Lecture 44th: Android Dialog box (1)

Lecture 44th: Android Dialog box (1)

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Description: Dialog box

1. Introduction to Dialog
Dialog is also a common user interface element in Android. It is not a subclass of View like Menu. Let's take a look at its inheritance relationship:

DatePickerDialog, ProgressDialog, and TimePickerDialog, which we have already discussed in the previous chapter.

Example 1: a prompt is displayed when you press the return button to ensure correct operations. A Common Dialog Box style is used.

The main interface file MainActivity. java is as follows:

Public class MainActivity extends Activity {@ Overrideprotected void onCreate (Bundle savedInstanceState) {super. onCreate (savedInstanceState); setContentView (R. layout. activity_main);} protected void dialog () {// define the dialog box object AlertDialog. builder builder = new Builder (MainActivity. this); builder. setMessage ("are you sure you want to exit? "); Builder. setTitle ("prompt"); builder. setPositiveButton ("OK", new OnClickListener () {@ Overridepublic void onClick (DialogInterface dialog, int which) {dialog. dismiss (); // close the MainActivity dialog box. this. finish (); // exit}); builder. setNegativeButton ("cancel", new OnClickListener () {@ Overridepublic void onClick (DialogInterface dialog, int which) {dialog. dismiss () ;}}); builder. create (). show (); // display dialog box} // call this method in the onKeyDown (int keyCode, KeyEvent event) method @ Overridepublic boolean onKeyDown (int keyCode, KeyEvent event) {if (keyCode = KeyEvent. KEYCODE_BACK & event. getRepeatCount () = 0) {dialog () ;}return false ;}}

The running result is as follows:

Example 2: changed the chart in the dialog box and added three buttons.

The main interface file MainActivity. java is as follows:

Public class MainActivity extends Activity {private Button B; @ Overrideprotected void onCreate (Bundle savedInstanceState) {super. onCreate (savedInstanceState); setContentView (R. layout. activity_main); B = (Button) findViewById (R. id. button); B. setOnClickListener (new View. onClickListener () {@ Overridepublic void onClick (View arg0) {Dialog () ;}});} private void diid () {Dialog = new AlertDialog. builder (th Is). setIcon (android. R. drawable. btn_star). setTitle ("Preferences"). setMessage ("do you like her? "). SetPositiveButton ("very fond", new OnClickListener () {@ Overridepublic void onClick (DialogInterface arg0, int arg1) {Toast. makeText (MainActivity. this, "I like her very much. ", Toast. LENGTH_LONG ). show ();}}). setNegativeButton ("dislike", new OnClickListener () {@ Overridepublic void onClick (DialogInterface dialog, int which) {Toast. makeText (MainActivity. this, "I don't like her. ", Toast. LENGTH_LONG ). show ();}}). setNeutralButton ("General", new OnClickListener () {@ Overridepublic void onClick (DialogInterface dialog, int which) {Toast. makeText (MainActivity. this, "I do not like it or not. ", Toast. LENGTH_LONG). show () ;}}). create (); dialog. show ();}}

The running result is as follows:

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