Android的numberpicker，永遠不會從OnValueChangedListener斷點傳遞

Question

我擴展了NumberPicker類，我將它重寫爲setOnValueChangedListener，但是當我調試代碼時，我點擊了numberpicker的加號按鈕，它永遠不會傳入方法setOnValueChangedListener中的斷點處。 有什麼不對嗎？

@TargetApi(Build.VERSION_CODES.HONEYCOMB)//For backward-compability 
public class NumberPickerCustom extends NumberPicker 
{ 
    private int clickNumber = 0; 

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

    public NumberPickerCustom(Context context, AttributeSet attrs) { 
     super(context, attrs); 
     processAttributeSet(attrs); 
    } 

    public NumberPickerCustom(Context context, AttributeSet attrs, int defStyle) { 
     super(context, attrs, defStyle); 
     processAttributeSet(attrs); 
    } 
    private void processAttributeSet(AttributeSet attrs) { 
     //This method reads the parameters given in the xml file and sets the properties according to it 
     this.setMinValue(attrs.getAttributeIntValue(null, "min", 0)); 
     this.setMaxValue(attrs.getAttributeIntValue(null, "max", 0)); 
     this.setValue(attrs.getAttributeIntValue(null, "value", 0)); 
    } 

    @Override 
    public void setOnValueChangedListener(
      OnValueChangeListener onValueChangedListener) 
    { 
     super.setOnValueChangedListener(onValueChangedListener); 
     if (onValueChangedListener==null) 
     { 
      onValueChangedListener = new OnValueChangeListener() { 

       @Override 
       public void onValueChange(NumberPicker picker, int oldVal, int newVal) 
       { 
        clickNumber++; 
        if (clickNumber>10) 
        { 
         clickNumber = -1000; 
         Toast.makeText(getContext(), "Clicca sul numero centrale per inserire direttamente un valore", Toast.LENGTH_SHORT).show(); 
        } 
       } 
      }; 
     } 
    } 
} 

Answer 1

您可以initializze您的自定義數字選擇器

View rootView = inflater.inflate(R.layout.fragment_random_block, container, false); 
NumberPickerCustom np = (NumberPickerCustom) rootView.findViewById(R.id.numberPickerCustom); 
np.setOnValueChangedListener(this); 

確保您的類實現

implements OnValueChangeListener 

然後

@Override 
public void onValueChange(NumberPicker picker, int oldVal, int newVal) { 
    Toast.makeText(MainActivity.this, "Clicca sul numero centrale per inserire direttamente un valore", Toast.LENGTH_SHORT).show(); 
    } 
} 

快照：

當您更改值時，您會看到烤麪包根據您的要求進行相同的修改。

編輯：

更改如下

public class NumberPickerCustom extends NumberPicker implements OnValueChangeListener 
{ 
    public NumberPickerCustom(Context context) { 
     super(context); 
    } 

    public NumberPickerCustom(Context context, AttributeSet attrs) { 
     super(context, attrs); 
     processAttributeSet(attrs); 
    } 

    public NumberPickerCustom(Context context, AttributeSet attrs, int defStyle) { 
     super(context, attrs, defStyle); 
     processAttributeSet(attrs); 
    } 
    private void processAttributeSet(AttributeSet attrs) { 
     //This method reads the parameters given in the xml file and sets the properties according to it 
     this.setMinValue(attrs.getAttributeIntValue(null, "min", 0)); 
     this.setMaxValue(attrs.getAttributeIntValue(null, "max", 0)); 
     this.setValue(attrs.getAttributeIntValue(null, "value", 0)); 
     this.setOnValueChangedListener(this); 
    } 

    @Override 
    public void onValueChange(NumberPicker picker, int oldVal, int newVal) { 
     Toast.makeText(getContext(), "New Value is"+newVal, Toast.LENGTH_SHORT).show(); 
    } 
} 

快照