Measuring text height to be drawn on Canvas ( Android ) - android

Any straight forward way to measure the height of text?
The way I am doing it now is by using Paint's measureText() to get the width, then by trial and error finding a value to get an approximate height. I've also been messing around with FontMetrics, but all these seem like approximate methods that suck.
I am trying to scale things for different resolutions. I can do it, but I end up with incredibly verbose code with lots of calculations to determine relative sizes. I hate it! There has to be a better way.

There are different ways to measure the height depending on what you need.
#1 getTextBounds
If you are doing something like precisely centering a small amount of fixed text, you probably want getTextBounds. You can get the bounding rectangle like this
Rect bounds = new Rect();
mTextPaint.getTextBounds(mText, 0, mText.length(), bounds);
int height = bounds.height();
As you can see for the following images, different strings will give different heights (shown in red).
These differing heights could be a disadvantage in some situations when you just need a constant height no matter what the text is. See the next section.
#2 Paint.FontMetrics
You can calculate the hight of the font from the font metrics. The height is always the same because it is obtained from the font, not any particular text string.
Paint.FontMetrics fm = mTextPaint.getFontMetrics();
float height = fm.descent - fm.ascent;
The baseline is the line that the text sits on. The descent is generally the furthest a character will go below the line and the ascent is generally the furthest a character will go above the line. To get the height you have to subtract ascent because it is a negative value. (The baseline is y=0 and y descreases up the screen.)
Look at the following image. The heights for both of the strings are 234.375.
If you want the line height rather than just the text height, you could do the following:
float height = fm.bottom - fm.top + fm.leading; // 265.4297
These are the bottom and top of the line. The leading (interline spacing) is usually zero, but you should add it anyway.
The images above come from this project. You can play around with it to see how Font Metrics work.
#3 StaticLayout
For measuring the height of multi-line text you should use a StaticLayout. I talked about it in some detail in this answer, but the basic way to get this height is like this:
String text = "This is some text. This is some text. This is some text. This is some text. This is some text. This is some text.";
TextPaint myTextPaint = new TextPaint();
myTextPaint.setAntiAlias(true);
myTextPaint.setTextSize(16 * getResources().getDisplayMetrics().density);
myTextPaint.setColor(0xFF000000);
int width = 200;
Layout.Alignment alignment = Layout.Alignment.ALIGN_NORMAL;
float spacingMultiplier = 1;
float spacingAddition = 0;
boolean includePadding = false;
StaticLayout myStaticLayout = new StaticLayout(text, myTextPaint, width, alignment, spacingMultiplier, spacingAddition, includePadding);
float height = myStaticLayout.getHeight();

What about paint.getTextBounds() (object method)

#bramp's answer is correct - partially, in that it does not mention that the calculated boundaries will be the minimum rectangle that contains the text fully with implicit start coordinates of 0, 0.
This means, that the height of, for example "Py" will be different from the height of "py" or "hi" or "oi" or "aw" because pixel-wise they require different heights.
This by no means is an equivalent to FontMetrics in classic java.
While width of a text is not much of a pain, height is.
In particular, if you need to vertically center-align the drawn text, try getting the boundaries of the text "a" (without quotes), instead of using the text you intend to draw.
Works for me...
Here's what I mean:
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG | Paint.LINEAR_TEXT_FLAG);
paint.setStyle(Paint.Style.FILL);
paint.setColor(color);
paint.setTextAlign(Paint.Align.CENTER);
paint.setTextSize(textSize);
Rect bounds = new Rect();
paint.getTextBounds("a", 0, 1, bounds);
buffer.drawText(this.myText, canvasWidth >> 1, (canvasHeight + bounds.height()) >> 1, paint);
// remember x >> 1 is equivalent to x / 2, but works much much faster
Vertically center aligning the text means vertically center align the bounding rectangle - which is different for different texts (caps, long letters etc). But what we actually want to do is to also align the baselines of rendered texts, such that they did not appear elevated or grooved. So, as long as we know the center of the smallest letter ("a" for example) we then can reuse its alignment for the rest of the texts. This will center align all the texts as well as baseline-align them.

The height is the text size you have set on the Paint variable.
Another way to find out the height is
mPaint.getTextSize();

You could use the android.text.StaticLayout class to specify the bounds required and then call getHeight(). You can draw the text (contained in the layout) by calling its draw(Canvas) method.

