ギャラリーからimageviewに画像を設定して保存しますか？

あなたの主な活動：

  public class MainActivity extends Activity {
        private static int RESULT_LOAD_IMG = 1;
        String imgDecodableString;
     
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
        }
     
        public void loadImagefromGallery(View view) {
            // Create intent to Open Image applications like Gallery, Google Photos
            Intent galleryIntent = new Intent(Intent.ACTION_PICK,
                    android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
            // Start the Intent
            startActivityForResult(galleryIntent, RESULT_LOAD_IMG);
        }
     
        @Override
        protected void onActivityResult(int requestCode, int resultCode, Intent data) {
            super.onActivityResult(requestCode, resultCode, data);
            try {
                // When an Image is picked
                if (requestCode == RESULT_LOAD_IMG && resultCode == RESULT_OK
                        && null != data) {
                    // Get the Image from data
     
                    Uri selectedImage = data.getData();
                    String[] filePathColumn = { MediaStore.Images.Media.DATA };
     
                    // Get the cursor
                    Cursor cursor = getContentResolver().query(selectedImage,
                            filePathColumn, null, null, null);
                    // Move to first row
                    cursor.moveToFirst();
     
                    int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
                    imgDecodableString = cursor.getString(columnIndex);
                    cursor.close();
                    ImageView imgView = (ImageView) findViewById(R.id.imgView);
                    // Set the Image in ImageView after decoding the String
                    imgView.setImageBitmap(BitmapFactory
                            .decodeFile(imgDecodableString));
     
                } else {
                    Toast.makeText(this, "You haven't picked Image",
                            Toast.LENGTH_LONG).show();
                }
            } catch (Exception e) {
                Toast.makeText(this, "Something went wrong", Toast.LENGTH_LONG)
                        .show();
            }
     
        }
     
    }

あなたのXml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <ImageView
        android:id="@+id/imgView"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1" >
    </ImageView>

    <Button
        android:id="@+id/buttonLoadPicture"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_weight="0"
        android:onClick="loadImagefromGallery"
        android:text="Load Picture" >
    </Button>

</LinearLayout>

マニフェストの許可：

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />