Saturday, 27 June 2015

android Tutorial


Android FrameLayout Example
Android FrameLayout Example
activity_main.xml
File: activity_main.xml
1.    <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"  
2.        xmlns:tools="http://schemas.android.com/tools"  
3.        android:id="@+id/FrameLayout1"  
4.        android:layout_width="match_parent"  
5.        android:layout_height="match_parent"  
6.        tools:context=".MainActivity" >  
7.      
8.        <ImageButton  
9.            android:id="@+id/imageButton1"  
10.          android:layout_width="wrap_content"  
11.          android:layout_height="wrap_content"  
12.          android:src="@drawable/ic_launcher" />  
13.        
14.  </FrameLayout>  

Activity class
File: MainActivity.java
1.    package com.example.framelayout;  
2.      
3.    import android.os.Bundle;  
4.    import android.app.Activity;  
5.    import android.view.Menu;  
6.      
7.    public class MainActivity extends Activity {  
8.      
9.        @Override  
10.      protected void onCreate(Bundle savedInstanceState) {  
11.          super.onCreate(savedInstanceState);  
12.          setContentView(R.layout.activity_main);  
13.      }  
14.    
15.      @Override  
16.      public boolean onCreateOptionsMenu(Menu menu) {  
17.          // Inflate the menu; this adds items to the action bar if it is present.  
18.          getMenuInflater().inflate(R.menu.activity_main, menu);  
19.          return true;  
20.      }  
21.    
22.  }  

Android FrameLayout Example
Android FrameLayout Example
activity_main.xml
File: activity_main.xml
1.    <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"  
2.        xmlns:tools="http://schemas.android.com/tools"  
3.        android:id="@+id/FrameLayout1"  
4.        android:layout_width="match_parent"  
5.        android:layout_height="match_parent"  
6.        tools:context=".MainActivity" >  
7.      
8.        <ImageButton  
9.            android:id="@+id/imageButton1"  
10.          android:layout_width="wrap_content"  
11.          android:layout_height="wrap_content"  
12.          android:src="@drawable/ic_launcher" />  
13.        
14.  </FrameLayout>  

Activity class
File: MainActivity.java
1.    package com.example.framelayout;  
2.      
3.    import android.os.Bundle;  
4.    import android.app.Activity;  
5.    import android.view.Menu;  
6.      
7.    public class MainActivity extends Activity {  
8.      
9.        @Override  
10.      protected void onCreate(Bundle savedInstanceState) {  
11.          super.onCreate(savedInstanceState);  
12.          setContentView(R.layout.activity_main);  
13.      }  
14.    
15.      @Override  
16.      public boolean onCreateOptionsMenu(Menu menu) {  
17.          // Inflate the menu; this adds items to the action bar if it is present.  
18.          getMenuInflater().inflate(R.menu.activity_main, menu);  
19.          return true;  
20.      }  
21.    
22.  }  