You can simply get the text size for a Paint object using getTextSize() method.
For example:
Paint mTextPaint = new Paint (Paint.ANTI_ALIAS_FLAG);
//use densityMultiplier to take into account different pixel densities
final float densityMultiplier = getContext().getResources()
.getDisplayMetrics().density;
mTextPaint.setTextSize(24.0f*densityMultiplier);
//...
float size = mTextPaint.getTextSize();

You must use Rect.width() and Rect.Height() which returned from getTextBounds() instead. That works for me.

If anyone still has problem, this is my code.
I have a custom view which is square (width = height) and I want to assign a character to it. onDraw() shows how to get height of character, although I'm not using it. Character will be displayed in the middle of view.
public class SideBarPointer extends View {
private static final String TAG = "SideBarPointer";
private Context context;
private String label = "";
private int width;
private int height;
public SideBarPointer(Context context) {
super(context);
this.context = context;
init();
}
public SideBarPointer(Context context, AttributeSet attrs) {
super(context, attrs);
this.context = context;
init();
}
public SideBarPointer(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
this.context = context;
init();
}
private void init() {
// setBackgroundColor(0x64FF0000);
}
#Override
public void onMeasure(int widthMeasureSpec, int heightMeasureSpec){
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
height = this.getMeasuredHeight();
width = this.getMeasuredWidth();
setMeasuredDimension(width, width);
}
protected void onDraw(Canvas canvas) {
float mDensity = context.getResources().getDisplayMetrics().density;
float mScaledDensity = context.getResources().getDisplayMetrics().scaledDensity;
Paint previewPaint = new Paint();
previewPaint.setColor(0x0C2727);
previewPaint.setAlpha(200);
previewPaint.setAntiAlias(true);
Paint previewTextPaint = new Paint();
previewTextPaint.setColor(Color.WHITE);
previewTextPaint.setAntiAlias(true);
previewTextPaint.setTextSize(90 * mScaledDensity);
previewTextPaint.setShadowLayer(5, 1, 2, Color.argb(255, 87, 87, 87));
float previewTextWidth = previewTextPaint.measureText(label);
// float previewTextHeight = previewTextPaint.descent() - previewTextPaint.ascent();
RectF previewRect = new RectF(0, 0, width, width);
canvas.drawRoundRect(previewRect, 5 * mDensity, 5 * mDensity, previewPaint);
canvas.drawText(label, (width - previewTextWidth)/2, previewRect.top - previewTextPaint.ascent(), previewTextPaint);
super.onDraw(canvas);
}
public void setLabel(String label) {
this.label = label;
Log.e(TAG, "Label: " + label);
this.invalidate();
}
}

Related

How to fade out the end of the last line in a TextView?

