Android Open Source - 2014-Droid-code Main Activity

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License

The source code is released under:

GNU General Public License

Java Source Code

package ca.campbell.simplegridview;
/*// w  ww.java 2  s.  c  o  m
 * Code from http://developer.android.com/guide/topics/ui/layout/gridview.html
 */
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.Toast;

public class MainActivity extends Activity {

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    GridView gridview = (GridView) findViewById(R.id.gridview);
    gridview.setAdapter(new ImageAdapter(this));
    gridview.setOnItemClickListener(handleClick); 

  }
  
  private OnItemClickListener handleClick = new OnItemClickListener() {

    public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
      Toast.makeText(MainActivity.this, "" + position, Toast.LENGTH_SHORT).show();
    }
  };
/*
 * First, this implements some required methods inherited from BaseAdapter. 
 * The constructor and getCount() are self-explanatory. 
 * Normally, getItem(int) should return the actual object at the specified position in the adapter,
 * but it's ignored for this example. 
 * Likewise, getItemId(int) should return the row id of the item, but it's not needed here.
 * 
 * The first method necessary is getView(). This method creates a new View for each image added to the ImageAdapter.
 *  When this is called, a View is passed in, which is normally a recycled object
 *  (at least after this has been called once), so there's a check to see if the object is null.
 *  If it is null, an ImageView is instantiated and configured with desired properties 
 *  for the image presentation:
 *  -setLayoutParams(ViewGroup.LayoutParams) sets the height and width for the View?
 *    this ensures that, no matter the size of the drawable, each image is resized and 
 *    cropped to fit in these dimensions, as appropriate.
 *  -setScaleType(ImageView.ScaleType) declares that images should be cropped toward the center (if necessary).
 *  -setPadding(int, int, int, int) defines the padding for all sides. 
 *    (Note that, if the images have different aspect-ratios, then less padding will cause more cropping 
 *    of the image if it does not match the dimensions given to the ImageView.)  
 *  
 *  If the View passed to getView() is not null, then the local ImageView is initialized with
 *  the recycled View object.  At the end of the getView() method, the position integer passed into
 *  the method is used to select an image from the mThumbIds array, which is set as the image resource
 *  for the ImageView.  All that's left is to define the mThumbIds array of drawable resources.
 */
  public class ImageAdapter extends BaseAdapter {
    private Context context;

    public ImageAdapter(Context c) {
      context = c;
    }

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

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

    public long getItemId(int position) {
      return 0;
    }

    // create a new ImageView for each item referenced by the Adapter
    public View getView(int position, View convertView, ViewGroup parent) {
      ImageView imageView;
      if (convertView == null) {  // if it's not recycled, initialize some attributes
        imageView = new ImageView(context);
        imageView.setLayoutParams(new GridView.LayoutParams(85, 85));
        imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
        imageView.setPadding(8, 8, 8, 8);
      } else {
        imageView = (ImageView) convertView;
      }

      imageView.setImageResource(mThumbIds[position]);
      return imageView;
    }

    // references to our images
    private Integer[] mThumbIds = {
        R.drawable.sample_2, R.drawable.sample_3,
        R.drawable.sample_4, R.drawable.sample_5,
        R.drawable.sample_6, R.drawable.sample_7,
        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,
        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
    };
  }
}

Java Source Code List

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