Dialog 2种显示方式

建议用onCreateDialog(int)和 showDialog(int)这种模式显示Dialog, 系统来管理dialog状态，第一次创建时候，调用 onCreateDialog(int)，而 onPrepareDialog(int, Dialog)每次弹出都调用，用来动态改变dialog。

 

When you use this callback, the Android system automatically manages the state of each dialog and hooks them to the Activity, effectively making it the "owner" of each dialog.

 

When you want to show a dialog, call showDialog(int) and pass it an integer that uniquely identifies the dialog that you want to display.

When a dialog is requested for the first time, Android calls onCreateDialog(int) from your Activity, which is where you should instantiate the Dialog . This callback method is passed the same ID that you passed to showDialog(int) . After you create the Dialog, return the object at the end of the method.

Before the dialog is displayed, Android also calls the optional callback method onPrepareDialog(int, Dialog) . Define this method if you want to change any properties of the dialog each time it is opened. This method is called every time a dialog is opened, whereas onCreateDialog(int) is only called the very first time a dialog is opened. If you don't define onPrepareDialog() , then the dialog will remain the same as it was the previous time it was opened. This method is also passed the dialog's ID, along with the Dialog object you created in onCreateDialog() .

 

 

 

 

Example1:
public class ActivityMain extends Activity {
    private static final int DIALOG1 = 1;
    private static final int DIALOG2 = 2;
    private static final int DIALOG4 = 4;
    private static final int DIALOG3 = 3;

    @Override
    protected Dialog onCreateDialog(int id) {
        switch (id) {
        case DIALOG1:
            return buildDialog1(ActivityMain.this);
        case DIALOG2:
            return buildDialog2(ActivityMain.this);
        case DIALOG3:
            return buildDialog3(ActivityMain.this);
        case DIALOG4:
            return buildDialog4(ActivityMain.this);
        }
        return null;
    }

    protected void onPrepareDialog(int id, Dialog dialog) {
        if (id == DIALOG1) {
            setTitle("测试");
        }
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.alert_dialog);

        Button button1 = (Button) findViewById(R.id.button1);
        button1.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {
                showDialog(DIALOG1);
            }
        });

        Button buttons2 = (Button) findViewById(R.id.buttons2);
        buttons2.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {
                showDialog(DIALOG2);
            }
        });

        Button button3 = (Button) findViewById(R.id.button3);
        button3.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {
                showDialog(DIALOG3);
            }
        });

        Button button4 = (Button) findViewById(R.id.button4);
        button4.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {
                showDialog(DIALOG4);
            }
        });
    }

    private Dialog buildDialog1(Context context) {
        AlertDialog.Builder builder = new AlertDialog.Builder(context);
        builder.setIcon(R.drawable.alert_dialog_icon);
        builder.setTitle(R.string.alert_dialog_two_buttons_title);
        builder.setPositiveButton(R.string.alert_dialog_ok,
                new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int whichButton) {

                        setTitle("点击了对话框上的确定按钮: " + whichButton);
                    }
                });
        builder.setNegativeButton(R.string.alert_dialog_cancel,
                new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int whichButton) {

                        setTitle("点击了对话框上的取消按钮: " + whichButton);
                    }
                });

        return builder.create();

    }

    private Dialog buildDialog2(Context context) {
        AlertDialog.Builder builder = new AlertDialog.Builder(context);
        builder.setIcon(R.drawable.alert_dialog_icon);
        builder.setTitle(R.string.alert_dialog_two_buttons_msg);
        builder.setMessage(R.string.alert_dialog_two_buttons2_msg);
        builder.setPositiveButton(R.string.alert_dialog_ok,
                new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int whichButton) {

                        setTitle("点击了对话框上的确定按钮: " + whichButton);
                    }
                });
        builder.setNeutralButton(R.string.alert_dialog_something,
                new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int whichButton) {

                        setTitle("点击了对话框上的进入详细按钮: " + whichButton);
                    }
                });
        builder.setNegativeButton(R.string.alert_dialog_cancel,
                new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int whichButton) {

                        setTitle("点击了对话框上的取消按钮: " + whichButton);
                    }
                });
        return builder.create();
    }

    private Dialog buildDialog3(Context context) {
        LayoutInflater inflater = LayoutInflater.from(this);
        final View textEntryView = inflater.inflate(
                R.layout.alert_dialog_text_entry, null);
        AlertDialog.Builder builder = new AlertDialog.Builder(context);
        builder.setIcon(R.drawable.alert_dialog_icon);
        builder.setTitle(R.string.alert_dialog_text_entry);
        builder.setView(textEntryView);
        builder.setPositiveButton(R.string.alert_dialog_ok,
                new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int whichButton) {
                        setTitle("点击了对话框上的确定按钮: " + whichButton);
                    }
                });
        builder.setNegativeButton(R.string.alert_dialog_cancel,
                new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int whichButton) {
                        setTitle("点击了对话框上的取消按钮: " + whichButton);
                    }
                });
        return builder.create();
    }

    private Dialog buildDialog4(Context context) {
        ProgressDialog dialog = new ProgressDialog(context);
        dialog.setTitle("正在下载歌曲");
        dialog.setMessage("请稍候……");
        return dialog;
    }
}

 

Example2:
public class EX03_17 extends Activity
{
  /** Called when the activity is first created. */
  @Override
  public void onCreate(Bundle savedInstanceState)
  {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
  }
 
  public boolean onCreateOptionsMenu(Menu menu)
  {
    menu.add(0, 0, 0, R.string.app_about);
    menu.add(0, 1, 1, R.string.str_exit);
    return super.onCreateOptionsMenu(menu);
  }
 
  public boolean onOptionsItemSelected(MenuItem item)
  {
    super.onOptionsItemSelected(item);
    switch(item.getItemId())
    {
      case 0:
        openOptionsDialog();
        break;
      case 1:
        finish();
        break;
    }
    return true;
  }
 
  private void openOptionsDialog()
  {
    new AlertDialog.Builder(this)
    .setTitle(R.string.app_about)
    .setMessage(R.string.app_about_msg)
    .setPositiveButton(R.string.str_ok,
        new DialogInterface.OnClickListener()
        {
         public void onClick(DialogInterface dialoginterface, int i)
         {
         }
         }
        )
    .show();
  }
}