How can we achieve the fade-out effect on the last line of a TextView, like in the "WHAT'S NEW" section in the Play Store app?
That fade effect can be accomplished by subclassing a TextView class to intercept its draw, and doing something like what the View class does to fade out edges, but only in the last stretch of the final text line.
In this example, we create a unit horizontal linear gradient that goes from transparent to solid black. As we prepare to draw, this unit gradient is scaled to a length calculated as a simple fraction of the TextView's final line length, and then positioned accordingly.
An off-screen buffer is created, and we let the TextView draw its content to that. We then draw the fade gradient over it with a transfer mode of PorterDuff.Mode.DST_OUT, which essentially clears the underlying content to a degree relative to the gradient's opacity at a given point. Drawing that buffer back on-screen results in the desired fade, no matter what is in the background.
public class FadingTextView extends AppCompatTextView {
private static final float FADE_LENGTH_FACTOR = .4f;
private final RectF drawRect = new RectF();
private final Rect realRect = new Rect();
private final Path selection = new Path();
private final Matrix matrix = new Matrix();
private final Paint paint = new Paint();
private final Shader shader =
new LinearGradient(0f, 0f, 1f, 0f, 0x00000000, 0xFF000000, Shader.TileMode.CLAMP);
public FadingTextView(Context context) {
this(context, null);
}
public FadingTextView(Context context, AttributeSet attrs) {
this(context, attrs, android.R.attr.textViewStyle);
}
public FadingTextView(Context context, AttributeSet attrs, int defStyleAttribute) {
super(context, attrs, defStyleAttribute);
paint.setShader(shader);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_OUT));
}
#Override
protected void onDraw(Canvas canvas) {
// Locals
final RectF drawBounds = drawRect;
final Rect realBounds = realRect;
final Path selectionPath = selection;
final Layout layout = getLayout();
// Figure last line index, and text offsets there
final int lastLineIndex = getLineCount() - 1;
final int lastLineStart = layout.getLineStart(lastLineIndex);
final int lastLineEnd = layout.getLineEnd(lastLineIndex);
// Let the Layout figure a Path that'd cover the last line text
layout.getSelectionPath(lastLineStart, lastLineEnd, selectionPath);
// Convert that Path to a RectF, which we can more easily modify
selectionPath.computeBounds(drawBounds, false);
// Naive text direction determination; may need refinement
boolean isRtl =
layout.getParagraphDirection(lastLineIndex) == Layout.DIR_RIGHT_TO_LEFT;
// Narrow the bounds to just the fade length
if (isRtl) {
drawBounds.right = drawBounds.left + drawBounds.width() * FADE_LENGTH_FACTOR;
} else {
drawBounds.left = drawBounds.right - drawBounds.width() * FADE_LENGTH_FACTOR;
}
// Adjust for drawables and paddings
drawBounds.offset(getTotalPaddingLeft(), getTotalPaddingTop());
// Convert drawing bounds to real bounds to determine
// if we need to do the fade, or a regular draw
drawBounds.round(realBounds);
realBounds.offset(-getScrollX(), -getScrollY());
boolean needToFade = realBounds.intersects(getTotalPaddingLeft(), getTotalPaddingTop(),
getWidth() - getTotalPaddingRight(), getHeight() - getTotalPaddingBottom());
if (needToFade) {
// Adjust and set the Shader Matrix
final Matrix shaderMatrix = matrix;
shaderMatrix.reset();
shaderMatrix.setScale(drawBounds.width(), 1f);
if (isRtl) {
shaderMatrix.postRotate(180f, drawBounds.width() / 2f, 0f);
}
shaderMatrix.postTranslate(drawBounds.left, drawBounds.top);
shader.setLocalMatrix(shaderMatrix);
// Save, and start drawing to an off-screen buffer
final int saveCount;
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
saveCount = canvas.saveLayer(null, null);
} else {
saveCount = canvas.saveLayer(null, null, Canvas.ALL_SAVE_FLAG);
}
// Let TextView draw itself to the buffer
super.onDraw(canvas);
// Draw the fade to the buffer, over the TextView content
canvas.drawRect(drawBounds, paint);
// Restore, and draw the buffer back to the Canvas
canvas.restoreToCount(saveCount);
} else {
// Regular draw
super.onDraw(canvas);
}
}
}
This is a drop-in replacement for TextView, and you'd use it in your layout similarly.
<com.example.app.FadingTextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#e2f3eb"
android:textColor="#0b8043"
android:lineSpacingMultiplier="1.2"
android:text="#string/umang" />
Notes:
The fade length calculation is based on a constant fraction of the final line's text length, here determined by FADE_LENGTH_FACTOR. This seems to be the same basic methodology of the Play Store component, as the absolute length of the fade appears to vary with line length. The FADE_LENGTH_FACTOR value can be altered as desired.
FadingTextView currently extends AppCompatTextView, but it works perfectly well as a plain TextView, if you should need that instead. I would think that it will work as a MaterialTextView too, though I've not tested that thoroughly.
This example is geared mainly toward relatively plain use; i.e., as a simple wrapped, static label. Though I've attempted to account for and test every TextView setting I could think of that might affect this – e.g., compound drawables, paddings, selectable text, scrolling, text direction and alignment, etc. – I can't guarantee that I've thought of everything.

How to calculate line height containing TextView with specific height in Android?

