I have a GridView that is created based on an array of items. I need to add more images as the grid is scrolled to the bottom, but I'm not sure how to do that.
Now I do understand the following:
- I have an adapter which parses the array and provides ImageIds to the class that will return the
ImageViews - Somehow I have to change this array and let the adapter know about it, so my question is, how do I get a reference to this adapter?
This is my code:
package com.wm.grid;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.AbsListView;
import android.widget.AbsListView.OnScrollListener;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ListAdapter;
import android.widget.Toast;
public class GridActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
final Integer[] mThumbIds12 = {
R.drawable.sample_2, R.drawable.sample_3,R.drawable.s1,
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
};
final Integer[] mThumbIds1 = {
R.drawable.sample_2, R.drawable.sample_3,R.drawable.s1,
R.drawable.sample_2, R.drawable.sample_3,R.drawable.s1,
R.drawable.sample_2, R.drawable.sample_3,R.drawable.s1,
R.drawable.sample_2, R.drawable.sample_3,R.drawable.s1,
};
final GridView gridview = (GridView) findViewById(R.id.gridview);
gridview.setAdapter(new ImageAdapter(this,mThumbIds12));
gridview.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
Toast.makeText(GridActivity.this, "" + position, Toast.LENGTH_SHORT).show();
}
});
gridview.setOnScrollListener(new OnScrollListener() {
public void onScrollStateChanged(AbsListView view, int scrollState) {
switch (scrollState) {
case OnScrollListener.SCROLL_STATE_IDLE:
//List is idle
break;
case OnScrollListener.SCROLL_STATE_TOUCH_SCROLL:
//Toast.makeText(GridActivity.this, "X", Toast.LENGTH_SHORT).show();
break;
case OnScrollListener.SCROLL_STATE_FLING:
//Toast.makeText(GridActivity.this, "Z", Toast.LENGTH_SHORT).show();
break;
}
}
public void onScroll(AbsListView view, int firstVisibleItem,
int visibleItemCount, int totalItemCount) {
if(firstVisibleItem + visibleItemCount == totalItemCount){
Toast.makeText(GridActivity.this, "BOTTOM", Toast.LENGTH_SHORT).show();
}
//Toast.makeText(GridActivity.this, "TOP", Toast.LENGTH_SHORT).show();
}
});
}
}
Now there is some redundant code, but this is my testing project. All I know is that the updating of the adapter has to happen when firstVisibleItem + visibleItemCount == totalItemCount (i.e. when the GridView has reached the bottom).
This is my ImageAdapter (based on the Android dev site)
package com.wm.grid;
import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;
import com.wm.grid.R;
public class ImageAdapter extends BaseAdapter {
private Context mContext;
private Integer[] mThumbIds;
public ImageAdapter(Context c,Integer[] m) {
mContext = c;
mThumbIds = m;
}
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(mContext);
imageView.setLayoutParams(new GridView.LayoutParams(150, 150));
imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
imageView.setPadding(8, 8, 8, 8);
} else {
imageView = (ImageView) convertView;
}
imageView.setImageResource(mThumbIds[position]);
return imageView;
}
public Integer[] AddItems(Integer[] a){
final Integer[] aThumbIds;
final int i;
aThumbIds = a;
Integer[] a2 = new Integer[mThumbIds.length + aThumbIds.length];
System.arraycopy(mThumbIds, 0, a2, 0, mThumbIds.length);
System.arraycopy(aThumbIds, 0, a2, mThumbIds.length, aThumbIds.length);
return mThumbIds;
}
}
image.xml
<ImageView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/grid_item_image"
android:layout_width="50dp"
android:layout_height="50dp"
android:src="@drawable/s1"
>
</ImageView>
main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="@+id/layout1"
>
<LinearLayout
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1">
<TextView
android:id="@+id/tv1"
android:layout_width="fill_parent"
android:layout_height="40pt"
android:text="row three"
android:textSize="15pt" />
</LinearLayout>
<LinearLayout
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_weight="1">
<GridView
android:id="@+id/gridview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:columnWidth="150dp"
android:numColumns="auto_fit"
android:verticalSpacing="2dp"
android:horizontalSpacing="2dp"
android:stretchMode="columnWidth"
android:gravity="center"
/>
</LinearLayout>
</LinearLayout>
How should I approach this?
