ソフトウェアエンジニアの技術ブログ：Software engineer tech blog

int unreadEmails = “10”; -> quotes should be string.
int unreadEmails = 10; -> should be camel case
intunreadEmails = 10; -> needed space and this one is definitely problem

integer number; computer recognize int
int int; variable name cannot be a java keyword
int integer;

String currentlyPlaying = “Pinocchio – Penguin Prison”;
string currentlyPlaying = “Fantasy – Alina Baraz & Galimatias”;
String currentlyPlaying = “Call Me Up – Chromeo”

String-name = “Katherine”
String “name” = “Kunal”;
String name on profile = “Lyla”;

int weekday = 5;
int weekend = 9;
int optimalHours = 7*8;
int actualHours = weekday;
actualHours = actualHours + weekend*2;
int solution = optimalHours – actualHours;
display(solution)
solution:-33

public class MainActivity extends AppCompactActivity{
	
	public void voteDacicola(View view){
		int dacicolaVotes = 0;
		dacicolaVotes = dacicolaVotes + 1;
	}
	public void votePepcity(View view){
		int pepcityVote;
		pepcityVotes = pepcityVotes + 1;
	}
	public void showMeVotes(View view){
		display(dacicolaVotes + "vs. " + pepcityVotes);
	}
}

“I need” + “2 cups of coffee” + “on Monday”

package com.example.android.justjava;

import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.View;
import android.widget.TextView;

import java.text.NumberFormat;

public class MainActivity extends ActionBarActivity {

	int quantity = 2;
	
	@Override
	protected void onCreate(Bundle savedInstanceState){
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
	}

	public void increment(View view){
		quantity = quantity + 1;
		display(quantity);
	}

	public void decrement(View view){
		quantity = quantity - 1;
		display(quantity);
	}

	public void submitOrder(View view){
		int price = quantity * 5;
		String priceMessage = "That would be $" + price + "please.";
		priceMessage = priceMessage + "\nThank you!";
		displayMessage(priceMessage);
	}

	/**
	* This method displays the given text on the screen.
	*/
	private void displayMessage(String message) {
	TextView priceTextView = (TextView) findViewById(R.id.price_text_view);
	priceTextView.setText(message);
	}

	private void display(int number){
		TextView quantityTextView = (TextView) findViewById(
			R.id.quantity_text_view);
		quantityTextView.setText("" + number);
	}

	private void displayPrice(int number){
		TextView priceTextView = (TextView) findViewById(R.id.price_text_view);
		priceTextView.setText(NumberFormat.getCurrencyInstance().format(number));
	}
}

<LinearLayout xmlns:android="http://schemas.android."
	xmlns:tools="http://schemas.android.com/tools"
	android:layout_width="match_parent"
	android:layout_height="match_parent"
	android:paddingBottom="@dimen/activity_vertical"
	android:paddingLeft="@dimen/activity_horizontal"
	android:paddingRight="@dimen/activity_horizontal"
	android:paddingTop="@dimen/activity_vertical"
	android:orientation="vertical"
	tools:context=".MainActivity">

	<TextView
		android:layout_width="wrap_content"
		android:layout_height="wrap_content"
		android:layout_marginBottom="16dp"
		android:text="Quantity" 
		android:textAllCaps="true" />

	<LinearLayout
		android:layout_width="mach_parent"
		android:layout_height="wrapcontent"
		android:orientation="horizontal">

	 	<Button
	   	 android:layout_height="48dp"
	     android:layout_width="48dp"
	     android:text="-"
	     android:onClick="decrement" />

		<TextView
			android:id="@+id/quantity_text_view"
			android:layout_width="wrap_content"
			android:layout_height="wrap_content"
			android:paddingLeft="8dp"
			android:paddingRight="8dp"
			android:text="0"
			android:textSize="16sp"
			adnroid:textColor="@android:color/black" />

	 	<Button
	   	 android:layout_height="48dp"
	     android:layout_width="48dp"
	     android:text="+"
	     android:onClick="increment" />

