如何区分 Switch,Checkbox Value 是由用户更改还是以编程方式(包括保留)更改? [英] How can I distinguish whether Switch,Checkbox Value is changed by user or programmatically (including by retention)?

问题描述

setOnCheckedChangeListener(new OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                // How to check whether the checkbox/switch has been checked
                // by user or it has been checked programatically ?

                if (isNotSetByUser())
                    return;
                handleSetbyUser();
            }
        });

如何实现方法isNotSetByUser()?

推荐答案

答案 2:

一个非常简单的答案:

使用 OnClickListener 而不是 OnCheckedChangeListener

Use on OnClickListener instead of OnCheckedChangeListener

    someCheckBox.setOnClickListener(new OnClickListener(){

        @Override
        public void onClick(View v) {
            // you might keep a reference to the CheckBox to avoid this class cast
            boolean checked = ((CheckBox)v).isChecked();
            setSomeBoolean(checked);
        }

    });

现在您只需选择点击事件，而不必担心程序化更改.

Now you only pick up click events and don't have to worry about programmatic changes.

答案 1:

我创建了一个包装类(参见装饰器模式)，它以封装的方式处理这个问题:

I have created a wrapper class (see Decorator Pattern) which handles this problem in an encapsulated way:

public class BetterCheckBox extends CheckBox {
    private CompoundButton.OnCheckedChangeListener myListener = null;
    private CheckBox myCheckBox;

    public BetterCheckBox(Context context) {
        super(context);
    }

    public BetterCheckBox(Context context, CheckBox checkBox) {
        this(context);
        this.myCheckBox = checkBox;
    }

    // assorted constructors here...    

    @Override
    public void setOnCheckedChangeListener(
        CompoundButton.OnCheckedChangeListener listener){
        if(listener != null) {
            this.myListener = listener;
        }
        myCheckBox.setOnCheckedChangeListener(listener);
    }

    public void silentlySetChecked(boolean checked){
        toggleListener(false);
        myCheckBox.setChecked(checked);
        toggleListener(true);
    }

    private void toggleListener(boolean on){
        if(on) {
            this.setOnCheckedChangeListener(myListener);
        }
        else {
            this.setOnCheckedChangeListener(null);
        }
    }
}

CheckBox 仍然可以在 XML 中声明相同，但在代码中初始化 GUI 时使用它:

CheckBox can still be declared the same in XML, but use this when initializing your GUI in code:

BetterCheckBox myCheckBox;

// later...
myCheckBox = new BetterCheckBox(context,
    (CheckBox) view.findViewById(R.id.my_check_box));

如果您想在不触发侦听器的情况下从代码中设置已检查，请调用 myCheckBox.silentlySetChecked(someBoolean) 而不是 setChecked.

If you want to set checked from code without triggering the listener, call myCheckBox.silentlySetChecked(someBoolean) instead of setChecked.

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