Android LruCache in ListView

偏执的太偏执、 2023-10-17 16:13 48阅读 0赞

package zhangphil.cache;
    
    import android.app.ListActivity;
    import android.graphics.Bitmap;
    import android.graphics.BitmapFactory;
    import android.support.annotation.NonNull;
    import android.support.annotation.Nullable;
    import android.os.Bundle;
    import android.util.Log;
    import android.util.LruCache;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.ArrayAdapter;
    import android.widget.ImageView;
    
    public class MainActivity extends ListActivity {
        private LruCache<String, Bitmap> mLruCache;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
    
            int CACHE_SIZE = 8 * 1024 * 1024;
            mLruCache = new LruCache(CACHE_SIZE);
    
            ArrayAdapter mAdapter = new ArrayAdapter(this, 0) {
                @NonNull
                @Override
                public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
                    ImageView image = new ImageView(getContext());
                    load(R.mipmap.ic_launcher, image);
                    return image;
                }
    
                @Override
                public int getCount() {
                    return 20;
                }
            };
    
            setListAdapter(mAdapter);
        }
    
        private void load(int id, ImageView image) {
            Bitmap bmp = mLruCache.get(String.valueOf(id));
            if (bmp == null) {
                Log.d("LruCache缓存", "没有缓存，开始创建新数据资源并缓存之。");
                bmp = BitmapFactory.decodeResource(getResources(), id);
                mLruCache.put(String.valueOf(id), bmp);
            } else {
                Log.d("LruCache缓存", "已有缓存，复用。");
                image.setImageBitmap(bmp);
            }
        }
    }