I want to calculate the line (or layout) height (in DP) which contains only TextView as outcome of the TextView text size when using default line spacing ?
I.E. for this layout :
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal" >
<TextView
android:id="#+id/minRow1col1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:singleLine="true"
android:textIsSelectable="false"
android:textSize="11dp" />
</LinearLayout>
What will be the layout/line height ? (any formula ? I don't need the value in run time)
Thanks !
I don't know if this help you guys, but my solution to get the height of a line it's independent of the height of the layout, just take the font metrics like this:
myTextView.getPaint().getFontMetrics().bottom - myTextView.getPaint().getFontMetrics().top)
With this you will get the line height and for me, it's works with all words ( there are some chars like "g" or "j" that take some bottom space, the so called "descender" and so on ).
Try using the TextPaint object of TextView.
TextView tv = useTextView;
String text = tv.getText().toString();
Paint textPaint = tv.getPaint();
Rect textRect = new Rect();
textPaint.getTextBounds(text, 0, text.length(), textRext);
int textHeight = textRect.height();
Per documentation of Paint#getTextBound:
Return in bounds (allocated by the caller) the smallest rectangle that
encloses all of the characters, with an implied origin at (0,0).
Using the Paint object that the TextView uses will ensure it has the same parameters set that will be used to draw the text.
You have to create custom Textview and use getActualHeight() method. Where the formula is: actualHeight=(int) ((getLineCount()-1)*getTextSize());
public class TextViewHeightPlus extends TextView {
private static final String TAG = "TextView";
private int actualHeight=0;
public int getActualHeight() {
return actualHeight;
}
public TextViewHeightPlus(Context context) {
super(context);
}
public TextViewHeightPlus(Context context, AttributeSet attrs) {
super(context, attrs);
setCustomFont(context, attrs);
}
public TextViewHeightPlus(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
#Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
actualHeight=0;
actualHeight=(int) ((getLineCount()-1)*getTextSize());
}
}
You can try Paint.getTextBounds():
String finalVal ="Hello";
Paint paint = new Paint();
paint.setTextSize(18);
paint.setTypeface(Typeface.SANS_SERIF);
paint.setColor(Color.BLACK);
paint.setStyle(Paint.Style.FILL);
Rect result = new Rect();
// Measure the text rectangle to get the height
paint.getTextBounds(finalVal, 0, finalVal.length(), result);
Log.d("WIDTH :", String.valueOf(result.width()));
Log.d("HEIGHT :", String.valueOf(result.height()));
Source.
For my usecase I started out by assuming that the line height is a linear function that depends on the textsize, something like:
line_height = text_size*some_constant
Now some_constant is probably a function as well, that depends on what font you use. But since in my requirements the font was static, I was able to calculate some_constant and use repeatedly in a safe way.
To clue you in a little a bit more on my usecase, I was scaling a piece of multiline text in order to fit it in a box of variable height.
In my usecase I wanted to go a step further and included the space multiplier. It was quite simple, as it was just another factor in the equation:
line_height = text_size*some_constant*spacing_multiplier
In summary if you stick to the same font and you calculate the value of some_constant once, you can (probably) get your function.
DISCLAIMER: I say "probably" a lot because I haven't tested a lot of my assumptions, but like I said, it worked for a decently complex usecase.

Finding the height of the line spacing

I have the following code to find the screen dimensions calculate how much text fits on the screen.
Now I need to know how many lines fit on the screen. I have the size of the text from the ascent to the descent. I need to know the height of the line spacing. getFontSpacing also gives the value from the ascent to the descent.
Does anyone know if there is a way of finding the line spacing's value?
//Code for Getting screen Dimensions
Display display = getWindowManager().getDefaultDisplay();
Point size = new Point();
display.getSize(size);
int width = size.x;
int height = size.y;
//Breaking Text When Width Is Filled
Paint p = new Paint();
p.setTextSize(60);
int textNum = p.breakText(sText, 0, 20, forOrBack, width, null);
//Working Out How Many Lines Can Be Entered In The Screen
float fHeight = p.descent() - p.ascent();
int tHeight = (int) fHeight;
int numLines = height/tHeight;
The following will return the recommended line spacing
textView.getPaint().getFontSpacing()
you can get the height of you text several ways. I prefer paint's getTextBounds method and just add the two values together
For line spacing use textView.getLineHeight();
reference : http://developer.android.com/reference/android/widget/TextView.html#getLineHeight()
Paint.FontMetrics fm = paint.getFontMetrics();
float fullHeight = fm.top - fm.bottom;
As far as I remember, fm.bottom < 0, therefore by subtracting you actually get
Math.abs(fm.top) + Math.abs(fm.bottom)
This value is bigger than ascent-descent, and, I guess, it is the actual line size.
You may consider using TextView.getLineHeight() after setting TextSize and preferebly after layout is complete
(e.g in OnWindowFocusChanged).

Android font size not scaling on tablet [duplicate]

