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Friday, 14 March 2014

Android: Custom Toast Messages.

In last tutorial we saw how to use Toast Messages, and now we will see how to customize Toast messages.
Output will be as:
Android Custom Toast

Xml file:
res/layout
1. activity_main.xml
 <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" 
  > 
  <Button  
   android:id="@+id/button1" 
   android:layout_width="wrap_content" 
   android:layout_height="wrap_content" 
   android:text="Android Toast" 
   /> 
  </LinearLayout>
2. toast.xml
 <?xml version="1.0" encoding="utf-8"?> 
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
  android:id="@+id/toast_layout" 
  android:layout_width="match_parent" 
  android:layout_height="match_parent" 
  android:orientation="horizontal" > 
  <ImageView android:src="@drawable/rating_good" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     /> 
  <TextView android:id="@+id/tv1" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    /> 
 </LinearLayout>
Here we have defined a layout for our custom Toast. Also don't forget to add an image in your drawable folder.(res/drawable).

Java file:
src/
 package com.example.toastexample; 
 import android.os.Bundle; 
 import android.app.Activity; 
 import android.view.LayoutInflater; 
 import android.view.View; 
 import android.view.View.OnClickListener; 
 import android.view.ViewGroup; 
 import android.widget.Button; 
 import android.widget.TextView; 
 import android.widget.Toast; 
 public class MainActivity extends Activity implements OnClickListener { 
   Button b1; 
   @Override 
   protected void onCreate(Bundle savedInstanceState) { 
      super.onCreate(savedInstanceState); 
      setContentView(R.layout.activity_main); 
      b1=(Button) findViewById(R.id.button1); 
      b1.setOnClickListener(this); 
   } 
   @Override 
   public void onClick(View v) { 
      // TODO Auto-generated method stub 
      switch(v.getId()){ 
      case R.id.button1: 
        LayoutInflater inflater = getLayoutInflater(); 
        View layout = inflater.inflate(R.layout.toast, 
                (ViewGroup) findViewById(R.id.toast_layout));//referencing toast layout 
        TextView text1 = (TextView) layout.findViewById(R.id.tv1); 
        text1.setText("Well Done"); 
        Toast toast = new Toast(getApplicationContext()); 
        toast.setDuration(Toast.LENGTH_LONG); 
        toast.setView(layout); 
        toast.show(); 
        break; 
      } 
   } 
 }
Here we have referenced our custom toast layout(toast.xml) and added that layout on our toast message.

Android: Using Toast Messages.

Android Toast is a little message used to provide feedback to the user. Today in this tutorial we will see how to make use of these Toast messages.

Output will be as:
Android Toast Message


Xml file:
res/layout/
 <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" 
  > 
  <Button  
   android:id="@+id/button1" 
   android:layout_width="wrap_content" 
   android:layout_height="wrap_content" 
   android:text="Android Toast" 
   /> 
  </LinearLayout>

Java file:
src/
 package com.example.toastexample; 
 import android.os.Bundle; 
 import android.app.Activity; 
 import android.view.Menu; 
 import android.view.View; 
 import android.view.View.OnClickListener; 
 import android.widget.Button; 
 import android.widget.Toast; 
 public class MainActivity extends Activity implements OnClickListener { 
   Button b1; 
   @Override 
   protected void onCreate(Bundle savedInstanceState) { 
      super.onCreate(savedInstanceState); 
      setContentView(R.layout.activity_main); 
      b1=(Button) findViewById(R.id.button1); 
      b1.setOnClickListener(this); 
   } 
   @Override 
   public void onClick(View v) { 
      // TODO Auto-generated method stub 
      switch(v.getId()){ 
      case R.id.button1: 
        Toast.makeText(getApplicationContext(), "Android Toast Message", Toast.LENGTH_SHORT).show(); 
        //Display Toast message 
        break; 
      } 
   } 
 }
Here Toast.makeText() method is used to make a Toast message which takes Context, Message and the duration for which the toast is to be displayed. And then show() method is used to display the Toast Message.

