In my android program I am wanting to cycle through different images of traffic lights on the click of a button. Whenever the app loads it starts off with an image of a red light, and when I click it I want it to change the green light, and the another click to a yellow light. This is what I have in my Java file
package com.example.trafficsimulator; import androidx.appcompat.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.ImageView; public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } public void stopButton(View view){ final Button button = findViewById(R.id.button); ImageView image = findViewById(R.id.redLightImage); button.setBackgroundColor(getResources().getColor(R.color.yellowlight)); button.setText("Go"); image.setImageResource(R.drawable.yellowlight); }
and XML file
<?xml version="1.0" encoding="utf-8"?> <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".MainActivity"> <ImageView android:id="@+id/redLightImage" android:layout_width="217dp" android:layout_height="372dp" android:layout_marginStart="97dp" android:layout_marginTop="61dp" android:layout_marginEnd="97dp" android:layout_marginBottom="298dp" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" app:srcCompat="@drawable/redlight" /> <Button android:id="@+id/button" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginStart="156dp" android:layout_marginTop="76dp" android:layout_marginEnd="167dp" android:layout_marginBottom="173dp" android:background="#BA1C1C" android:onClick="stopButton" android:text="@string/stop" android:textColor="@android:color/white" android:textColorHint="#FFFFFF" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintHorizontal_bias="1.0" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toBottomOf="@+id/redLightImage" app:layout_constraintVertical_bias="0.0" /> </androidx.constraintlayout.widget.ConstraintLayout>
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Answer
You can achieve your goal like this
Main Activity
Button buttonChangeLight; ImageView imageLight; int counter = 0; public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); buttonChangeLight = findViewById(R.id.button); imageLight = findViewById(R.id.redLightImage); //to change lights changeLight(); } //change you light public void changeLight(){ buttonChangeLight.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { if(counter == 2){ counter = 0; image.setImageResource(R.drawable.redLight); }else if(counter == 1){ counter++; image.setImageResource(R.drawable.yellowLight); }else if(counter == 2){ counter++; image.setImageResource(R.drawable.greenLight); } } }); }