I'm trying to create a method for resizing multi-line text in a TextView such that it fits within the bounds (both the X and Y dimensions) of the TextView.
At present, I have something, but all it does is resize the text such that just the first letter/character of the text fills the dimensions of the TextView (i.e. only the first letter is viewable, and it's huge). I need it to fit all the lines of the text within the bounds of the TextView.
Here is what I have so far:
public static void autoScaleTextViewTextToHeight(TextView tv)
{
final float initSize = tv.getTextSize();
//get the width of the view's back image (unscaled)....
float minViewHeight;
if(tv.getBackground()!=null)
{
minViewHeight = tv.getBackground().getIntrinsicHeight();
}
else
{
minViewHeight = 10f;//some min.
}
final float maxViewHeight = tv.getHeight() - (tv.getPaddingBottom()+tv.getPaddingTop())-12;// -12 just to be sure
final String s = tv.getText().toString();
//System.out.println(""+tv.getPaddingTop()+"/"+tv.getPaddingBottom());
if(minViewHeight >0 && maxViewHeight >2)
{
Rect currentBounds = new Rect();
tv.getPaint().getTextBounds(s, 0, s.length(), currentBounds);
//System.out.println(""+initSize);
//System.out.println(""+maxViewHeight);
//System.out.println(""+(currentBounds.height()));
float resultingSize = 1;
while(currentBounds.height() < maxViewHeight)
{
resultingSize ++;
tv.setTextSize(resultingSize);
tv.getPaint().getTextBounds(s, 0, s.length(), currentBounds);
//System.out.println(""+(currentBounds.height()+tv.getPaddingBottom()+tv.getPaddingTop()));
//System.out.println("Resulting: "+resultingSize);
}
if(currentBounds.height()>=maxViewHeight)
{
//just to be sure, reduce the value
tv.setTextSize(resultingSize-1);
}
}
}
I think the problem is in the use of tv.getPaint().getTextBounds(...). It always returns small numbers for the text bounds... small relative to the tv.getWidth() and tv.getHeight() values... even if the text size is far larger than the width or height of the TextView.
The AutofitTextView library from MavenCentral handles this nicely. The source hosted on Github(1k+ stars) at https://github.com/grantland/android-autofittextview
Add the following to your app/build.gradle
repositories {
mavenCentral()
}
dependencies {
implementation 'me.grantland:autofittextview:0.2.+'
}
Enable any View extending TextView in code:
AutofitHelper.create(textView);
Enable any View extending TextView in XML:
<me.grantland.widget.AutofitLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:singleLine="true"
/>
</me.grantland.widget.AutofitLayout>
Use the built in Widget in code or XML:
<me.grantland.widget.AutofitTextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:singleLine="true"
/>
New since Android O:
https://developer.android.com/preview/features/autosizing-textview.html
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:autoSizeTextType="uniform"
android:autoSizeMinTextSize="12sp"
android:autoSizeMaxTextSize="100sp"
android:autoSizeStepGranularity="2sp"
/>
I have played with this for quite some time, trying to get my font sizes correct on a wide variety of 7" tablets (kindle fire, Nexus7, and some inexpensive ones in China with low-res screens) and devices.
The approach that finally worked for me is as follows. The "32" is an arbitrary factor that basically gives about 70+ characters across a 7" tablet horizontal line, which is a font size I was looking for. Adjust accordingly.
textView.setTextSize(getFontSize(activity));
public static int getFontSize (Activity activity) {
DisplayMetrics dMetrics = new DisplayMetrics();
activity.getWindowManager().getDefaultDisplay().getMetrics(dMetrics);
// lets try to get them back a font size realtive to the pixel width of the screen
final float WIDE = activity.getResources().getDisplayMetrics().widthPixels;
int valueWide = (int)(WIDE / 32.0f / (dMetrics.scaledDensity));
return valueWide;
}
I was able to answer my own question using the following code (see below), but my solution was very specific to the application. For instance, this will probably only look good and/or work for a TextView sized to approx. 1/2 the screen (with also a 40px top margin and 20px side margins... no bottom margin).
The using this approach though, you can create your own similar implementation. The static method basically just looks at the number of characters and determines a scaling factor to apply to the TextView's text size, and then incrementally increases the text size until the overall height (an estimated height -- using the width of the text, the text height, and the width of the TextView) is just below that of the TextView. The parameters necessary to determine the scaling factor (i.e. the if/else if statements) were set by guess-and-check. You'll likely have to play around with the numbers to make it work for your particular application.
This isn't the most elegant solution, though it was easy to code and it works for me. Does anyone have a better approach?
public static void autoScaleTextViewTextToHeight(final TextView tv, String s)
{
float currentWidth=tv.getPaint().measureText(s);
int scalingFactor = 0;
final int characters = s.length();
//scale based on # of characters in the string
if(characters<5)
{
scalingFactor = 1;
}
else if(characters>=5 && characters<10)
{
scalingFactor = 2;
}
else if(characters>=10 && characters<15)
{
scalingFactor = 3;
}
else if(characters>=15 && characters<20)
{
scalingFactor = 3;
}
else if(characters>=20 && characters<25)
{
scalingFactor = 3;
}
else if(characters>=25 && characters<30)
{
scalingFactor = 3;
}
else if(characters>=30 && characters<35)
{
scalingFactor = 3;
}
else if(characters>=35 && characters<40)
{
scalingFactor = 3;
}
else if(characters>=40 && characters<45)
{
scalingFactor = 3;
}
else if(characters>=45 && characters<50)
{
scalingFactor = 3;
}
else if(characters>=50 && characters<55)
{
scalingFactor = 3;
}
else if(characters>=55 && characters<60)
{
scalingFactor = 3;
}
else if(characters>=60 && characters<65)
{
scalingFactor = 3;
}
else if(characters>=65 && characters<70)
{
scalingFactor = 3;
}
else if(characters>=70 && characters<75)
{
scalingFactor = 3;
}
else if(characters>=75)
{
scalingFactor = 5;
}
//System.out.println(((int)Math.ceil(currentWidth)/tv.getWidth()+scalingFactor));
//the +scalingFactor is important... increase this if nec. later
while((((int)Math.ceil(currentWidth)/tv.getWidth()+scalingFactor)*tv.getTextSize())<tv.getHeight())
{
tv.setTextSize(TypedValue.COMPLEX_UNIT_SP, tv.getTextSize()+0.25f);
currentWidth=tv.getPaint().measureText(s);
//System.out.println(((int)Math.ceil(currentWidth)/tv.getWidth()+scalingFactor));
}
tv.setText(s);
}
Thanks.
I had the same problem and wrote a class that seems to work for me. Basically, I used a static layout to draw the text in a separate canvas and remeasure until I find a font size that fits. You can see the class posted in the topic below. I hope it helps.
Auto Scale TextView Text to Fit within Bounds
Stumbled upon this whilst looking for a solution myself... I'd tried all the other solutions out there that I could see on stack overflow etc but none really worked so I wrote my own.
Basically by wrapping the text view in a custom linear layout I've been able to successfully measure the text properly by ensuring it is measured with a fixed width.