    </LinearLayout>

	<TextView
		android:layout_width="wrap_content"
		android:layout_height="wrap_content"
		android:layout_marginTop="16dp"
		android:text="Price" 
		android:textAllCaps="true" />

	<TextView
		android:id="@+id/price_text_view"
		android:layout_width="wrap_content"
		android:layout_height="wrap_content"
		android:layout_marginTop="16dp"
		android:text="$0"
		android:textSize="16sp"
		adnroid:textColor="@android:color/black" />

 	<Button
   	 android:layout_height="wrap_content"
     android:layout_width="wrap_content"
     android:layout_marginTop="16dp"
     android:text="Order"
     android:onClick="submitOrder" />

</LinearLayout>

select views
・same as before(3 buttons, 4 textviews)

position views
・header followed by row of buttons/text, followed by header, text, button.
・can’t just use vertical LinearLayout, maybe RelativeLayout would work

style views

Nested viewgroups
https://gist.github.com/anonymous/256752a04db14a3947a8

	public void submitOrder(View view){
		String priceMessage = "Free";
		displayMessage(priceMessage);
	}

variable name java
https://docs.oracle.com/javase/tutorial/java/nutsandbolts/variables.html

java escape character
https://docs.oracle.com/javase/tutorial/java/data/characters.html

	public void submitOrder(View view){
		String priceMessage = "She sed \"1 dollar\"";
		displayMessage(priceMessage);
	}

package com.example.android.justjava;

import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.View;
import android.widget.TextView;

import java.text.NumberFormat;

public class MainActivity extends ActionBarActivity {

	int quantity = 2;
	
	@Override
	protected void onCreate(Bundle savedInstanceState){
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
	}

	public void increment(View view){
		quantity = quantity + 1;
		display(quantity);
	}

	public void decrement(View view){
		quantity = quantity - 1;
		display(quantity);
	}

	public void submitOrder(View view){
		displayPrice(quantity * 5);
	}

	private void display(int number){
		TextView quantityTextView = (TextView) findViewById(
			R.id.quantity_text_view);
		quantityTextView.setText("" + number);
	}

	private void displayPrice(int number){
		TextView priceTextView = (TextView) findViewById(R.id.price_text_view);
		priceTextView.setText(NumberFormat.getCurrencyInstance().format(number));
	}
}

<LinearLayout xmlns:android="http://schemas.android."
	xmlns:tools="http://schemas.android.com/tools"
	android:layout_width="match_parent"
	android:layout_height="match_parent"
	android:paddingBottom="@dimen/activity_vertical"
	android:paddingLeft="@dimen/activity_horizontal"
	android:paddingRight="@dimen/activity_horizontal"
	android:paddingTop="@dimen/activity_vertical"
	android:orientation="vertical"
	tools:context=".MainActivity">

	<TextView
		android:layout_width="wrap_content"
		android:layout_height="wrap_content"
		android:layout_marginBottom="16dp"
		android:text="Quantity" 
		android:textAllCaps="true" />

 	<Button
   	 android:layout_height="48dp"
     android:layout_width="48dp"
     android:text="+"
     android:onClick="increment" />

	<TextView
		android:id="@+id/quantity_text_view"
		android:layout_width="wrap_content"
		android:layout_height="wrap_content"
		android:text="0"
		android:textSize="16sp"
		adnroid:textColor="@android:color/black" />

 	<Button
   	 android:layout_height="48dp"
     android:layout_width="48dp"
     android:text="-"
     android:onClick="decrement" />

	<TextView
		android:layout_width="wrap_content"
		android:layout_height="wrap_content"
		android:layout_marginTop="16dp"
		android:text="Price" 
		android:textAllCaps="true" />

	<TextView
		android:id="@+id/price_text_view"
		android:layout_width="wrap_content"
		android:layout_height="wrap_content"
		android:layout_marginTop="16dp"
		android:text="$0"
		android:textSize="16sp"
		adnroid:textColor="@android:color/black" />

