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Screen size density independent pixel resolution


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Terms Screen size, density, density independent pixel, resolution as a picture - pictogram.
mobile-phone-screen-resolution-terms

Test your knowledge
Q: How to find out the phone screen size?
A: (By length of display diagonale in inch -  Not to measure a diagonal of device!!!)

Q: What resolution has 720 x 1280 display?
A: (921600 pixels)

Q: What does it mean "240 dpi" screen density?
A: (Display have density 240 x 240  dots - "Tri-color LED etc." - per every physical (real) square inch. If you have icon 240x240 pixels, this will just occupy an area of one square inch on the display.)

Q: Phone have screen density 240 dpi. Image for 160 dpi screen density have size 128x 128 pixels. What will be the size of the image for 240 dpi screen density?
A: (Calculate the virtual pixels size.   128 * (240/160)  =  192.  You have to resize image to new size 192 x 192 physical pixels and put into folder drawable-hdpi (high) ~240dpi  for phone with screen density 240 dpi. ) or use density independend pixels 128dp x 128dp.

 

 

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Další témata ....(Topics)


44

No resource found that matches the given name Eclipse Android xml file | no-resource-found-that-matches-the-given-name-eclipse-android-xml-file


No resource found that matches the given name - error examples.
Exist resource file?
Is code written correctly?

// No resource found that matches the given name (at id with value @id/myButton).
 android:id="@id/myButton" // invalid id notation
 android:id="@+id/myButton" // correct


 // No resource found that matches the given name 
// (at icon with value @drawable/icons).
// exist file icons in res/drawable folder?
<application android:icon="@drawable/icons" 

//No resource found that matches the given name 
//(at theme with value @style/MyThem).
<activity android:name=".Main"
                  android:label="@string/app_name"
                  android:theme="@style/MyThem">

// Exist style MyThem  in styles.xml ?  No only MyTheme
<style name="MyTheme" parent="android:Theme">
        <item name="android:windowTitleSize">50px</item>
</style>



// exist file my_background in folder drawable ?
android:background="@drawable/my_background" // 

// no resource found that matches the given name(at "label" with value "@string/app_name")
// have you the string resource defined in res/values/strings.xml ?
<string name="app_name">"My App"</string>


141

Create monochromatic bitmap Android example | create-monochromatic-bitmap-android-example



public class MainActivity extends Activity {
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(new SampleView(this));
	}

	private static class SampleView extends View {

		// CONSTRUCTOR
		public SampleView(Context context) {
			super(context);
			setFocusable(true);

		}
		@Override
		protected void onDraw(Canvas canvas) {
			Paint paint = new Paint();
			
			canvas.drawColor(Color.GREEN);
            
            Bitmap b = Bitmap.createBitmap(200, 200, Bitmap.Config.ALPHA_8);
             paint.setColor(Color.BLUE);
            
           Canvas c = new Canvas(b);
           c.drawRect(0, 0, 200, 200, paint);
           
           canvas.drawBitmap(b, 10,10, paint);
		}

	}
}



monochromatic bitmap
294

Get Bitmap Size Get Free Memory Exception Android | get-bitmap-size-get-free-memory-exception-android


Bitmap size calculation:
bmpHeight * bmpWidth
For example:
Resolution of image 1024x860 = 880 640 pixels
If every pixel get 4 byte of memory:
880 640x4= 3 522 560 (3.5MB)

Get bitmap size without allocation of memory:

   	BitmapFactory.Options options = new BitmapFactory.Options();
        // If set to true, the decoder will return null (no bitmap), but the out... fields will still
        // be set, allowing the caller to query the bitmap without having to allocate the memory for its pixels. 
    	options.inJustDecodeBounds = true; 
    	BitmapFactory.decodeResource(getResources(), R.drawable.my_image, options);
    	int imageHeight = options.outHeight; // 1024
    	int imageWidth = options.outWidth; // 860
    	String imageType = options.outMimeType; // .jpg .png .gif
 


Get Memory size:
Make your bitmap not bigger as maxMemory size
final int maxMemory = (int) (Runtime.getRuntime().maxMemory() / 1024);

    float density = getResources().getDisplayMetrics().density;

    Debug.MemoryInfo memoryInfo = new Debug.MemoryInfo();
    Debug.getMemoryInfo(memoryInfo);
    final int maxMemory = (int) (Runtime.getRuntime().maxMemory() / 1024);
    final int freeMemory = (int) (Runtime.getRuntime().freeMemory() / 1024);
    String memMessage = String.format(
        "Free=%d kB,

MaxMem=%d kB,
Memory: Pss=%.2f MB, Private=%.2f MB, Shared=%.2f MB", freeMemory, maxMemory, memoryInfo.getTotalPss() / 1024.0, memoryInfo.getTotalPrivateDirty() / 1024.0, memoryInfo.getTotalSharedDirty() / 1024.0); ((TextView)findViewById(R.id.textViewInfo)).setText(memMessage );
176

HTC Desire HD | htc-desire-hd


HTC Desire HD cena od 7 000 KCZ Kč (únor.2012)
HTC Desire HD je chytrý telefon běžící na operačním systému Android.
HTC Desire HD je (22.února2012) druhým nejpoužívanějším chytrým telefonem u programu Sky Map viz tabulka.

Smartphone má hliníkový unibody design, vybaven je Androidem 2.2 (Froyo) a HTC Sense displayem. Na zadní straně jsou dvě plastové krytky, jedna obsahuje baterii, druhá SIM kartu a paměťovou kartu microSDHC. Telefon je vybaven 4,3 palcovým WVGA LCD TFT dotykovým displayem, 8 megapixelovým fotoaparátem (lze nahrávat 720p video), podpora pro HSPA / W-CDMA a quad-band GSM / GPRS / EDGE.


Telefon je vybaven 1 GHz CPU Scorpion MSM8255 procesorem. Tato druhá generace Snapdragon procesoru má nízkou spotřebu energie.

HTC HD má 768 MB RAM a 1,5 GB interní paměti flash. K dispozici je také slot pro microSDHC / XC kartu s kapacitou až 32 GB dat.

HTC Desire HD photo pic image
samsung galaxy s2
Zdroj obrázku: wikipedia
35

Android startup tutorial for developers video | android-startup-tutorial-for-developers-video




Editace: 2015-11-29 12:26:12
Počet článků v kategorii: 397
Url:screen-size-density-independent-pixel-resolution

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