<!-- TextView wrapped in the custom LinearLayout that expects one child TextView -->
<!-- This view should specify the size you would want the text view to be displayed at -->
<com.custom.ResizeView
android:layout_width="fill_parent"
android:layout_height="0dp"
android:layout_margin="10dp"
android:layout_weight="1"
android:orientation="horizontal" >
<TextView
android:id="#+id/CustomTextView"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
</com.custom.ResizeView>
Then the linear layout code
public class ResizeView extends LinearLayout {
public ResizeView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public ResizeView(Context context) {
super(context);
}
#Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
super.onLayout(changed, left, top, right, bottom);
// oldWidth used as a fixed width when measuring the size of the text
// view at different font sizes
final int oldWidth = getMeasuredWidth() - getPaddingBottom() - getPaddingTop();
final int oldHeight = getMeasuredHeight() - getPaddingLeft() - getPaddingRight();
// Assume we only have one child and it is the text view to scale
TextView textView = (TextView) getChildAt(0);
// This is the maximum font size... we iterate down from this
// I've specified the sizes in pixels, but sp can be used, just modify
// the call to setTextSize
float size = getResources().getDimensionPixelSize(R.dimen.solutions_view_max_font_size);
for (int textViewHeight = Integer.MAX_VALUE; textViewHeight > oldHeight; size -= 0.1f) {
textView.setTextSize(TypedValue.COMPLEX_UNIT_PX, size);
// measure the text views size using a fixed width and an
// unspecified height - the unspecified height means measure
// returns the textviews ideal height
textView.measure(MeasureSpec.makeMeasureSpec(oldWidth, MeasureSpec.EXACTLY), MeasureSpec.UNSPECIFIED);
textViewHeight = textView.getMeasuredHeight();
}
}
}
Hope this helps someone.
maybe try setting setHoriztonallyScrolling() to true before taking text measurements so that the textView doesn't try to layout your text on multiple lines
One way would be to specify different sp dimensions for each of the generalized screen sizes. For instance, provide 8sp for small screens, 12sp for normal screens, 16 sp for large and 20 sp for xlarge. Then just have your layouts refer to #dimen text_size or whatever and you can rest assured, as density is taken care of via the sp unit. See the following link for more info on this approach.
http://www.developer.android.com/guide/topics/resources/more-resources.html#Dimension
I must note, however, that supporting more languages means more work during the testing phase, especially if you're interested in keeping text on one line, as some languages have much longer words. In that case, make a dimens.xml file in the values-de-large folder, for example, and tweak the value manually. Hope this helps.
Here is a solution that I created based on some other feedback. This solution allows you to set the size of the text in XML which will be the max size and it will adjust itself to fit the view height.
Size Adjusting TextView
private float findNewTextSize(int width, int height, CharSequence text) {
TextPaint textPaint = new TextPaint(getPaint());
float targetTextSize = textPaint.getTextSize();
int textHeight = getTextHeight(text, textPaint, width, targetTextSize);
while(textHeight > height && targetTextSize > mMinTextSize) {
targetTextSize = Math.max(targetTextSize - 1, mMinTextSize);
textHeight = getTextHeight(text, textPaint, width, targetTextSize);
}
return targetTextSize;
}
private int getTextHeight(CharSequence source, TextPaint paint, int width, float textSize) {
paint.setTextSize(textSize);
StaticLayout layout = new StaticLayout(source, paint, width, Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, true);
return layout.getHeight();
}
If your only requirement is to have the text automatically split and continue in the next line and the height is not important then just have it like this.
<TextView
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:maxEms="integer"
android:width="integer"/>
This will have your TextView wrap to it's content vertically depending on your maxEms value.
Check if my solution helps you:
Auto Scale TextView Text to Fit within Bounds
I found that this worked well for me. see: https://play.google.com/store/apps/details?id=au.id.rupert.chauffeurs_name_board&hl=en
Source Code at http://www.rupert.id.au/chauffeurs_name_board/verson2.php
http://catchthecows.com/?p=72 and https://github.com/catchthecows/BigTextButton
This is based on mattmook's answer. It worked well on some devices, but not on all. I moved the resizing to the measuring step, made the maximum font size a custom attribute, took margins into account, and extended FrameLayout instead of LineairLayout.
public class ResizeView extends FrameLayout {
protected float max_font_size;
public ResizeView(Context context, AttributeSet attrs) {
super(context, attrs);
TypedArray a = context.getTheme().obtainStyledAttributes(
attrs,
R.styleable.ResizeView,
0, 0);
max_font_size = a.getDimension(R.styleable.ResizeView_maxFontSize, 30.0f);
}
public ResizeView(Context context) {
super(context);
}
#Override
protected void onMeasure(final int widthMeasureSpec, final int heightMeasureSpec) {
// Use the parent's code for the first measure
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
// Assume we only have one child and it is the text view to scale
final TextView textView = (TextView) getChildAt(0);
// Check if the default measure resulted in a fitting textView
LayoutParams childLayout = (LayoutParams) textView.getLayoutParams();
final int textHeightAvailable = getMeasuredHeight() - getPaddingTop() - getPaddingBottom() - childLayout.topMargin - childLayout.bottomMargin;
int textViewHeight = textView.getMeasuredHeight();
if (textViewHeight < textHeightAvailable) {
return;
}
final int textWidthSpec = MeasureSpec.makeMeasureSpec(
MeasureSpec.getSize(widthMeasureSpec) - getPaddingLeft() - getPaddingRight() - childLayout.leftMargin - childLayout.rightMargin,
MeasureSpec.EXACTLY);
final int textHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
for (float size = max_font_size; size >= 1.05f; size-=0.1f) {
textView.setTextSize(TypedValue.COMPLEX_UNIT_PX, size);
textView.measure(textWidthSpec, textHeightSpec);
textViewHeight = textView.getMeasuredHeight();
if (textViewHeight <= textHeightAvailable) {
break;
}
}
}
}
And this in attrs.xml:
<declare-styleable name="ResizeView">
<attr name="maxFontSize" format="reference|dimension"/>
</declare-styleable>
And finally used like this:
<PACKAGE_NAME.ui.ResizeView xmlns:custom="http://schemas.android.com/apk/res/PACKAGE_NAME"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="start|center_vertical"
android:padding="5dp"
custom:maxFontSize="#dimen/normal_text">
<TextView android:id="#+id/tabTitle2"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</PACKAGE_NAME.ui.ResizeView>
Try this...
tv.setText("Give a very large text anc check , this xample is very usefull");
countLine=tv.getLineHeight();
System.out.println("LineCount " + countLine);
if (countLine>=40){
tv.setTextSize(15);
}

