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 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()}.
 * * @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); } } /** * 
Returns the identifier of the selected radio button in this group. * Upon empty selection, the returned value is -1.
 * * @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; } /** * 
Clears the selection. When the selection is cleared, no radio button * in this group is selected and {@link #getCheckedRadioButtonId()} returns * null.
 * * @see #check(int) * @see #getCheckedRadioButtonId() */ public void clearCheck() { check(-1); } /** * 
Register a callback to be invoked when the checked radio button * changes in this group.
 * * @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); } /** * 
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.
 * * @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; } } } /** * 
Interface definition for a callback to be invoked when the checked * radio button changed in this group.
 */ public interface OnCheckedChangeListener { /** * 
Called when the checked radio button has changed. When the * selection is cleared, checkedId is -1.
 * * @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); } } /** * 
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.
 */ 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); } } } }