long in java example
Android development
long is 64 bit signed type and used when int is not large enough to hold the value.
long je celé číslo 64 bitů -9223372036854775808 +9223372036854775807 a používá se tam, kde typ int není schopen pojmout takovou hodnotu čísla.
long is 64 bit signed type and used when int is not large enough to hold the value.
long je celé číslo 64 bitů -9223372036854775808 +9223372036854775807 a používá se tam, kde typ int není schopen pojmout takovou hodnotu čísla.
// declaration and assignment of value type long
long n = 22337203685477580L;
// print formated value
System.out.printf("The value of x is %d%n", n); // 22337203685477580
System.out.format("%+,8d%n%n", n); // +22 337 203 685 477 580
// declaring more variables in single statement
long lo1 = 12L, lo2 = 56, lo3 = 1455555555589L;
// long range of value
System.out.println(Long.MAX_VALUE); // 9223372036854775807
System.out.println(Long.MIN_VALUE); // -9223372036854775808
// check if a string is a valid number in Java example
// convert string to long Java example
String sLong = "1288888888888888";
long longParse = Long.parseLong(sLong);
// convert strings to numbers
long longFromString = (Long.valueOf(sLong)).longValue();
// long to string in Java example code
Long longObj = new Long(229999999999L);
String str = longObj.toString();
// else
Long longS = 888888888888L;
String strLong = longS.toString();
// compare two long variables
Long longComp1 = 5555L;
if (longComp1.equals(55555555L))
System.out.print("true");
// compares the two specified long values in Java example
int i = longS.compareTo(444444L); // -1 first < second
// 0 first == second
// 1 first > second
System.out.print(i);
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// single line
/*
multi line
*/
Canvas, drawCircle(), Paint, onDraw(), setStrokeWidth(), 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(4.5f);
// opacity
//p.setAlpha(0x80); //
canvas.drawCircle(50, 50, 30, p);
}
}
}
Bitmap Width, Height without memory allocation:
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeResource(getResources(), R.id.myimage, options);
// now opts.outWidth and opts.outHeight are the dimension of the
// bitmap, even though Bitmap is null
int imageHeight = options.outHeight;
int imageWidth = options.outWidth;
String imageType = options.outMimeType;
static boolean mbThemeLight = false;
@Override
public void onCreate(Bundle savedInstanceState) {
if(mbThemeLight)
setTheme(android.R.style.Theme_Light);
super.onCreate(savedInstanceState);
// bla bla bla..........
}
private void switchTheme(){
mbThemeLight = true;
this.recreate();
}
Emulator window was out of view and was recentred
Emulator] WARNING: Data partition already in use. Changes will not persist!
Emulator] WARNING: SD Card image already in use: C:\Documents and Settings\user_name\.android\avd\hvga21_up1_7.avd/sdcard.img
Emulator] WARNING: Cache partition already in use. Changes will not persist!
Basic step
Try restart Eclipse if using from menu File->Restart
Other solutions
Solution 1: try restart ADB server
//android.okhelp.cz/how-quickly-restart-adb-exe-adb-server-android-emulator-example/
Solution 2:
//android.okhelp.cz/android-emulator-wont-run-application-started-from-eclipse/
Solution 3:
Try delete:
Try solution 4:
Eclipse menu select Window->Preferences->Android
Windows 32
FROM: C:\Program Files\Android\android-sdk
TO: C:\PROGRA~1\Android\android-sdk
Windows 64
FROM: C:\Program Files (x86)\Android\android-sdk
TO: C:\PROGRA~2\Android\android-sdk
Emulator] WARNING: Data partition already in use. Changes will not persist!
Emulator] WARNING: SD Card image already in use: C:\Documents and Settings\user_name\.android\avd\hvga21_up1_7.avd/sdcard.img
Emulator] WARNING: Cache partition already in use. Changes will not persist!
Basic step
Try restart Eclipse if using from menu File->Restart
Other solutions
Solution 1: try restart ADB server
//android.okhelp.cz/how-quickly-restart-adb-exe-adb-server-android-emulator-example/
Solution 2:
Delete Run Configuration
//android.okhelp.cz/android-emulator-wont-run-application-started-from-eclipse/
Solution 3:
Try delete:
c:\Documents and Settings\user_name\.android\avd\my_avd.avd\cache.img
c:\Documents and Settings\user_name\.android\avd\my_avd.avd\userdata-qemu.img
Try solution 4:
Eclipse menu select Window->Preferences->Android
Windows 32
FROM: C:\Program Files\Android\android-sdk
TO: C:\PROGRA~1\Android\android-sdk
Windows 64
FROM: C:\Program Files (x86)\Android\android-sdk
TO: C:\PROGRA~2\Android\android-sdk
Editace: 2011-09-26 20:49:35
Počet článků v kategorii: 396
Url:long-in-java-example