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How to sum of arrays of floating point numbers

How to sum of arrays of floating point numbers..as the results from distance that the array float come from results Location.distanceBetween(latStart, longStart, latB, longB, results); method in Google maps api ,,i'm trying with this, but at some point it decrease, it should always incrementing. what am i missing?
EDIT:
public float total(ArrayList<LatLng> listPoints){
if(listPoints.size()==2){
listPoints.clear();
}
listPoints.add(latLng);
float[] results = new float[2];
float sum = 0.0f;
for (int z = 0; z < listPoints.size(); z++) {
if(listPoints.size() == 1){
latStart = listPoints.get(z).latitude;
longStart = listPoints.get(z).longitude;
Toast.makeText(this, "listPoint 1", Toast.LENGTH_SHORT).show();
}else if(listPoints.size() == 2){
latB = listPoints.get(z).latitude;
longB = listPoints.get(z).longitude;
Toast.makeText(this, "listPoint 2", Toast.LENGTH_SHORT).show();
}
Location.distanceBetween(latStart, longStart, latB, longB, results);
sum+=results[0];
}
tvJarakTotal.setText(sum + "");
return sum;
}
EDIT:
the distance came from onLocationChanged() method as the user location is moving,
EDIT:
I Finally find the solution myself, by creating some trick using sharedPreference. but the accepted answer is correct to the question.

It is not entirely clear what you think you were doing in your code above. First of all, the Location#distanceBetween API takes in a pair of latitude longitude values, i.e. two geographic points, and then returns the distance between them in results[0] (q.v. the documentation).
Next, it isn't clear what the starting and ending points are intended to be. I answered below under the assumption that the listPoints are one set of points (either starting or ending), and the vales latB and longB are a fixed set of starting/ending points. Without this assumption, an answer really can't be given here.
public float total(ArrayList<LatLng> listPoints) {
float[] results;
float sum = 0.0f;
for (int z=0; z < listPoints.size(); z++) {
double latStart = listPoints.get(z).latitude;
double longStart = listPoints.get(z).longitude;
Location.distanceBetween(latStart, longStart, latB, longB, results);
sum += results[0];
tvJarak.setText(sum + "");
}
return sum;
}

Please take a look your code carefully.
float[] results = new float[listPoints.size()];
results variable is declared as a local variable but it's not initialized with any values yet.
In this case it has random value.
That's why sum gives random minus value.

float[] results = new float[listPoints.size()];
In this case your result array stored size of the listPoints array. After that you are trying to iterate result array by using listPointers array size.
Assume your :- float [] results = new [2];
Now you try to add up same value again and again inside you for a loop. Please make sure your scenario is correct or not.
You should store api date someware inside your code. like this:
lat = listPoints.get(z).latitude;
long = listPoints.get(z).longitude;
if you want you can do it like this,
public float total(ArrayList<LatLng> listPoints) {
float[] results;
float sum = 0.0f;
float lat = 0.0f, long = 0.0f;
for (int z=0; z < listPoints.size(); z++) {
lat = listPoints.get(z).latitude;
long = listPoints.get(z).longitude;
Location.distanceBetween(lat, long, latB, longB, results);
sum+=results[z];
tvJarak.setText(sum + "");
}
return sum;
}

Why I can not see the double value in a textView

Why I can not see the double value in a textView?
textView = (TextView) findViewById(R.id.textView);
double x = 5/2;
textView.setText(String.valueOf(x)); // I see this result as 2.0 and not as the 2.5

In Android TextView, you can use in that way,
Use Double.toString:
result = number1/number2
String stringdouble= Double.toString(result);
textview1.setText(stringdouble));
or you can use the NumberFormat:
Double result = number1/number2;
NumberFormat nm = NumberFormat.getNumberInstance();
textview1.setText(nm.format(result));
To force for 3 units precision:
private static DecimalFormat REAL_FORMATTER = new DecimalFormat("0.###");
textview1.setText(REAL_FORMATTER.format(result));

You are seeing 2.0 because 5/2 is integer division. Change the line to double x = 5.0/2; or similar.
See this question for more.

This should work double x = ((double) 5) /2.

How to convert double to int in Android? [duplicate]

This question already has answers here:
Converting double to integer in Java
(3 answers)
Closed 6 years ago.
I just wants to convert from double to int in my UI i am rendering as a double but for the backend i want convert to integer.
Double d = 45.56;
OutPut = 4556;
Please can anybody tell me how to get the value in this format.

