动态改变actionbar上menu的图标

工作中遇到了一个需求是，在滚动的时候让actionbar上的图标进行变色。实现后在这里总结下思路。

 

一、先在主题中定义好Actionbar的style

 <style name="AppTheme" parent="BaseTheme">



        <item name="actionBarStyle">@style/NAActionBarStyle</item>

        <item name="actionBarSize">@dimen/actionbar_height</item>


        <item name="actionBarItemBackground">@drawable/action_bar_selector</item>



        <item name="actionOverflowButtonStyle">@style/MyOverFlow.Dark</item>

        <item name="homeAsUpIndicator">@drawable/action_bar_icon_back_dark</item>



    </style>

 

二、分区域进行改变

2.1 改变最左边的返回按钮

getSupportActionBar().setHomeAsUpIndicator(R.drawable.action_bar_icon_back_light);

 

2.2 改变文字的颜色和透明度

这个比较复杂，首先要定义这样一个类：

package com.duitang.main.util;



import android.graphics.Color;

import android.os.Parcel;

import android.support.annotation.NonNull;

import android.text.TextPaint;

import android.text.style.ForegroundColorSpan;



/**

 * Created by YlorD on 14-12-16.

 * @author YlorD

 * @since v3.7

 * from Cyril Mottier

 */

public class AlphaForegroundColorSpan extends ForegroundColorSpan {



    private float mAlpha;



    public AlphaForegroundColorSpan(int color) {

        super(color);

    }



    public AlphaForegroundColorSpan(Parcel src) {

        super(src);

    }



    @Override

    public void updateDrawState(@NonNull TextPaint ds) {

        ds.setColor(getAlphaColor());

    }



    public float getAlpha() {

        return mAlpha;

    }



    public void setAlpha(float alpha) {

        mAlpha = alpha;

    }



    private int getAlphaColor() {

        int foregroundColor = getForegroundColor();

        return Color.argb((int) (mAlpha * 255), Color.red(foregroundColor),

                Color.green(foregroundColor), Color.blue(foregroundColor));

    }

}

然后在代码中动态调用actionbar的setTitle方法就行。

    private AlphaForegroundColorSpan mAlphaForegroundColorSpan;



    private SpannableStringBuilder mSpannableStringBuilder;

mAlphaForegroundColorSpan = new AlphaForegroundColorSpan(getResources().getColor(R.color.dark));

    private void setTitleAlpha(float alpha) {

        mAlphaForegroundColorSpan.setAlpha(alpha);

        mSpannableStringBuilder.setSpan(mAlphaForegroundColorSpan, 0,

                mSpannableStringBuilder.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);

        getSupportActionBar().setTitle(mSpannableStringBuilder);

    }

 

2.3 改变最右边的menu图标

    MenuItem moreItem;



    @Override

    public boolean onCreateOptionsMenu(Menu menu) {

        moreItem = menu.add(Menu.NONE, Menu.FIRST, Menu.FIRST, null);

        moreItem.setIcon(R.drawable.action_bar_icon_more);

        moreItem.setShowAsAction(MenuItem.SHOW_AS_ACTION_ALWAYS);

        

        return super.onCreateOptionsMenu(menu);

    }

动态改变

 if (moreItem != null) {

     moreItem.setIcon(R.drawable.action_bar_icon_more_light);

 }

 

2.4 改变最右边的OverFlow

如果是多个menuItem聚合在了一起，那么就会显示三个小点。怎么动态改变这三个小点的图标呢？

在style中定义好overFlow的样式：

<style name="MyOverFlow.Dark" parent="@style/Widget.AppCompat.Light.ActionButton.Overflow">

        <item name="android:src">@drawable/action_bar_icon_more_dark</item>

        <item name="android:contentDescription">@string/accessibility_overflow</item>

</style>

这里面的关键点在于写了一个contentDescription，作为overFlow的标识。然后在代码中写上如下的代码：

private TintImageView overflow;

 　　   // The content description used to locate the overflow button

        final String overflowDesc = getString(R.string.accessibility_overflow);

        // The top-level window

        final ViewGroup decor = (ViewGroup) getWindow().getDecorView();

        // Wait a moment to ensure the overflow button can be located

        decor.post(new Runnable() {

            @Override

            public void run() {

                // The List that contains the matching views

                final ArrayList<View> outViews = new ArrayList<>();

                // Traverse the view-hierarchy and locate the overflow button

                decor.findViewsWithText(outViews, overflowDesc, View.FIND_VIEWS_WITH_CONTENT_DESCRIPTION);

                // Guard against any errors

                if (outViews.isEmpty()) {

                    return;

                }

                // Do something with the view

                overflow = (TintImageView) outViews.get(0);

            }

        });

之后就可以在代码中动态的改变了：

　　　　　　  if (overflow != null) {

                overflow.setImageResource(R.drawable.action_bar_icon_more_light);

            }

参考自：http://stackoverflow.com/questions/22046903/changing-the-android-overflow-menu-icon-programmatically