我遇到了一个大问题： 我想在android上制作三个状态复选框。 它是带有复选框的ListView上的复选框。它应该允许用户在三种状态之间切换：
并且可选择在变化时保留misc状态。
如果我是对的，我应该创建CompoundButton类的子类，并实现boolean mchecked的int mstate intead。 然后我应该覆盖事件监听器，保存状态的函数，以及状态getter和setter。
我的问题基本上是如何实现的？ 如何在可绘制状态之间切换？ （我已经在xml中实现了middle_state）以及如何正确实现事件处理程序？
以下是我开始实施的内容：
public class TriStateCheckBox extends CompoundButton{
private int state;
public TriStateCheckBox(Context context) {
super(context);
}
public static interface onCheckChangedListener{
void onCheckChanged(TriStateCheckBox view, int state);
}
public void onCheckChanged(TriStateCheckBox view, int state){
this.state = state;
}
}
以下是股票CompoundButton的代码：
/*
* Copyright (C) 2007 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.widget;
import com.android.internal.R;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.drawable.Drawable;
import android.os.Parcel;
import android.os.Parcelable;
import android.util.AttributeSet;
import android.view.Gravity;
import android.view.ViewDebug;
import android.view.accessibility.AccessibilityEvent;
import android.view.accessibility.AccessibilityNodeInfo;
/**
* <p>
* A button with two states, checked and unchecked. When the button is pressed
* or clicked, the state changes automatically.
* </p>
*
* <p><strong>XML attributes</strong></p>
* <p>
* See {@link android.R.styleable#CompoundButton
* CompoundButton Attributes}, {@link android.R.styleable#Button Button
* Attributes}, {@link android.R.styleable#TextView TextView Attributes}, {@link
* android.R.styleable#View View Attributes}
* </p>
*/
public abstract class CompoundButton extends Button implements Checkable {
private boolean mChecked;
private int mButtonResource;
private boolean mBroadcasting;
private Drawable mButtonDrawable;
private OnCheckedChangeListener mOnCheckedChangeListener;
private OnCheckedChangeListener mOnCheckedChangeWidgetListener;
private static final int[] CHECKED_STATE_SET = {
R.attr.state_checked
};
public CompoundButton(Context context) {
this(context, null);
}
public CompoundButton(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public CompoundButton(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
TypedArray a =
context.obtainStyledAttributes(
attrs, com.android.internal.R.styleable.CompoundButton, defStyle, 0);
Drawable d = a.getDrawable(com.android.internal.R.styleable.CompoundButton_button);
if (d != null) {
setButtonDrawable(d);
}
boolean checked = a
.getBoolean(com.android.internal.R.styleable.CompoundButton_checked, false);
setChecked(checked);
a.recycle();
}
public void toggle() {
setChecked(!mChecked);
}
@Override
public boolean performClick() {
/*
* XXX: These are tiny, need some surrounding 'expanded touch area',
* which will need to be implemented in Button if we only override
* performClick()
*/
/* When clicked, toggle the state */
toggle();
return super.performClick();
}
@ViewDebug.ExportedProperty
public boolean isChecked() {
return mChecked;
}
/**
* <p>Changes the checked state of this button.</p>
*
* @param checked true to check the button, false to uncheck it
*/
public void setChecked(boolean checked) {
if (mChecked != checked) {
mChecked = checked;
refreshDrawableState();
// Avoid infinite recursions if setChecked() is called from a listener
if (mBroadcasting) {
return;
}
mBroadcasting = true;
if (mOnCheckedChangeListener != null) {
mOnCheckedChangeListener.onCheckedChanged(this, mChecked);
}
if (mOnCheckedChangeWidgetListener != null) {
mOnCheckedChangeWidgetListener.onCheckedChanged(this, mChecked);
}
mBroadcasting = false;
}
}
/**
* Register a callback to be invoked when the checked state of this button
* changes.
*
* @param listener the callback to call on checked state change
*/
public void setOnCheckedChangeListener(OnCheckedChangeListener listener) {
mOnCheckedChangeListener = listener;
}
/**
* Register a callback to be invoked when the checked state of this button
* changes. This callback is used for internal purpose only.
*
* @param listener the callback to call on checked state change
* @hide
*/
void setOnCheckedChangeWidgetListener(OnCheckedChangeListener listener) {
mOnCheckedChangeWidgetListener = listener;
}
/**
* Interface definition for a callback to be invoked when the checked state
* of a compound button changed.
*/
public static interface OnCheckedChangeListener {
/**
* Called when the checked state of a compound button has changed.
