth
paint.style = Paint.Style.STROKE
super.onDraw(canvas)
setTextColor(textColor)
paint.strokeWidth = 0f
paint.style = Paint.Style.FILL
isDrawing = false
super.onDraw(canvas)
} else {
super.onDraw(canvas)
}
}
Here's the trick I found that works better than MagicTextView's stroke IMO
#Override
protected void onDraw(Canvas pCanvas) {
int textColor = getTextColors().getDefaultColor();
setTextColor(mOutlineColor); // your stroke's color
getPaint().setStrokeWidth(10);
getPaint().setStyle(Paint.Style.STROKE);
super.onDraw(pCanvas);
setTextColor(textColor);
getPaint().setStrokeWidth(0);
getPaint().setStyle(Paint.Style.FILL);
super.onDraw(pCanvas);
}
I've written a class to perform text with outline and still support all the other attributes and drawing of a normal text view.
it basically uses the super.onDraw(Canves canvas) on the TextView but draws twice with different styles.
hope this helps.
public class TextViewOutline extends TextView {
// constants
private static final int DEFAULT_OUTLINE_SIZE = 0;
private static final int DEFAULT_OUTLINE_COLOR = Color.TRANSPARENT;
// data
private int mOutlineSize;
private int mOutlineColor;
private int mTextColor;
private float mShadowRadius;
private float mShadowDx;
private float mShadowDy;
private int mShadowColor;
public TextViewOutline(Context context) {
this(context, null);
}
public TextViewOutline(Context context, AttributeSet attrs) {
super(context, attrs);
setAttributes(attrs);
}
private void setAttributes(AttributeSet attrs){
// set defaults
mOutlineSize = DEFAULT_OUTLINE_SIZE;
mOutlineColor = DEFAULT_OUTLINE_COLOR;
// text color
mTextColor = getCurrentTextColor();
if(attrs != null) {
TypedArray a = getContext().obtainStyledAttributes(attrs,R.styleable.TextViewOutline);
// outline size
if (a.hasValue(R.styleable.TextViewOutline_outlineSize)) {
mOutlineSize = (int) a.getDimension(R.styleable.TextViewOutline_outlineSize, DEFAULT_OUTLINE_SIZE);
}
// outline color
if (a.hasValue(R.styleable.TextViewOutline_outlineColor)) {
mOutlineColor = a.getColor(R.styleable.TextViewOutline_outlineColor, DEFAULT_OUTLINE_COLOR);
}
// shadow (the reason we take shadow from attributes is because we use API level 15 and only from 16 we have the get methods for the shadow attributes)
if (a.hasValue(R.styleable.TextViewOutline_android_shadowRadius)
|| a.hasValue(R.styleable.TextViewOutline_android_shadowDx)
|| a.hasValue(R.styleable.TextViewOutline_android_shadowDy)
|| a.hasValue(R.styleable.TextViewOutline_android_shadowColor)) {
mShadowRadius = a.getFloat(R.styleable.TextViewOutline_android_shadowRadius, 0);
mShadowDx = a.getFloat(R.styleable.TextViewOutline_android_shadowDx, 0);
mShadowDy = a.getFloat(R.styleable.TextViewOutline_android_shadowDy, 0);
mShadowColor = a.getColor(R.styleable.TextViewOutline_android_shadowColor, Color.TRANSPARENT);
}
a.recycle();
}
PFLog.d("mOutlineSize = " + mOutlineSize);
PFLog.d("mOutlineColor = " + mOutlineColor);
}
private void setPaintToOutline(){
Paint paint = getPaint();
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeWidth(mOutlineSize);
super.setTextColor(mOutlineColor);
super.setShadowLayer(mShadowRadius, mShadowDx, mShadowDy, mShadowColor);
}
private void setPaintToRegular() {
Paint paint = getPaint();
paint.setStyle(Paint.Style.FILL);
paint.setStrokeWidth(0);
super.setTextColor(mTextColor);
super.setShadowLayer(0, 0, 0, Color.TRANSPARENT);
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
setPaintToOutline();
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
#Override
public void setTextColor(int color) {
super.setTextColor(color);
mTextColor = color;
}
#Override
public void setShadowLayer(float radius, float dx, float dy, int color) {
super.setShadowLayer(radius, dx, dy, color);
mShadowRadius = radius;
mShadowDx = dx;
mShadowDy = dy;
mShadowColor = color;
}
public void setOutlineSize(int size){
mOutlineSize = size;
}
public void setOutlineColor(int color){
mOutlineColor = color;
}
#Override
protected void onDraw(Canvas canvas) {
setPaintToOutline();
super.onDraw(canvas);
setPaintToRegular();
super.onDraw(canvas);
}
}
attr.xml
<declare-styleable name="TextViewOutline">
<attr name="outlineSize" format="dimension"/>
<attr name="outlineColor" format="color|reference"/>
<attr name="android:shadowRadius"/>
<attr name="android:shadowDx"/>
<attr name="android:shadowDy"/>
<attr name="android:shadowColor"/>
</declare-styleable>
I have created a library based on Nouman Hanif's answer with some additions. For example, fixing a bug that caused an indirect infinite loop on View.invalidate() calls.
