Develop Reference

Android Resizing Radio Button programmatically

Is it possible to assign width and height to RadioButton in Android programmatically? I know we can do it by using scaleX and scaleY properties. What I am looking for is, if user gives a width and height in int, how can we apply to the RadioButton?

Try this:
myRadioButton.getButtonDrawable().setBounds(/* play around with the bounds */);
The documentation on the Drawable class says this is how you change a Drawable's size. Unfortunately, it's not really clear how it works, so you'll need to play around.

Since RadioButton, inherits from TextView, you can use myRadioButton.setHeight(int pixels) and .setWidth(int pixels) to set the size of the entire button area, but not the text nor the selection circle. To change the size of the content but not the overall area, you can use .setScaleX(float scale) and .setScaleY() you will change the text and selection circle, but not the button area.
So to change both the button area and the size of its contents:
int desiredWidth = 500; // Set to your desired width.
int currentWidth = radioButton.getWidth();
radioButton.setScaleX(desiredWidth / currentWidth);
radioButton.setWidth(desiredWidth);
And likewise for the height.
If you want to maintain the aspect ratio, set just the desired width and then:
desired_height = desired_width * current_height / current_width
Like this:
int desiredWidth = 500;
int currentHeight = radioButton.getHeight();
int currentWidth = radioButton.getWidth();
int desiredHeight = desiredWidth * currentHeight / currentWidth;
radioButton.setScaleY(desiredHeight / currentHeight);
radioButton.setHeight(desiredHeight);
radioButton.setScaleX(desiredWidth / currentWidth);
radioButton.setWidth(desiredWidth);
It appears that the scale is adjusted from the center, without adjusting the position, so you might have to change the position (maybe this will be moot if you use a ConstraintLayout--with a LinearLayout my buttons bled off the screen when I resized them this way).

Use x/y coordinates to set bounds of a moving particle

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

RelativeLayout for Android?

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);

RelativeLayout margin shrinks ImageView

I'm trying to dynamically build a layout, so it scales and looks more or less identical on all screen sizes and resolutions. I do this by programmatically placing my views inside a RelativeLayout and scaling everything according to a certain factor.
I noticed something strange when moving an ImageView around though, the bigger the values on margins get, the smaller the ImageView gets. This gets really annoying when trying to get things at right place and size.
private void initializeObjects() {
Display display = getWindowManager().getDefaultDisplay();
Point screenSize = new Point();
display.getSize(screenSize);
float scale = screenSize.x / ( (screenSize.x < screenSize.y) ? 480 : 800 ); // Scale according to Galaxy S II resolution
RelativeLayout screenLayout = (RelativeLayout) findViewById(R.id.main_layout);
mRobotView = new ImageView(getApplicationContext());
mRobotView.setImageResource(R.drawable.soomla_logo_new); // a 743 x 720 png
mRobotView.setScaleX(scale * 100 / 743); // Make sure the image is 100 "units" in size
mRobotView.setScaleY(scale * 100 / 720);
mRobotView.setPivotX(scale * 100 / 743); // reset the image origin according to scale
mRobotView.setPivotY(scale * 100 / 720);
RelativeLayout.LayoutParams robotParams = new RelativeLayout.LayoutParams(743, 720);
robotParams.leftMargin = 0xDEADBEEF; // The bigger these get the smaller the view gets
robotParams.topMargin = 0xDEADBEEF;
screenLayout.addView(mRobotView, robotParams);
}
Any idea what's causing this?

