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double in Java example for Android development


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Java double is 64 bit double precision type used when fractional
precision calculation is required.

Java double je datový typ (reálné číslo) o velikosti 64 bitů. Používá se například pro přesný výsledek po dělení za desetinnou tečkou. Pokud nepotřebuje tak veliké číslo použijte raději typ float, šetříte tím paměť mobilního telefonu.


		// declaration and assignment of value  type double
		double x = 18.41785;
		//print formated  value
		System.out.printf("The value of x is %.3f%n", x); // 18.418
                
                // declaring more variables in single statement
                double d1 = 12.4, d2 = 564.5, d3 = 14.589;

		// double range of value
		System.out.println(Double.MIN_VALUE); // 4.9E-324
		System.out.println(Double.MAX_VALUE); // 1.7976931348623157E308

		// is NaN  Not-a-Number
		double f = (double) Math.sqrt(-15);
		boolean bNaN = Double.isNaN(f);
		System.out.print(bNaN); // true
		
                // check if a string is a valid number in Java example
                // convert string to double Java example
		String sD = "12.8";
		double dParse = Double.parseDouble(sD);

	       // convert strings to numbers
	      String sDl = "15.48";
	      double dFromString = (Double.valueOf(sDl)).doubleValue();

// format double, float or long value to string
	DecimalFormat formatter = new DecimalFormat(".##");
	String s = formatter.format(-.5678);             // -0.57
// .###  -0.568
// .#### -0.5678
// .000000  -.567800

// -123.456
// .##  -123.46
// #.##  -123.46

// #E0  -.1E3
// ##E0  -1.2E2
//###E0  -123E0

// double to string in Java example code
Double dObj = new Double(68.5);
String str = dObj.toString();
// else 
Double dS = 11.6;
String sdouble = dS.toString();

// compare two double variables
	      Double dComp1 = 4.3;
	      if(dComp1.equals(4.3))
	  		System.out.print("true");

	// compares the two specified double values in Java example
	// int i =	compare(double d1, double d2);
	    int i =	Double.compare(11.5, 11.7); // -1 first < second
	    // 0 first == second
	    // 1 first > second
	    System.out.print(i);



397LW NO topic_id




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387

Error type 3 Activity class does not exist | error-type-3-activity-class-does-not-exist


Try some solution - each individually or all

  1. Check AndroidManifest.xml activity declaration
    <activity
                android:name=".EnableProfileActivity"
                android:label="@string/app_name" />


  2. Delete BUILD folder in module tree and Clean / Rebuild project

  3. Restart Android Studio

230

Eclipse Log.e println needs a message | eclipse-log-e-println-needs-a-message


Log.e println needs a message error.
E/AndroidRuntime(330): FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start activity ComponentInfo{b.paint/b.paint.MainActivity}: java.lang.NullPointerException: println needs a message

Try this code:

		// Error
                String s = null;
		Log.e("bla", s); // !!! error Log.e println needs a message error.
                // OK
		String s = null;
		Log.e("bla", s+""); // OK 


236

IndexOutOfBounds TextView Html Android 4.1 error | indexoutofbounds-textview-html-android-4-1-error


Try before html tags put space and check if every tag is closed b - /b.
For example:

My text (<i>some text</i>) blah blah...
Change to:
My text (   <i>some text</i>) blah blah...

"java.lang.IndexOutOfBoundsException
at android.graphics.Paint.getTextRunAdvances(Paint.java:1731)
at android.graphics.Paint.getTextRunAdvances(Paint.java:1704)
at android.text.MeasuredText.addStyleRun(MeasuredText.java:164)
at android.text.MeasuredText.addStyleRun(MeasuredText.java:204)
at android.text.StaticLayout.generate(StaticLayout.java:281)
at android.text.StaticLayout.(StaticLayout.java:140)
at android.text.StaticLayout.(StaticLayout.java:80)
at android.text.StaticLayout.(StaticLayout.java:59)
at android.widget.TextView.makeSingleLayout(TextView.java:5901)
at android.widget.TextView.makeNewLayout(TextView.java:5741)
at android.widget.TextView.onMeasure(TextView.java:6098)
at android.view.View.measure(View.java:15172)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4814)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1390)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:681)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:574)
at android.view.View.measure(View.java:15172)
at android.widget.ListView.setupChild(ListView.java:1847)
at android.widget.ListView.makeAndAddView(ListView.java:1772)
at android.widget.ListView.fillDown(ListView.java:672)
at android.widget.ListView.fillSpecific(ListView.java:1330)
at android.widget.ListView.layoutChildren(ListView.java:1600)
at android.widget.AbsListView.onLayout(AbsListView.java:2102)
at android.view.View.layout(View.java:13754)
at android.view.ViewGroup.layout(ViewGroup.java:4362)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1649)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1507)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1420)
at android.view.View.layout(View.java:13754)
at android.view.ViewGroup.layout(ViewGroup.java:4362)
at android.widget.FrameLayout.onLayout(FrameLayout.java:448)
at android.view.View.layout(View.java:13754)
at android.view.ViewGroup.layout(ViewGroup.java:4362)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1649)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1507)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1420)
at android.view.View.layout(View.java:13754)
at android.view.ViewGroup.layout(ViewGroup.java:4362)
at android.widget.FrameLayout.onLayout(FrameLayout.java:448)
at android.view.View.layout(View.java:13754)
at android.view.ViewGroup.layout(ViewGroup.java:4362)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:1866)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1687)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:998)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4212)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:725)
at android.view.Choreographer.doCallbacks(Choreographer.java:555)
at android.view.Choreographer.doFrame(Choreographer.java:525)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:711)
at android.os.Handler.handleCallback(Handler.java:615)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4745)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
"
259

Shuffle Array of String Java Example | shuffle-array-of-string-java-example



       String[] sAr = new String[] {"one","two","three"};
       List<String> wordList = Arrays.asList(sAr);
       Collections.shuffle( wordList);
       String[]myShuffledArray = wordList.toArray(new String[wordList.size()]);




Editace: 2011-09-26 20:49:42
Počet článků v kategorii: 397
Url:double-in-java-example-for-android-development

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