double in Java example for Android development
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.
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);
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Další témata ....(Topics)
Set in AndroidManifest.xml android:theme="@android:style/Theme.NoTitleBar" AndroidManifest.xml example source code.
AndroidManifest.xml
AndroidManifest.xml
<manifest xmlns:android="//schemas.android.com/apk/res/android"
package="com.myexample.without_titlebar">
<application android:label="My app">
<activity android:name="NoTitleBar"
android:theme="@android:style/Theme.NoTitleBar"
android:screenOrientation="portrait"
android:configChanges="keyboardHidden|orientation">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
- create div with class with name e.g. circle
- create in styleSheet.css class circle
html code
<div class="circle" id="">3</div>
css code
.circle {
border-radius: 50%;
width: 50px;
height: 50px;
background: yellow;
position: absolute;
display: block;
border: 6px solid blue;
font-size: 50px;
text-align: center;
}
3
Check if in drawable folder have two picture with same name and delete one.
For example:
Check the module build folder in Android Studio for two files with same names.
For example:
image_1.jpg
image_1.png
Check the module build folder in Android Studio for two files with same names.
C:\Users\myFolder\AndroidStudioProjects\Project\yourModule\build\intermediates\res\merged\debug\drawable\
How include layout defined in other xml file into another xml file example:
res/layout/my_layout.xml into
main.xml
res/layout/my_layout.xml into
main.xml
<include layout="@layout/my_layout" android:id="@+id/idMyLayout" />
Update TextView from TimerTask, Handler, schedule, run, cancel TimerTask, Android example
public class TimerActivity extends Activity {
TimerTask mTimerTask;
final Handler handler = new Handler();
Timer t = new Timer();
TextView hTextView;
TableRow hTableRow;
Button hButton, hButtonStop;
private int nCounter = 0;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
hTextView = (TextView)findViewById(R.id.idTextView);
hButton = (Button)findViewById(R.id.idButton);
hButton.setOnClickListener(mButtonStartListener);
hButtonStop = (Button)findViewById(R.id.idButtonStop);
hButtonStop.setOnClickListener(mButtonStopListener);
} // end onCreate
View.OnClickListener mButtonStartListener = new OnClickListener() {
public void onClick(View v) {
doTimerTask();
}
};
View.OnClickListener mButtonStopListener = new OnClickListener() {
public void onClick(View v) {
stopTask();
}
};
public void doTimerTask(){
mTimerTask = new TimerTask() {
public void run() {
handler.post(new Runnable() {
public void run() {
nCounter++;
// update TextView
hTextView.setText("Timer: " + nCounter);
Log.d("TIMER", "TimerTask run");
}
});
}};
// public void schedule (TimerTask task, long delay, long period)
t.schedule(mTimerTask, 500, 3000); //
}
public void stopTask(){
if(mTimerTask!=null){
hTextView.setText("Timer canceled: " + nCounter);
Log.d("TIMER", "timer canceled");
mTimerTask.cancel();
}
}
}
Editace: 2011-09-26 20:49:42
Počet článků v kategorii: 397
Url:double-in-java-example-for-android-development