*
* @param buttonView The compound button view whose state has changed.
* @param isChecked The new checked state of buttonView.
*/
void onCheckedChanged(CompoundButton buttonView, boolean isChecked);
}
/**
* Set the background to a given Drawable, identified by its resource id.
*
* @param resid the resource id of the drawable to use as the background
*/
public void setButtonDrawable(int resid) {
if (resid != 0 && resid == mButtonResource) {
return;
}
mButtonResource = resid;
Drawable d = null;
if (mButtonResource != 0) {
d = getResources().getDrawable(mButtonResource);
}
setButtonDrawable(d);
}
/**
* Set the background to a given Drawable
*
* @param d The Drawable to use as the background
*/
public void setButtonDrawable(Drawable d) {
if (d != null) {
if (mButtonDrawable != null) {
mButtonDrawable.setCallback(null);
unscheduleDrawable(mButtonDrawable);
}
d.setCallback(this);
d.setState(getDrawableState());
d.setVisible(getVisibility() == VISIBLE, false);
mButtonDrawable = d;
mButtonDrawable.setState(null);
setMinHeight(mButtonDrawable.getIntrinsicHeight());
}
refreshDrawableState();
}
@Override
public void onInitializeAccessibilityEvent(AccessibilityEvent event) {
super.onInitializeAccessibilityEvent(event);
event.setChecked(mChecked);
}
@Override
public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
super.onInitializeAccessibilityNodeInfo(info);
info.setCheckable(true);
info.setChecked(mChecked);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
final Drawable buttonDrawable = mButtonDrawable;
if (buttonDrawable != null) {
final int verticalGravity = getGravity() & Gravity.VERTICAL_GRAVITY_MASK;
final int height = buttonDrawable.getIntrinsicHeight();
int y = 0;
switch (verticalGravity) {
case Gravity.BOTTOM:
y = getHeight() - height;
break;
case Gravity.CENTER_VERTICAL:
y = (getHeight() - height) / 2;
break;
}
buttonDrawable.setBounds(0, y, buttonDrawable.getIntrinsicWidth(), y + height);
buttonDrawable.draw(canvas);
}
}
@Override
protected int[] onCreateDrawableState(int extraSpace) {
final int[] drawableState = super.onCreateDrawableState(extraSpace + 1);
if (isChecked()) {
mergeDrawableStates(drawableState, CHECKED_STATE_SET);
}
return drawableState;
}
@Override
protected void drawableStateChanged() {
super.drawableStateChanged();
if (mButtonDrawable != null) {
int[] myDrawableState = getDrawableState();
// Set the state of the Drawable
mButtonDrawable.setState(myDrawableState);
invalidate();
}
}
@Override
protected boolean verifyDrawable(Drawable who) {
return super.verifyDrawable(who) || who == mButtonDrawable;
}
@Override
public void jumpDrawablesToCurrentState() {
super.jumpDrawablesToCurrentState();
if (mButtonDrawable != null) mButtonDrawable.jumpToCurrentState();
}
static class SavedState extends BaseSavedState {
boolean checked;
/**
* Constructor called from {@link CompoundButton#onSaveInstanceState()}
*/
SavedState(Parcelable superState) {
super(superState);
}
/**
* Constructor called from {@link #CREATOR}
*/
private SavedState(Parcel in) {
super(in);
checked = (Boolean)in.readValue(null);
}
@Override
public void writeToParcel(Parcel out, int flags) {
super.writeToParcel(out, flags);
out.writeValue(checked);
}
@Override
public String toString() {
return "CompoundButton.SavedState{"
+ Integer.toHexString(System.identityHashCode(this))
+ " checked=" + checked + "}";
}
public static final Parcelable.Creator<SavedState> CREATOR
= new Parcelable.Creator<SavedState>() {
public SavedState createFromParcel(Parcel in) {
return new SavedState(in);
}
public SavedState[] newArray(int size) {
return new SavedState[size];
}
};
}
@Override
public Parcelable onSaveInstanceState() {
// Force our ancestor class to save its state
setFreezesText(true);
Parcelable superState = super.onSaveInstanceState();
SavedState ss = new SavedState(superState);
ss.checked = isChecked();
return ss;
}
@Override
public void onRestoreInstanceState(Parcelable state) {
SavedState ss = (SavedState) state;
super.onRestoreInstanceState(ss.getSuperState());
setChecked(ss.checked);
