Question

I have two activities: one displays an image and a button, the other displays a photo gallery. I want to be able to select any of the images in the gallery and then display them on the first activity in place of the default image.

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.gallery);

    Gallery g = (Gallery) findViewById(R.id.gallery);
    g.setAdapter(new ImageAdapter(this));

    g.setOnItemClickListener(new OnItemClickListener() {
        public void onItemClick(AdapterView parent, View v, int position, long id) {
            Toast.makeText(PhotoGallery.this, "Position: " + id, Toast.LENGTH_SHORT).show();

            Intent intent=new Intent();   
            intent.putExtra("PictureID", position);
            setResult(RESULT_OK, intent);
            finish();


        }
    });
}

Am I even close here? I’m not quite sure what to do with any string or int I would attach to the Intent — can I attach the object itself? I’d much rather pass back at minimum the string name of the resource (image), but the only thing I can seem to figure out right now is how to pass back the position of the picture … not a great solution. I can clarify more if necessary — thanks.

EDIT:

For anyone who comes across this in the future, here’s the result of my app. Simple, but works!
http://www.youtube.com/watch?v=WJjEvwy8yDc

Answer 1

As you are new to Android you should take a look at the Android samples provided with the SDk. What you want to do can be achieved by an ImageSwitcher. You can take a look at the ImageSwitcher example in the Android ApiDemos sample.

Sample from Android samples :

ImageSwitcher1.java

/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.example.android.apis.view;

import com.example.android.apis.R;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.view.Window;
import android.view.animation.AnimationUtils;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.Gallery.LayoutParams;
import android.widget.ImageSwitcher;
import android.widget.ImageView;
import android.widget.ViewSwitcher;


public class ImageSwitcher1 extends Activity implements
        AdapterView.OnItemSelectedListener, ViewSwitcher.ViewFactory {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);

        setContentView(R.layout.image_switcher_1);

        mSwitcher = (ImageSwitcher) findViewById(R.id.switcher);
        mSwitcher.setFactory(this);
        mSwitcher.setInAnimation(AnimationUtils.loadAnimation(this,
                android.R.anim.fade_in));
        mSwitcher.setOutAnimation(AnimationUtils.loadAnimation(this,
                android.R.anim.fade_out));

        Gallery g = (Gallery) findViewById(R.id.gallery);
        g.setAdapter(new ImageAdapter(this));
        g.setOnItemSelectedListener(this);
    }

    public void onItemSelected(AdapterView parent, View v, int position, long id) {
        mSwitcher.setImageResource(mImageIds[position]);
    }

    public void onNothingSelected(AdapterView parent) {
    }

    public View makeView() {
        ImageView i = new ImageView(this);
        i.setBackgroundColor(0xFF000000);
        i.setScaleType(ImageView.ScaleType.FIT_CENTER);
        i.setLayoutParams(new ImageSwitcher.LayoutParams(LayoutParams.MATCH_PARENT,
                LayoutParams.MATCH_PARENT));
        return i;
    }

    private ImageSwitcher mSwitcher;

    public class ImageAdapter extends BaseAdapter {
        public ImageAdapter(Context c) {
            mContext = c;
        }

        public int getCount() {
            return mThumbIds.length;
        }

        public Object getItem(int position) {
            return position;
        }

        public long getItemId(int position) {
            return position;
        }

        public View getView(int position, View convertView, ViewGroup parent) {
            ImageView i = new ImageView(mContext);

            i.setImageResource(mThumbIds[position]);
            i.setAdjustViewBounds(true);
            i.setLayoutParams(new Gallery.LayoutParams(
                    LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
            i.setBackgroundResource(R.drawable.picture_frame);
            return i;
        }

        private Context mContext;

    }

    private Integer[] mThumbIds = {
            R.drawable.sample_thumb_0, R.drawable.sample_thumb_1,
            R.drawable.sample_thumb_2, R.drawable.sample_thumb_3,
            R.drawable.sample_thumb_4, R.drawable.sample_thumb_5,
            R.drawable.sample_thumb_6, R.drawable.sample_thumb_7};

    private Integer[] mImageIds = {
            R.drawable.sample_0, R.drawable.sample_1, R.drawable.sample_2,
            R.drawable.sample_3, R.drawable.sample_4, R.drawable.sample_5,
            R.drawable.sample_6, R.drawable.sample_7};

}

image_switcher_1.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright (C) 2007 The Android Open Source Project

     Licensed under the Apache License, Version 2.0 (the "License");
     you may not use this file except in compliance with the License.
     You may obtain a copy of the License at

          http://www.apache.org/licenses/LICENSE-2.0

     Unless required by applicable law or agreed to in writing, software
     distributed under the License is distributed on an "AS IS" BASIS,
     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     See the License for the specific language governing permissions and
     limitations under the License.
-->

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent"> 

    <ImageSwitcher android:id="@+id/switcher"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true"
    />

    <Gallery android:id="@+id/gallery"
        android:background="#55000000"
        android:layout_width="match_parent"
        android:layout_height="60dp"
        android:layout_alignParentBottom="true"
        android:layout_alignParentLeft="true"

        android:gravity="center_vertical"
        android:spacing="16dp"
    />

</RelativeLayout>