OTOH, the library also supports outlined text in EditText widgets, as it was my real goal and it needed a bit more work than TextView.
Here is the link to my library: https://github.com/biomorgoth/android-outline-textview
Thanks to Nouman Hanif for the initial idea on the solution!
I found simple way to outline view without inheritance from TextView.
I had wrote simple library that use Android's Spannable for outlining text.
This solution gives possibility to outline only part of text.
I already had answered on same question (answer)
Class:
class OutlineSpan(
#ColorInt private val strokeColor: Int,
#Dimension private val strokeWidth: Float
): ReplacementSpan() {
override fun getSize(
paint: Paint,
text: CharSequence,
start: Int,
end: Int,
fm: Paint.FontMetricsInt?
): Int {
return paint.measureText(text.toString().substring(start until end)).toInt()
}
override fun draw(
canvas: Canvas,
text: CharSequence,
start: Int,
end: Int,
x: Float,
top: Int,
y: Int,
bottom: Int,
paint: Paint
) {
val originTextColor = paint.color
paint.apply {
color = strokeColor
style = Paint.Style.STROKE
this.strokeWidth = this#OutlineSpan.strokeWidth
}
canvas.drawText(text, start, end, x, y.toFloat(), paint)
paint.apply {
color = originTextColor
style = Paint.Style.FILL
}
canvas.drawText(text, start, end, x, y.toFloat(), paint)
}
}
Library: OutlineSpan
MagicTextView is very useful to make stroke font, but in my case, it cause error like
this
this error caused by duplication background attributes which set by MagicTextView
so you need to edit attrs.xml and MagicTextView.java
attrs.xml
<attr name="background" format="reference|color" />
↓
<attr name="mBackground" format="reference|color" />
MagicTextView.java 88:95
if (a.hasValue(R.styleable.MagicTextView_mBackground)) {
Drawable background = a.getDrawable(R.styleable.MagicTextView_mBackground);
if (background != null) {
this.setBackgroundDrawable(background);
} else {
this.setBackgroundColor(a.getColor(R.styleable.MagicTextView_mBackground, 0xff000000));
}
}
So you want a stroke around the textview? Unfortunately there is no simple way to do it with the styling. You'll have to create another view and place your textview over-top, making the parent view (the one it's on top of) just a few pixels bigger - this should create an outline.
Here is the simplest way I could find by extending TextView
public class CustomTextView extends androidx.appcompat.widget.AppCompatTextView {
float mStroke;
public CustomTextView(Context context, #Nullable AttributeSet attrs) {
super(context, attrs);
TypedArray a = context.obtainStyledAttributes(attrs,
R.styleable.CustomTextView);
mStroke=a.getFloat(R.styleable.CustomTextView_stroke,1.0f);
a.recycle();
}
#Override
protected void onDraw(Canvas canvas) {
TextPaint paint = this.getPaint();
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeWidth(mStroke);
super.onDraw(canvas);
}
}
then you only need to add the following to the attrs.xml file
<declare-styleable name="CustomTextView">
<attr name="stroke" format="float"/>
</declare-styleable>
and now you will be able to set the stroke widht by app:stroke while retaining all other desirable properties of TextView. my solution only draws the stroke w/o a fill. this makes it a bit simpler than the others. bellow a screencapture with the result while setting a custom font to my customtextview.

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