requestLayout();
}
}
这是我的xml state-liste实现（工作）：
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<item android:state_checked="false"
android:state_pressed="true"
android:drawable="@drawable/btn_check_off_pressed" /> <!-- unchecked pressed -->
<item android:state_checked="false"
android:state_selected="true"
android:drawable="@drawable/btn_check_off_selected" /> <!-- unchecked selected -->
<item android:state_checked="true"
android:state_pressed="false"
android:state_focused="false"
android:drawable="@drawable/btn_check_on" /> <!-- checked -->
<item android:state_checked="true"
android:state_pressed="true"
android:drawable="@drawable/btn_check_on_pressed" /> <!-- checked pressed-->
<item android:state_checked="true"
android:state_selected="true"
android:drawable="@drawable/btn_check_on_selected" /> <!-- checked selected-->
<item android:state_middle="true"
android:state_pressed="false"
android:state_focused="false"
android:drawable="@drawable/btn_check_middle" /> <!-- middle -->
<item android:state_middle="true"
android:state_pressed="true"
android:drawable="@drawable/btn_check_middle_pressed" /> <!-- middle pressed-->
<item android:state_middle="true"
android:state_selected="true"
android:drawable="@drawable/btn_check_middle_selected" /> <!-- middle selected-->
<item android:drawable="@drawable/btn_check_off" /> <!-- unchecked -->
</selector>
这是复选框的库存xml实现：
<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright (C) 2008 The Android Open Source Project
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-->
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<!-- Enabled states -->
<item android:state_checked="true" android:state_window_focused="false"
android:state_enabled="true"
android:drawable="@drawable/btn_check_on" />
<item android:state_checked="false" android:state_window_focused="false"
android:state_enabled="true"
android:drawable="@drawable/btn_check_off" />
<item android:state_checked="true" android:state_pressed="true"
android:state_enabled="true"
android:drawable="@drawable/btn_check_on_pressed" />
<item android:state_checked="false" android:state_pressed="true"
android:state_enabled="true"
android:drawable="@drawable/btn_check_off_pressed" />
<item android:state_checked="true" android:state_focused="true"
android:state_enabled="true"
android:drawable="@drawable/btn_check_on_selected" />
<item android:state_checked="false" android:state_focused="true"
android:state_enabled="true"
android:drawable="@drawable/btn_check_off_selected" />
<item android:state_checked="false"
android:state_enabled="true"
android:drawable="@drawable/btn_check_off" />
<item android:state_checked="true"
android:state_enabled="true"
android:drawable="@drawable/btn_check_on" />
<!-- Disabled states -->
<item android:state_checked="true" android:state_window_focused="false"
android:drawable="@drawable/btn_check_on_disable" />
<item android:state_checked="false" android:state_window_focused="false"
android:drawable="@drawable/btn_check_off_disable" />
<item android:state_checked="true" android:state_focused="true"
android:drawable="@drawable/btn_check_on_disable_focused" />
<item android:state_checked="false" android:state_focused="true"
android:drawable="@drawable/btn_check_off_disable_focused" />
<item android:state_checked="false" android:drawable="@drawable/btn_check_off_disable" />
<item android:state_checked="true" android:drawable="@drawable/btn_check_on_disable" />
</selector>
答案 0 :(得分：12)
老话题，但我给出了解决方案的解决方案：
public class CheckBoxTriStates extends CheckBox
{
static private final int UNKNOW = -1;
static private final int UNCHECKED = 0;
static private final int CHECKED = 1;
private int state;
public CheckBoxTriStates(Context context) {
super(context);
init();
}
public CheckBoxTriStates(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public CheckBoxTriStates(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init()
{
state = UNKNOW;
updateBtn();
setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
// checkbox status is changed from uncheck to checked.
