To display images in straight Android we have to go about things in a slightly different way than we did with Processing.

In this case, we have to use a Bitmap object which can be displayed on an ImageView.

Here is an example which allows the user to pick an image from the gallery, resizes the image to the screen resolution and then displays it in an ImageView.

package com.mobvcasting.simpledisplayimage;

import android.app.Activity;
import android.os.Bundle;
import java.io.FileNotFoundException;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.util.Log;
import android.view.Display;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;

public class SimpleDisplayImageActivity extends Activity implements OnClickListener {

	ImageView chosenImageView;
	Button choosePicture;

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);

		chosenImageView = (ImageView) this.findViewById(R.id.ChosenImageView);
		choosePicture = (Button) this.findViewById(R.id.ChoosePictureButton);

		choosePicture.setOnClickListener(this);
	}

	public void onClick(View v) {
		Intent choosePictureIntent = new Intent(Intent.ACTION_PICK,
				android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
		startActivityForResult(choosePictureIntent, 0);
	}

	protected void onActivityResult(int requestCode, int resultCode, Intent intent) {
		super.onActivityResult(requestCode, resultCode, intent);

		if (resultCode == RESULT_OK) {
			Uri imageFileUri = intent.getData();

			Display currentDisplay = getWindowManager().getDefaultDisplay();
			int dw = currentDisplay.getWidth();
			int dh = currentDisplay.getHeight();

			try {
				// Load up the image's dimensions not the image itself
				BitmapFactory.Options bmpFactoryOptions = new BitmapFactory.Options();
				bmpFactoryOptions.inJustDecodeBounds = true;
				Bitmap bmp = BitmapFactory
						.decodeStream(getContentResolver().openInputStream(
								imageFileUri), null, bmpFactoryOptions);

				int heightRatio = (int) Math.ceil(bmpFactoryOptions.outHeight
						/ (float) dh);
				int widthRatio = (int) Math.ceil(bmpFactoryOptions.outWidth
						/ (float) dw);

				if (heightRatio > 1 && widthRatio > 1) {
					if (heightRatio > widthRatio) {
						bmpFactoryOptions.inSampleSize = heightRatio;
					} else {
						bmpFactoryOptions.inSampleSize = widthRatio;
					}
				}

				bmpFactoryOptions.inJustDecodeBounds = false;
				bmp = BitmapFactory
						.decodeStream(getContentResolver().openInputStream(
								imageFileUri), null, bmpFactoryOptions);

				chosenImageView.setImageBitmap(bmp);

			} catch (FileNotFoundException e) {
				Log.v("ERROR", e.toString());
			}
		}
	}
}

It requires the following main.xml file to be in the res/layout folder:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<Button
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="Choose Picture" android:id="@+id/ChoosePictureButton"/>
<ImageView android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/ChosenImageView">
Of course, very similar code to this could be written to display an image from the built-in camera application which is triggered through an Intent.