Database Users

[Q] How to Open New Screen in Android

Hello All,
I am following this article to learn how to open new screen on button click: http://learnandroid.blogspot.com/2008/01/opening-new-screen-in-android.html
But I am getting 3 error messages like this:
Code:
Description Resource Path Location Type
id cannot be resolved or is not a field screen1.java /screen1/src/test/android line 18 Java Problem
id cannot be resolved or is not a field screen2.java /screen1/src/test/android line 13 Java Problem
Unparsed aapt error(s)! Check the console for output. screen1 line 1 Android ADT Problem
This is what I have done till now:
screen1.java
Code:
package test.android;
import android.app.Activity;
import android.os.Bundle;
import android.content.Intent;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class screen1 extends Activity
{
public void onCreate(Bundle icicle)
{
super.onCreate(icicle);
setContentView(R.layout.screen1);
Button b = (Button)findViewById(R.id.btnClick);
b.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
Intent i = new Intent(screen1.this, screen2.class);
startActivity(i);
}
});
}
}
screen2.java
Code:
package test.android;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class screen2 extends Activity
{
public void onCreate(Bundle icicle)
{
super.onCreate(icicle);
setContentView(R.layout.screen2);
Button b = (Button) findViewById(R.id.btnClick2);
b.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
setResult(RESULT_OK);
finish();
}
});
}
}
AndroidManifest.xml
Code:
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="test.android">
<application android:icon="@drawable/icon">
<activity class=".Screen1" android:label="Screen 1">
<intent-filter>
<action android:value="android.intent.action.MAIN" />
<category android:value="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity class=".Screen2" android:label="Screen 2">
</activity>
</application>
</manifest>
screen1.xml
Code:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="You are in the first Screen"
/>
<Button
id ="@+id/btnClick"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Open New Screen"
/>
</LinearLayout>
screen2.xml
Code:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="You are in the New Screen"
/>
<Button
id ="@+id/btnClick2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Close"
/>
</LinearLayout>
Please help guys !

To give you an idea, this is screenshot of my project
{
"lightbox_close": "Close",
"lightbox_next": "Next",
"lightbox_previous": "Previous",
"lightbox_error": "The requested content cannot be loaded. Please try again later.",
"lightbox_start_slideshow": "Start slideshow",
"lightbox_stop_slideshow": "Stop slideshow",
"lightbox_full_screen": "Full screen",
"lightbox_thumbnails": "Thumbnails",
"lightbox_download": "Download",
"lightbox_share": "Share",
"lightbox_zoom": "Zoom",
"lightbox_new_window": "New window",
"lightbox_toggle_sidebar": "Toggle sidebar"
}

You have to import the the other class as well. import screen2 in class screen1.
Cmd+Shift+o on mac. probably Ctrl+Shift+o on Windows.

I just tried by placing my cursor on screen1.java
nothing happened ?
and why I am getting those 3 errors ? is it something to do with class ?

Try clicking the "Project -> Clean... -> Select your project -> Click OK" and see if that fixes the problem.

You don't seem to have your resources imported. For example, in my programs, I have "com.package.R" imported. This class links your resources to your java code, and hence it won't find your ID's if you haven't imported it.
Try clean your project (Eclipse is project -> clean, not sure about the others), and see if it then nags you to import it. Otherwise, try manually importing it - it's found under the "gen" folder.
MrP.

try adding "android:" in front of id

Rootstonian said:
try adding "android:" in front of id
Click to expand...
Click to collapse
I think that's the answer. Its supposed to be android:id="@+id/someid"
That and then do a clean build to get R.java to update
From something awesome

killersnowman said:
I think that's the answer. Its supposed to be android:id="@+id/someid"
From something awesome
Click to expand...
Click to collapse
Yes this is correct. Didn't even phase me haha

dolby71 said:
You have to import the the other class as well. import screen2 in class screen1.
Cmd+Shift+o on mac. probably Ctrl+Shift+o on Windows.
Click to expand...
Click to collapse
Not true. screen1 and screen2 are in the same package. As long as the package is defined in each class you don't have to import any classes from that package. And the call to screen2.class is a static call
http://www.programmersheaven.com/mb/java_beginners/288070/288070/import-and-package/
From something awesome

