By Barry Burd

Part of Java Programming for Android Developers For Dummies Cheat Sheet

“I have to create an enhanced for statement. Can someone remind me how to code an enhanced for statement? And while you’re at it, how can I catch an exception? Where can I find all that Java stuff quickly?”

You find all that stuff right here in this cheat sheet. The Java program in this cheat sheet contains snippets of code representing many of Java’s most important language features, including switches, strings, breaks, if . . . else statements, and arrays. As an added bonus, the program even contains a sly reference to that classic Marx Brothers movie, Animal Crackers. Enjoy!
package com.example.cheetsheet;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.view.View;

import android.widget.EditText;

import android.widget.TextView;

import android.widget.Toast;



import java.util.ArrayList;



public class MainActivity extends AppCompatActivity {

EditText editText;

TextView textView;

int myInt = 42;

double myDouble = 27649.00;

boolean myBoolean = true;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

editText = (EditText) findViewById(R.id.editText);

textView = (TextView) findViewById(R.id.textView);

}

 

public void onButtonClick(View view) {

char myChar = 'B';

String myString = "Hello";

ArrayList<String> myList = new ArrayList<String>();

String[] myArray = {"This ", "is ", "an ", "array."};

textView.append("myInt is " + Integer.toString(myInt) + "\n");

textView.append("myChar is " + Character.toString(myChar) + "\n");

Toast.makeText(this, myString, Toast.LENGTH_LONG).show();

textView.append("myInt + myString + \" \" + myDouble is ");

textView.append(myInt + " " + myString + " " + myDouble + "\n");

try {

myInt = Integer.parseInt(editText.getText().toString());

} catch (NumberFormatException e) {

e.printStackTrace();

}

textView.append("myInt is ");

if (myInt < 5) {

textView.append("small\n");

} else {

textView.append("large\n");

}

 

textView.append("Is myBoolean true? ");

if (myBoolean) {

textView.append("Yes\n");

}

 

textView.append("myInt is ");

switch (myInt) {

case 1:

textView.append("one\n");

break;

case 2:

case 3:

textView.append("a small number\n");

break;

default:

textView.append("a lot\n");

break;

}

for (int i = 0; i < 10; i++) {

textView.append(Integer.toString(i));

textView.append(" ");

}

textView.append("\n");

int i = 0;

while (i < 10) {

textView.append(i++ + " ");

}

textView.append("\n");

int j = 0;

do {

textView.append(Integer.toString(j++));

textView.append(j <= 9 ? ", " : "");

} while (j < 10);

textView.append("\n");

myList.add("Three ");

myList.add("cheers ");

myList.add("for ");

myList.add("Captain ");

myList.add("Spaulding");

for (String word : myList) {

textView.append(word);

}

textView.append("\n");

textView.append(addPeriod("Spaulding"));

textView.append("\n");

for (int n = 0; n < myArray.length; n++) {

textView.append(myArray[n]);

}

textView.append("\n");

}

 

String addPeriod(String string) {

return string + ".";

}

 

}