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).
Related
I have two bitmaps that I draw onto the center of a canvas:
One is only a background, it's a spirit level in top view which doesnt move. The second one is a bitmap looking like a "air bubble". When the user tilts the phone, the sensors read the tilt and the air bubble moves according to the sensor values along the x-axis. However, I need to make sure that the air bubble doesnt move too far, e.g out of the background-bitmap.
So I tried to which x coordinate the bubble can travel to,
before I have to set xPos = xPos -1 using trial and error
This works fine on my device.
To clarify: On my phone, the air bubble could move to the coordinate x = 50 from the middle of the screen. This would be the point, where the bitmap is at the very left of the background spirit level.
On a larger phone, the position x = 50 is too far left, and therefore looking like the air bubble travelled out of the water level.
Now I've tried following:
I calculated the area in % in which the air bubble can move. Let's say that
is 70% of the entire width of the bitmap. So I tried to calculate the two x boundary values:
leftBoundary = XmiddlePoint - (backgroundBitmap.getWidth() * 0.35);
rightBoundary = XmiddlePoint + (backgroundBitmap.getWidth() * 0.35);
...which doesnt work when testing with different screen sizes :(
Is it possible to compensate for different screen sizes and densities using absolute coordinates or do I have to rethink my idea?
If you need any information that I forgot about, please let me know. If this question has already been answered, I would appreciate a link :) Thanks in advance!
Edit:
I load my bitmaps like this:
private Bitmap backgroundBitmap;
private static final int BITMAP_WIDTH = 1898;
private static final int BITMAP_HEIGHT = 438;
public class SimulationView extends View implements SensorEventListener{
public SimulationView(Context context){
Bitmap map = BitmapFactory.decodeResource(getResources, R.mipmap.backgroundImage);
backgroundBitmap = Bitmap.createScaledBitmap(map, BITMAP_WIDTH, BITMAP_HEIGHT, true;
}
and draw it like this:
protected void onDraw(Canvas canvas){
canvas.drawBitmap(backgroundBitmap, XmiddlePoint - BITMAP_WIDTH / 2, YmiddlePont - BITMAP_HEIGHT / 2, null);
}
backgroundBitmap.getWidth() and getHeight() prints out the correct sizes.
Calculating like mentioned above would return following boundaries:
DisplayMetrics displayMetrics = new DisplayMetrics();
((Activity) getContext()).getWindowManager().getDefaultDisplay().getMetrics(displayMetrics);
int width = displayMetrics.widthPixels;
//which prints out width = 2392
xMiddlePoint = width / 2;
// = 1196
leftBoundary = xMiddlePoint - (BITMAP.getWidth()* 0.35);
// = 531,7
However, when I use trial and error, the right x coordinate seems to be at around 700.
I've come across a great explanation on how to fix my issue here.
As user AgentKnopf explained, you have to scale coordinates or bitmaps like this:
X = (targetScreenWidth / defaultScreenWidth) * defaultXCoordinate
Y = (targetScreenHeight / defaultScreenHeight) * defaultYCoordinate
which, in my case, translates to:
int defaultScreenWidth = 1920;
int defaultXCoordinate = 333;
DisplayMetrics displayMetrics = new DisplayMetrics();
((Activity) getContext()).getWindowManager().getDefaultDisplay().getMetrics(displayMetrics);
displayWidth = displayMetrics.widthPixels;
leftBoundary = (displayWidth / defaultScreenWidth) * defaultXCoordinates
I need to calculate how many characters (having pre-defined size eg 20dp) will fit on the text view to divide the long text into different Views? Like any reader app
I'm using the following code that works fine for a single line. My question is how to determine the max number of lines that will fit in text view in various screen sizes?
string abc = "This string is a loooong string";
final float densityMultiplier = getResources().getDisplayMetrics().density;
final float scaledPx = 20 * densityMultiplier;
int numChars;
Paint paint = txtArea.getPaint();
paint.setTextSize(scaledPx);
for (numChars = 1; numChars <= abc.length(); ++numChars)
{
if (paint.measureText(abc, 0, numChars) >= screenWidthDp)
{
break;
}
}
Simply use TextView.getLineHeight() to get height of a line
So I have been experimenting today with making an Android Application, but I have tried the LineairLayout to make a welcom screen for my application, but I cannot get it right..