Android LinearLayout Example
Android LinearLayout Example
activity_main.xml
File: activity_main.xml
1.    <!-- <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  
2.        xmlns:tools="http://schemas.android.com/tools"  
3.        android:layout_width="match_parent"  
4.        android:layout_height="match_parent"  
5.        tools:context=".MainActivity" >  
6.      
7.        <Button  
8.            android:id="@+id/button1"  
9.            android:layout_width="wrap_content"  
10.          android:layout_height="wrap_content"  
11.          android:text="Button1" />  
12.    
13.      <Button  
14.          android:id="@+id/button2"  
15.          android:layout_width="wrap_content"  
16.          android:layout_height="wrap_content"  
17.          android:text="Button2" />  
18.    
19.      <Button  
20.          android:id="@+id/button3"  
21.          android:layout_width="wrap_content"  
22.          android:layout_height="wrap_content"  
23.          android:text="Button3" />  
1.      
24.  </LinearLayout> -->  
25.  <!-- <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  
26.      xmlns:tools="http://schemas.android.com/tools"  
27.      android:layout_width="match_parent"  
28.      android:layout_height="match_parent"  
29.      tools:context=".MainActivity" >  
30.    
31.      <Button  
32.          android:id="@+id/button1"  
33.          android:layout_width="wrap_content"  
34.          android:layout_height="fill_parent"  
35.          android:text="Button1" />  
36.    
37.      <Button  
38.          android:id="@+id/button2"  
39.          android:layout_width="wrap_content"  
40.          android:layout_height="fill_parent"  
41.          android:text="Button2" />  
42.    
43.      <Button  
44.          android:id="@+id/button3"  
45.          android:layout_width="wrap_content"  
46.          android:layout_height="fill_parent"  
47.          android:text="Button3" />  
48.    
49.  </LinearLayout> -->  
50.  <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  
51.      xmlns:tools="http://schemas.android.com/tools"  
52.      android:layout_width="fill_parent"  
53.      android:layout_height="match_parent"  
54.      android:orientation="vertical"  
55.      tools:context=".MainActivity" >  
56.    
57.      <Button  
58.          android:id="@+id/button2"  
59.          android:layout_width="match_parent"  
60.          android:layout_height="wrap_content"  
61.          android:text="Button2" />  
62.    
63.      <Button  
64.          android:id="@+id/button1"  
65.          android:layout_width="match_parent"  
66.          android:layout_height="wrap_content"  
67.          android:text="Button1" />  
68.    
69.      <Button  
70.          android:id="@+id/button3"  
71.          android:layout_width="match_parent"  
72.          android:layout_height="wrap_content"  
73.          android:text="Button3" />  
74.       
75.  </LinearLayout>  

Activity class
File: MainActivity.java
1.    package com.example.linearlayout;  
2.      
3.    import android.os.Bundle;  
4.    import android.app.Activity;  
5.    import android.view.Menu;  
6.      
7.    public class MainActivity extends Activity {  
8.      
9.        @Override  
10.      protected void onCreate(Bundle savedInstanceState) {  
11.          super.onCreate(savedInstanceState);  
12.          setContentView(R.layout.activity_main);  
13.      }  
14.    
15.      @Override  
16.      public boolean onCreateOptionsMenu(Menu menu) {  
17.          // Inflate the menu; this adds items to the action bar if it is present.  
18.          getMenuInflater().inflate(R.menu.activity_main, menu);  
19.          return true;  
20.      }  
21.    
22.  }  

Android Table Layout

Android TableLayout going to be arranged groups of views into rows and columns. You will use the <TableRow> element to build a row in the table. Each row has zero or more cells; each cell can hold one View object.
TableLayout containers do not display border lines for their rows, columns, or cells.

TableLayout Attributes


Following are the important attributes specific to TableLayout −
Attribute
Description
android:id
This is the ID which uniquely identifies the layout.
android:collapseColumns
This specifies the zero-based index of the columns to collapse. The column indices must be separated by a comma: 1, 2, 5.
android:collapseColumns
The zero-based index of the columns to shrink. The column indices must be separated by a comma: 1, 2, 5.
android:stretchColumns
The zero-based index of the columns to stretch. The column indices must be separated by a comma: 1, 2, 5.

Example

This example will take you through simple steps to show how to create your own Android application using Table Layout. Follow the following steps to modify the Android application we created in Hello World Example chapter −
Step
Description
1
You will use Android Studio IDE to create an Android application and name it asdemo under a package com.example.demo as explained in the Hello World Example chapter.
2
Modify the default content of res/layout/activity_main.xml file to include few widgets in table layout.
3
No need to modify string.xml, Android studio takes care of default constants
4
Run the application to launch Android emulator and verify the result of the changes done in the application.
Following is the content of the modified main activity filesrc/com.example.demo/MainActivity.java. This file can include each of the fundamental lifecycle methods.
package com.example.demo;
 
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
 
public class MainActivity extends Activity {
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
   }
   
   @Override
   public boolean onCreateOptionsMenu(Menu menu) {
      getMenuInflater().inflate(R.menu.main, menu);
      return true;
   }
}
Following will be the content of res/layout/activity_main.xml file −
<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
   android:layout_width="fill_parent"
   android:layout_height="fill_parent">
   
