Load photo and scale down to suit ImageView

This example show how to load photo using Intent.ACTION_OPEN_DOCUMENT, and scale-down to suitable size, to display in ImageView.


MainActivity.java

package com.blogspot.android_er.androidimage;

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

import java.io.FileNotFoundException;

public class MainActivity extends AppCompatActivity {

 private static final int RQS_OPEN = 1;
 Button buttonOpen;
 ImageView imageView;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 buttonOpen = (Button) findViewById(R.id.opendocument);
 buttonOpen.setOnClickListener(buttonOpenOnClickListener);

 imageView = (ImageView)findViewById(R.id.image);
 }

 View.OnClickListener buttonOpenOnClickListener =
 new View.OnClickListener() {
 @Override
 public void onClick(View v) {
 Intent intent = new Intent();
 intent.setAction(Intent.ACTION_OPEN_DOCUMENT);
 intent.addCategory(Intent.CATEGORY_OPENABLE);
 intent.setType("image/*");
 startActivityForResult(intent, RQS_OPEN);
 }
 };

 @Override
 protected void onActivityResult(int requestCode, int resultCode, Intent data) {
 if (resultCode == RESULT_OK && requestCode == RQS_OPEN) {
 Uri dataUri = data.getData();
 int w = imageView.getWidth();
 int h = imageView.getHeight();
 Toast.makeText(MainActivity.this,
 dataUri.toString() + " " +
 w + " : " + h,
 Toast.LENGTH_LONG).show();

 try {
 Bitmap bm = loadScaledBitmap(dataUri, w, h);
 imageView.setImageBitmap(bm);
 Toast.makeText(MainActivity.this,
 bm.getWidth() + " x " + bm.getHeight(),
 Toast.LENGTH_SHORT).show();
 } catch (FileNotFoundException e) {
 e.printStackTrace();
 Toast.makeText(MainActivity.this, e.getMessage(), Toast.LENGTH_LONG).show();
 }
 }
 }

 /*
 reference:
 Load scaled bitmap
 http://android-er.blogspot.com/2013/08/load-scaled-bitmap.html
 */
 private Bitmap loadScaledBitmap(Uri src, int req_w, int req_h) throws FileNotFoundException {

 Bitmap bm = null;

 // First decode with inJustDecodeBounds=true to check dimensions
 final BitmapFactory.Options options = new BitmapFactory.Options();
 options.inJustDecodeBounds = true;
 BitmapFactory.decodeStream(getBaseContext().getContentResolver().openInputStream(src),
 null, options);

 // Calculate inSampleSize
 options.inSampleSize = calculateInSampleSize(options, req_w, req_h);

 // Decode bitmap with inSampleSize set
 options.inJustDecodeBounds = false;
 bm = BitmapFactory.decodeStream(
 getBaseContext().getContentResolver().openInputStream(src), null, options);

 return bm;
 }

 public int calculateInSampleSize(BitmapFactory.Options options,
 int reqWidth, int reqHeight) {
 // Raw height and width of image
 final int height = options.outHeight;
 final int width = options.outWidth;
 int inSampleSize = 1;

 if (height > reqHeight || width > reqWidth) {

 // Calculate ratios of height and width to requested height and
 // width
 final int heightRatio = Math.round((float) height
 / (float) reqHeight);
 final int widthRatio = Math.round((float) width / (float) reqWidth);

 // Choose the smallest ratio as inSampleSize value, this will
 // guarantee
 // a final image with both dimensions larger than or equal to the
 // requested height and width.
 inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio;
 }

 return inSampleSize;
 }
}

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