Relative Layout In Android

Relativelayout is a Viewgroup that shows kid View components in relative positions. The position of a View could be defined as in respect to kin components, (for example, to the left-of or underneath a given component) or in positions with respect to the Relativelayout zone, (for example, adjusted to the bottom, left of focus).

Utilizing Relative Layout we can plan extravagant and excellent GUI.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

    <Button
        android:id="@+id/btnButton1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Button 1"/>

    <Button
        android:id="@+id/btnButton2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Button 2"
        android:layout_toRightOf="@+id/btnButton1"/>

     <Button
        android:id="@+id/btnButton3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Button 3"
        android:layout_below="@+id/btnButton1"/>

     <TextView
         android:id="@+id/textView1"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_below="@+id/btnButton3"
         android:layout_marginTop="94dp"
         android:text="User :"
         android:textAppearance="?android:attr/textAppearanceLarge" />

     <EditText
         android:id="@+id/editText1"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_alignParentRight="true"
         android:layout_alignTop="@+id/textView1"
         android:layout_toRightOf="@+id/btnButton3" />

     <Button
         android:id="@+id/btnSubmit"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_alignParentRight="true"
         android:layout_below="@+id/editText1"
         android:text="Submit" />

</RelativeLayout>

Android Advanced Interview Questions And Answers

When to use?
The Service can be used in tasks with no UI, but shouldn't be too long. If you need to perform long tasks, you must use threads within Service.
The IntentService can be used in long tasks usually with no communication to Main Thread. If communication is required, can use Main Thread handler or broadcast intents. Another case of use is when callbacks are needed (Intent triggered tasks).

How to trigger?
The Service is triggered calling to method onStartService().
The IntentService is triggered using an Intent, it spawns a new worker thread and the method onHandleIntent() is called on this thread.

Triggered From
The Service may be triggered from any thread.
The IntentService must be triggered from Main Thread.

Runs On
The Service runs in background but it runs on the Main Thread of the application.
The IntentService runs on a separate worker thread.

Limitations / Drawbacks
The Service may block the Main Thread of the application.
The IntentService cannot run tasks in parallel. Hence all the consecutive intents will go into the message queue for the worker thread and will execute sequentially.

Make a phone call from your android application

Set permissions in the manifest file

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.bubudsadasdas"
      android:versionCode="1"
      android:versionName="1.0">
    <application android:icon="@drawable/icon"android:label="@string/app_name">
        <activity android:name=".phonecalls"
                  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>
    <uses-sdk android:minSdkVersion="3" />
<uses-permission android:name="android.permission.CALL_PHONE"></uses-permission>
</manifest>

Create a new activity

private void call(String num) {
    try {
        Intent callIntent = new Intent(Intent.ACTION_CALL);
       num="tel:"+num;
        callIntent.setData(Uri.parse(num));
        startActivity(callIntent);
    } catch (ActivityNotFoundException e) {
        Log.e("helloandroid dialing example", "Call failed", e);
    }
}

What happens when you begin a telephone call depends, partially, on the phone system. The number may be inaccurate. The system may be occupied or generally inaccessible. The call could be interfered. Here, on the other hand, you see no failure taking care of rationale, aside from discovering and logging special cases that might be tossed if slip experiences an issue when discovering applications that can prepare Intent articles.

import android.app.Activity;
import android.content.ActivityNotFoundException;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class phonecalls extends Activity implements OnClickListener {
 /** Called when the activity is first created. */
 private EditText mEtNum;
 private Button mBtnCall;

 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.main);
  mEtNum = (EditText) findViewById(R.id.xEtNumber);
  mBtnCall = (Button) findViewById(R.id.xBtnCall);
  mBtnCall.setOnClickListener(this);
 }

 public void onClick(View v) {
  String num = mEtNum.getText().toString();
  if (num.length() > 5) {
   call(num);
  } else {
   Toast.makeText(getApplicationContext(), " Wrong Number ", 1).show();
  }
 }

 private void call(String num) {
  try {
   Intent callIntent = new Intent(Intent.ACTION_CALL);
   num = "tel:" + num;
   callIntent.setData(Uri.parse(num));
   startActivity(callIntent);
  } catch (ActivityNotFoundException activityException) {
   Log.e("dialing-example", "Call failed", activityException);
  }
 }

}

Send SMS Message In Android

In Android, you can use SmsManager API or device’s Built-in SMS application to send a SMS message.

SmsManager smsManager = SmsManager.getDefault();
smsManager.sendTextMessage("phoneNo", null, "sms message", null, null);

Inside the application put the following code.

Intent sendIntent = new Intent(Intent.ACTION_VIEW);
sendIntent.putExtra("sms_body", "default content"); 
sendIntent.setType("vnd.android-dir/mms-sms");

startActivity(sendIntent);

Set the permission inside manifest file

<uses-permission android:name="android.permission.SEND_SMS" />

SmsManager Example

main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/linearLayout1"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/textViewPhoneNo"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Enter Phone Number : "
        android:textAppearance="?android:attr/textAppearanceLarge" />

    <EditText
        android:id="@+id/editTextPhoneNo"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:phoneNumber="true" >
    </EditText>

    <TextView
        android:id="@+id/textViewSMS"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Enter SMS Message : "
        android:textAppearance="?android:attr/textAppearanceLarge" />

    <EditText
        android:id="@+id/editTextSMS"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:inputType="textMultiLine"
        android:lines="5"
        android:gravity="top" />

    <Button
        android:id="@+id/buttonSend"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Send" />


</LinearLayout>

SendSMSActivity.java

package com.mkyong.android;

import android.app.Activity;
import android.os.Bundle;
import android.telephony.SmsManager;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class SendSMSActivity extends Activity {

Button buttonSend;
EditText textPhoneNo;
EditText textSMS;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

buttonSend = (Button) findViewById(R.id.buttonSend);
textPhoneNo = (EditText) findViewById(R.id.editTextPhoneNo);
textSMS = (EditText) findViewById(R.id.editTextSMS);

// main Logic to Send SMS 

buttonSend.setOnClickListener(new OnClickListener() {


 @Override

public void onClick(View v) {
String phoneNo = textPhoneNo.getText().toString();
String sms = textSMS.getText().toString();
try {
SmsManager smsManager = SmsManager.getDefault();
smsManager.sendTextMessage(phoneNo, null, sms, null, null);
Toast.makeText(getApplicationContext(), "SMS Sent!",Toast.LENGTH_LONG).show();
} catch (Exception e) {
Toast.makeText(getApplicationContext(),"SMS faild, please try again later!",Toast.LENGTH_LONG).show();
 }
}
});
}


}

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.mkyong.android"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk android:minSdkVersion="10" />

    <uses-permission android:name="android.permission.SEND_SMS" />

    <application
        android:debuggable="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" >
        <activity
            android:label="@string/app_name"
            android:name=".SendSMSActivity" >
            <intent-filter >
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>


</manifest>

YOU'ER DONE!