Создание флажка с тремя состояниями на android

Я застреваю перед большой проблемой: Я хотел бы сделать три флажка состояния на Android. Это флажок в ListView с флажками. Он должен позволять пользователю переключаться между тремя состояниями:

  • все отмеченные
  • none checked
  • проверочно проверено

И при необходимости сохраните разное состояние при изменении.

Если я прав, я должен сделать подкласс класса CompoundButton и реализовать int mstate с помощью boolean mchecked. Затем я должен переопределить прослушиватель событий, функции сохранения состояния, а также состояние получателя и сеттер.

Мой вопрос в основном как я могу это реализовать? Как переключаться между доступными состояниями? (Я реализовал middle_state в xml) и как правильно реализовать обработчик событий?

Вот реализация, которую я начал:

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;
    }
}

Вот код запаса CompoundButton:

/*
 * 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();
    }
}

Вот моя xml state-liste реализация (работа):

<?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>

И вот реализация xml для фона для флажка:

<?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>

ОТВЕТЫ

Ответ 1

Старая тема, но я даю свое решение для тех, кто интересуется:

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) {
                    default:
                    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) {
            default:
            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();
    }
}

Вы можете найти ресурсы кнопки здесь. Это работает отлично.

Ответ 2

Если вы действительно настаиваете на использовании CheckBox, где каждый элемент имеет 3 состояния, тогда может работать следующее, но я не пробовал: - Создайте класс, который расширяет класс CheckBox. - Добавить переменную: "checkstate" типа int или byte. Класс должен иметь логическую переменную "isChecked". - переопределить метод onClick или onCheck, чтобы он менял переменную checkstate между тремя состояниями вместо переключения переменной isChecked. - После отображения проверьте "checkstate" и сделайте визуальный эффект, чтобы показать третье состояние. - Наконец, скажите мне, работает ли это.