Try this way, Courtesy
double d = 45.56;
int i = (int) d;
For better info you can visit converting double to integer in java

If you just want to convert the Double to int,
Double D = 45.56;
int i = Integer.valueOf(D.intValue());
//here i becomes 45
But if you want to remove all decimal numbers and count the whole value,
//first convert the Double to String
double D = 45.56;
String s = String.valueOf(D);
// remove all . (dots) from the String
String str = str.replace(".", "");
//Convert the string back to int
int i = Integer.parseInt(str);
// here i becomes 4556

You are using the Double as object(Wrapper for type double). You need to fist convert it in to string and then int.
Double d=4.5;
int i = Integer.parseInt(d.toString());
If you want it in the Integer Object Wrapper then can be written as
Integer i = Integer.parseInt(d.toString());
EDIT
If you want to get the desired result -
You can go like this-
Double d = 4.5;
double tempD = d;
int tempI = (int) tempD * 100;
//Integer i = tempI;

try this code
double d = 45.56;
String temp = String.valueOf(d);
if (temp .contains(".")) {
temp = temp .replaceAll(".","");
}
// After if you want to convert to integer then
int output = Integer.parseInt(temp);

how can i reduce the digits after the decimal point?

private void findLatLongDistance(double prelat,double prelon,double lat,double lon) {
// TODO Auto-generated method stub
try{
double prelatval=prelat;
double prelongval=prelon;
double curlat=lat;
double curlon=lon;
Log.w("inside finalatlon...........................","the daya");
if(prelatval>0.0 && prelongval>0.0 && lat>0.0 && lat>0.0 && gpsdataElements.Speed>0.0){
float distance2 = getDistance(prelatval,prelongval,curlat,curlon);
odometer_sum= (distance2/1000 );
// for maximum value after decimal
//df.setMaximumFractionDigits(0);
//rounding the km digits after decimal
Math.round(distance2);
//for minimum distance after decimal
df.setMinimumFractionDigits(2);
df.format(odometer_sum);
gpsdataElements.Distance = gpsdataElements.Distance + odometer_sum;
}
}catch(Exception e){
e.printStackTrace();
}
}
here is my code. I want distance(i.e km)value digits after decimal is two digits. Example i want km value in 1.54km not like 1.4568923km. How to get like this.I tried a lot for that but i din't got any possible solution. Any one know please help me.

In more simple ways you can do this by using this :
double roundOff = Math.round(yourValue * 100.0) / 100.0;
Otherwise you can also do this as
String.format("%.2f", d)

DecimalFormat formatter = new DecimalFormat(".##");
String s = formatter.format(value);

use this code to format text in two digits after decimal.
double i2=i/60000;
tv.setText(new DecimalFormat("##.##").format(i2));

double roundof = Math.round(a * 100.0) / 100.0;
output:roundoff(eg:12).oo
12.00

Something like this :
String.format("%.2f", distance);

Make function like this pass the value as per you requirment and return value as per your requirment first function will take float value and after decimal it put 3 value as per argument if you want to change decimal value then you can change 3,2,4 etc... Second function will take String value and round it in 3 decimal point:
public static BigDecimal round(float d) {
BigDecimal bd = new BigDecimal(Float.toString(d));
bd = bd.setScale(3, BigDecimal.ROUND_HALF_UP);
return bd;
}
public static BigDecimal round(String d) {
BigDecimal bd = new BigDecimal(Float.parseFloat(d));
bd = bd.setScale(3, BigDecimal.ROUND_HALF_UP);
return bd;
}

How get battery temperature with decimal?

How can i get the battery temperature with decimal? Actually i can calculate it with
int temp = intent.getIntExtra(BatteryManager.EXTRA_TEMPERATURE,0);
But in this way the result will be for example 36 °C.. I want something that show me 36.4 °C How can i do?

Google says here :
Extra for ACTION_BATTERY_CHANGED: integer containing the current battery temperature.
The returned value is an int representing, for example, 27.5 Degrees Celcius as "275" , so it is accurate to a tenth of a centigrade. Simply cast this to a float and divide by 10.
Using your example:
int temp = intent.getIntExtra(BatteryManager.EXTRA_TEMPERATURE,0);
float tempTwo = ((float) temp) / 10;
OR
float temp = ((float) intent.getIntExtra(BatteryManager.EXTRA_TEMPERATURE,0) / 10;
You don't need to worry about the 10 as an int since only one operand needs to be a float for the result to be one too.

public static String batteryTemperature(Context context)
{
Intent intent = context.registerReceiver(null, new IntentFilter(Intent.ACTION_BATTERY_CHANGED));
float temp = ((float) intent.getIntExtra(BatteryManager.EXTRA_TEMPERATURE,0)) / 10;
return String.valueOf(temp) + "*C";
}

That's the only way I know you can get the battery temperature, and is always an int.
According to documentation:
public static final String EXTRA_TEMPERATURE
Extra for ACTION_BATTERY_CHANGED: integer containing the current battery
temperature.
But you can divide by 10.0f to get one decimal.
float ftemp = temp/10.0f;