[GUIDE][NOOB Friendly][HOW-TO]Simple Calculator App

HOW-To Make A Simple Android Calculator​
How To Make A Simple Calculator
Step 1
. Select Create New Android Application
{
"lightbox_close": "Close",
"lightbox_next": "Next",
"lightbox_previous": "Previous",
"lightbox_error": "The requested content cannot be loaded. Please try again later.",
"lightbox_start_slideshow": "Start slideshow",
"lightbox_stop_slideshow": "Stop slideshow",
"lightbox_full_screen": "Full screen",
"lightbox_thumbnails": "Thumbnails",
"lightbox_download": "Download",
"lightbox_share": "Share",
"lightbox_zoom": "Zoom",
"lightbox_new_window": "New window",
"lightbox_toggle_sidebar": "Toggle sidebar"
}
Creating XML For Layout
To create a calculator first we need to create the layout of the calculator.
Layout is created using XML file given below
Copy This To Your “activity_main” (Note- If you named the layout activity main or something else please change it to activity_main or it will give a couple of errors)
Code:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<EditText
android:id="@+id/result_id"
android:layout_width="fill_parent"
android:layout_height="120dp"
/>
<Button
android:id="@+id/Btn7_id"
android:layout_width="70dp"
android:layout_height="60dp"
android:layout_below="@id/result_id"
android:text="7"
android:onClick="btn7Clicked"
/>
<Button
android:id="@+id/Btn8_id"
android:layout_width="70dp"
android:layout_height="60dp"
android:layout_below="@id/result_id"
android:layout_toRightOf="@id/Btn7_id"
android:text="8"
android:onClick="btn8Clicked"
/>
<Button
android:id="@+id/Btn9_id"
android:layout_width="70dp"
android:layout_height="60dp"
android:layout_below="@id/result_id"
android:layout_toRightOf="@id/Btn8_id"
android:text="9"
android:onClick="btn9Clicked"
/>
<Button
android:id="@+id/Btnclear_id"
android:layout_width="90dp"
android:layout_height="60dp"
android:layout_below="@id/result_id"
android:layout_toRightOf="@id/Btn9_id"
android:text="clear"
android:onClick="btnclearClicked"
/>
<Button
android:id="@+id/Btn4_id"
android:layout_width="70dp"
android:layout_height="60dp"
android:layout_below="@id/Btn7_id"
android:text="4"
android:onClick="btn4Clicked"
/> <Button
android:id="@+id/Btn5_id"
android:layout_width="70dp"
android:layout_height="60dp"
android:layout_below="@id/Btn8_id"
android:layout_toRightOf="@id/Btn4_id"
android:text="5"
android:onClick="btn5Clicked"
/> <Button
android:id="@+id/Btn6_id"
android:layout_width="70dp"
android:layout_height="60dp"
android:layout_below="@id/Btn9_id"
android:layout_toRightOf="@id/Btn5_id"
android:text="6"
android:onClick="btn6Clicked"
/>
<Button
android:id="@+id/Btnplus_id"
android:layout_width="90dp"
android:layout_height="60dp"
android:layout_below="@id/Btnclear_id"
android:layout_toRightOf="@id/Btn6_id"
android:text="+"
android:onClick="btnplusClicked"
/>
<Button
android:id="@+id/Btn1_id"
android:layout_width="70dp"
android:layout_height="60dp"
android:layout_below="@id/Btn4_id"
android:text="1"
android:onClick="btn1Clicked"
/>
<Button
android:id="@+id/Btn2_id"
android:layout_width="70dp"
android:layout_height="60dp"
android:layout_below="@id/Btn5_id"
android:layout_toRightOf="@id/Btn1_id"
android:text="2"
android:onClick="btn2Clicked"
/>
<Button
android:id="@+id/Btn3_id"
android:layout_width="70dp"
