Friday, October 30, 2009

Loading Android Resource in GridView

Refer to Android document R.drawable, there are a number of System Resources from 17301504 to 17301655.

This exercise modify the last GridView exercise to load the System Resources, instead of loading from /res/drawable.



mThumbIds[] is used to hold the resources id, to be passed to ImageAdapter. It is initialized in initResourceID()in ImageAdapter's constructor.

Each object is passed to to imageView using imageView.setImageResource(mThumbIds[position]) inside getView().

The main.xml is same as that in GridView exercise.

AndroidGridView2.java
package com.exercise.AndroidGridView2;

import android.app.Activity;
import android.content.Context;
import android.content.res.Resources;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.Toast;

public class AndroidGridView2 extends Activity {

final int resourceStart = 17301504;
final int resourceEnd = 17301655;
final int ResourceLength = resourceEnd - resourceStart + 1;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

GridView gridview = (GridView) findViewById(R.id.gridview);
gridview.setAdapter(new ImageAdapter(this));

gridview.setOnItemClickListener(gridviewOnItemClickListener);
}

private GridView.OnItemClickListener gridviewOnItemClickListener =
new GridView.OnItemClickListener(){

@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
long arg3) {
// TODO Auto-generated method stub
String strResource =
arg0.getAdapter().getItem(arg2).toString() +
" " +
Resources.getSystem().getResourceName(arg2+resourceStart);
Toast.makeText(AndroidGridView2.this,
strResource,
Toast.LENGTH_LONG).show();
}
};


public class ImageAdapter extends BaseAdapter {
private Context mContext;

public ImageAdapter(Context c) {
mContext = c;
initResourceID();
}

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

public Object getItem(int position) {
return mThumbIds[position];
}

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

// 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(mContext);
imageView.setLayoutParams(new GridView.LayoutParams(50, 50));
imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
imageView.setPadding(8, 8, 8, 8);
} else {
imageView = (ImageView) convertView;
}

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

private int[] mThumbIds = new int[ResourceLength];
private void initResourceID(){
for ( int i = 0; i < ResourceLength; i++)
{
mThumbIds[i] = i + resourceStart;
}
}
}
}


Download the files.

1 comment:

viswanath said...

What is the use of this line in the above example?

imageView.setLayoutParams(new GridView.LayoutParams(50, 50));

if i want to change 50 to 100 at runtime... how to configure it? Please tell me.