我想编写一个应用程序,其中包括：使用sdcard中的图片文件填充列表视图,b：从列表中选择选项时显示图像.
但是,它与上述例外有关.我看不出为什么……？请帮忙！
主要活动：
public class ProjektJimmuActivity extends ListActivity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
navigateTo("/sdcard/");
}
public void navigateTo(String dir){
setListAdapter(new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,getListOfFiles(dir)));
getListView().setTextFilterEnabled(true);
}
public String[] getListOfFiles(String dir){
File file = new File(dir);
String[] files = file.list(new Filter());
return files;
}
@Override
protected void onListItemClick(ListView l,View v,int position,long id) {
super.onListItemClick(l,v,position,id);
Object item = l.getItemAtPosition(position);
Toast.makeText(this,"Selection: "+ item.toString(),Toast.LENGTH_SHORT).show();
setContentView(new PictureView(this,item.toString()));
}
private class Filter implements FilenameFilter{
public boolean accept(File dir,String filename) {
return (( filename.endsWith("jpg") || filename.endsWith("png") || filename.endsWith("gif") ) && !filename.startsWith("._") );
}
}
}
图片视图：
public class PictureView extends View{
private Bitmap bitmap;
int width,height;
private Canvas canvas;
public PictureView(Context context,String pictureFile) {
super(context);
setFocusable(true);
bitmap = BitmapFactory.decodeFile("/sdcard/"+pictureFile);
height = bitmap.getHeight();
width = bitmap.getWidth();
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawColor(0xFFCCCCCC);
canvas.drawBitmap(bitmap,null,null);
}
}
