I have run into an issue that closes my app upon switching activities. I don't mean for this to be a "fix my code" question, but if it seems that way, let me know what I can do to fix that. I am going to explain what the program does, and what it is supposed to do, and hopefully the good people of StackExchange can help me figure out a fix.
Purpose: The code is supposed to be for a sumple game I designed so that I could become acquainted with android studio (I already know some Java, and wanted to put it to use). The game lands the user on a splash screen (I don't think that code is relevant, but if you wish for me to include it, I will), then once the user taps, they are taken to the "GameActivity" (code below). My code plays a "ready, set, go" intro, then the game begins. The screen changes between green, yellow, and red at random intervals. If the player taps while the screen is green, they earn 1 point. If the screen is yellow, they earn double. Tapping on a red screen will lose them the game. The colors switch at shorter and less predictable intervals over time.
What is actually happening: As soon as I switch activities, I am given an error message. I was able to switch activities and the app functioned properly when I only had the "intro" code, but after adding the rest, the issue has presented itself. In Android Studio, I have no warnings, errors of any kind, or suggestions (on the right side where android studio helps you fix your code). I don't think it is a problem with the manifest or XML because they were working fine at an earlier stage.
package com.nateolson.taptap;
import android.graphics.Color;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.widget.TextView;
import java.util.concurrent.ThreadLocalRandom;
public class GameActivity extends AppCompatActivity {
final Handler introHandler = new Handler();
boolean gameActive = false;
final View layout = findViewById(R.id.layout);
//for main method only
int playerPoints = 0;
long timeMinMillis = 1000;
long timeMaxMillis = 3000;
long randTime;
long switchReferenceTime = System.currentTimeMillis();
String colorStage = "green";
//for main method only
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_game);
final TextView readyMessageView = (TextView) findViewById(R.id.readyTV);
final TextView getSetMessageView = (TextView) findViewById(R.id.setTV);
getSetMessageView.setVisibility(View.INVISIBLE);
final TextView goMessageView = (TextView) findViewById(R.id.goTV);
goMessageView.setVisibility(View.INVISIBLE);
layout.setBackgroundColor(Color.RED);
Runnable switchToYellow = new Runnable() {
@Override
public void run() {
readyMessageView.setVisibility(View.GONE);
layout.setBackgroundColor(Color.YELLOW);
getSetMessageView.setVisibility(View.VISIBLE);
}
};
Runnable switchToGreen = new Runnable() {
@Override
public void run() {
getSetMessageView.setVisibility(View.GONE);
layout.setBackgroundColor(Color.GREEN);
goMessageView.setVisibility(View.VISIBLE);
}
};
Runnable gameRunnable = new Runnable() {
public void run() {
gameActive = true;
}
};
introHandler.postDelayed(switchToYellow, 1500);
introHandler.postDelayed(switchToGreen, 3000);
introHandler.postDelayed(gameRunnable, 4500);
main();
}
public void main() {
while(gameActive) {
randTime = ThreadLocalRandom.current().nextLong(timeMinMillis, timeMaxMillis);
if (System.currentTimeMillis() - switchReferenceTime >= randTime) {
switch (colorStage) {
case "green":
colorStage = "yellow";
break;
case "yellow":
colorStage = "red";
break;
case "red":
colorStage = "green";
break;
}
switchReferenceTime = System.currentTimeMillis();
}
switch (colorStage) {
case "green": layout.setBackgroundColor(Color.GREEN);
case "yellow": layout.setBackgroundColor(Color.YELLOW);
case "red": layout.setBackgroundColor(Color.RED);
}
timeMinMillis -= .03 * timeMinMillis;
timeMaxMillis -= .02 * timeMaxMillis;
layout.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
switch (colorStage) {
case "green": playerPoints++;
case "yellow": playerPoints += 2;
case "red":
playerPoints = 0;
gameActive = false;
}
return false;
}
});
}
Java for the previous activity (splash screen):
package com.nateolson.taptap;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void onSplashPageClick(View view) {
Intent intent = new Intent(this, GameActivity.class);
startActivity(intent);
finish();
}
}
GameActivity XML:
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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"
android:id="@+id/layout"
tools:context="com.nateolson.taptap.GameActivity">
<TextView
android:id="@+id/readyTV"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:fontFamily="monospace"
android:text="Ready?"
android:textAlignment="center"
android:textAllCaps="false"
android:textAppearance="@style/TextAppearance.AppCompat.Display2"
android:textColor="@android:color/background_light"
android:visibility="visible"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="@+id/setTV"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:fontFamily="monospace"
android:text="Set... "
android:textAlignment="center"
android:textAppearance="@style/TextAppearance.AppCompat.Display2"
android:textColor="@android:color/background_light"
android:visibility="visible"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintHorizontal_bias="0.502"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="@+id/goTV"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:fontFamily="monospace"
android:text="GO!"
android:textAlignment="center"
android:textAppearance="@style/TextAppearance.AppCompat.Display2"
android:textColor="@android:color/background_light"
android:visibility="visible"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>
XML for MainActivity:
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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="com.nateolson.taptap.MainActivity"
android:gravity="center"
android:background="#679933"
android:orientation="vertical"
android:onClick="onSplashPageClick"
>
<ImageView
android:layout_height="212dp"
android:layout_width="288dp"
android:src="@mipmap/splash_screen_logo"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
android:layout_marginTop="31dp" />
<TextView
android:fontFamily="sans-serif-thin"
android:textSize="50dp"
android:textColor="#274D00"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="T a p T a p"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
tools:layout_constraintTop_creator="1"
tools:layout_constraintBottom_creator="1"
app:layout_constraintHorizontal_bias="0.426"
app:layout_constraintVertical_bias="0.537" />
</android.support.constraint.ConstraintLayout>
Manifest:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.nateolson.taptap">
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
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>
<activity android:name=".GameActivity"
android:parentActivityName=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.GAME" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
</application>
</manifest>
I'm not asking for a handout, and I don't just want someone to fix my code for me. I want to figure out a solution, then learn what I did wrong. I have also tried fixes mentioned in similar posts, to no avail. This is not the same as the "Unfortunately MyApp has stopped" question because I have provided my own code which has not been fixed by any of the solutions suggested in that thread. That question seems very generic and non-specific to any certain scenario as well.
Thank you,
Nate Olson
