Android自定义View之RadioGroup实现跨多行显示

import android.content.context;
import android.content.res.typedarray;
import android.util.attributeset;
import android.view.motionevent;
import android.view.view;
import android.view.viewgroup;
import android.view.accessibility.accessibilityevent;
import android.view.accessibility.accessibilitynodeinfo;
import android.widget.compoundbutton;
import android.widget.linearlayout;
import android.widget.radiobutton;

public class radiogroup extends linearlayout {
 // holds the checked id; the selection is empty by default 
 private int mcheckedid = -1;
 // tracks children radio buttons checked state 
 private compoundbutton.oncheckedchangelistener mchildoncheckedchangelistener;
 // when true, moncheckedchangelistener discards events 
 private boolean mprotectfromcheckedchange = false;
 private oncheckedchangelistener moncheckedchangelistener;
 private passthroughhierarchychangelistener mpassthroughlistener;

 /**
  * {@inheritdoc}
  */
 public radiogroup(context context) {
  super(context);
  setorientation(vertical);
  init();
 }

 /**
  * {@inheritdoc}
  */
 public radiogroup(context context, attributeset attrs) {
  super(context, attrs);
  mcheckedid = view.no_id;

  final int index = vertical;
  setorientation(index);

  init();
 }

 private void init() {
  mchildoncheckedchangelistener = new checkedstatetracker();
  mpassthroughlistener = new passthroughhierarchychangelistener();
  super.setonhierarchychangelistener(mpassthroughlistener);
 }

 /**
  * {@inheritdoc}
  */
 @override
 public void setonhierarchychangelistener(onhierarchychangelistener listener) {
  // the user listener is delegated to our pass-through listener 
  mpassthroughlistener.monhierarchychangelistener = listener;
 }

 /**
  * {@inheritdoc}
  */
 @override
 protected void onfinishinflate() {
  super.onfinishinflate();

  // checks the appropriate radio button as requested in the xml file 
  if (mcheckedid != -1) {
   mprotectfromcheckedchange = true;
   setcheckedstateforview(mcheckedid, true);
   mprotectfromcheckedchange = false;
   setcheckedid(mcheckedid);
  }
 }

 @override
 public void addview(final view child, int index, viewgroup.layoutparams params) {
  if (child instanceof radiobutton) {
   child.setontouchlistener(new ontouchlistener() {

    @override
    public boolean ontouch(view v, motionevent event) {
     ((radiobutton) child).setchecked(true);
     checkradiobutton((radiobutton) child);
     if (moncheckedchangelistener != null) {
      moncheckedchangelistener.oncheckedchanged(radiogroup.this, child.getid());
     }
     return true;
    }
   });
  } else if (child instanceof linearlayout) {
   int childcount = ((linearlayout) child).getchildcount();
   for (int i = 0; i < childcount; i++) {
    view view = ((linearlayout) child).getchildat(i);
    if (view instanceof radiobutton) {
     final radiobutton button = (radiobutton) view;
     button.setontouchlistener(new ontouchlistener() {

      @override
      public boolean ontouch(view v, motionevent event) {
       button.setchecked(true);
       checkradiobutton(button);
       if (moncheckedchangelistener != null) {
        moncheckedchangelistener.oncheckedchanged(radiogroup.this, button.getid());
       }
       return true;
      }
     });
    }
   }
  }
  super.addview(child, index, params);
 }

 private void checkradiobutton(radiobutton radiobutton) {
  view child;
  int radiocount = getchildcount();
  for (int i = 0; i < radiocount; i++) {
   child = getchildat(i);
   if (child instanceof radiobutton) {
    if (child == radiobutton) {
     // do nothing 
    } else {
     ((radiobutton) child).setchecked(false);
    }
   } else if (child instanceof linearlayout) {
    int childcount = ((linearlayout) child).getchildcount();
    for (int j = 0; j < childcount; j++) {
     view view = ((linearlayout) child).getchildat(j);
     if (view instanceof radiobutton) {
      final radiobutton button = (radiobutton) view;
      if (button == radiobutton) {
       // do nothing 
      } else {
       button.setchecked(false);
      }
     }
    }
   }
  }
 }

 /**
  * <p>sets the selection to the radio button whose identifier is passed in
  * parameter. using -1 as the selection identifier clears the selection;
  * such an operation is equivalent to invoking {@link #clearcheck()}.</p>
  *
  * @param id the unique id of the radio button to select in this group
  * @see #getcheckedradiobuttonid()
  * @see #clearcheck()
  */
 public void check(int id) {
  // don't even bother 
  if (id != -1 && (id == mcheckedid)) {
   return;
  }

  if (mcheckedid != -1) {
   setcheckedstateforview(mcheckedid, false);
  }

  if (id != -1) {
   setcheckedstateforview(id, true);
  }

  setcheckedid(id);
 }

 private void setcheckedid(int id) {
  mcheckedid = id;
 }

 private void setcheckedstateforview(int viewid, boolean checked) {
  view checkedview = findviewbyid(viewid);
  if (checkedview != null && checkedview instanceof radiobutton) {
   ((radiobutton) checkedview).setchecked(checked);
  }
 }

 /**
  * <p>returns the identifier of the selected radio button in this group.
  * upon empty selection, the returned value is -1.</p>
  *
  * @return the unique id of the selected radio button in this group
  * @attr ref android.r.styleable#radiogroup_checkedbutton
  * @see #check(int)
  * @see #clearcheck()
  */
 public int getcheckedradiobuttonid() {
  return mcheckedid;
 }

