Articles on Trending Technologies

Technical articles with clear explanations and examples

How do you animate the change of background color of a view on iOS?

Sadiqaadil
Sadiqaadil
Updated on 11-Sep-2019 2K+ Views

In this post we will learn how to change the background color of view with animation.In this example we will change background color of view on click of a button. On clicking the button the background color will change to red, then on next click it would change to blue, on next click to red again.Step 1 − Open Xcode → New Project → Single View Application → Let’s name it “ChangeBGColor”Step 2 − Open Main.storyboard add a button as shown belowStep 3 − Add one @IBAction for touchUpInside of ‘Change Background’ button. Name the function as changeBackgroundClicked.Step 4 − ...

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How to read data from one file and print to another file in Java?

Maruthi Krishna
Maruthi Krishna
Updated on 10-Sep-2019 3K+ Views

Java provides I/O Streams to read and write data where a Stream represents an input source or an output destination which could be a file, i/o devise, other programs, etc.In general, a Stream will be an input stream or, an output stream.InputStream − This is used to read data from a source.OutputStream − This is used to write data to a destination.Based on the data they handle there are two types of streams −Byte Streams − These handle data in bytes (8 bits) i.e., the byte stream classes read/write data of 8 bits. Using these you can store characters, videos, ...

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Can we use readUTF() to read a string from a .txt file in Java?

Maruthi Krishna
Maruthi Krishna
Updated on 10-Sep-2019 491 Views

The readUTF() method of the java.io.DataOutputStream reads data that is in modified UTF-8 encoding, into a String and returns it.ExampleThe following Java program reads a UTF-8 text from a .txt file using the readUTF() method.import java.io.DataInputStream; import java.io.EOFException; import java.io.FileInputStream; import java.io.IOException; public class UTF8Example {    public static void main(String args[]) {       StringBuffer buffer = new StringBuffer();       try {          //Instantiating the FileInputStream class          FileInputStream fileIn = new FileInputStream("D:\test.txt");          //Instantiating the DataInputStream class          DataInputStream inputStream = new DataInputStream(fileIn); ...

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Reading UTF8 data from a file using Java

Maruthi Krishna
Maruthi Krishna
Updated on 10-Sep-2019 4K+ Views

In general, data is stored in a computer in the form of bits (1 or, 0). There are various coding schemes available specifying the set of bytes represented by each character.Unicode (UTF) − Stands for Unicode Translation Format. It is developed by The Unicode Consortium. if you want to create documents that use characters from multiple character sets, you will be able to do so using the single Unicode character encodings. It provides 3 types of encodings.UTF-8 − It comes in 8-bit units (bytes), a character in UTF8 can be from 1 to 4 bytes long, making UTF8 variable width.UTF-16 ...

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Can 'false' match some string in MySQL?

AmitDiwan
AmitDiwan
Updated on 09-Sep-2019 121 Views

Yes, you can use false as 0 to match.Let us first create a table −mysql> create table DemoTable804 ( Id varchar(100) ); Query OK, 0 rows affected (0.66 sec)Insert some records in the table using insert command −mysql> insert into DemoTable804 values('101John'); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable804 values('Carol1002'); Query OK, 1 row affected (0.22 sec) mysql> insert into DemoTable804 values('1000'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable804 values('1010Bob'); Query OK, 1 row affected (0.10 sec)Display all records from the table using select statement −mysql> select *from DemoTable804;This ...

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Set DEFAULT values for columns while creating a table in MySQL

AmitDiwan
AmitDiwan
Updated on 09-Sep-2019 2K+ Views

To set default values for columns while creating a table, DEFAULT. Let us first see an example and create a table. As you can see below, while creating the table, we have set DEFAULT −mysql> create table DemoTable803 ( UserId int DEFAULT 101, UserName varchar(100) DEFAULT 'Chris' ); Query OK, 0 rows affected (1.18 sec)Insert some records in the table using insert command. For the values we are not inserting, the default values will get set automatically −mysql> insert into DemoTable803 values(102, 'Chris'); Query OK, 1 row affected (0.34 sec) mysql> insert into DemoTable803(UserName) ...

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Display and concatenate records ignoring NULL values in MySQL

AmitDiwan
AmitDiwan
Updated on 09-Sep-2019 870 Views

Use CONCAT() to concatenate records whereas IFNULL() to check for NULL values.Let us first create a table −mysql> create table DemoTable802 ( FirstName varchar(100), LastName varchar(100) ); Query OK, 0 rows affected (1.01 sec)Insert some records in the table using insert command −mysql> insert into DemoTable802 values('Adam', 'Smith'); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable802 values('Carol', NULL); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable802 values(NULL, 'Taylor'); Query OK, 1 row affected (0.09 sec) mysql> insert into DemoTable802 values(NULL, NULL); Query OK, 1 row affected (0.21 sec)Display ...

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MySQL query to perform sort order on same field

AmitDiwan
AmitDiwan
Updated on 09-Sep-2019 207 Views

For this, use ORDER BY IF().Let us first create a table −mysql> create table DemoTable801 ( Score int ); Query OK, 0 rows affected (0.69 sec)Insert some records in the table using insert command −mysql> insert into DemoTable801 values(30); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable801 values(99); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable801 values(45); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable801 values(55); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable801 values(99); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable801 values(69); ...

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MySQL select only a single value from 5 similar values?

AmitDiwan
AmitDiwan
Updated on 09-Sep-2019 227 Views

Let us first create a table −mysql> create table DemoTable800 ( Value int ); Query OK, 0 rows affected (0.59 sec)Insert some records in the table using insert command. Here, we have inserted 5 similar values −mysql> insert into DemoTable800 values(10); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable800 values(10); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable800 values(10); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable800 values(10); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable800 values(10); Query OK, 1 row affected (0.10 sec)Display all ...

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Why the #1054 - Unknown column error occurs in MySQL and how to fix it?

AmitDiwan
AmitDiwan
Updated on 09-Sep-2019 4K+ Views

Let’s see when the #1054 error occurs in MySQL. While inserting a varchar value, if you will forget to add single quotes, then this error will arise. Following is the error −mysql> insert into DemoTable798 values(100, Adam); ERROR 1054 (42S22): Unknown column 'Adam' in 'field list'You need to use single quotes around the string value to fix this error as shown below −mysql> insert into DemoTable798 values(100, ’Adam’);Let us first create a table −mysql> create table DemoTable798 ( StudentId int, StudentName varchar(100) ); Query OK, 0 rows affected (0.51 sec)Insert some records in the ...

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