Make a popup, dialog in Android

protected void onCreate(Bundle savedValues) {
//...
Button button = (Button)findViewById(R.id.tennut);
button.setOnClickListener(this);
//...
}
// Remember to implements OnClickListener layer

// implements function onClick() of OnClickListener layer
public void onClick(View v) {
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage("報告内容").setCancelable(false)
.setPositiveButton("賛成です。", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
MyActivity.this.finish();
}
})
.setNegativeButton("賛成しない。", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
dialog.cancel();
}
});
AlertDialog alert = builder.create();
}