Saturday, 8 March 2014

Android:Styling Buttons

In this tutorial we will see how we can change the default appearance of a button. For this we need to customize three different states of button i.e. default state, pressed state and focused state.
Output will be as:(When button is pressed)



 Xml files:
1. activity_main(res/layout):
 <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:padding="10dp" 
    android:orientation="vertical" 
  > 
  <Button  
   android:id="@+id/button1" 
   android:layout_width="200dp" 
   android:layout_height="50dp" 
   android:background="@drawable/custom_button" 
   android:text="Button" 
   /> 
  </LinearLayout>
2. custom_button.xml(res/drawable):
Now here we need to create a new xml file(custom_button.xml) under res/drawable that will customize the three states of button.
 <?xml version="1.0" encoding="utf-8"?> 
 <selector xmlns:android="http://schemas.android.com/apk/res/android" > 
  <item android:state_pressed="true"  
   android:drawable="@color/change" 
   > 
  </item> 
  <item android:state_focused="true" 
   android:drawable="@color/change" 
   > 
  </item>  
  <item android:drawable="@color/default_color"> 
  </item> 
 </selector>
3. colors.xml(res/values):
We also need to create colors.xml under res/values to define the colors.
 <?xml version="1.0" encoding="utf-8"?> 
 <resources> 
  <color name="change">#5F9EA0</color> 
  <color name="default_color">#ACACAC</color> 
 </resources>

Thursday, 6 March 2014

Android: Passing Messages between Activities

Intents are the messages which are passed between Activities, Broadcast Receivers, Services and Content Providers. So intent can be used to start a new Activity and to pass a message between activities. In our application first activity will pass some message to second activity, which will be simply retrieved and displayed by the second activity.

Output will be as:





 Xml files: res---layout
activity_main.xml 
 <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" 
  android:padding="10dp" 
  > 
  <EditText  
   android:id="@+id/etmessage" 
   android:layout_width="fill_parent" 
   android:layout_height="wrap_content" 
   android:hint="Enter Message" 
   /> 
  <Button  
   android:id="@+id/button1" 
   android:layout_width="wrap_content" 
   android:layout_height="wrap_content" 
   android:text="Send" 
   /> 
  </LinearLayout>

message.xml: 
 <?xml version="1.0" encoding="utf-8"?> 
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
  android:layout_width="match_parent" 
  android:layout_height="match_parent" 
  android:orientation="vertical"  
  android:padding="10dp" 
  > 
  <TextView  
   android:id="@+id/tvMessage" 
   android:layout_width="wrap_content" 
   android:layout_height="wrap_content" 
   android:textSize="24dp" 
   android:textColor="#FF0000" 
   android:layout_gravity="center" 
   /> 
 </LinearLayout>

Java files:
MainActivity.java
 import android.os.Bundle; 
 import android.app.Activity; 
 import android.content.Intent; 
 import android.view.Menu; 
 import android.view.View; 
 import android.view.View.OnClickListener; 
 import android.widget.Button; 
 import android.widget.EditText; 
 public class MainActivity extends Activity implements OnClickListener { 
   EditText et; 
   Button b1; 
   @Override 
   protected void onCreate(Bundle savedInstanceState) { 
      super.onCreate(savedInstanceState); 
      setContentView(R.layout.activity_main); //referencing UI 
      et=(EditText) findViewById(R.id.etmessage);//referencing EditText 
      b1=(Button) findViewById(R.id.button1);//referencing Button 
      b1.setOnClickListener(this); //adding click event 
   } 
   @Override 
   public boolean onCreateOptionsMenu(Menu menu) { 
      // Inflate the menu; this adds items to the action bar if it is present. 
      getMenuInflater().inflate(R.menu.main, menu); 
      return true; 
   } 
   @Override 
   public void onClick(View v) { 
      // TODO Auto-generated method stub 
      switch(v.getId()){ 
      case R.id.button1: 
        String message=et.getText().toString(); 
        Intent i=new Intent(this,Message_class.class);//Intent used to start a new Activity 
        Bundle extras=new Bundle(); 
        extras.putString("key", message);//binding data to bundle 
        i.putExtras(extras);//Adding extras(bundle) to intent 
        startActivity(i);//starting new Activity 
        finish();//finishing current activity 
        break; 
      } 
   } 
 }
Here we have simply used Bundle that binds our data with Intent.
After adding bundle to an intent, startActivity() method is used to start a new Activity.

Message_class.java
 import android.app.Activity; 
 import android.os.Bundle; 
 import android.widget.TextView; 
 public class Message_class extends Activity { 
  TextView tv; 
   @Override 
   protected void onCreate(Bundle savedInstanceState) { 
      // TODO Auto-generated method stub 
      super.onCreate(savedInstanceState); 
      setContentView(R.layout.message); 
      tv=(TextView) findViewById(R.id.tvMessage); 
      Bundle extras=this.getIntent().getExtras();//retrieving bundle from intnet 
      if(extras!=null){ 
        String msg=extras.getString("key");//retrieving message from bundle 
        tv.setText(msg); 
      } 
   } 
 }

