Convert ImageView to black and white and set brightness using ColorFilter

MainActivity.java

package com.blogspot.android_er.androidcolorfilter;

import android.graphics.ColorFilter;
import android.graphics.ColorMatrixColorFilter;
import android.graphics.PorterDuff;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.ImageView;
import android.widget.SeekBar;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

 ImageView imageView;
 SeekBar brightnessBar;
 TextView brightnessInfo;

 PorterDuff.Mode[] optMode = PorterDuff.Mode.values();

 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);

 imageView = (ImageView)findViewById(R.id.iv);
 brightnessBar = (SeekBar)findViewById(R.id.bar_brightness);
 brightnessInfo = (TextView)findViewById(R.id.brightness_info);

 brightnessBar.setOnSeekBarChangeListener(brightnessBarChangeListener);

 setBlackAndWhite(imageView);
 }

 SeekBar.OnSeekBarChangeListener brightnessBarChangeListener
 = new SeekBar.OnSeekBarChangeListener(){

 @Override
 public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
 setBlackAndWhite(imageView);
 }

 @Override
 public void onStartTrackingTouch(SeekBar seekBar) {

 }

 @Override
 public void onStopTrackingTouch(SeekBar seekBar) {

 }
 };

 private void setBlackAndWhite(ImageView iv){

 float brightness = (float)(brightnessBar.getProgress() - 255);

 float[] colorMatrix = {
 0.33f, 0.33f, 0.33f, 0, brightness, //red
 0.33f, 0.33f, 0.33f, 0, brightness, //green
 0.33f, 0.33f, 0.33f, 0, brightness, //blue
 0, 0, 0, 1, 0 //alpha
 };

 ColorFilter colorFilter = new ColorMatrixColorFilter(colorMatrix);
 iv.setColorFilter(colorFilter);

 brightnessInfo.setText(String.valueOf(brightness));
 }

}

layout/activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
 
 
 android_layout_width="match_parent"
 android_layout_height="match_parent"
 android_padding="16dp"
 android_orientation="vertical"
 tools_context=".MainActivity">

 <TextView
 android_layout_width="wrap_content"
 android_layout_height="wrap_content"
 android_layout_gravity="center_horizontal"
 android_autoLink="web"
 android_text="http://android-er.blogspot.com/"
 android_textStyle="bold" />

 <ImageView
 android_id="@+id/iv"
 android_layout_width="wrap_content"
 android_layout_height="wrap_content"
 android_src="@mipmap/ic_launcher"/>

 <TextView
 android_layout_width="wrap_content"
 android_layout_height="wrap_content"
 android_text="Brightness"/>

 <SeekBar
 android_id="@+id/bar_brightness"
 android_layout_width="match_parent"
 android_layout_height="wrap_content"
 android_max="512"
 android_progress="255"/>

 <TextView
 android_id="@+id/brightness_info"
 android_layout_width="wrap_content"
 android_layout_height="wrap_content"
 android_text="Brightness"/>
</LinearLayout>

Related:
- Android example code using ColorFilter

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