Help me making this simple calculation in my extension

luv.ak.tech · November 17, 2020, 5:58am

hammerhai:

import com.google.appinventor.components.runtime.util.YailList;
import java.lang.NumberFormatException;
import java.util.Arrays;
import java.util.List;

...

// Place this inside of your extension class
@SimpleFunction
public int LoopOverList(YailList list) {
  List listOfNumbers = Arrays.asList(list.toArray());
  int finalResult = 0;

  for (Object itemInList : listOfNumbers) {
    try {
      finalResult += Integer.parseInt(itemInList);
    } catch(NumberFormatException nfe) {
      // Not a number
      nfe.printStackTrace();
    }
  }

  return finalResult;
}

so is this correct or not please tell

hammerhai · November 17, 2020, 5:59am

Ohhhhh I know why now, an Object cannot be passed to Integer.parseInt()… To fix it, just change that piece to Integer.parseInt(itemInList.toString()). Or you can change the lines to the new lines…

list.toArray() can be switched to list.toStringArray(), BUT Object itemInList must be changed to String itemInList… Nothing else must be changed… OR,

Just change Integer.parseInt(itemInList) to Integer.parseInt(itemInList.toString()) as I said first… Whichever seems easier to you.

@luv.ak.tech below would be proper.

import com.google.appinventor.components.runtime.util.YailList;
import java.lang.NumberFormatException;
import java.util.Arrays;
import java.util.List;

...

// Place this inside of your extension class
@SimpleFunction
public int LoopOverList(YailList list) {
  List listOfNumbers = Arrays.asList(list.toStringArray());
  int finalResult = 0;

  for (String itemInList : listOfNumbers) {
    try {
      finalResult += Integer.parseInt(itemInList);
    } catch(NumberFormatException nfe) {
      // Not a number
      nfe.printStackTrace();
    }
  }

  return finalResult;
}

Thank you for pointing that out @Srrazmi!

luv.ak.tech · November 17, 2020, 6:05am

sorry i am asking too many questions
because i started making extensions just yesterday

what does this do?

Peter · November 17, 2020, 6:07am

You also have multiple accounts on the same ip adress. You are only allowed to have one on the community. Which one should i delete?

luv.ak.tech · November 17, 2020, 6:07am

i think i have only one more account
you can delete my @Niraj_Kumar account

hammerhai · November 17, 2020, 6:09am

It basically logs the error to system logs… I think, as my knowledge goes with printStackTrace and system logs. Though it would only occur if an item was not a number! You can remove it if you’d like, just don’t break; the list.

luv.ak.tech · November 17, 2020, 6:12am

hammerhai:

import com.google.appinventor.components.runtime.util.YailList;
import java.lang.NumberFormatException;
import java.util.Arrays;
import java.util.List;

...

// Place this inside of your extension class
@SimpleFunction
public int LoopOverList(YailList list) {
  List listOfNumbers = Arrays.asList(list.toStringArray());
  int finalResult = 0;

  for (String itemInList : listOfNumbers) {
    try {
      finalResult *= Integer.parseInt(itemInList);
    } catch(NumberFormatException nfe) {
      // Not a number
      nfe.printStackTrace();
    }
  }

  return finalResult;
}

if we need to make the same thing just do mutiply instead of plus shall we need to do like this?

hammerhai · November 17, 2020, 6:14am

If you want to multiply finalResult by Integer.parseInt(itemInList) then yes. But it wouldn’t really work because finalResult = 0 and well all know that 0 multiplied by another number still equals 0, so you’d probably want to change finalResult to finalResult = 1.

luv.ak.tech · November 17, 2020, 6:17am

thank you for the help
@hammerhai
@Srrazmi
@Peter
@golumaths100

luv.ak.tech · November 17, 2020, 6:26am

help me there is an error coming
/projects/goldv2/appinventor-sources/appinventor/build.xml:35: The following error occurred while executing this line:
/projects/goldv2/appinventor-sources/appinventor/build-common.xml:372: The following error occurred while executing this line:
/projects/goldv2/appinventor-sources/appinventor/components/build.xml:141: The following error occurred while executing this line:
/projects/goldv2/appinventor-sources/appinventor/build-common.xml:118: Compile failed; see the compiler error output for details.

Mohamed_Tamer · November 17, 2020, 6:35am

That isn’t an error , you might share the whole error.

hammerhai · November 17, 2020, 6:37am

@luv.ak.tech can you share the error? That only tells me that the build failed.

luv.ak.tech · November 17, 2020, 6:50am

ok i will share

luv.ak.tech · November 17, 2020, 6:52am

Buildfile: /projects/goldv2/appinventor-sources/appinventor/build.xml

extensions:

clean:

init:

common_CommonUtils:

init:

CommonUtils:

common_CommonVersion:

init:

CommonVersion:
[exec] Result: 128
[exec] Result: 128

CopyToRunLibDir:

components_AndroidRuntime:

init:

CommonConstants:
[javac] Compiling 6 source files to /projects/goldv2/appinventor-sources/appinventor/components/build/classes/CommonConstants
[javac] warning: [options] bootstrap class path not set in conjunction with -source 1.7
[javac] 1 warning

