نمایش یک پنجره دیالوگ

مواقعی نیاز است که یک پنجره دیالوگ را به کاربر نمایش داد به عنوان مثال زمان هایی که برای انجام یه سری کارا نیاز به تائید کاربر داریم در این موارد میتونیم از متد   ()  onCreatedDialog استفاده کنیم که در کلاس پایه اکتیویتی است

 package ir.exampel.Dialog;

import android.app.Activity;
import android.app.AlertDialog;
import android.app.AlertDialog.Builder;
import android.app.Dialog;
import android.app.ProgressDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;

public class DialogActivity extends Activity {
	CharSequence[] items = { "Google", "Apple", "Microsoft" };
	boolean[] itemsChecked = new boolean [items.length];

    ProgressDialog progressDialog;


	/** Called when the activity is first created. */
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);		
	}

	public void onClick(View v) {
		showDialog(0);
	}

	public void onClick2(View v) {
		//---show the dialog---
		final ProgressDialog dialog = ProgressDialog.show(
			this, "Doing something", "Please wait...", true);
	    new Thread(new Runnable(){
		    public void run(){
			    try {
			    	//---simulate doing something lengthy---
			        Thread.sleep(5000);
			        //---dismiss the dialog---
					dialog.dismiss();
				} catch (InterruptedException e) {					
				    e.printStackTrace();
				}		
			}
		}).start();
	}		

	public void onClick3(View v) {
		showDialog(1);        
        progressDialog.setProgress(0);        

        new Thread(new Runnable(){
		    public void run(){
		    	for (int i=1; i<=15; i++) {
				    try {
				    	//---simulate doing something lengthy---
				        Thread.sleep(1000);
				        //---update the dialog---
				        progressDialog.incrementProgressBy((int)(100/15));
					} catch (InterruptedException e) {					
					    e.printStackTrace();
					}
		    	}
		        progressDialog.dismiss();
			}
		}).start();
	}	

	@Override
	protected Dialog onCreateDialog(int id) { 
		switch (id) {
		case 0:	
			/*
		    Builder builder = new AlertDialog.Builder(this);
		    builder.setIcon(R.drawable.ic_launcher);
		    builder.setTitle("This is a dialog with some simple text...");
		    builder.setPositiveButton("OK", 
		    	new DialogInterface.OnClickListener() {
					public void onClick(DialogInterface dialog,	int whichButton) {
						Toast.makeText(getBaseContext(),
								"OK clicked!", Toast.LENGTH_SHORT).show();
					}
		        }
		    );

		    builder.setNegativeButton("Cancel", 
				new DialogInterface.OnClickListener() {
					public void onClick(DialogInterface dialog, int whichButton) {
						Toast.makeText(getBaseContext(),
							"Cancel clicked!", Toast.LENGTH_SHORT).show();
					}
				}
			);

		    builder.setMultiChoiceItems(items, itemsChecked, 
				new DialogInterface.OnMultiChoiceClickListener() {				
					public void onClick(DialogInterface dialog, 
					int which, boolean isChecked) {
						Toast.makeText(getBaseContext(),
							items[which] + (isChecked ? " checked!":" unchecked!"), 
							Toast.LENGTH_SHORT).show();
					}
				}
			);		    
		    return builder.create();
		    */			

			return new AlertDialog.Builder(this)
			.setIcon(R.drawable.ic_launcher)
			.setTitle("This is a dialog with some simple text...")
			.setPositiveButton("OK", 
				new DialogInterface.OnClickListener() {
					public void onClick(DialogInterface dialog,	int whichButton)
					{
						Toast.makeText(getBaseContext(),
								"OK clicked!", Toast.LENGTH_SHORT).show();
					}
			    }
			)
			.setNegativeButton("Cancel", 
				new DialogInterface.OnClickListener() {
					public void onClick(DialogInterface dialog, int whichButton)
					{
						Toast.makeText(getBaseContext(),
								"Cancel clicked!", Toast.LENGTH_SHORT).show();
					}
				}
			)
			.setMultiChoiceItems(items, itemsChecked, 
			    new DialogInterface.OnMultiChoiceClickListener() {					
					public void onClick(DialogInterface dialog, 
					int which, boolean isChecked) {
						Toast.makeText(getBaseContext(),
							items[which] + (isChecked ? " checked!":" unchecked!"), 
							Toast.LENGTH_SHORT).show();
					}
			    }
			).create();

		case 1:
            progressDialog = new ProgressDialog(this);
            progressDialog.setIcon(R.drawable.ic_launcher);
            progressDialog.setTitle("Downloading files...");
            progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
            progressDialog.setButton(DialogInterface.BUTTON_POSITIVE, "OK", 
            	new DialogInterface.OnClickListener() {
	                public void onClick(DialogInterface dialog,
	                int whichButton)
	                {
	                    Toast.makeText(getBaseContext(),
	                            "OK clicked!", Toast.LENGTH_SHORT).show();
	                }
            });
            progressDialog.setButton(DialogInterface.BUTTON_NEGATIVE, "Cancel", 
                new DialogInterface.OnClickListener() {
	                public void onClick(DialogInterface dialog,
	                    int whichButton)
	                {
	                    Toast.makeText(getBaseContext(),
	                            "Cancel clicked!", Toast.LENGTH_SHORT).show();
	                }
            });
            return progressDialog;
		}		
		return null;
	}
}