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android自定义radiogroup,自定义RadioGroup

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2023-12-01

自定义RadioGroup

在Android系统中,自带的RadioGroup只能指定横向和纵向两种布局,所以有的时候我们需要自定义RadioGroup。

首先分析一下,就是在系统自带的RadioGroup中,如果我们嵌套了,LinearLayout的话,就会失效,因为系统的RadioGroup没有考虑到这种情况,所以我们需要自定义一个Group,初步的打算是继承自LinearLayout。

具体代码如下:

package linsir.fuyizhulao.com.love_map;

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;

/**

*

This class is used to create a multiple-exclusion scope for a set of radio

* buttons. Checking one radio button that belongs to a radio group unchecks

* any previously checked radio button within the same group.

*

*

Intially, all of the radio buttons are unchecked. While it is not possible

* to uncheck a particular radio button, the radio group can be cleared to

* remove the checked state.

*

*

The selection is identified by the unique id of the radio button as defined

* in the XML layout file.

*

*

XML Attributes

*

See {@link android.R.styleable#RadioGroup RadioGroup Attributes},

* {@link android.R.styleable#LinearLayout LinearLayout Attributes},

* {@link android.R.styleable#ViewGroup ViewGroup Attributes},

* {@link android.R.styleable#View View Attributes}

*

Also see

* {@link android.widget.LinearLayout.LayoutParams LinearLayout.LayoutParams}

* for layout attributes.

*

* @see 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) {

((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;

((RadioButton) button).setOnTouchListener(new OnTouchListener() {

@Override

public boolean onTouch(View v, MotionEvent event) {

((RadioButton) button).setChecked(true);

checkRadioButton((RadioButton) 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 {

((RadioButton) button).setChecked(false);

}

}

}

}

}

}

/**

*

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

*

* @see #check(int)

* @see #clearCheck()

*

* @attr ref android.R.styleable#RadioGroup_checkedButton

*/

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());

}

/**

*

This set of layout parameters defaults the width and the height of

* the children to {@link #WRAP_CONTENT} when they are not specified in the

* XML file. Otherwise, this class ussed the value read from the XML file.

*

*

See

* {@link android.R.styleable#LinearLayout_Layout LinearLayout Attributes}

* for a list of all child view attributes that this class supports.

*

*/

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

*/

public 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);

}

}

}

}

这样我们的RadioGroup下面就可以使用布局了,不过目前仅对LinearLayout做了兼容,一般来说这样,就已经可以满足我们的需求了,当然如果我们喜欢的话,也可以对其他的布局进行兼容。

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