使用数据绑定在自定义视图中调用自定义方法

Question

使用数据绑定，我将如何引用自定义视图内的自定义方法？我试图把我的自定义视图中的监听器...

public class MyCustomView extends LinearLayout { 

    //...view init stuff 

    private VisibilityListener mListener; 

    public void setVisibilityListener(VisibilityListener listener) { 
     mListener = listener; 
    } 

    public interface VisibilityListener { 
     void onVisibilityChanged(boolean isVisible); 
    } 
} 

public class MainActivity extends AppCompatActivity implements VisibilityListener { 

    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(); 

     MainActivityBinding binding = DataBindingUtil.setContentView(this, R.layout.main_activity); 

     // What I'm trying to accomplish... 
     binding.myCustomView.setVisibilityListener(this); 
    } 
} 

Answer 1

您可以通过使用自定义视图的布局本身具有id实现正是这一点。

<package.of.MyCustomView 
     android:id="@+id/my_custom_view" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" /> 

像这个数据绑定将定义一个成员MyCustomView类型的myCustomView内的结合。因此你可以简单地打电话给setVisibilityListener()。

binding.myCustomView.setVisibilityListener(this); 

Answer 2

我实现了在取色（CustomView）一个简单的colorChangeListener（CustomListener）。这可以帮助你解决你的问题

ColorPicker.java

public class ColorPicker extends View { 

    private ArrayList<OnColorChangeListener> mColorChangeListeners = new ArrayList<>(); 
    private int mColor; 

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

    public ColorPicker(Context context, @Nullable AttributeSet attrs) { 
     super(context, attrs); 
    } 

    public ColorPicker(Context context, @Nullable AttributeSet attrs, int defStyleAttr) { 
     super(context, attrs, defStyleAttr); 
    } 

    @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP) 
    public ColorPicker(Context context, @Nullable AttributeSet attrs, int defStyleAttr, int defStyleRes) { 
     super(context, attrs, defStyleAttr, defStyleRes); 
    } 

    public void setColor(int color){ 
     mColor = color; 
     setBackgroundColor(mColor); 
     if (mColorChangeListeners != null && !mColorChangeListeners.isEmpty()){ 
      for (OnColorChangeListener onColorChangeListener: mColorChangeListeners) { 
       onColorChangeListener.onColorChangeListener(this,mColor); 
      } 
     } 
    } 

    public int getColor() { 
     return mColor; 
    } 

    public void removeListener(OnColorChangeListener oldListener) { 
     mColorChangeListeners.remove(oldListener); 
    } 

    public void addListener(OnColorChangeListener newListener) { 
     mColorChangeListeners.add(newListener); 
    } 

    public interface OnColorChangeListener { 
     void onColorChangeListener(ColorPicker colorPicker, int newColor); 
    } 
} 

BindingAdapter：

@BindingAdapter(value={"event:onColorChange", "colorAttrChanged"}, requireAll = false) 
    public static void setColorChangeListener(ColorPicker view, 
               final ColorPicker.OnColorChangeListener onColorChangeListener, 
               final InverseBindingListener inverseBindingListener) { 

     ColorPicker.OnColorChangeListener newListener; 
     if (inverseBindingListener == null) { 
      newListener = onColorChangeListener; 
     } else { 
      newListener = new ColorPicker.OnColorChangeListener() { 
       @Override 
       public void onColorChangeListener(ColorPicker colorPicker, 
              int newColor) { 
        if (onColorChangeListener != null) { 
         onColorChangeListener.onColorChangeListener(colorPicker, 
           newColor); 
        } 
        inverseBindingListener.onChange(); 
       } 
      }; 
     } 

     ColorPicker.OnColorChangeListener oldListener = 
       ListenerUtil.trackListener(view, newListener, 
         R.id.onColorChangedListner); 

     if (oldListener != null) { 
      view.removeListener(oldListener); 
     } 

     if (newListener != null) { 
      view.addListener(newListener); 
     } 
    } 

XML：

<variable 
      name="eventCallBack" 
      type="bytes.wit.databinding.HomeActivity.EventHandler"/> 

<bytes.wit.databinding.ColorPicker 
      android:id="@+id/color_picker" 
      android:layout_width="0dp" 
      android:layout_height="24dp" 
      app:color="@={placeModel.color}" 
      app:onColorChange="@{(v, color) -> eventCallBack.onColorChanged(placeModel.color)}" 
      app:layout_constraintBottom_toBottomOf="parent" 
      app:layout_constraintLeft_toLeftOf="parent" 
      app:layout_constraintRight_toRightOf="parent" /> 

事件处理

public class EventHandler{ 
     public void onColorChanged(int color){ 
      Toast.makeText(HomeActivity.this,"Color "+color,Toast.LENGTH_SHORT).show(); 
     } 
    } 

设置事件处理

eventHandler = new EventHandler(); 
binding.setEventCallBack(eventHandler);