Manifest file:
 <?xml version="1.0" encoding="utf-8"?> 
 <manifest xmlns:android="http://schemas.android.com/apk/res/android" 
 package="com.example.message_example" 
 android:versionCode="1" 
 android:versionName="1.0" > 
 <uses-sdk 
 android:minSdkVersion="8" 
 android:targetSdkVersion="17" /> 
 <application 
 android:allowBackup="true" 
 android:icon="@drawable/ic_launcher" 
 android:label="@string/app_name" 
 android:theme="@style/AppTheme" > 
 <activity 
 android:name="com.example.message_example.MainActivity" 
 android:label="@string/app_name" > 
 <intent-filter> 
 <action android:name="android.intent.action.MAIN" /> 
 <category android:name="android.intent.category.LAUNCHER" /> 
 </intent-filter> 
 </activity> 
  <activity 
 android:name=".Message_class" 
 android:label="New Activity" 
 ></activity> 
 </application> 
 </manifest>
Here we have added our new activity i.e Message_class to our manifest file.
Feel free to ask me your doubts in the comments below.

Tuesday, 4 March 2014

Android: Using ListView

In last tutorial we saw how to add click event to buttons and now in this tutorial we will see how to use a listview.

Output will be as:

XML file: res---layout
 <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" 
 > 
 <EditText  
  android:id="@+id/etText" 
  android:layout_width="fill_parent" 
  android:layout_height="wrap_content" 
  android:hint="Enter text" 
  /> 
 <Button  
  android:id="@+id/bAdd" 
  android:layout_width="wrap_content" 
  android:layout_height="wrap_content" 
   android:text="Add"  
  /> 
 <ListView  
  android:id="@+id/listDisplay" 
  android:layout_width="fill_parent" 
  android:layout_height="wrap_content" 
  > 
 </ListView> 
 </LinearLayout>

In our layout file we have added one EditText, Button and a ListView.
Clicking a button will take the user data and add it to a ListView.

Java file: src---your package name
 import java.util.ArrayList; 
 import android.os.Bundle; 
 import android.app.Activity; 
 import android.view.Menu; 
 import android.view.View; 
 import android.view.View.OnClickListener; 
 import android.widget.ArrayAdapter; 
 import android.widget.Button; 
 import android.widget.EditText; 
 import android.widget.ListView; 
 public class MainActivity extends Activity implements OnClickListener { 
   Button b1; 
   ListView list; 
   EditText et; 
   private ArrayAdapter<String> adapter; 
   private ArrayList<String> items; 
   @Override 
   protected void onCreate(Bundle savedInstanceState) { 
      super.onCreate(savedInstanceState); 
      setContentView(R.layout.activity_main);//referencing UI 
      b1=(Button) findViewById(R.id.bAdd); //referencing button 
      list=(ListView) findViewById(R.id.listDisplay); //referencing listview 
      et=(EditText) findViewById(R.id.etText); //referencing edittext 
      b1.setOnClickListener(this); //adding click event to button 
      items=new ArrayList<String>(); 
      adapter=new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,items); 
      //Adapter used to bind array to the listview 
      list.setAdapter(adapter);//applying adapter to listview 
   } 
   @Override 
   public boolean onCreateOptionsMenu(Menu menu) { 
      // Inflate the menu; this adds items to the action bar if it is present. 
      getMenuInflater().inflate(R.menu.main, menu); 
      return true; 
   } 
   @Override 
   public void onClick(View v) { 
      // TODO Auto-generated method stub 
      switch(v.getId()){ 
      case R.id.bAdd: 
        items.add(0, et.getText().toString());//getting data from edittext 
        adapter.notifyDataSetChanged();//refereshes the adapter (listview) 
        et.setText(""); 
        break; 
      } 
   } 
 }
Here we have used an ArrayAdapter which will bind the array(i.e ArrayList) to the ListView.
The onClick method does the job of retrieving user data from EditText and adding it to the ArrayList and the function notifyDataSetChanged() is used to refresh the adapter.

Manifest file:
 <?xml version="1.0" encoding="utf-8"?> 
 <manifest xmlns:android="http://schemas.android.com/apk/res/android" 
  package="com.example.listvieweg" 
  android:versionCode="1" 
  android:versionName="1.0" > 
  <uses-sdk 
   android:minSdkVersion="8" 
   android:targetSdkVersion="17" /> 
  <application 
   android:allowBackup="true" 
   android:icon="@drawable/ic_launcher" 
   android:label="@string/app_name" 
   android:theme="@style/AppTheme" > 
   <activity 
    android:name="com.example.listvieweg.MainActivity" 
    android:label="@string/app_name" > 
    <intent-filter> 
     <action android:name="android.intent.action.MAIN" /> 
     <category android:name="android.intent.category.LAUNCHER" /> 
    </intent-filter> 
   </activity> 
  </application> 
 </manifest>
No need to make any changes in a Manifest file.

Test your application and if you have any doubts feel free to ask me in the comments below.
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