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked)
{
switch (state)
{
case UNKNOW:
state = UNCHECKED;
break;
case UNCHECKED:
state = CHECKED;
break;
case CHECKED:
state = UNKNOW;
break;
}
updateBtn();
}
});
}
private void updateBtn()
{
int btnDrawable = R.drawable.ic_checkbox_indeterminate_black;
switch (state)
{
case UNKNOW:
btnDrawable = R.drawable.ic_checkbox_indeterminate_black;
break;
case UNCHECKED:
btnDrawable = R.drawable.ic_checkbox_unchecked_black;
break;
case CHECKED:
btnDrawable = R.drawable.ic_checkbox_checked_black;
break;
}
setButtonDrawable(btnDrawable);
}
public int getState()
{
return state;
}
public void setState(int state)
{
this.state = state;
updateBtn();
}
}
您可以找到按钮资源Here。它完美无缺。
答案 1 :(得分：1)
如果你真的坚持使用CheckBox，其中每个元素都有3个状态，那么以下内容可能会有效但我还没有尝试过： - 创建一个扩展CheckBox类的类。 - 添加一个变量：＆＃34; checkstate＆＃34;类型为int或byte。该类应该有一个布尔＆＃34; isChecked＆＃34;变量。 - 重写onClick或onCheck方法，以便更改3个状态之间的checkstate变量，而不是切换isChecked变量。 - 显示后，检查＆＃34; checkstate＆＃34;并做一些视觉效果来显示第三状态。 - 最后，告诉我它是否有效。
答案 2 :(得分：0)
如果要在更改状态时不使用矢量动画的复选框，请尝试使用此简单的自定义类来确定状态的复选框
在此处查看github示例
答案 3 :(得分：0)
以前我想做同样的事情。在做了一些艰苦的研究之后，我接近了这个。
优点：
TriStateMaterialCheckBox.kt：
import android.content.Context
import android.util.AttributeSet
import androidx.annotation.StyleableRes
import com.google.android.material.checkbox.MaterialCheckBox
class TriStateMaterialCheckBox : MaterialCheckBox {
constructor(context: Context) : this(context, null)
constructor(context: Context, attrs: AttributeSet?) : this(context, attrs, com.google.android.material.R.attr.checkboxStyle)
constructor(context: Context, attrs: AttributeSet?, defStyleAttr: Int) : super(context, attrs, defStyleAttr) {
val sets = intArrayOf(R.attr.state)
val typedArray = context.obtainStyledAttributes(attrs, sets)
try {
state = typedArray.getInt(ATTR_STATE, STATE_UNCHECKED)
} finally {
typedArray.recycle()
}
initComponent()
}
companion object {
// @formatter:off
@StyleableRes private const val ATTR_STATE = 0
// @formatter:on
const val STATE_UNCHECKED: Int = 0
const val STATE_INDETERMINATE: Int = 1
const val STATE_CHECKED: Int = 2
private val UNCHECKED = intArrayOf(R.attr.state_unchecked)
private val INDETERMINATE = intArrayOf(R.attr.state_indeterminate)
private val CHECKED = intArrayOf(R.attr.state_checked)
}
private var isChangingState = false
var state: Int
@Throws(IllegalStateException::class)
set(value) {
if (isChangingState) return
if (field == value) return
isChangingState = true
field = value
isChecked = when (value) {
STATE_UNCHECKED -> false
STATE_INDETERMINATE -> true
STATE_CHECKED -> true
else -> throw IllegalStateException("$value is not a valid state for ${this.javaClass.name}")
}
refreshDrawableState()
isChangingState = false
onStateChanged?.let { it(this@TriStateMaterialCheckBox, value) }
}
var onStateChanged: ((TriStateMaterialCheckBox, Int) -> Unit)? = null
private fun initComponent() {
setButtonDrawable(R.drawable.tri_state_button)
setOnCheckedChangeListener { _, _ ->
state = when (state) {
STATE_UNCHECKED -> STATE_CHECKED
STATE_INDETERMINATE -> STATE_CHECKED
STATE_CHECKED -> STATE_UNCHECKED
else -> -1
}
}
}
override fun onCreateDrawableState(extraSpace: Int): IntArray {
val drawableState = super.onCreateDrawableState(extraSpace + 1)
mergeDrawableStates(
drawableState, when (state) {
STATE_UNCHECKED -> UNCHECKED
STATE_INDETERMINATE -> INDETERMINATE
STATE_CHECKED -> CHECKED
else -> throw IllegalStateException("$state is not a valid state for ${this.javaClass.name}")
}
)
return drawableState
}
}
attrs.xml:
<?xml version="1.0" encoding="utf-8"?>
<resources>
<attr name="state" format="enum">
<enum name="unchecked" value="0" />
<enum name="indeterminate" value="1" />
<enum name="checked" value="2" />
</attr>
<declare-styleable name="TriStateMaterialCheckBox">
<attr name="state" />
<attr name="state_unchecked" format="boolean" />
<attr name="state_indeterminate" format="boolean" />
<attr name="state_checked" format="boolean" />
</declare-styleable>
</resources>
tri_state_button.xml：
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" android:enterFadeDuration="@android:integer/config_shortAnimTime" android:exitFadeDuration="@android:integer/config_shortAnimTime">
<item android:drawable="@drawable/ic_unchecked" app:state_unchecked="true" />
<item android:drawable="@drawable/ic_indeterminate" app:state_indeterminate="true" />
<item android:drawable="@drawable/ic_checked" app:state_checked="true" />
<item android:drawable="@drawable/ic_unchecked" />
</selector>