So I tried RelativeLayout and I saw I can move my ImageViews and buttons to everywhere. So my question is if I will move the items to places like center, bottom left and bottom right. Would this be a problem or all phones since not all phones have the same dimensions?
public class WelcomeActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.welcome_screen_relative);
final ImageView logo = (ImageView) findViewById(R.id.myImageView);
DisplayMetrics metrics = Resources.getSystem().getDisplayMetrics();
int displayHeight = metrics.heightPixels;
int displayWidth = metrics.widthPixels;
float scaledDensity = metrics.scaledDensity;
BitmapFactory.Options dimensions = new BitmapFactory.Options();
dimensions.inJustDecodeBounds = true;
Bitmap mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.log, dimensions);
int imageHeight = dimensions.outHeight;
int imageWidth = dimensions.outWidth;
float percentageToMoveViewDown = (float) 20.0;
float viewY_float = (float) ((displayHeight / 100.0) * percentageToMoveViewDown);
int viewY_int = Math.round(viewY_float);
RelativeLayout.LayoutParams view_Layout_params = new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
view_Layout_params.topMargin = viewY_int;
logo.setLayoutParams(view_Layout_params);
logo.getLayoutParams().height = imageHeight;
logo.getLayoutParams().width = imageWidth;
}
Thats depends. If you give objects a fixed size of course it will. for dp/dpi make sure to test it in Emu or real devices. You can also create density and orientation specific layout to support many screens. Consider that there are not only changes in size but also aspect ration and resolution and DPI.
For most apps RelativeLayout is might be the right approach.
You can read an excelent article about it here: http://developer.android.com/guide/practices/screens_support.html
If the items have fixed sizes you always will have trouble with some phones. For the big ones it may be too small, for the small ones too big...
In my experience Androids small/normal/large screens won't help you much for configuring, since the differences are just too big.
If you want to make sure everything sits where it belongs to, you could get the device metrics. That way you don't even need to rely on center, but you can work with percentages to place everything where you want it to be. Plus you can set the sizes in percentage, which is great. Like you could say I want a button thats width is 50% of the screen, no matter how large the screen is. Its more work (maybe even overkill), but I really like that approach. Once you figured it out its basically just a bit copy paste at the start of your classes.
Example:
DisplayMetrics metrics = Resources.getSystem().getDisplayMetrics();
int displayHeight = metrics.heightPixels;
int displayWidth = metrics.widthPixels;
float scaledDensity = metrics.scaledDensity;
//move some View 20% down:
float percentageToMoveViewDown = (float) 20.0;
float viewY_float = (float) ((displayHeight / 100.0) * percentageToMoveViewDown);
int viewY_int = Math.round(viewY_float);
RelativeLayout.LayoutParams view_Layout_params = new RelativeLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
view_Layout_params.topMargin = viewY_int;
view.setLayoutParams(view_Layout_params);
//even works with text size for a TextView:
float percentageToResizeTextViewTextSize = (float) 3.1;
float textViewTextSize_float = (float) ((displayHeight / 100.0) * percentageToResizeTextViewTextSize);
int textViewTextSize_int = Math.round(textViewTextSize_float / scaledDensity);
textView.setTextSize(textViewTextSize_int);
Just a side note for the overkill thing: This should be only necessary if you want to support small devices (they mostly run something like android 2.3, but still are sold as budget phones) and big devices as well, but the trouble with the big ones is not as big as the trouble with the small ones. I personally rather put more effort in it than less, you never know.
Edit: ImageView by code
The easiest way is to do it hybridly, using xml and code. Note that you will have to change width and height if you set it to 0 in xml like in the following example.
Just place it in the xml where you would anyways, somewhere in your RelativeLayout.
In your xml:
<ImageView
android:id="#+id/myImageView"
android:layout_width="0dp"
android:layout_height="0dp" />
In your Code:
ImageView myImageView = (ImageView)findViewById(R.id.myImageView);
You now can work with that myImageView as I did it with view and textView. You can even set the image right here in code.
This imageView with the size of 0,0 is now placed where it would have been before. Now you could set the width to like 50% of the screenwidth and the height to...lets say 40% of the screen height. Then You would need to place it. If you want to center it you know that there must be 25% of the screen on each side, so you can add 25% as left and right margin.
Edit 2: maintain original imagesize
If you want to keep the original size of a image in your drawables, you can get its width and height like this:
BitmapFactory.Options dimensions = new BitmapFactory.Options();
dimensions.inJustDecodeBounds = true;
Bitmap mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.yourImageName, dimensions);
int imageHeight = dimensions.outHeight;
int imageWidth = dimensions.outWidth;
Now that you have that, you could use it to calculate the aspect ratio to keep it.
Now since you know the devices width and height, you can easily calculate how much of the screen this image will need.(imageheight/screenheight*100 = your percentage of the screen you want the imageviews height to be). So the Height you set to the imageview would be displayHeight / 100 * (imageHeight / displayHeight * 100).
How to place that?
Now if you take a Screenheight of 100 and a imageheight of 80 you get 80%. You would now take this percentage and divide it from 100. Divide that /2 and you know how much space you would have as top and bottom margins if you wanted it to be placed in the middle of the screen (you would have to do the same for width).
Caution: If you don't want it to be relative to the screensize but the original size, that percentage approach is kind of pointless. If you do to your image what I just described, it may still be too big for small devices and too small for big ones. Instead you could think about what percentage would look good in proportion to the rest of the stuff on the screen and resize it to that, since it would have that relative size on all devices.
Edit 3:
Since you load the image in original size, it will be small on big devices if it is a small image.
