java-me - 如何在 Canvas 中创建多个复选框

Question

当我尝试在 Canvas 中创建复选框时遇到问题。

我的复选框运行良好，但我不知道如何存储每个项目的值，这意味着当用户检查第 1 行，然后他们移动到另一行复选框仍然检查第 1 行，当用户检查第 1 行和第 2 行并移动时到另一行，复选框将选中第 1 行和第 2 行。

但我找不到这个问题的解决方案

Answer 1

修改您的代码以使用 selectTodelete作为 bool 数组而不是int，大约如下所示

    // ...initialization of DataList
    boolean[] selectTodelete = new boolean[2]; // instead of int
    { selectTodelete[0] = selectTodelete[1] = false; } // init array
    Command editCommand, backCommand,selectCmd, unselectCmd,selectAll;
    //...

    protected void paint(Graphics g) {
        //...
        for(int i =0 ; i<countRow; i++ ){
            //draw background
            //...
                     if(selectTodelete[i]){ // was selectTodelete == 1
                            //draw select dot at location for row 'i'
                            //...
                     }
            // remove: you don't need that anymore: if(selectTodelete == 2) {
                            //draw select dot...
            //}

            // draw a checkbox before each item
            // ...
        }
    }

    public void commandAction(Command c, Displayable d) {
        //...
        if(c == selectCmd){
            selectTodelete[selectedItem] = true;
        }
        if(c== unselectCmd){
            selectTodelete[selectedItem] = false;
        }
        if(c == selectAll){
            selectTodelete[0] = selectTodelete[1] = true;
        }
        repaint();
    }
    //...
}

更新 - 在评论中回答问题

I want to get RCID fit to checked it mean when row was checked I can get this id and when I use delete command it will delete all rows were checked

为此，您可以公开 selectTodelete用于在其类之外与 getter 一起使用，或者更好的是，使用如下方法...

    boolean isSelected(int elementNum) {
        return elementNum >= 0 && elementNum < selectTodelete.length
                && selectTodelete[elementNum];
    } // modelled after javax.microedition.lcdui.Choice.isSelected

...当您需要处理 RCID 时，可以在任何地方进一步使用这样公开的信息，例如在下面的方法中:

    Vector useSelection(DataList dataList, DataStore[][] ds) {
        Vector result = new Vector();
        int count = ds.length;
        for(int i = 0; i < count; i++ ) {
            if (!dataList.isSelected(i)) {
                continue; // skip non selected
            }
            System.out.println("RCID selected: [" + ds[i][5].cellText + "]");
            result.addElement(ds[i][5]);
        }
        return result;
    }