如何区分开关，复选框值是由用户还是以编程方式（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）{
 //如何检查复选框/开关已经被用户检查了
 //或者已经被编程检查了？
 
 if（isNotSetByUser（））
 return; 
 handleSetbyUser 
} 
}）; 
  

如何实现 isNotSetByUser（）？

解决方案

回答2：

p>

使用OnClickListener而不是OnCheckedChangeListener

  someCheckBox.setOnClickListener（new OnClickListener ）{
 
 @Override 
 public void onClick（View v）{
 //您可能会保留对CheckBox的引用以避免此类转换
 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。

---

答案1：

我已经创建了一个包装类Pattern）以封装的方式处理这个问题：

  public class BetterCheckBox extends CheckBox {
 private CompoundButton.OnCheckedChangeListener myListener = null; 
 private CheckBox myCheckBox; 
 
 public BetterCheckBox（Context context）{
 super（context）; 
} 
 
 public BetterCheckBox（上下文上下文，CheckBox复选框）{
 this（context）; 
 this.myCheckBox = checkBox; 
} 
 
 //这里的分类构造函数... 
 
 @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仍然可以声明为同样在XML中，但在代码初始化GUI时使用这个：

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

如果要设置从代码检查而不触发侦听器，请调用 myCheckBox .silentlySetChecked（someBoolean）而不是 setChecked 。

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();
            }
        });

How to implement method isNotSetByUser()?

解决方案

Answer 2:

A very simple answer:

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);
        }

    });

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

---

Answer 1:

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 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));

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

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