Here I have created a simple Dialog, like:

custom_dialog.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="80dp"    android:background="#3E80B4"    android:orientation="vertical" >    <TextView        android:id="@+id/txt_dia"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_gravity="center"        android:layout_margin="10dp"        android:text="Do you realy want to exit ?"        android:textColor="@android:color/white"        android:textSize="15dp"        android:textStyle="bold"/>        <LinearLayout        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_gravity="center"        android:background="#3E80B4"        android:orientation="horizontal" >        <Button            android:id="@+id/btn_yes"            android:layout_width="100dp"            android:layout_height="30dp"            android:background="@android:color/white"            android:clickable="true"            android:text="Yes"            android:textColor="#5DBCD2"            android:textStyle="bold" />        <Button            android:id="@+id/btn_no"            android:layout_width="100dp"            android:layout_height="30dp"            android:layout_marginLeft="5dp"            android:background="@android:color/white"            android:clickable="true"            android:text="No"            android:textColor="#5DBCD2"            android:textStyle="bold" />    </LinearLayout></LinearLayout>

You have to extends Dialog and implements OnClickListener

public class CustomDialogClass extends Dialog implements    android.view.View.OnClickListener {  public Activity c;  public Dialog d;  public Button yes, no;  public CustomDialogClass(Activity a) {    super(a);    // TODO Auto-generated constructor stub    this.c = a;  }  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    requestWindowFeature(Window.FEATURE_NO_TITLE);    setContentView(R.layout.custom_dialog);    yes = (Button) findViewById(R.id.btn_yes);    no = (Button) findViewById(R.id.btn_no);    yes.setOnClickListener(this);    no.setOnClickListener(this);  }  @Override  public void onClick(View v) {    switch (v.getId()) {    case R.id.btn_yes:      c.finish();      break;    case R.id.btn_no:      dismiss();      break;    default:      break;    }    dismiss();  }}

How to Call Dialog ?

R.id.TXT_Exit:CustomDialogClass cdd=new CustomDialogClass(Values.this);cdd.show();  

Updates

After a long time one of my friends asked me to make a curved shape dialog with a transparent background. So, Here I have implemented it.

To Make a curved shape you need to create a separate curve_shap.XML as below,

<shape xmlns:android="http://schemas.android.com/apk/res/android" >    <solid android:color="#000000" />    <stroke        android:width="2dp"        android:color="#ffffff" />    <corners        android:bottomLeftRadius="20dp"        android:bottomRightRadius="20dp"        android:topLeftRadius="20dp"        android:topRightRadius="20dp" /></shape>

Now, add this curve_shap.XML in your main view Layout. In my case I have used LinearLayout

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"        android:layout_width="fill_parent"        android:layout_height="80dp"        android:background="@drawable/curve_shap"        android:orientation="vertical" >...</LinearLayout>

How to call this ?

CustomDialogClass cdd = new CustomDialogClass(MainActivity.this);cdd.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));cdd.show();

I hope that works for you.

This is an example dialog, create with xml.

the next code xml is just an example, the design or view is implemented here:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"android:orientation="vertical"android:layout_width="match_parent"android:layout_height="wrap_content"android:background="#ffffffff"><ImageView    android:layout_width="match_parent"    android:layout_height="120dp"    android:id="@+id/a"    android:gravity="center"    android:background="#DA5F6A"    android:src="@drawable/dialog_cross"    android:scaleType="fitCenter" /><TextView    android:layout_width="wrap_content"    android:layout_height="wrap_content"    android:text="TEXTO"    android:id="@+id/text_dialog"    android:layout_below="@+id/a"    android:layout_marginTop="20dp"    android:layout_marginLeft="4dp"    android:layout_marginRight="4dp"    android:layout_marginBottom="20dp"    android:textSize="18sp"    android:textColor="#ff000000"    android:layout_centerHorizontal="true"    android:gravity="center_horizontal" /><Button    android:layout_width="wrap_content"    android:layout_height="30dp"    android:text="OK"    android:id="@+id/btn_dialog"    android:gravity="center_vertical|center_horizontal"    android:layout_below="@+id/text_dialog"    android:layout_marginBottom="20dp"    android:background="@drawable/btn_flat_red_selector"    android:layout_centerHorizontal="true"    android:textColor="#ffffffff" /></RelativeLayout>

this lines of code are resources of drawable:

android:src="@drawable/dialog_cross"android:background="@drawable/btn_flat_red_selector"

you could do a class extends Dialog, also something like this:

public class ViewDialog {    public void showDialog(Activity activity, String msg){        final Dialog dialog = new Dialog(activity);        dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);        dialog.setCancelable(false);        dialog.setContentView(R.layout.dialog);        TextView text = (TextView) dialog.findViewById(R.id.text_dialog);        text.setText(msg);        Button dialogButton = (Button) dialog.findViewById(R.id.btn_dialog);        dialogButton.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                dialog.dismiss();            }        });        dialog.show();    }}

finally the form of call, on your Activity for example:

ViewDialog alert = new ViewDialog();alert.showDialog(getActivity(), "Error de conexión al servidor");

I hope its work for you.

UPDATE

Drawable XML For dialog :

<shape xmlns:android="schemas.android.com/apk/res/android"> <stroke android:width="2dp" android:color="#FFFFFF" /> <gradient android:angle="180" android:endColor="@color/NaranjaOTTAA" android:startColor="@color/FondoActionBar" /> <corners android:bottomLeftRadius="7dp" android:bottomRightRadius="7dp" android:topLeftRadius="7dp" android:topRightRadius="7dp" /> </shape> 

This xml was provided by @GastónSaillén.

Another easy way to do this.

step 1) create a layout with proper id's.

step 2) use the following code wherever you desire.

LayoutInflater factory = LayoutInflater.from(this);final View deleteDialogView = factory.inflate(R.layout.mylayout, null);final AlertDialog deleteDialog = new AlertDialog.Builder(this).create();deleteDialog.setView(deleteDialogView);deleteDialogView.findViewById(R.id.yes).setOnClickListener(new OnClickListener() {        @Override    public void onClick(View v) {        //your business logic         deleteDialog.dismiss();    }});deleteDialogView.findViewById(R.id.no).setOnClickListener(new OnClickListener() {        @Override    public void onClick(View v) {        deleteDialog.dismiss();        }});deleteDialog.show();