Draw Arc Android basic example

AD MOB

drawArc(), Canvas, Paint, setStyle()


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) {

			canvas.drawColor(Color.CYAN);
			Paint p = new Paint();
			// smooths
			p.setAntiAlias(true);
			p.setColor(Color.RED);
			p.setStyle(Paint.Style.STROKE); 
			p.setStrokeWidth(5);
			// opacity
			//p.setAlpha(0x80); //
 
			RectF rectF = new RectF(50, 20, 100, 80);
			canvas.drawOval(rectF, p);
			p.setColor(Color.BLACK);
			canvas.drawArc (rectF, 90, 45, true, p);
		}

	}
}

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289

Call requires API level xx current min is xx android | call-requires-api-level-xx-current-min-is-xx-android

Call requires API level 16 (current min is 4): android
Change The SDK version in AndroidManifest.xml to higher


<uses-sdk android:minSdkVersion="4" />
// 
<uses-sdk android:minSdkVersion="8" />

345

Pixel to density independent pixel to pixel conversion | pixel-to-density-independent-pixel-to-pixel-conversion

Physical pixel (px)
Density independent pixel (dp)
Dots per inch (dpi) .. physical pixels per inch
px = dp * (dpi / 160)


public static int dpToPx(int dp)
{
    return (int) (dp * Resources.getSystem().getDisplayMetrics().density);
}

public static int pxToDp(int px)
{
    return (int) (px / Resources.getSystem().getDisplayMetrics().density);
}

194

SAMSUNG i9220 Galaxy Note | samsung-i9220-galaxy-note

Displej 1280 x 800, 5.3 "
Rozměry 146.85 mm x 83 mm x 9.7 mm
Rozlišení fotoaparátu 8 Mpix
HD video, natačení videosekvencí
Operační system Android
Hlasové ovládání
Přehrávání MP3
Baterie Li-Ion ,doba hovoru 1570 min
Frekvence procesoru 1.4 GHz
Uživatelská paměť 16000 MB
Datové funkce: GPS modul, WiFi, Bluetooth, GPRS, EDGE, HSCSD, Hardwarový modem, Infraport
Podporované sítě GSM&EDGE 850 / 900 / 1.800 / 1.900
Formát videosouborů 3GPP / H.263 / H.264 / MPEG4 / WMV

samsung-i9220-galaxy-note

How going life cycle if screen orientation changed Android example | how-going-life-cycle-if-screen-orientation-changed-android-example

onSaveInstanceState, onRestoreInstanceState life cycle if screen orientation changed from log file.


// starts activity
15:27:12.801: INFO/onCreate(1828): onCreate()
15:27:12.811: INFO/onStart(1828): onStart()
15:27:12.821: INFO/onResume(1828): onResume()
// activity is running 

15:27:33.651: DEBUG/dalvikvm(307): GC_EXPLICIT freed 186K, 53% 
free 2770K/5831K, external 981K/1038K, paused 99ms

// change emulator state Ctrl+F11 landscape, portrait
15:27:40.427: INFO/ActivityManager(74): Config changed: 
{ scale=1.0 imsi=310/260 loc=en_US touch=3 keys=2/1/2 nav=3/1 orien=2 layout=18 uiMode=17 seq=64}

// saved all variable values if need
15:27:40.581: INFO/onSaveInstanceState(1828): onSaveInstanceState()

15:27:40.602: INFO/onPause(1828): onPause()
15:27:40.612: INFO/onStop(1828): onStop()
15:27:40.631: INFO/onDestroy(1828): onDestroy()

// activity goes back to onCreate !!!!!!!!!
15:27:40.692: INFO/onCreate(1828): onCreate()
15:27:40.701: INFO/onStart(1828): onStart()

// restore all saved values of variables 
15:27:40.711: INFO/onRestoreInstanceState(1828): onRestoreInstanceState()
// you can using saved values by onSaveInstanceState() in onResume
15:27:40.721: INFO/onResume(1828): onResume()

Diagram of life cycle onSaveInstanceState, onRestoreInstanceState

[caption id="attachment_1169" align="alignleft" width="229" caption="Life cycle onRestoreInstanceState"]