Unable to run code for Simple Counter App for Android

Question

I am trying to make an application on Android Studio with the help of a tutorial. I managed to get the User Interface right and I think that I have assigned the correct buttons too. I am unable to get where I am going wrong with my code. I am new to Java and so I am unable to pinpoint the error I have committed. I am posting below the code from the files I was asked to edit in the tutorial.

package com.example.to_dolistapplication.app;

import android.os.Bundle;
import android.util.TypedValue;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.app.Activity;
import android.graphics.Color;

public class MainActivity extends Activity implements OnClickListener {

    Button btn1;
    Button btn2;
    Button btn3;
    TextView textTitle;
    EditText scoreText;
    int counter = 0;

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

        btn1 = (Button)findViewById(R.id.button);
        btn2 = (Button)findViewById(R.id.button2);
        btn3 = (Button)findViewById(R.id.button3);
        scoreText = (EditText)findViewById(R.id.textView);
        textTitle = (TextView)findViewById(R.id.editText);

        //---set on click listeners on the buttons-----
        btn1.setOnClickListener(this);
        btn2.setOnClickListener(this);
        btn3.setOnClickListener(this);

        // change font size of the text
        textTitle.setTextSize(TypedValue.COMPLEX_UNIT_SP, 24);
    }

    @Override
    public void onClick(View v) {
        if (v == btn1){
            counter++;
            scoreText.setText(Integer.toString(counter));
            scoreText.setBackgroundColor(Color.CYAN);
        }
        if (v == btn2){
            counter--;
            scoreText.setText(Integer.toString(counter));
            scoreText.setBackgroundColor(Color.GREEN);
        }

        if (v == btn3){
            counter = 0;
            scoreText.setText(Integer.toString(counter));
            scoreText.setBackgroundColor(Color.RED);
        }
    }

}
Above is the File from MainActivity.java



<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
tools:context="com.example.to_dolistapplication.app.MainActivity">


<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="+1"
    android:id="@+id/button"
    android:onClick="@string/intro"
    android:layout_below="@+id/editText"
    android:layout_toRightOf="@+id/textView"
    android:layout_marginTop="79dp"
    android:layout_alignRight="@+id/editText"
    android:layout_alignEnd="@+id/editText" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="-1"
    android:id="@+id/button2"
    android:layout_centerVertical="true"
    android:layout_alignLeft="@+id/button"
    android:layout_alignStart="@+id/button"
    android:layout_alignRight="@+id/editText"
    android:layout_alignEnd="@+id/editText" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Reset"
    android:id="@+id/button3"
    android:layout_below="@+id/button2"
    android:layout_marginTop="64dp"
    android:layout_alignRight="@+id/button2"
    android:layout_alignEnd="@+id/button2"
    android:layout_alignLeft="@+id/button2"
    android:layout_alignStart="@+id/button2" />

<TextClock
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/textClock"
    android:layout_alignParentTop="true"
    android:layout_alignParentRight="true"
    android:layout_alignParentEnd="true"
    android:layout_toRightOf="@+id/textView2"
    android:layout_alignBottom="@+id/textView2" />

<EditText
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:inputType="numberDecimal"
    android:ems="10"
    android:id="@+id/editText"
    android:layout_below="@+id/textView2"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="29dp" />

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceMedium"
    android:text="Score"
    android:id="@+id/textView"
    android:layout_alignBottom="@+id/editText"
    android:layout_toLeftOf="@+id/editText" />

This is from the file activity_main.xml.

The app, when run on emulator, displays Unfortunately Counter App has stopped. what might be the reason for the app not working? Please help.

Answer 1

**EditText** scoreText = (EditText)findViewById(R.id.textView); **TextView** textTitle = (TextView)findViewById(R.id.editText);

you missmathed with types: android:id="@+id/editText" is EditText, but in Activity you wrote his id to TextView.

And you missmathed with types: android:id="@+id/textView" is TextView, but but in Activity you wrote his id as EditText.

Answer 2

You've mismatched id's in onCreate() method. Use the debug mode or just look at your console output