Bitmap From ImageView | Android Studio | Kotlin

 

Exploring Bitmaps in Android Studio Using Java: A Comprehensive Guide

Introduction:

In the dynamic world of Android app development, understanding and effectively manipulating images are crucial skills for creating visually appealing and efficient applications. One fundamental aspect of image processing in Android is working with Bitmaps. In this blog post, we will delve into the world of Bitmaps, exploring their significance, and learning how to handle them using Java in Android Studio.

What is a Bitmap? 

To kick things off, we'll provide a clear definition of what a Bitmap is in the context of Android development. Readers will gain insights into how Android represents images as Bitmaps and why they are the go-to data structure for handling pixel information.

Loading Bitmaps 

Here, we will guide readers through the process of loading Bitmaps into their Android application. Whether it's loading from resources, assets, or the web, we'll cover the various methods available in Android Studio to seamlessly incorporate images into your project.

Manipulating Bitmaps 

Understanding how to manipulate Bitmaps is essential for tasks such as resizing, cropping, and applying filters to images. We'll walk readers through practical examples and Java code snippets to demonstrate how to perform these operations efficiently.

Memory Management 

Bitmaps can be memory-intensive, and improper handling can lead to performance issues or even crashes. This section will focus on best practices for managing Bitmap memory in Android Studio, including techniques such as caching and recycling.

Displaying Bitmaps 

Now that readers have a solid grasp of Bitmaps and how to manipulate them, we'll explore different ways to display these images in an Android app. This includes using ImageView, custom views, and other UI components to showcase the final results to users.

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Code Snippet

BitmapDrawable bitmapDrawable = (BitmapDrawable) wallImageView.getDrawable();
Bitmap bitmap = bitmapDrawable.getBitmap();

In the above code snippet wallImageView  is the ImageView from which you want to get Bitmap

Full Example

activity_main.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"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <ImageView
        android:id="@+id/wallImageView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_weight="1"
        tools:src="@tools:sample/backgrounds/scenic" />

    <com.google.android.material.button.MaterialButton
        android:id="@+id/getBitmapBtn"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="10dp"
        android:text="Get Bitmap" />

</LinearLayout>

MainActivity.java

package com.technifysoft.myapplication

import android.graphics.drawable.BitmapDrawable
import android.os.Bundle
import android.widget.ImageView
import androidx.appcompat.app.AppCompatActivity
import com.google.android.material.button.MaterialButton

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        //init ImageView from which we want to get Bitmap
        val wallImageView = findViewById<ImageView>(R.id.wallImageView)
        //init MaterialButton which we will click to  get Bitmap from ImageView
        val getBitmapBtn = findViewById<MaterialButton>(R.id.getBitmapBtn)

        //handle getBitmapBtn click, get Bitmap from ImageView
        getBitmapBtn.setOnClickListener {
            val bitmapDrawable = wallImageView.drawable as BitmapDrawable
            val bitmap = bitmapDrawable.bitmap
        }
        
    }
    
}

Output