   <TableRow
      android:layout_width="fill_parent"
      android:layout_height="fill_parent">
   <TextView
      android:text="Time"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_column="1" />
   <TextClock
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:id="@+id/textClock"
      android:layout_column="2" />
   </TableRow>
   
   <TableRow>
   <TextView
      android:text="First Name"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_column="1" />
   <EditText
      android:width="200px"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content" />
   </TableRow>
   
   <TableRow>
   <TextView
      android:text="Last Name"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_column="1" />
   <EditText
      android:width="100px"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content" />
   </TableRow>
   
   <TableRow
      android:layout_width="fill_parent"
      android:layout_height="fill_parent">
   <RatingBar
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:id="@+id/ratingBar"
      android:layout_column="2" />
   </TableRow>
   
   <TableRow
      android:layout_width="fill_parent"
      android:layout_height="fill_parent"/>
   <TableRow
      android:layout_width="fill_parent"
      android:layout_height="fill_parent">
   <Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Submit"
      android:id="@+id/button"
      android:layout_column="2" />
   </TableRow>
 
</TableLayout>
Following will be the content of res/values/strings.xml to define two new constants −
<?xml version="1.0" encoding="utf-8"?>
<resources>
   <string name="app_name">HelloWorld</string>
   <string name="action_settings">Settings</string>
</resources>
Let's try to run our modified Hello World! application we just modified. I assume you had created your AVD while doing environment setup. To run the app from Android Studio, open one of your project's activity files and click Run Eclipse Run Icon icon from the toolbar. Android studio installs the app on your AVD and starts it and if everything is fine with your setup and application, it will display following Emulator window −

Android Absolute Layout

An Absolute Layout lets you specify exact locations (x/y coordinates) of its children. Absolute layouts are less flexible and harder to maintain than other types of layouts without absolute positioning.

ABSOLUTE LAYOUT

AbsoluteLayout Attributes

Following are the important attributes specific to AbsoluteLayout −
Attribute
Description
android:id
This is the ID which uniquely identifies the layout.
android:layout_x
This specifies the x-coordinate of the view.
android:layout_y
This specifies the y-coordinate of the view.

Public Constructors

AbsoluteLayout(Context context)
AbsoluteLayout(Context context, AttributeSet attrs)
AbsoluteLayout(Context context, AttributeSet attrs, int defStyleAttr)
AbsoluteLayout(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes)

Example

This example will take you through simple steps to show how to create your own Android application using absolute layout. Follow the following steps to modify the Android application we created in Hello World Example chapter −
Step
Description
1
You will use Android studio IDE to create an Android application and name it asdemo under a package com.example.demo as explained in the Hello World Example chapter.
2
Modify the default content of res/layout/activity_main.xml file to include few widgets in absolute layout.
3
No need to modify string.xml, Android studio takes care of default constants
4
Run the application to launch Android emulator and verify the result of the changes done in the application.
Following is the content of the modified main activity filesrc/com.example.demo/MainActivity.java. This file can include each of the fundamental lifecycle methods.
package com.example.demo;
 
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
 
public class MainActivity extends Activity {
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
   }
   
   @Override
   public boolean onCreateOptionsMenu(Menu menu) {
      getMenuInflater().inflate(R.menu.main, menu);
      return true;
   }
}
Following will be the content of res/layout/activity_main.xml file −
<AbsoluteLayout xmlns:android="http://schemas.android.com/apk/res/android"
   android:layout_width="fill_parent"
   android:layout_height="fill_parent">
   
   <Button
      android:layout_width="100dp"
      android:layout_height="wrap_content"
      android:text="OK"
      android:layout_x="50px"
      android:layout_y="361px" />
   <Button
      android:layout_width="100dp"
      android:layout_height="wrap_content"
      android:text="Cancel"
      android:layout_x="225px"
      android:layout_y="361px" />
 
</AbsoluteLayout>
Following will be the content of res/values/strings.xml to define two new constants −
<?xml version="1.0" encoding="utf-8"?>
<resources>
   <string name="app_name">demo</string>
   <string name="action_settings">Settings</string>
</resources>
Let's try to run our modified Hello World! application we just modified. I assume you had created your AVD while doing environment setup. To run the app from Android Studio, open one of your project's activity files and click Run Eclipse Run Icon icon from the toolbar. Android Studio installs the app on your AVD and starts it and if everything is fine with your setup and application, it will display following Emulator window −

Android Frame Layout

Frame Layout is designed to block out an area on the screen to display a single item. Generally, FrameLayout should be used to hold a single child view, because it can be difficult to organize child views in a way that's scalable to different screen sizes without the children overlapping each other.