HtmlEntities:

common_CommonVersion:

init:

CommonVersion:
[exec] Result: 128
[exec] Result: 128

AndroidRuntime:
[javac] Compiling 332 source files to /projects/goldv2/appinventor-sources/appinventor/components/build/classes/AndroidRuntime
[javac] warning: [options] bootstrap class path not set in conjunction with -source 1.7
[javac] /projects/goldv2/appinventor-sources/appinventor/components/src/com/appybuilder/contact2niraj/Maths_extension/Maths_extension.java:58: error: cannot find symbol
[javac] public int LoopOverList(YailList list) {
[javac] ^
[javac] symbol: class YailList
[javac] location: class Maths_extension
[javac] /projects/goldv2/appinventor-sources/appinventor/components/src/com/appybuilder/contact2niraj/Maths_extension/Maths_extension.java:75: error: cannot find symbol
[javac] public int LoopOverList(YailList list) {
[javac] ^
[javac] symbol: class YailList
[javac] location: class Maths_extension
[javac] /projects/goldv2/appinventor-sources/appinventor/components/src/com/appybuilder/contact2niraj/Maths_extension/Maths_extension.java:62: error: incompatible types: Object cannot be converted to String
[javac] for (String itemInList : listOfNumbers) {
[javac] ^
[javac] /projects/goldv2/appinventor-sources/appinventor/components/src/com/appybuilder/contact2niraj/Maths_extension/Maths_extension.java:79: error: incompatible types: Object cannot be converted to String
[javac] for (String itemInList : listOfNumbers) {
[javac] ^
[javac] Note: Some input files use or override a deprecated API.
[javac] Note: Recompile with -Xlint:deprecation for details.
[javac] Note: Some input files use unchecked or unsafe operations.
[javac] Note: Recompile with -Xlint:unchecked for details.
[javac] 4 errors
[javac] 1 warning

BUILD FAILED
/projects/goldv2/appinventor-sources/appinventor/build.xml:35: The following error occurred while executing this line:
/projects/goldv2/appinventor-sources/appinventor/build-common.xml:372: The following error occurred while executing this line:
/projects/goldv2/appinventor-sources/appinventor/components/build.xml:141: The following error occurred while executing this line:
/projects/goldv2/appinventor-sources/appinventor/build-common.xml:118: Compile failed; see the compiler error output for details.

Total time: 7 seconds
lList list) {
[javac] ^
[javac] symbol: class YailList
[javac] location: class Maths_extension
[javac] /projects/goldv2/appinventor-sources/appinventor/components/src/com/appybuilder/contact2niraj/Maths_extension/Maths_extension.java:75: error: cannot find symbol
[javac] public int LoopOverList(YailList list) {
[javac] ^
[javac] symbol: class YailList
[javac] location: class Maths_extension
[javac] /projects/goldv2/appinventor-sources/appinventor/components/src/com/appybuilder/contact2niraj/Maths_extension/Maths_extension.java:62: error: incompatible types: Object cannot be converted to String
[javac] for (String itemInList : listOfNumbers) {
[javac] ^
[javac] /projects/goldv2/appinventor-sources/appinventor/components/src/com/appybuilder/contact2niraj/Maths_extension/Maths_extension.java:79: error: incompatible types: Object cannot be converted to String
[javac] for (String itemInList : listOfNumbers) {
[javac] ^
[javac] Note: Some input files use or override a deprecated API.
[javac] Note: Recompile with -Xlint:deprecation for details.
[javac] Note: Some input files use unchecked or unsafe operations.
[javac] Note: Recompile with -Xlint:unchecked for details.
[javac] 4 errors
[javac] 1 warning

BUILD FAILED
/projects/goldv2/appinventor-sources/appinventor/build.xml:35: The following error occurred while executing this line:
/projects/goldv2/appinventor-sources/appinventor/build-common.xml:372: The following error occurred while executing this line:
/projects/goldv2/appinventor-sources/appinventor/components/build.xml:141: The following error occurred while executing this line:
/projects/goldv2/appinventor-sources/appinventor/build-common.xml:118: Compile failed; see the compiler error output for details.

Total time: 7 seconds

hammerhai · November 17, 2020, 6:53am

Do you have import com.google.appinventor.components.runtime.util.YailList;?

luv.ak.tech · November 17, 2020, 6:54am

sorry i forgot to add that

hammerhai · November 17, 2020, 6:55am

hammerhai:

@SimpleFunction
public int LoopOverList(YailList list) {
  List listOfNumbers = Arrays.asList(list.toStringArray());
  int finalResult = 0;

  for (String itemInList : listOfNumbers) {
    try {
      finalResult += Integer.parseInt(itemInList);
    } catch(NumberFormatException nfe) {
      // Not a number
      nfe.printStackTrace();
    }
  }

  return finalResult;
}

After you add the class, make sure the function looks like that.

luv.ak.tech · November 17, 2020, 6:57am

it looks like this

hammerhai · November 17, 2020, 7:06am

~~Are you ok?~~

Oop, they went offline

luv.ak.tech · November 17, 2020, 7:53am

its still showing error