Hi Android Framework Gurus! I am hoping someone out there can answer a question for me about re- using views in my adapters. My understanding, is that for performance reasons this is something I should always always always do. Yet in my experience, doing so always results in the view, whether a grid or list, going wonky once I get very many children in the view. I suspect, I'm just doing something flat out wrong. So I put together a simple straight-forward project to demonstrate both how I attempt to re-use the views in a grid view, and how it goes bonkers if you add a few hundred entries and scroll the list. I've tested on both the cupcake emulator as well as my gingerbread device with the same results.
Thanks in advance to anyone who takes the time to respond! ==Layouts== main.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" > <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="Reuse Views Demo" /> <GridView android:id="@+id/gridview" android:layout_width="fill_parent" android:layout_height="fill_parent" android:padding="5dp" android:verticalSpacing="5dp" android:horizontalSpacing="10dp" android:numColumns="auto_fit" android:columnWidth="60dp" android:stretchMode="columnWidth" android:gravity="center_horizontal"/> </LinearLayout> grid_item.xml <LinearLayout xmlns:android="http://schemas.android.com/apk/res/ android" android:id="@+id/GridItem" android:layout_width="fill_parent" android:layout_height="wrap_content" android:orientation="vertical" android:gravity="center_horizontal"> <TextView android:id="@+id/grid_item_text" android:layout_width="wrap_content" android:layout_height="wrap_content" android:gravity="center_horizontal" android:layout_marginBottom="4dip"/> </LinearLayout> ==source== Main.java package com.authorwjf.reuseviews; import java.util.ArrayList; import android.app.Activity; import android.os.Bundle; import android.widget.GridView; public class Main extends Activity { private CustomAdapter mAdapter; private ArrayList<String> mItems = new ArrayList<String>(); @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); for (int i = 0; i<200; i++) { mItems.add(Integer.toString(i)); } mAdapter = new CustomAdapter(this, mItems); GridView g = (GridView) findViewById(R.id.gridview); g.setAdapter(mAdapter); } } CustomAdapter.java package com.authorwjf.reuseviews; import java.util.ArrayList; import com.authorwjf.reuseviews.R; import android.content.Context; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.BaseAdapter; import android.widget.TextView; public class CustomAdapter extends BaseAdapter { private Context mContext; private ArrayList<String> mItems; public CustomAdapter(Context c, ArrayList<String> items) { mContext = c; mItems = items; } @Override public int getCount() { return mItems.size(); } @Override public Object getItem(int position) { return mItems.get(position); } @Override public long getItemId(int position) { return position; } @Override public View getView(int position, View convertView, ViewGroup parent) { View v = convertView; if (v == null) { LayoutInflater li = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE); v = li.inflate(R.layout.grid_item, null); TextView tv = (TextView)v.findViewById(R.id.grid_item_text); tv.setText("Item #"+mItems.get(position)); } return v; } } -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