 /**
  * <p>clears the selection. when the selection is cleared, no radio button
  * in this group is selected and {@link #getcheckedradiobuttonid()} returns
  * null.</p>
  *
  * @see #check(int)
  * @see #getcheckedradiobuttonid()
  */
 public void clearcheck() {
  check(-1);
 }

 /**
  * <p>register a callback to be invoked when the checked radio button
  * changes in this group.</p>
  *
  * @param listener the callback to call on checked state change
  */
 public void setoncheckedchangelistener(oncheckedchangelistener listener) {
  moncheckedchangelistener = listener;
 }

 /**
  * {@inheritdoc}
  */
 @override
 public layoutparams generatelayoutparams(attributeset attrs) {
  return new radiogroup.layoutparams(getcontext(), attrs);
 }

 /**
  * {@inheritdoc}
  */
 @override
 protected boolean checklayoutparams(viewgroup.layoutparams p) {
  return p instanceof radiogroup.layoutparams;
 }

 @override
 protected linearlayout.layoutparams generatedefaultlayoutparams() {
  return new layoutparams(layoutparams.wrap_content, layoutparams.wrap_content);
 }

 @override
 public void oninitializeaccessibilityevent(accessibilityevent event) {
  super.oninitializeaccessibilityevent(event);
  event.setclassname(radiogroup.class.getname());
 }

 @override
 public void oninitializeaccessibilitynodeinfo(accessibilitynodeinfo info) {
  super.oninitializeaccessibilitynodeinfo(info);
  info.setclassname(radiogroup.class.getname());
 }

 public static class layoutparams extends linearlayout.layoutparams {
  /**
   * {@inheritdoc}
   */
  public layoutparams(context c, attributeset attrs) {
   super(c, attrs);
  }

  /**
   * {@inheritdoc}
   */
  public layoutparams(int w, int h) {
   super(w, h);
  }

  /**
   * {@inheritdoc}
   */
  public layoutparams(int w, int h, float initweight) {
   super(w, h, initweight);
  }

  /**
   * {@inheritdoc}
   */
  public layoutparams(viewgroup.layoutparams p) {
   super(p);
  }

  /**
   * {@inheritdoc}
   */
  public layoutparams(marginlayoutparams source) {
   super(source);
  }

  /**
   * <p>fixes the child's width to
   * {@link android.view.viewgroup.layoutparams#wrap_content} and the child's
   * height to {@link android.view.viewgroup.layoutparams#wrap_content}
   * when not specified in the xml file.</p>
   *
   * @param a   the styled attributes set
   * @param widthattr the width attribute to fetch
   * @param heightattr the height attribute to fetch
   */
  @override
  protected void setbaseattributes(typedarray a, int widthattr, int heightattr) {
   if (a.hasvalue(widthattr)) {
    width = a.getlayoutdimension(widthattr, "layout_width");
   } else {
    width = wrap_content;
   }

   if (a.hasvalue(heightattr)) {
    height = a.getlayoutdimension(heightattr, "layout_height");
   } else {
    height = wrap_content;
   }
  }
 }

 /**
  * <p>interface definition for a callback to be invoked when the checked
  * radio button changed in this group.</p>
  */
 public interface oncheckedchangelistener {
  /**
   * <p>called when the checked radio button has changed. when the
   * selection is cleared, checkedid is -1.</p>
   *
   * @param group  the group in which the checked radio button has changed
   * @param checkedid the unique identifier of the newly checked radio button
   */
  void oncheckedchanged(radiogroup group, int checkedid);
 }

 private class checkedstatetracker implements compoundbutton.oncheckedchangelistener {
  public void oncheckedchanged(compoundbutton buttonview, boolean ischecked) {
   // prevents from infinite recursion 
   if (mprotectfromcheckedchange) {
    return;
   }

   mprotectfromcheckedchange = true;
   if (mcheckedid != -1) {
    setcheckedstateforview(mcheckedid, false);
   }
   mprotectfromcheckedchange = false;

   int id = buttonview.getid();
   setcheckedid(id);
  }
 }

 /**
  * <p>a pass-through listener acts upon the events and dispatches them
  * to another listener. this allows the table layout to set its own internal
  * hierarchy change listener without preventing the user to setup his.</p>
  */
 private class passthroughhierarchychangelistener implements viewgroup.onhierarchychangelistener {
  private viewgroup.onhierarchychangelistener monhierarchychangelistener;

  /**
   * {@inheritdoc}
   */
  public void onchildviewadded(view parent, view child) {
   if (parent == radiogroup.this && child instanceof radiobutton) {
    int id = child.getid();
    // generates an id if it's missing 
    if (id == view.no_id) {
     id = child.hashcode();
     child.setid(id);
    }
    ((radiobutton) child).setoncheckedchangelistener(mchildoncheckedchangelistener);
   }

   if (monhierarchychangelistener != null) {
    monhierarchychangelistener.onchildviewadded(parent, child);
   }
  }

  /**
   * {@inheritdoc}
   */
  public void onchildviewremoved(view parent, view child) {
   if (parent == radiogroup.this && child instanceof radiobutton) {
    ((radiobutton) child).setoncheckedchangelistener(null);
   }

   if (monhierarchychangelistener != null) {
    monhierarchychangelistener.onchildviewremoved(parent, child);
   }
  }
 }
}