How to get string width on Android?

I would like to get height too if possible.
You can use the getTextBounds(String text, int start, int end, Rect bounds) method of a Paint object. You can either use the paint object supplied by a TextView or build one yourself with your desired text appearance.
Using a Textview you Can do the following:
Rect bounds = new Rect();
Paint textPaint = textView.getPaint();
textPaint.getTextBounds(text, 0, text.length(), bounds);
int height = bounds.height();
int width = bounds.width();
If you just need the width you can use:
float width = paint.measureText(string);
http://developer.android.com/reference/android/graphics/Paint.html#measureText(java.lang.String)
There are two different width measures for a text. One is the number of pixels which has been drawn in the width, the other is the number of 'pixels' the cursor should be advanced after drawing the text.
paint.measureText and paint.getTextWidths returns the number of pixels (in float) which the cursor should be advanced after drawing the given string. For the number of pixels painted use paint.getTextBounds as mentioned in other answer. I believe this is called the 'Advance' of the font.
For some fonts these two measurements differ (alot), for instance the font Black Chancery have letters which extend past the other letters (overlapping) - see the capital 'L'. Use paint.getTextBounds as mentioned in other answer to get pixels painted.
I have measured width in this way:
String str ="Hiren Patel";
Paint paint = new Paint();
paint.setTextSize(20);
Typeface typeface = Typeface.createFromAsset(getAssets(), "Helvetica.ttf");
paint.setTypeface(typeface);
paint.setColor(Color.BLACK);
paint.setStyle(Paint.Style.FILL);
Rect result = new Rect();
paint.getTextBounds(str, 0, str.length(), result);
Log.i("Text dimensions", "Width: "+result.width());
This would help you.
Most likely you want to know the painted dimensions for a given string of text with a given font (i.e. a particular Typeface such as the “sans-serif” font family with a BOLD_ITALIC style, and particular size in sp or px).
Rather than inflating a full-blown TextView, you can go lower level and work with a Paint object directly for single-line text, for example:
// Maybe you want to construct a (possibly static) member for repeated computations
Paint paint = new Paint();
// You can load a font family from an asset, and then pick a specific style:
//Typeface plain = Typeface.createFromAsset(assetManager, pathToFont);
//Typeface bold = Typeface.create(plain, Typeface.DEFAULT_BOLD);
// Or just reference a system font:
paint.setTypeface(Typeface.create("sans-serif",Typeface.BOLD));
// Don't forget to specify your target font size. You can load from a resource:
//float scaledSizeInPixels = context.getResources().getDimensionPixelSize(R.dimen.mediumFontSize);
// Or just compute it fully in code:
int spSize = 18;
float scaledSizeInPixels = TypedValue.applyDimension(
TypedValue.COMPLEX_UNIT_SP,
spSize,
context.getResources().getDisplayMetrics());
paint.setTextSize(scaledSizeInPixels);
// Now compute!
Rect bounds = new Rect();
String myString = "Some string to measure";
paint.getTextBounds(myString, 0, myString.length(), bounds);
Log.d(TAG, "width: " + bounds.width() + " height: " + bounds.height());


