Android imageview 更改色调以模拟按钮单击 [英] Android imageview change tint to simulate button click

问题描述

我有一个图像视图，我在其上设置了从 url 获取的位图.在 imageview 上，我设置了一个 onClickListener 来打开一个对话框.

I have an imageview on which I have set a bitmap fetched from an url. On the imageview I have set an onClickListener which opens up a dialog.

我想在按下 imageview 时以某种方式改变色调(使其变暗)，以提供一种类似按钮点击的感觉.

I want to somehow change the tint (make it darker) when the imageview is pressed upon to provide a sort of button click like feel.

你有什么建议?

推荐答案

happydude 的回答是处理这个问题的最优雅的方法，但不幸的是(如评论中所指出的)ImageView 的源代码只接受一个整数(纯色).Issue 18220 解决这个问题已经有几年了，我已经在那里发布了一个解决方法，我将在这里总结:

happydude's answer is the most elegant way to handle this but unfortunately (as pointed out in the comments) the source code for ImageView only accepts an integer (solid colour). Issue 18220 has been around for a couple years addressing this, I've posted a workaround there that I'll summarize here:

扩展 ImageView 并使用根据新状态设置色调的代码包装 drawableStateChanged():

Extend ImageView and wrap drawableStateChanged() with code that sets the tint based on the new state:

TintableImageView.java

package com.example.widgets;

import android.content.Context;
import android.content.res.ColorStateList;
import android.content.res.TypedArray;
import android.util.AttributeSet;
import android.support.v7.widget.AppCompatImageView;

import com.example.R;

public class TintableImageView extends AppCompatImageView {

    private ColorStateList tint;

    public TintableImageView(Context context) {
        super(context);
    }

    public TintableImageView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init(context, attrs, 0);
    }

    public TintableImageView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        init(context, attrs, defStyle);
    }

    private void init(Context context, AttributeSet attrs, int defStyle) {
        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.TintableImageView, defStyle, 0);
        tint = a.getColorStateList(R.styleable.TintableImageView_tintColorStateList);
        a.recycle();
    }

    @Override
    protected void drawableStateChanged() {
        super.drawableStateChanged();
        if (tint != null && tint.isStateful())
            updateTintColor();
    }    

    private void updateTintColor() {
        int color = tint.getColorForState(getDrawableState(), 0);
        setColorFilter(color);
    }

}

定义自定义属性:

attrs.xml

<?xml version="1.0" encoding="UTF-8"?>
<resources>

    <declare-styleable name="TintableImageView">
        <attr name="tintColorStateList" format="reference|color" />
    </declare-styleable>

</resources>

将小部件和自定义属性与您的本地命名空间一起使用，而不是 Android 的:

Use the widget and custom attribute with your local namespace instead of Android's:

example_layout.xml

<?xml version="1.0" encoding="UTF-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal">

    <com.example.widgets.TintableImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/example"
        android:clickable="true"
        app:tintColorStateList="@color/color_selector"/>

</LinearLayout>

然后您可以使用像happydude建议的颜色选择器:

You can then use a colour selector like happydude suggested:

color_selector.xml

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_pressed="true" android:color="@color/pressed_color"/>
    <item android:color="#00000000"/>
</selector>

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