列表视图中的单选按钮

Question

我在列表视图格式中显示 sting 列表，我使用默认列表视图并使用 simple_list_item_single_choice 放置了一个单选按钮。但这在右侧显示了单选按钮，我想在左侧显示单选按钮。是否可以使用默认列表视图在左侧显示单选按钮

Answer 1

simple_list_item_single_choice.xml 使用CheckedTextView 类

这里是simple_list_item_single_choice.xml

 <CheckedTextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@android:id/text1"
    android:layout_width="match_parent"
    android:layout_height="?android:attr/listPreferredItemHeight"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:gravity="center_vertical"
    android:checkMark="?android:attr/listChoiceIndicatorSingle"
    android:paddingLeft="6dip"
    android:paddingRight="6dip"
   />

您需要根据需要创建自定义 xml 并使用 CheckBox 来实现您的目标 这是你的custom.xml

 <CheckBox
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@android:id/text1"
    android:layout_width="fill_parent"
    android:layout_height="?android:attr/listPreferredItemHeight"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:gravity="center_vertical"
    android:button="?android:attr/listChoiceIndicatorSingle"
    android:paddingLeft="6dip"
    android:paddingRight="6dip"
   />

只需在您的代码中使用custom.xml 代替simple_list_item_single_choice.xml。

希望对你有帮助。

Answer 2

这是不可能的，默认情况下单选按钮在右侧。如果您希望它位于左侧，则应从 SDK 中获取 simple_list_item_single_choice.xml 布局的源代码并进行适当的更改，然后使用此自定义布局而不是默认布局。

Answer 3

simple_list_item_single_choice 使用 CheckedTextView 类。

<?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.
-->

<CheckedTextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@android:id/text1"
    android:layout_width="match_parent"
    android:layout_height="?android:attr/listPreferredItemHeight"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:gravity="center_vertical"
    android:checkMark="?android:attr/listChoiceIndicatorSingle"
    android:paddingLeft="6dip"
    android:paddingRight="6dip"
/>

CheckedTextView 类是 android.widget 包。

本课程来源如下。

/*

 * 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.util.AttributeSet;
import android.view.Gravity;
import android.view.ViewDebug;
import android.view.accessibility.AccessibilityEvent;


/**
 * An extension to TextView that supports the {@link android.widget.Checkable} interface.
 * This is useful when used in a {@link android.widget.ListView ListView} where the it's 
 * {@link android.widget.ListView#setChoiceMode(int) setChoiceMode} has been set to
 * something other than {@link android.widget.ListView#CHOICE_MODE_NONE CHOICE_MODE_NONE}.
 *
 */
public class CheckedTextView extends TextView implements Checkable {
    private boolean mChecked;
    private int mCheckMarkResource;
    private Drawable mCheckMarkDrawable;
    private int mBasePaddingRight;
    private int mCheckMarkWidth;

    private static final int[] CHECKED_STATE_SET = {
        R.attr.state_checked
    };

    public CheckedTextView(Context context) {
        this(context, null);
    }

    public CheckedTextView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public CheckedTextView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);

        TypedArray a = context.obtainStyledAttributes(attrs,
                R.styleable.CheckedTextView, defStyle, 0);

        Drawable d = a.getDrawable(R.styleable.CheckedTextView_checkMark);
        if (d != null) {
            setCheckMarkDrawable(d);
        }

        boolean checked = a.getBoolean(R.styleable.CheckedTextView_checked, false);
        setChecked(checked);

        a.recycle();
    }

    public void toggle() {
        setChecked(!mChecked);
    }

    @ViewDebug.ExportedProperty
    public boolean isChecked() {
        return mChecked;
    }

    /**
     * <p>Changes the checked state of this text view.</p>
     *
     * @param checked true to check the text, false to uncheck it
     */
    public void setChecked(boolean checked) {
        if (mChecked != checked) {
            mChecked = checked;
            refreshDrawableState();
        }
    }


    /**
     * Set the checkmark to a given Drawable, identified by its resourece id. This will be drawn
     * when {@link #isChecked()} is true.
     * 
     * @param resid The Drawable to use for the checkmark.
     */
    public void setCheckMarkDrawable(int resid) {
        if (resid != 0 && resid == mCheckMarkResource) {
            return;
        }

        mCheckMarkResource = resid;

        Drawable d = null;
        if (mCheckMarkResource != 0) {
            d = getResources().getDrawable(mCheckMarkResource);
        }
        setCheckMarkDrawable(d);
    }

    /**
     * Set the checkmark to a given Drawable. This will be drawn when {@link #isChecked()} is true.
     *
     * @param d The Drawable to use for the checkmark.
     */
    public void setCheckMarkDrawable(Drawable d) {
        if (mCheckMarkDrawable != null) {
            mCheckMarkDrawable.setCallback(null);
            unscheduleDrawable(mCheckMarkDrawable);
        }
        if (d != null) {
            d.setCallback(this);
            d.setVisible(getVisibility() == VISIBLE, false);
            d.setState(CHECKED_STATE_SET);
            setMinHeight(d.getIntrinsicHeight());

            mCheckMarkWidth = d.getIntrinsicWidth();
            mPaddingRight = mCheckMarkWidth + mBasePaddingRight;
            d.setState(getDrawableState());
        } else {
            mPaddingRight = mBasePaddingRight;
        }
        mCheckMarkDrawable = d;
        requestLayout();
    }

    @Override
    public void setPadding(int left, int top, int right, int bottom) {
        super.setPadding(left, top, right, bottom);
        mBasePaddingRight = mPaddingRight;
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        final Drawable checkMarkDrawable = mCheckMarkDrawable;
        if (checkMarkDrawable != null) {
            final int verticalGravity = getGravity() & Gravity.VERTICAL_GRAVITY_MASK;
            final int height = checkMarkDrawable.getIntrinsicHeight();

            int y = 0;

            switch (verticalGravity) {
                case Gravity.BOTTOM:
                    y = getHeight() - height;
                    break;
                case Gravity.CENTER_VERTICAL:
                    y = (getHeight() - height) / 2;
                    break;
            }

            int right = getWidth();
            checkMarkDrawable.setBounds(
                    right - mCheckMarkWidth - mBasePaddingRight, 
                    y, 
                    right - mBasePaddingRight, 
                    y + height);
            checkMarkDrawable.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 (mCheckMarkDrawable != null) {
            int[] myDrawableState = getDrawableState();

            // Set the state of the Drawable
            mCheckMarkDrawable.setState(myDrawableState);

            invalidate();
        }
    }

    @Override
    public boolean dispatchPopulateAccessibilityEvent(AccessibilityEvent event) {
        boolean populated = super.dispatchPopulateAccessibilityEvent(event);
        if (!populated) {
            event.setChecked(mChecked);
        }
        return populated;
    }
}

您正在 onDraw 修改。和 simple_list_item_single_choice.xml 修改。

例如。

<**your class(modifyed CheckedTextView)** xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@android:id/text1"
    android:layout_width="match_parent"
    android:layout_height="?android:attr/listPreferredItemHeight"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:gravity="center_vertical"
    android:checkMark="?android:attr/listChoiceIndicatorSingle"
    android:paddingLeft="6dip"
    android:paddingRight="6dip"
/>