Android imageview change tint to simulate button c

问题:

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.

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.

What do you suggest?

回答1:

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:

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);
    }

}

Define a custom attribute:

attrs.xml

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

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

</resources>

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>

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>

回答2:

One way would be to use a combination of a ColorFilter and a ColorStateList that contains your tint color for when the button is pressed. The xml for the ColorStateList in the res/color directory would look like this:

button_pressed.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>

where @color/pressed_color is your tint color (which should be partially transparent). Then in your ImageView subclass, you apply the color by overriding drawableStateChanged().

@Override
protected void drawableStateChanged() {
    super.drawableStateChanged();

    ColorStateList list = getResources().getColorStateList(R.color.button_pressed);
    int color = list.getColorForState(getDrawableState(), Color.TRANSPARENT);
    setColorFilter(color);
    invalidate();
}

Any time the button's state changes, this code is called and will automatically set the tint as appropriate.

回答3:

I'd have to test it out, but you should be able to set an xml with that behaviour as the ImageView drawable, and then set your bitmap as the ImageView background.

回答4:

For me a simple solution is working, using setAlpha(180) in onClick event make the image darker, giving the user a feedback that it was clicked or touched.

final ImageView myImage = (ImageView) findViewById(R.id.ivDocument);
myImage.setImage...(... your image ...); // load your ImageView
myImage.setClickable(true);
myImage.setFocusable(true);
myImage.setOnClickListener(new OnClickListener() {
    @Override
    public void onClick(View v) {
        myImage.setAlpha(180);
        doWhateverYouWantHere(v);
    }
});

Regarding your XML layout, nothing special.

回答5:

This code snippet worked for me:

porterDuffColorFilter = newPorterDuffColorFilter(getResources().getColor(R.color.cardview_dark_background),PorterDuff.Mode.MULTIPLY);

imgView.getDrawable().setColorFilter(porterDuffColorFilter);
imgView.setBackgroundColor(Color.TRANSPARENT);