blackberry起步-step1-优快云博客

本文链接：https://blog.youkuaiyun.com/zhang_zining/article/details/83703638

本文介绍了UI事件处理的各种方法，包括菜单项创建、关闭事件、按钮点击事件、列表点击事件及热键点击事件等。通过具体代码示例展示了如何在不同场景下响应用户的交互行为。

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1、创建菜单项：

protected void makeMenu(Menu menu, int instance){       
  menu.add(showItem); 
  menu.add(closeItem); 
}

2、创建关闭事件：


public boolean onClose(){ 
    if ( Dialog.ask(Dialog.D_YES_NO, "确定退出吗?")==Dialog.YES ){ 
        System.exit(0); 
        return true; 
    } 
    return false; 
}

3、按钮（域）点击事件：实现FieldChangeListener接口


final class HelloWorldScreen extends MainScreen implements FieldChangeListener { 
    public void fieldChanged(Field field, int ctx){ 
        if (field == btnShow) {        
            Dialog.alert("欢迎您-"+edtName.getText()); 
        } 
    }
}

4、列表点击事件

protected boolean navigationClick(int status, int time) { 
    Message message = list.getSelectedMessage(); 
    //Open message screen 
    MessageViewScreen screen = new MessageViewScreen(list,message,false); 
    UiApplication.getUiApplication().pushScreen(screen); 
    return true; 
}

5、热键点击事件

protected boolean keyChar(char key, int status, int time) { 
    boolean retVal = false; 
    if(key == Characters.ENTER){ 
        Message message = list.getSelectedMessage(); 
        //Open message screen 
        MessageViewScreen screen = new MessageViewScreen(list, message, false); 
        UiApplication.getUiApplication().pushScreen(screen); 
        retVal = true; 
    } 
    return retVal; 
}

6、创建一个按钮点击监听，给按钮绑定监听

FieldChangeListener myButtonListener = new FieldChangeListener() {
    public void fieldChanged(Field field, int context) {
        ButtonField fieldChanged = (ButtonField) field;
        //begin testing to see what field changed
        if( fieldChanged == agreeButton) {
            _message.setStatus(Message.STATUS_APPROVED);
            close();
	}
        if( fieldChanged == returnButton) {
            //_message.setStatus(Message.STATUS_APPROVED);
            close();
        }
    }
};
newButton = new ButtonField("提交");
newButton.setChangeListener(myButtonListener);
manager.add(newButton);
add(manager);

7、阻止屏幕save菜单弹出

public boolean onSavePrompt(){
    return true;
}