FrameLayout Attributes

Following are the important attributes specific to FrameLayout −
Attribute
Description
android:id
This is the ID which uniquely identifies the layout.
android:foreground
This defines the drawable to draw over the content and possible values may be a color value, in the form of "#rgb", "#argb", "#rrggbb", or "#aarrggbb".
android:foregroundGravity
Defines the gravity to apply to the foreground drawable. The gravity defaults to fill. Possible values are top, bottom, left, right, center, center_vertical, center_horizontal etc.
android:measureAllChildren
Determines whether to measure all children or just those in the VISIBLE or INVISIBLE state when measuring. Defaults to false.

Example

This example will take you through simple steps to show how to create your own Android application using frame layout. Follow the following steps to modify the Android application we created in Hello World Example chapter −
Step
Description
1
You will use Android studio IDE to create an Android application and name it asdemo under a package com.example.demo as explained in the Hello World Example chapter.
2
Modify the default content of res/layout/activity_main.xml file to include few widgets in frame layout.
3
No need to change string.xml, android takes care default constants
4
Run the application to launch Android emulator and verify the result of the changes done in the application.
Following is the content of the modified main activity filesrc/com.example.demo/MainActivity.java. This file can include each of the fundamental lifecycle methods.
package com.example.demo;
 
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
 
public class MainActivity extends Activity {
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
   }
   
   @Override
   public boolean onCreateOptionsMenu(Menu menu) {
      getMenuInflater().inflate(R.menu.main, menu);
      return true;
   }
}
Following will be the content of res/layout/activity_main.xml file −
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
   android:layout_width="fill_parent"
   android:layout_height="fill_parent">
   
   <ImageView 
      android:src="@drawable/ic_launcher"
      android:scaleType="fitCenter"
      android:layout_height="250px"
      android:layout_width="250px"/>
   
   <TextView
      android:text="Frame Demo"
      android:textSize="30px"
      android:textStyle="bold"
      android:layout_height="fill_parent"
      android:layout_width="fill_parent"
      android:gravity="center"/>
</FrameLayout>
Following will be the content of res/values/strings.xml to define two new constants −
<?xml version="1.0" encoding="utf-8"?>
<resources>
   <string name="app_name">demo</string>
   <string name="action_settings">Settings</string>
</resources>
Let's try to run our modified Hello World! application we just modified. I assume you had created your AVD while doing environment setup. To run the app from Android Studio, open one of your project's activity files and click Run Eclipse Run Icon icon from the toolbar. Android Studio installs the app on your AVD and starts it and if everything is fine with your setup and application, it will display following Emulator window −

Android List View

Android ListView is a view which groups several items and display them in vertical scrollable list. The list items are automatically inserted to the list using an Adapter that pulls content from a source such as an array or database.

LIST VIEW

An adapter actually bridges between UI components and the data source that fill data into UI Component. Adapter holds the data and send the data to adapter view, the view can takes the data from adapter view and shows the data on different views like as spinner, list view, grid view etc.
The ListView and GridView are subclasses of AdapterView and they can be populated by binding them to an Adapter, which retrieves data from an external source and creates a View that represents each data entry.
Android provides several subclasses of Adapter that are useful for retrieving different kinds of data and building views for an AdapterView ( i.e. ListView or GridView). The common adapters are ArrayAdapter,Base Adapter, CursorAdapter,SimpleCursorAdapter,SpinnerAdapter and WrapperListAdapter. We will see separate examples for both the adapters.