//first you need to know your aspect ratio.
float ratio = imageWidth / imageHeight;
//lets say you wanted the image to be 50% of the screen:
float percentageToResizeImageTo = (float) 50.0;
float imageX_float = (float) ((displayHeight / 100.0) * percentageToResizeImageTo);
int imageX_int = Math.round(imageX_float);
//now you know how much 50% of the screen is
imageWidth = imageX_int;
imageHeight = imageWidth * ratio;
RelativeLayout.LayoutParams view_Layout_params = new RelativeLayout.LayoutParams(imageHeight, imageWidth);
view_Layout_params.topMargin = viewY_int;
logo.setLayoutParams(view_Layout_params);
logo.setScaleType(ImageView.ScaleType.Fit_XY);
I have countdown functionality in my app.
Every second a timer sets the current time to a TextView.
So strings are: "56:05","56:04","56:03","56:02"...
I want to make the text size as big as possible
Therefore I've written the following code.
private void measureAndSetText(String text) {
Paint pMeasure = new Paint();
Integer iWidth = _tvContent.getWidth();
Float maxTextSize = 1000f;
pMeasure.setTextSize(maxTextSize);
pMeasure.setFakeBoldText(true);
Float fCurrentWidth = pMeasure.measureText(text);
while (fCurrentWidth > iWidth) {
pMeasure.setTextSize(maxTextSize -= 1);
fCurrentWidth = pMeasure.measureText(text);
}
_tvContent.setText(text);
_tvContent.setTextSize(TypedValue.COMPLEX_UNIT_PX, maxTextSize);
}
This code seems to work on my Note2, Lg Optimus 4x HD, Galay ACE and some others.
But not on my Xperia Z in landscape mode.
I guess the reason is the Full Hd Display but I don't understand why.
On the Xperia Z just the ":" sign is displayed in landscape mode. So I think the text is wrapped but I don't know why.
It would make sense to me if the text size I set to it is higher than the screen height (in landscape mode this is actually screen width -> 1080) but this isn't the case.
When I try to set a longer text -> "asdfasd asdf" it is correctly displayed.
Can someone point me to the problem?
Cheers,
Stefan
UPDATE:
I figured out that my iWidth variable which holds the width of my TextView (_tvContent.getWidth()) has the value 1770.
How can that be since my Xperia Z has just 1920x1080???
So I thought that it may be a failure in TextView.getWidth() and added the following code:
Display display3 = getWindowManager().getDefaultDisplay();
Point size3 = new Point();
display3.getSize(size3);
int width = size3.x;
Display display1 = getWindowManager().getDefaultDisplay();
int width1 = display1.getWidth(); // deprecated
int height1 = display1.getHeight(); // deprecated
Display display = getWindowManager().getDefaultDisplay();
Integer iWidth = display.getWidth(); // deprecated
int height = display.getHeight(); // deprecated
Results:
Point(1080, 1776)
Display id 0: DisplayInfo{"Integrierter Bildschirm", app 1080 x 1776, real 1080 x 1920, largest app 1794 x 1701, smallest app 1080 x 1005, 60.0 fps, rotation 0, density 480, 442.451 x 443.345 dpi, layerStack 0, type BUILT_IN, address null, FLAG_SECURE, FLAG_SUPPORTS_PROTECTED_BUFFERS}, DisplayMetrics{density=3.0, width=1080, height=1776, scaledDensity=3.0, xdpi=442.451, ydpi=443.345}, isValid=true
Is this a Bug on site of Sony?
After I implemented my own TextView with its own OnDraw I've seen that there is an error in LogCat: ERROR/OpenGLRenderer(2503): Font size to large to fit in cache.
After a short research I figgured out that this is really a Bug in Android.
Addding this line to my custom TextView did the trick for me:
this.setLayerType(View.LAYER_TYPE_SOFTWARE, null);
I need to get a ascender/descender and x-height..
By using following code I can find the descender and the total height:
descender_height = paint.descent();
total_height = descender_height - paint.ascent();
//ascender = ?; is this always equal to descender height?
//x_height = ?; total_height - 2*descender_height ?
Thanks
I would think the ascender and descender height would typically be the same, but I wouldn't depend on it for every font. I don't really see a direct way to get to the x-height, but a trick you could use would be something like the below. Also, for the total height, are you talking about the absolute distance from the highest ascender to the lowest descender? I've also included something for that below. I haven't tested these myself, but it should work (but let me know if I'm misinterpreting something you've said):
// Assuming TextPaint/Paint tp;
Rect bounds;
// this will just retrieve the bounding rect for 'x'
tp.getTextBounds("x", 0, 1, bounds);
int xHeight = bounds.height();
Paint.FontMetrics metrics = tp.getFontMetrics();
int totalHeight = metrics.top - metrics.bottom;
This is what worked for me:
Paint.FontMetrics fm = paint.getFontMetrics();
int totalHeight = (int)(fm.bottom - fm.top + .5f);