Sample code for a simple image picker for android

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
    tools:context="io.github.cyb3rn4u7.imagepicker.MainActivity">


    <ImageView
        android:id="@+id/display_image"
        android:layout_width="256dp"
        android:layout_height="256dp"
        android:src="@drawable/ic_photo_size_select"
        android:layout_centerInParent="true"
        />

    <Button
        android:id="@+id/pick_img"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Select image"
        android:drawableTop="@drawable/ic_insert_photo"
        android:layout_alignParentBottom="true"
        android:layout_centerInParent="true"
        android:layout_marginBottom="16dp"
        />

</RelativeLayout>

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="io.github.cyb3rn4u7.imagepicker">
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

MainActivity.java

package io.github.cyb3rn4u7.imagepicker;

import android.content.Intent;
import android.graphics.Bitmap;
import android.net.Uri;
import android.provider.MediaStore;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    private static final int IMG_RESULT = 101 ;
    private ImageView imageView;
    private Button button;


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

        imageView = findViewById(R.id.display_image);
        button = findViewById(R.id.pick_img);

        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(Intent.ACTION_PICK,
                        android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);

                startActivityForResult(intent, IMG_RESULT);
            }
        });



    }


    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        try {

            if (requestCode == IMG_RESULT && resultCode == RESULT_OK
                    && null != data) {

                // get the selected image
                Uri imageUri = data.getData();
                Bitmap bitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), imageUri);
                // display the image
                imageView.setImageBitmap(bitmap);



            }
        } catch (Exception e) {
            Toast.makeText(this,"oops something went wrong", Toast.LENGTH_LONG)
                    .show();
        }
    }
}