For multi-line or spanned text (SpannedString), consider using a StaticLayout, in which you provide the width and derive the height. For 
a very elaborate answer on measuring and drawing text to a canvas in a custom view doing that, see: https://stackoverflow.com/a/41779935/954643
Also worth noting #arberg's reply below about the pixels painted vs the advance width ("number of pixels (in float) which the cursor should be advanced after drawing the given string"), in case you need to deal with that.
I'd like to share a better way (more versatile then the current accepted answer) of getting the exact width of a drawn text (String) with the use of static class StaticLayout:
StaticLayout.getDesiredWidth(text, textPaint))
this method is more accurate than textView.getTextBounds(), since you can calculate width of a single line in a multiline TextView, or you might not use TextView to begin with (for example in a custom View implementation).
This way is similar to textPaint.measureText(text), however it seems to be more accurate in rare cases.
simplay i tack max charcter in the line and defieded it with max space and create new line
v_y = v_y + 30;
String tx = "مبلغ وقدرة : "+ AmountChar+" لا غير";
myPaint.setTextAlign(Paint.Align.RIGHT);
int pxx = 400;
int pxy = v_y ;
int word_no = 1;
int word_lng = 0;
int max_word_lng = 45;
int new_line = 0;
int txt_lng = tx.length();
int words_lng =0;
String word_in_line = "" ;
for (String line : tx.split(" "))
{
word_lng = line.length() ;
words_lng += line.length() + 1;
if (word_no == 1 )
{word_in_line = line;
word_no += 1;
}
else
{ word_in_line += " " + line;
word_no += 1;
}
if (word_in_line.length() >= max_word_lng)
{
canvas.drawText(word_in_line, pxx, pxy, myPaint);
new_line += 1;
pxy = pxy + 30;
word_no = 1;
word_in_line = "";
}
if (txt_lng <= words_lng )
{ canvas.drawText(word_in_line, pxx, pxy, myPaint); }
}
v_y = pxy;

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