Use
android:layout_height="720px"
android:layout_height="743px"
in the main_layout.xml to have the image not shrinked

Scale a view and its layered subviews relatively

(This is somewhat a follow-up on Android: How do you scale multiple views together?)
My task is to port an iPhone / iPad app on Android that consists of a simple image view on which animations are layered on top in absolute positions. While this sounds rather easy on iOS where you only have to target a few possible screen sizes, it gets rather messy with Android.
My current setup is this: A RelativeLayout in which I place my main (background) image on left = 0, top = 0 and multiple ViewFlipper instances used as "animation containers" that are positioned relatively to the upper left corner of the parent layout instance.
This approach has two basic problems:
The positioned "animations" are mis-positioned as soon as the actual size of the layout does not match the size of the main background image.
The positioned "animations" are also mis-sized, because since they usually have "enough space" around themselves, Android doesn't scale them to fit into the RelativeLayout (nor would it scale them relatively to the original background.
Since the animations itself must be interactive, its not a solution to place and position all of the animations on a transparent layer that has the same size as the main (background) image, as they'd overlap each other and only the upper-most would be interactive at all.
I thought of different solutions:
To get the the scale factor of the main image, I could retrieve its measuredWidth and measuredHeight and set this into relation of the original width and height of the view. Then I'd use this scale factor for custom positioning and eventually custom scaling. But, apparently the measuredWidth/-Height properties are only set during the onMeasure() call and this is called after the component tree was built, so I don't know if this solution is feasible at all.
Implement my own layout manager and scale / position the views accordingly. I had a look at the implementation of RelativeLayout, but have to admit that the onMeasure() method scares me a bit.
What would you do in my case? Is there anything I haven't yet taken into account?
Thanks in advance.

Well, answering my own question - here is the way I resolved the issue:
I placed the background image on the top of my ImageView with ImageView.setScaleType(ScaleType.FIT_START)
I calculated the scale factor of my background image like so:
WindowManager mgr = (WindowManager) context
.getSystemService(Context.WINDOW_SERVICE);
DisplayMetrics metrics = new DisplayMetrics();
mgr.getDefaultDisplay().getMetrics(metrics);
Drawable image = context.getResources().getDrawable(R.drawables.someImage);
float scale = metrics.widthPixels / (float) image.getIntrinsicWidth();
Finally, I used this scale in a custom ImageView class that loads the overlays to position and scale the view properly:
public class OverlayImage extends ImageView
{
private int imgWidth, imgHeight;
private final float scale;
public OverlayImage(Context context, int xPos, int yPos, float scale)
{
super(context);
this.scale = scale;
LayoutParams animParams = new LayoutParams(LayoutParams.WRAP_CONTENT,
LayoutParams.WRAP_CONTENT);
animParams.addRule(RelativeLayout.ALIGN_PARENT_LEFT);
animParams.addRule(RelativeLayout.ALIGN_PARENT_TOP);
animParams.leftMargin = (int) (scale * xPos);
animParams.topMargin = (int) (scale * yPos);
setLayoutParams(animParams);
Drawable dr = context.getResources().getDrawable(R.id.someImage);
setBackgroundDrawable(dr);
imgWidth = dr.getIntrinsicWidth();
imgHeight = dr.getIntrinsicHeight();
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
{
setMeasuredDimension((int) (scale * imgWidth),
(int) (scale * imgHeight));
}
}

I lately needed to do something similar, i also had to port a IPad app to android, the screen had many images that had to be in specific locations.
I solved this slightly differently, absolute layout, and run through all the views and set the coordinated and size of each.
//This gets the scale of the screen change:
DisplayMetrics displaymetrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(displaymetrics);
Drawable image = getResources().getDrawable(R.drawable.background_image);
float scaleW = displaymetrics.widthPixels / (float)image.getIntrinsicWidth();
float scaleH = displaymetrics.heightPixels / (float)image.getIntrinsicHeight();
//And this scales each view accordingly:
for(int i = 0; i < mainLayout.getChildCount(); i++)
{
View v = mainLayout.getChildAt(i);
v.setLayoutParams(new AbsoluteLayout.LayoutParams(
Math.round(scaleW * v.getMeasuredWidth()),
Math.round(scaleH * v.getMeasuredHeight()),
Math.round(scaleW * ((AbsoluteLayout.LayoutParams)v.getLayoutParams()).x),
Math.round(scaleH * ((AbsoluteLayout.LayoutParams)v.getLayoutParams()).y)));
}