Android สอบถามปัญหาการใช้ Intent ครับ เนื่องจากบางหน้ากดเปลี่ยนหน้าไม่ได้ครับ

import com.devdroid.payardtang.note.Note_Expense;
import com.devdroid.payardtang.note.Note_in;
import com.devdroid.payardtang.plan.Plan_Main;
import com.devdroid.payardtang.report.Report;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ImageButton;


public class Main extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        btnIncome();
        btnExpense();
        btnPlan();
        btnReport();
        btnExit();
    }
    



	public void btnIncome() {
    	
    	ImageButton btnIncome = (ImageButton) findViewById(R.id.imgBtnIncome);
    	
    	btnIncome.setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
				Intent addIncome = new Intent(getApplicationContext(),Note_in.class);
				startActivity(addIncome);
				finish();
			}
		});
    }
	
    private void btnExpense() {
		ImageButton btnExpense = (ImageButton) findViewById(R.id.imgBtnExpense);
		
		btnExpense.setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
				Intent addExpense = new Intent(getApplicationContext(),Note_Expense.class);
				startActivity(addExpense);
				finish();
				
			}
		});
		
	}

    private void btnPlan() {
		ImageButton btnPlan = (ImageButton) findViewById(R.id.imgBtnPlan);
		
		btnPlan.setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
			Intent addPlan = new Intent(getApplicationContext(),Plan_Main.class);
			startActivity(addPlan);
			finish();
			}
		});
		
	}
    

	private void btnReport() {
		ImageButton btnReport =(ImageButton) findViewById(R.id.imgBtnReport);
		
		btnReport.setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
				Intent reportPage = new Intent(getApplicationContext(),Report.class);
				startActivity(reportPage);
				finish();
				
			}
		});
		
	}
    
    public void btnExit() {
    	 final Context context = this ;
    	 ImageButton btnExit = (ImageButton) findViewById(R.id.imgBtnExit);
    	 
    	 btnExit.setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View v) {
//				Toast.makeText(Main.this,
//				"ImageButton is clicked!", Toast.LENGTH_SHORT).show();
				 
				AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(context);
				 
					// set title
					//alertDialogBuilder.setTitle("ออกจากโปรแกรม");

					// set dialog message
					alertDialogBuilder
							.setMessage("Do you really want to exit?")
							.setCancelable(false)
							.setPositiveButton("Yes",
									new DialogInterface.OnClickListener() {
										public void onClick(DialogInterface dialog,
												int id) {
											// if this button is clicked, close
											// current activity
											Main.this.finish();
										}
									})
							.setNegativeButton("No",
									new DialogInterface.OnClickListener() {
										public void onClick(DialogInterface dialog,
												int id) {
											// if this button is clicked, just close
											// the dialog box and do nothing
											dialog.cancel();
										}
									});

					// create alert dialog
					AlertDialog alertDialog = alertDialogBuilder.create();

					// show it
					alertDialog.show();

				}
    	 });
				
			}
		
    

    @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;
    }
    
}

import com.devdroid.payardtang.R;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ImageButton;

public class Note_in extends Activity {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.onCreate(savedInstanceState);
		setContentView(R.layout.note_in);
		
	}
	public void addIncome(){
		
		ImageButton btnAddIncome =(ImageButton) findViewById(R.id.imgaadIncome);
		 btnAddIncome.setOnClickListener(new OnClickListener() {
			
			public void onClick(View v) {
				// TODO Auto-generated method stub
			Intent addIncome_l2 = new Intent(Note_in.this,Note_in_add.class);
			startActivity(addIncome_l2);
				
				
				
			}
		});
		
	}
	

}

import com.devdroid.payardtang.R;

import android.app.Activity;
import android.os.Bundle;

public class Note_in_add extends Activity{

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.onCreate(savedInstanceState);
		setContentView(R.layout.note_in_add);
	}
	
	

}