android:layout_height="60dp"
android:layout_below="@id/Btn6_id"
android:layout_toRightOf="@id/Btn2_id"
android:text="3"
android:onClick="btn3Clicked"
/>
<Button
android:id="@+id/Btnminus_id"
android:layout_width="90dp"
android:layout_height="60dp"
android:layout_below="@id/Btnplus_id"
android:layout_toRightOf="@id/Btn3_id"
android:text="-"
android:onClick="btnminusClicked"
/>
<Button
android:id="@+id/Btnequal_id"
android:layout_width="110dp"
android:layout_height="60dp"
android:layout_below="@id/Btn1_id"
android:text="="
android:onClick="btnequalClicked"
/>
<Button
android:id="@+id/Btndivide_id"
android:layout_width="90dp"
android:layout_height="60dp"
android:layout_below="@id/Btn1_id"
android:layout_toRightOf="@id/Btnequal_id"
android:text="/"
android:onClick="btndivideClicked"
/>
<Button
android:id="@+id/Btnmulti_id"
android:layout_width="90dp"
android:layout_height="60dp"
android:layout_below="@id/Btnminus_id"
android:layout_toRightOf="@id/Btndivide_id"
android:text="*"
android:onClick="btnmultiClicked"
/>
</RelativeLayout>
The Graphical Layout Will look Like this
Then You have to Make The Buttons work and calculate your numbers
Simply find your MainActivity.java (It Is place under package name)
Copy This to your java file :
Code:
package com.dc.simplecalculator;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
public class MainActivity extends Activity {
public String str ="";
Character op = 'q';
int i,num,numtemp;
EditText showResult;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
showResult = (EditText)findViewById(R.id.result_id);
}
public void btn1Clicked(View v){
insert(1);
}
public void btn2Clicked(View v){
insert(2);
}
public void btn3Clicked(View v){
insert(3);
}
public void btn4Clicked(View v){
insert(4);
}
public void btn5Clicked(View v){
insert(5);
}
public void btn6Clicked(View v){
insert(6);
}
public void btn7Clicked(View v){
insert(7);
}
public void btn8Clicked(View v){
insert(8);
}
public void btn9Clicked(View v){
insert(9);
}
public void btnplusClicked(View v){
perform();
op = '+';
}
public void btnminusClicked(View v){
perform();
op = '-';
}
public void btndivideClicked(View v){
perform();
op = '/';
}
public void btnmultiClicked(View v){
perform();
op = '*';
}
public void btnequalClicked(View v){
calculate();
}
public void btnclearClicked(View v){
reset();
}
private void reset() {
// TODO Auto-generated method stub
str ="";
op ='q';
num = 0;
numtemp = 0;
showResult.setText("");
}
private void insert(int j) {
// TODO Auto-generated method stub
str = str+Integer.toString(j);
num = Integer.valueOf(str).intValue();
showResult.setText(str);
}
private void perform() {
// TODO Auto-generated method stub
str = "";
numtemp = num;
}
private void calculate() {
// TODO Auto-generated method stub
if(op == '+')
num = numtemp+num;
else if(op == '-')
num = numtemp-num;
else if(op == '/')
num = numtemp/num;
else if(op == '*')
num = numtemp*num;
showResult.setText(""+num);
}
}
Next Step!
Testing Your App, Fingers Crossed
Simply Click On Run>Run As Android Application
Congo! You Just Made A Simple Calc App……
Exporting Your App
Open Android Manifest.xml
Select use Export Wizard
That’s All….
If you have any queries post in this thread I will try my best to solve it…
Sucess!
Have A Good Day!
​

