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Josh Gold
12,207 PointsCompile error: "Lambda expressions are not supported at this language level."
Just wondering how I can convert this code to be supported. I didn't have a lot of luck trying to get lambda expressions from Java 8 to work for me. I have 3 instances of lambda expressions (line 33, line 46 and line 59.
Also this is based on the code for the Fun Facts training module in Tree House.
package com.joshbgold.spanishwordoftheday;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.View;
import android.widget.Button;
import android.widget.RelativeLayout;
import android.widget.TextView;
public class MainActivity extends ActionBarActivity {
private PirateWords mPirateWords = new PirateWords();
private ColorRandomizer mColorRandomizer = new ColorRandomizer();
private int currentNumber = 0;
private boolean stayHere = true; //while true, will use to keep running the program
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//Declare our view variables & assign views from the layout file
final TextView pirateLabel = (TextView) findViewById(R.id.pirateView);
final Button pirateButton = (Button) findViewById(R.id.pirateButton);
final Button pirateAnswerButton = (Button) findViewById(R.id.pirateAnswerButton);
final Button exitButton = (Button) findViewById(R.id.exitButton);
final RelativeLayout relativeLayout = (RelativeLayout) findViewById(R.id.relativeLayout);
do {
currentNumber = mPirateWords.getRandomNumber();
View.OnClickListener listener = (view) -> {
String fact = mPirateWords.getPirateWord(currentNumber);
//Update the label with our dynamic fact
pirateLabel.setText(fact);
int color = mColorRandomizer.getColor();
relativeLayout.setBackgroundColor(color);
pirateButton.setLinkTextColor(color);
};
View.OnClickListener listenerAnswer = (view) -> {
String fact = mPirateWords.getPirateAnswer(currentNumber);
//Update the label with our dynamic fact
pirateLabel.setText(fact);
int color = mColorRandomizer.getColor();
relativeLayout.setBackgroundColor(color);
pirateButton.setLinkTextColor(color);
};
View.OnClickListener walkThePlank = (view) -> {
System.exit(0);
};
pirateButton.setOnClickListener(listener);
pirateAnswerButton.setOnClickListener(listenerAnswer);
exitButton.setOnClickListener(walkThePlank);
} while (stayHere); //user has not walked the plank
}
}
1 Answer
Josh Gold
12,207 PointsOk I replaced the lambda expressions (lambda expressions are shown in the original code as arrows). Java 7 SDK does not support lambda expressions it seems. As a beginner in Java, I didn't want to get mired into trying to figure out how to get Java 8 working with Android Studio. I actually spent about 20 minutes working on setting up Java 8, and then I decided to take a break and come back to this later.
The lambda expressions are actually really cool because they require far less code. Maybe they will be more mainstream in 6-12 months, and that style of coding will be second nature for all of us.
Well today I replaced the lambda expressions. I will show you an example of the old code and the new working code:
Old code with lambdas, requires Java 8
View.OnClickListener walkThePlank = view -> {
System.exit(0);
};
New code without lambdas
View.OnClickListener walkThePlank = new View.OnClickListener() {
@Override
public void onClick (View view) {
System.exit(0);
}
};