 	<Button
   	 android:layout_height="wrap_content"
     android:layout_width="wrap_content"
     android:layout_marginTop="16dp"
     android:text="Order"
     android:onClick="submitOrder" />

</LinearLayout>

variable name java
https://docs.oracle.com/javase/tutorial/java/nutsandbolts/variables.html

data type variable name = initial value
int numberOfCoffees = 2;
display(numberOfCoffees);
display(numberOfCoffees * 5);

DDMS stands for Dalvik Debug Monitor Server, and is a tool in Android to help you debug your app.
https://developer.android.com/studio/profile/ddms.html?utm_source=udacity&utm_medium=course&utm_campaign=android_basics
Debug, Crashes, Compile time error, Runtime error, System log, Stacktrace

debugging android studio
https://developer.android.com/studio/debug/index.html

int quantity = 2;
quantity = 3;
quantity = 4;
quantity = 5;

int quantity = 2;
quantity = quantity + 1;

Main Activity

package com.example.android.justjava;

import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.View;
import android.widget.TextView;

public class MainActivity extends ActionBarActivity {
	
	@Override
	protected void onCreate(Bundle savedInstanceState){
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
	}

	public void submitOrder(View view){
		display(1);
	}

	private void display(int number){
		TextView quantityTextView = (TextView) findViewById(
			R.id.quantity_text_view);
		quantityTextView.setText("" + number);
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu){
		// Inflate the menu; this adds items to the action
		getMenuInflater().inflate(R.menu.menu_main, menu);
		return true;
	}

	@Override
	public boolean onOptionsItemSelected(MenuItem item){

		int id = item.getItemId();

		if ( id == R.id.action_settings){

		}
	}
}

getting paste error
1. read the error message
2. compare to working code
3. undo
4. ask for help

git hub gist

	private void displayPrice(int number){
		TextView priceTextView = (TextView) findViewById(R.id.price_text_view);
		priceTextView.setText(NumberFormat.getCurrencyInstance().format(number));
	}

Select views
-2 TextViews, 1 Button

Position views
-Use LinearLayout as parent ViewGroup for these 3 children view set LinearLayout orientation to be vertical

Style views
-Quanity header should be in all caps
-Quantity value should be in black font color
-Add spacing between views

activity_main.xml

<LinearLayout xmlns:android="http://schemas.android."
	xmlns:tools="http://schemas.android.com/tools"
	android:layout_width="match_parent"
	android:layout_height="match_parent"
	android:paddingBottom="@dimen/activity_vertical"
	android:paddingLeft="@dimen/activity_horizontal"
	android:paddingRight="@dimen/activity_horizontal"
	android:paddingTop="@dimen/activity_vertical"
	android:orientation="vertical"
	tools:context=".MainActivity">

	<TextView
		android:layout_width="wrap_content"
		android:layout_height="wrap_content"
		android:layout_marginBottom="16dp"
		android:text="Quantity" 
		android:textAllCaps="true" />

	<TextView
		android:layout_width="wrap_content"
		android:layout_height="wrap_content"
		android:text="0"
		android:textSize="16sp"
		adnroid:textColor="@android:color/black" />

 	<Button
   	 android:layout_height="wrap_content"
     android:layout_width="wrap_content"
     android:layout_marginTop="16dp"
     android:text="Order" />

</LinearLayout>

button android
https://developer.android.com/reference/android/widget/Button.html

conversation list activity

Java file -> MainActivity.java

package com.example.android.justjava;

import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.View;
import android.widget.TextView;

public class MainActivity extends ActionBarActivity {
	
	@Override
	protected void onCreate(Bundle savedInstanceState){
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu){
		// Inflate the menu; this adds items to the action
		getMenuInflater().inflate(R.menu.menu_main, menu);
		return true;
	}

	@Override
	public boolean onOptionsItemSelected(MenuItem item){

		int id = item.getItemId();

		if ( id == R.id.action_settings){

		}
	}
}

comments java
http://journals.ecs.soton.ac.uk/java/tutorial/getStarted/application/comments.html