Reserved

[Tutorial] Create a Blur Effect on Android with RenderScript

Hello,
I create that thread to present you a tutorial aiming to learn you how to create a Blur Effect on Android with the RenderScript Library. You can discover the tutorial in video on Youtube too :
Create a Blur Effect on Android with RenderScript
In image processing, a Blur Effect, also known as Gaussian Blur, is the result of blurring an image by applying a Gaussian function. The Blur Effect is widely used in graphics software. In that tutorial, you're going to learn how to apply a Blur Effect on Android by using the RenderScript Library.
1. Configure your environment to use RenderScript
First step is to configure your development environment to enable RenderScript in your Android project. Note that your need the following Android SDK using these APIs:
Android SDK Tools revision 22.2 or higher
Android SDK Build-tools revision 18.1.0 or higher
You need to open your build.gradle and then add the following RenderScript properties :
Code:
android {
compileSdkVersion 23
buildToolsVersion "23.0.3"
defaultConfig {
minSdkVersion 9
targetSdkVersion 19
renderscriptTargetApi 18
renderscriptSupportModeEnabled true
}
}
2. Implement the Blur Effect with RenderScript
Note that we will use the RenderScript API in V8. This version is located in the android.support.v8.renderscript.* packages. So, be sure to import the correct classes in your code. We are going to create a BlurBuilder class with a static blur method taking the Bitmap to blur and returning the blurred Bitmap. We will use a blur radius constant to define which radius we want to apply on the original image.
Code for the BlurBuilder class should be like that :
Code:
package com.ssaurel.blureffect;
import android.content.Context;
import android.graphics.Bitmap;
import android.support.v8.renderscript.Allocation;
import android.support.v8.renderscript.Element;
import android.support.v8.renderscript.RenderScript;
import android.support.v8.renderscript.ScriptIntrinsicBlur;
/**
* Created by ssaurel on 29/09/2016.
*/
public class BlurBuilder {
private static final float BITMAP_SCALE = 0.6f;
private static final float BLUR_RADIUS = 15f;
public static Bitmap blur(Context context, Bitmap image) {
int width = Math.round(image.getWidth() * BITMAP_SCALE);
int height = Math.round(image.getHeight() * BITMAP_SCALE);
Bitmap inputBitmap = Bitmap.createScaledBitmap(image, width, height, false);
Bitmap outputBitmap = Bitmap.createBitmap(inputBitmap);
RenderScript rs = RenderScript.create(context);
ScriptIntrinsicBlur intrinsicBlur = ScriptIntrinsicBlur.create(rs, Element.U8_4(rs));
Allocation tmpIn = Allocation.createFromBitmap(rs, inputBitmap);
Allocation tmpOut = Allocation.createFromBitmap(rs, outputBitmap);
intrinsicBlur.setRadius(BLUR_RADIUS);
intrinsicBlur.setInput(tmpIn);
intrinsicBlur.forEach(tmpOut);
tmpOut.copyTo(outputBitmap);
return outputBitmap;
}
}
Like you can see, we choose to apply a scale on the original bitmap but it's not mandatory. Then, we create a RenderScript instance. The RenderScript V8 API offers us a ScriptIntrinsicBlur class that implements a Blur Effect with RenderScript. We use it with the RenderScript instance in parameter. Then, we need to allocate memory for the input Bitmap and the ouput Bitmap. Last step is to configure the Blur Effect by applying the radius parameter.
Finally, we get the blurred image in result and we returned it.
3. Define images in your main layout
To see our Blur Effect in action, we need to create a layout with two images. The first will be used to show an initial image and the second to show the blurred image. We will use the following layout :
Code:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.ssaurel.blureffect.MainActivity">
<ImageView
android:layout_width="256dp"
android:layout_height="256dp"
android:id="@+id/originalImage"
android:layout_marginTop="20dp"
android:layout_centerHorizontal="true"
android:src="@drawable/logo_ssaurel"/>
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/resultImage"
android:layout_below="@id/originalImage"
android:layout_centerHorizontal="true"/>
</RelativeLayout>
4. Apply the Blur Effect
Now, it's time to apply the Blur Effect in the Main Activity of our application :
Code:
package com.ssaurel.blureffect;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.ImageView;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ImageView resultImage = (ImageView) findViewById(R.id.resultImage);
Bitmap resultBmp = BlurBuilder.blur(this, BitmapFactory.decodeResource(getResources(), R.drawable.logo_ssaurel));
resultImage.setImageBitmap(resultBmp);
}
}
We get our initial image as a Bitmap with the static method decodeResource of the BitmapFactory class, then we apply the Blur Effect on it. Finally, we set the blurred bitmap on the result image view.
5. Blur Effect Result
Now, you can enjoy the result of your Blur Effect :
{
"lightbox_close": "Close",
"lightbox_next": "Next",
"lightbox_previous": "Previous",
"lightbox_error": "The requested content cannot be loaded. Please try again later.",
"lightbox_start_slideshow": "Start slideshow",
"lightbox_stop_slideshow": "Stop slideshow",
"lightbox_full_screen": "Full screen",
"lightbox_thumbnails": "Thumbnails",
"lightbox_download": "Download",
"lightbox_share": "Share",
"lightbox_zoom": "Zoom",
"lightbox_new_window": "New window",
"lightbox_toggle_sidebar": "Toggle sidebar"
}
Don't hesitate to try to create this Blur Effect and give me your feedbacks.
Thanks.
Sylvain

