Android If statement fails

Question

I'm using this simple if/else statement to check which RadioButton is selected and set the text of a TextView regarding the selection. Well, for the first two cases (if rb1.isChecked() and if rb2.isChecked()) the code executes correctly and it just makes a calculation of two numbers. However, when the third case comes out (!rb1.isChecked() && !rb2.isChecked()) the application crashes. What is wrong?

        if (rb1.isChecked()) {
        int sum = x + y;
        String result = String.valueOf(sum);
        tv3.setText(result);
    } else if (rb2.isChecked()) {
        int rest = x - y;
        String result = String.valueOf(rest);
        tv3.setText(result);
    } else if (!rb1.isChecked() && !rb2.isChecked()){
        tv3.setText("Select an option!");
    }

UPDATE:
The Manifest.xml:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.logixor.advancedcalc">

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity android:name=".MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>

</manifest>

The MainActivity.java:

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.RadioButton;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
public EditText et1,et2;
public TextView tv3;
public RadioButton rb1,rb2;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    et1=(EditText)findViewById(R.id.et1);
    et2=(EditText)findViewById(R.id.et2);
    tv3=(TextView)findViewById(R.id.tv3);
    rb1=(RadioButton)findViewById(R.id.rb1);
    rb2=(RadioButton)findViewById(R.id.rb2);
}

public void calc(View view) {
    String valA = et1.getText().toString();
    String valB = et2.getText().toString();
    int x = Integer.parseInt(valA);
    int y =Integer.parseInt(valB);

    if (rb1.isChecked()) {
        int sum = x + y;
        String result = String.valueOf(sum);
        tv3.setText(result);
    } else if (rb2.isChecked()) {
        int rest = x - y;
        String result = String.valueOf(rest);
        tv3.setText(result);
    }

    if (!rb1.isChecked() && !rb2.isChecked()){
        tv3.setText("Select an option!");
    }
}
}

The activity_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.logixor.advancedcalc.MainActivity">

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/textNumber"
    android:id="@+id/tv2"
    android:layout_marginTop="27dp"
    android:layout_below="@+id/et1"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true" />

<EditText
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:inputType="number"
    android:ems="10"
    android:id="@+id/et2"
    android:layout_below="@+id/tv2"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"
    android:hint="@string/writeHere" />

<RadioGroup
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="29dp"
    android:padding="20dp"
    android:layout_below="@+id/et2"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"
    android:id="@+id/rg1">

    <RadioButton
        android:text="@string/sum"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/rb1"
        android:layout_weight="1" />

    <RadioButton
        android:text="@string/rest"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/rb2"
        android:layout_weight="1" />

</RadioGroup>

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/textNumber"
    android:layout_marginTop="25dp"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"
    android:id="@+id/tv1" />

<Button
    android:text="@string/calc"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/button"
    android:layout_alignBottom="@+id/rg1"
    android:layout_marginBottom="27dp"
    android:layout_alignParentRight="true"
    android:layout_alignParentEnd="true"
    android:layout_toRightOf="@+id/rg1"
    android:layout_toEndOf="@+id/rg1"
    android:onClick="calc" />

<TextView
    android:text="@string/result"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="19dp"
    android:id="@+id/tv3"
    android:textSize="24sp"
    android:layout_below="@+id/rg1"
    android:textAlignment="center" />

<EditText
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:inputType="number"
    android:ems="10"
    android:layout_marginTop="8dp"
    android:id="@+id/et1"
    android:hint="@string/writeHere"
    android:layout_below="@+id/tv1"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true" />

</RelativeLayout>

The strings.xml:

<resources>
<string name="app_name">AdvancedCalc</string>
<string name="textNumber">Number</string>
<string name="writeHere">Write number here...</string>
<string name="result">Result</string>
<string name="calc">CALCULATE</string>
<string name="sum">Sum</string>
<string name="rest">Rest</string>
</resources>

The FATAL ERROR from the logcat:

E/AndroidRuntime: FATAL EXCEPTION: main 
Process: com.logixor.advancedcalc, PID: 23911
java.lang.IllegalStateException: Could not execute method for android:onClick
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:293)
at android.view.View.performClick(View.java:4640)
at android.view.View$PerformClick.run(View.java:19425)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:146)
at android.app.ActivityThread.main(ActivityThread.java:5593)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1283)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
at android.view.View.performClick(View.java:4640) 
at android.view.View$PerformClick.run(View.java:19425) 
at android.os.Handler.handleCallback(Handler.java:733) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:146) 
at android.app.ActivityThread.main(ActivityThread.java:5593) 
at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:515) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1283) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099) 
at dalvik.system.NativeStart.main(Native Method) 
Caused by: java.lang.NumberFormatException: Invalid int: ""
at java.lang.Integer.invalidInt(Integer.java:137)
at java.lang.Integer.parseInt(Integer.java:358)
at java.lang.Integer.parseInt(Integer.java:331)
at com.logixor.advancedcalc.MainActivity.calc(MainActivity.java:30)
at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:515) 
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288) 
at android.view.View.performClick(View.java:4640) 
at android.view.View$PerformClick.run(View.java:19425) 
at android.os.Handler.handleCallback(Handler.java:733) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:146) 
at android.app.ActivityThread.main(ActivityThread.java:5593) 
at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:515) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1283) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099) 
at dalvik.system.NativeStart.main(Native Method)

Onik · Accepted Answer · 2016-10-15T21:06:43.967

1

Caused by: java.lang.NumberFormatException: Invalid int: "" means that text in EditText is empty, so you get the exception at Integer.parseInt() inside of the calc() function. Check if it's empty with TextUtils.isEmpty(). Additionally you might make use of TextUtils.isDigitsOnly().

EDIT

With the android:inputType="number" xml attribute of EditText you'll make it to accept only digits.

edited Oct 15 '16 at 21:06

answered Oct 15 '16 at 20:20

Onik

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score 0 · Answer 2 · answered Oct 15 '16 at 17:27

1)use try catch statement to understand the error!
maybe the tv is equal to null .
2) no need to use else if (!rb1.isChecked() && !rb2.isChecked()), just use else{}
try this:

    try{
       if(tv == null)
       {
          Toast.makeText(getBaseContext(),"tv is null", 
                Toast.LENGTH_SHORT).show();
          return;
       }
    if (rb1.isChecked()) {
            int sum = x + y;
            String result = String.valueOf(sum);
            tv3.setText(result);
        } else if (rb2.isChecked()) {
            int rest = x - y;
            String result = String.valueOf(rest);
            tv3.setText(result);
        } else{
            tv3.setText("Select an option!");
        }
    }
    catch(Exception e)
    {
      Toast.makeText(getBaseContext(),"Err:"+r.toString(), 
                Toast.LENGTH_SHORT).show();
    }

Android If statement fails

2 Answers2