ListView Attributes

Following are the important attributes specific to GridView −
Attribute
Description
android:id
This is the ID which uniquely identifies the layout.
android:divider
This is drawable or color to draw between list items. .
android:dividerHeight
This specifies height of the divider. This could be in px, dp, sp, in, or mm.
android:entries
Specifies the reference to an array resource that will populate the ListView.
android:footerDividersEnabled
When set to false, the ListView will not draw the divider before each footer view. The default value is true.
android:headerDividersEnabled
When set to false, the ListView will not draw the divider after each header view. The default value is true.

ArrayAdapter

You can use this adapter when your data source is an array. By default, ArrayAdapter creates a view for each array item by calling toString() on each item and placing the contents in a TextView. Consider you have an array of strings you want to display in a ListView, initialize a new ArrayAdapter using a constructor to specify the layout for each string and the string array −
ArrayAdapter adapter = new ArrayAdapter<String>(this,R.layout.ListView,StringArray);
Here are arguments for this constructor −
·        First argument this is the application context. Most of the case, keep it this.
·        Second argument will be layout defined in XML file and having TextView for each string in the array.
·        Final argument is an array of strings which will be populated in the text view.
Once you have array adapter created, then simply call setAdapter() on your ListViewobject as follows −
ListView listView = (ListView) findViewById(R.id.listview);
listView.setAdapter(adapter);
You will define your list view under res/layout directory in an XML file. For our example we are going to using activity_main.xml file.

Example

Following is the example which will take you through simple steps to show how to create your own Android application using ListView. Follow the following steps to modify the Android application we created in Hello World Example chapter −
Step
Description
1
You will use Android Studio IDE to create an Android application and name it asListDisplay under a package com.example.ListDisplay as explained in the Hello World Example chapter.
2
Modify the default content of res/layout/activity_main.xml file to include ListView content with the self explanatory attributes.
3
No need to change string.xml, Android studio takes care of default string constants.
4
Create a Text View file res/layout/activity_listview.xml. This file will have setting to display all the list items. So you can customize its fonts, padding, color etc. using this file.
6
Run the application to launch Android emulator and verify the result of the changes done in the application.
Following is the content of the modified main activity filesrc/com.example.ListDisplay/ListDisplay.java. This file can include each of the fundamental life cycle methods.
package com.example.ListDisplay;
 
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.widget.ArrayAdapter;
import android.widget.ListView;
 
public class ListDisplay extends Activity {
   // Array of strings...
   String[] mobileArray = {"Android","IPhone","WindowsMobile","Blackberry","WebOS","Ubuntu","Windows7","Max OS X"};
   
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      
      ArrayAdapter adapter = new ArrayAdapter<String>(this, R.layout.activity_listview, mobileArray);
      
      ListView listView = (ListView) findViewById(R.id.mobile_list);
      listView.setAdapter(adapter);
   }
}
Following will be the content of res/layout/activity_main.xml file −
<LinearLayout 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"
   android:orientation="vertical"
   tools:context=".ListActivity" >
 
   <ListView
      android:id="@+id/mobile_list"
      android:layout_width="match_parent"
      android:layout_height="wrap_content" >
   </ListView>
 
</LinearLayout>
Following will be the content of res/values/strings.xml to define two new constants −
<?xml version="1.0" encoding="utf-8"?>
<resources>
   <string name="app_name">ListDisplay</string>
   <string name="action_settings">Settings</string>
</resources>
Following will be the content of res/layout/activity_listview.xml file:
<?xml version="1.0" encoding="utf-8"?>
<!--  Single List Item Design -->
 
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
   android:id="@+id/label"
   android:layout_width="fill_parent"
   android:layout_height="fill_parent"
   android:padding="10dip"
   android:textSize="16dip"
   android:textStyle="bold" >
</TextView>
Let's try to run our modified Hello World! application we just modified. I assume you had created your AVD while doing environment set-up. To run the app from Android studio, open one of your project's activity files and click Run Eclipse Run Icon icon from the tool bar. Android studio installs the app on your AVD and starts it and if everything is fine with your set-up and application, it will display following Emulator window −

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