[Tutorial] Learn to create a BMI Calculator for Android

Hello,
I create that thread to present you a tutorial aiming to learn you how to create a Body Mass Index Calculator for Android. This tutorial is ideal for beginners that want to discover how to create a first application. You can discover the tutorial in video on Youtube :
Create a Body Mass Index Calculator for Android
The Body Mass Index (BMI) or Quetelet index is a value derived from the mass weight and height of an individual. The BMI is defined as the body mass divided by the square of the body height, and is universally expressed in units of kg/m². By analyzing the BMI value, we can determine a diagnostic. First step for the application is to define a layout letting users to enter weight and height values to calculate the BMI index. Besides, we will need a button to launch the BMI calculation and also a TextView to display the result.
The layout will have the following form :
Code:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:orientation="vertical"
tools:context="com.ssaurel.bmicalculator.MainActivity">
<TextView
android:text="@string/weight"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:gravity="center_horizontal"
android:layout_marginTop="50dp"
android:textSize="20sp"/>
<EditText
android:id="@+id/weight"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:layout_marginTop="10dp"
android:ems="6"
android:inputType="number|numberDecimal"
android:textSize="20sp"/>
<TextView
android:text="@string/height"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:gravity="center_horizontal"
android:layout_marginTop="50dp"
android:textSize="20sp"/>
<EditText
android:id="@+id/height"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:layout_marginTop="10dp"
android:ems="6"
android:inputType="number|numberDecimal"
android:textSize="20sp"/>
<Button
android:id="@+id/calc"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:layout_marginTop="25dp"
android:onClick="calculateBMI"
android:text="@string/calculateBMI"
/>
<TextView
android:id="@+id/result"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:gravity="center_horizontal"
android:layout_marginTop="25dp"
android:textSize="20sp"/>
</LinearLayout>
Now, we can write the Java code in our Main Activity :
Code:
package com.ssaurel.bmicalculator;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
private EditText height;
private EditText weight;
private TextView result;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
height = (EditText) findViewById(R.id.height);
weight = (EditText) findViewById(R.id.weight);
result = (TextView) findViewById(R.id.result);
}
public void calculateBMI(View v) {
String heightStr = height.getText().toString();
String weightStr = weight.getText().toString();
if (heightStr != null && !"".equals(heightStr)
&& weightStr != null && !"".equals(weightStr)) {
float heightValue = Float.parseFloat(heightStr) / 100;
float weightValue = Float.parseFloat(weightStr);
float bmi = weightValue / (heightValue * heightValue);
displayBMI(bmi);
}
}
private void displayBMI(float bmi) {
String bmiLabel = "";
if (Float.compare(bmi, 15f) <= 0) {
bmiLabel = getString(R.string.very_severely_underweight);
} else if (Float.compare(bmi, 15f) > 0 && Float.compare(bmi, 16f) <= 0) {
bmiLabel = getString(R.string.severely_underweight);
} else if (Float.compare(bmi, 16f) > 0 && Float.compare(bmi, 18.5f) <= 0) {
bmiLabel = getString(R.string.underweight);
} else if (Float.compare(bmi, 18.5f) > 0 && Float.compare(bmi, 25f) <= 0) {
bmiLabel = getString(R.string.normal);
} else if (Float.compare(bmi, 25f) > 0 && Float.compare(bmi, 30f) <= 0) {
bmiLabel = getString(R.string.overweight);
} else if (Float.compare(bmi, 30f) > 0 && Float.compare(bmi, 35f) <= 0) {
bmiLabel = getString(R.string.obese_class_i);
} else if (Float.compare(bmi, 35f) > 0 && Float.compare(bmi, 40f) <= 0) {
bmiLabel = getString(R.string.obese_class_ii);
} else {
bmiLabel = getString(R.string.obese_class_iii);
}
bmiLabel = bmi + "\n\n" + bmiLabel;
result.setText(bmiLabel);
}
}
When a user click on the calculate BMI button, the calculateBMI method is called. We get the values entered by the user for the weight and the height. The height is entered in centimeter. For the formula, we need to have a height in meter. So, we divide the value entered by 100. Then, we apply the formula to calculate the BMI :
float bmi = weightValue / (heightValue * heightValue);
With the BMI value, we can display the result on the user interface. We define the displayBMI method for that. To determine the diagnostic associated to the BMI value, we are going to use the following table :
{
"lightbox_close": "Close",
"lightbox_next": "Next",
"lightbox_previous": "Previous",
"lightbox_error": "The requested content cannot be loaded. Please try again later.",
"lightbox_start_slideshow": "Start slideshow",
"lightbox_stop_slideshow": "Stop slideshow",
"lightbox_full_screen": "Full screen",
"lightbox_thumbnails": "Thumbnails",
"lightbox_download": "Download",
"lightbox_share": "Share",
"lightbox_zoom": "Zoom",
"lightbox_new_window": "New window",
"lightbox_toggle_sidebar": "Toggle sidebar"
}
The last step is just to display the BMI value and the diagnostic in the result TextView. After that, you can try the application and enjoy the BMI Calculator in action :
Don't hesitate to try this tutorial and give me your feedbacks.
Thanks.
Sylvain

Hello,
Some users asked me to publish the BMI Calculator Application made in the tutorial.
I made some UI refinements and I published the BMI Calculator on the Google Play Store : https://play.google.com/store/apps/details?id=com.ssaurel.bmicalculator
Don't hesitate to give it a try and give me your feedbacks.
Sylvain

[Tutorial] Learn to parse HTML Pages on Android with JSoup

Hello,
I create that thread to offer you a tutorial learning you to parse HTML pages on Android by using the JSoup Library. You can also discover this tutorial in video on Youtube :
When you make Android applications, you can have to parse HTML data or HTML pages got from the Web. One of the most known solution to make that in Java is to use JSoup Library. Like said on the official website of JSoup : "It is a Java library for working with real-world HTML. It provides a very convenient API for extracting and manipulating data, using the best of DOM, CSS, and jquery-like methods."
JSoup can be used in Android applications and we're going to study how to parse an HTML Page on Android with JSoup.
First, you need to add the JSoup dependency in your Gradle build file :
Code:
compile 'org.jsoup:jsoup:1.10.1'
For our example, we are going to download the content of the SSaurel's Blog and display all the links of the main page. To download the content of a website, JSoup offers the connect method and then a get method. This last method works synchronously. So, we should call these methods in a separated Thread. Our application will have just a simple layout with a Button to launch the download of the website and a TextView to display the links.
It will have the following form :
Code:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.ssaurel.jsouptut.MainActivity">
<Button
android:id="@+id/getBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Get website"
android:layout_marginTop="50dp"
android:layout_centerHorizontal="true"/>
<TextView
android:id="@+id/result"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Result ..."
android:layout_centerHorizontal="true"
android:layout_marginTop="30dp"
android:layout_below="@id/getBtn"
android:textSize="17sp"/>
</RelativeLayout>
In the main Activity of the application, we are going to get instances of the Button and the TextView from our layout. Then, we set a click listener on the Button to start the download of the website when the user will click it.
In the getWebsite() method, we create a new Thread to download the content of the website. We use the connect() method of the Jsoup object to connect the application to the website, then we call the get() method to download the content. These calls return a Document object instance. We have to call the select() method of this instance with the query to get all the links of the content. This query returns an Elements instance and finally, we have just to iterate on the elements contained in this object to display the content of each link to the screen.
At the end of our separated Thread, we refresh the UI with the links got from the website. This refresh is embedded inside a runOnUiThread call because it's forbidden to refresh the UI elements inside a separated thread.
The code of the MainActivity has the following form :
Code:
package com.ssaurel.jsouptut;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;
import java.io.IOException;
public class MainActivity extends AppCompatActivity {
private Button getBtn;
private TextView result;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
result = (TextView) findViewById(R.id.result);
getBtn = (Button) findViewById(R.id.getBtn);
getBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
getWebsite();
}
});
}
private void getWebsite() {
new Thread(new Runnable() {
@Override
public void run() {
final StringBuilder builder = new StringBuilder();
try {
Document doc = Jsoup.connect("http://www.ssaurel.com/blog").get();
String title = doc.title();
Elements links = doc.select("a[href]");
builder.append(title).append("\n");
for (Element link : links) {
builder.append("\n").append("Link : ").append(link.attr("href"))
.append("\n").append("Text : ").append(link.text());
}
} catch (IOException e) {
builder.append("Error : ").append(e.getMessage()).append("\n");
}
runOnUiThread(new Runnable() {
@Override
public void run() {
result.setText(builder.toString());
}
});
}
}).start();
}
}
Last step is to run the application and to enjoy the final result with all the links of the SSaurel's blog displayed on the screen :
{
"lightbox_close": "Close",
"lightbox_next": "Next",
"lightbox_previous": "Previous",
"lightbox_error": "The requested content cannot be loaded. Please try again later.",
"lightbox_start_slideshow": "Start slideshow",
"lightbox_stop_slideshow": "Stop slideshow",
"lightbox_full_screen": "Full screen",
"lightbox_thumbnails": "Thumbnails",
"lightbox_download": "Download",
"lightbox_share": "Share",
"lightbox_zoom": "Zoom",
"lightbox_new_window": "New window",
"lightbox_toggle_sidebar": "Toggle sidebar"
}
Don't hesitate to try JSoup on your Android application and give me your feedbacks on this tutorial.
Thanks.
Sylvain