Android Gridview适配器不调用getView(),尽管调用了getCount()
我试着逐字复制别人的代码,但我似乎无法让我的Android Gridview适配器不调用getView(),尽管调用了getCount(),android,gridview,android-adapter,Android,Gridview,Android Adapter,我试着逐字复制别人的代码,但我似乎无法让我的GridView显示除了白色页面之外的任何内容getCount()被调用并返回正确的数字,但是,getView()未被调用。任何想法都将不胜感激 public class drinkSaleList extends Activity { private ArrayList<String> drinkPhotoPaths = new ArrayList<String>(); @Override protected void o
GridView
显示除了白色页面之外的任何内容getCount()
被调用并返回正确的数字,但是,getView()
未被调用。任何想法都将不胜感激
public class drinkSaleList extends Activity {
private ArrayList<String> drinkPhotoPaths = new ArrayList<String>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_drink_sale_list);
GridView gridview = (GridView) findViewById(R.id.gridview);
SharedPreferences sharedPref = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
int drinkCount = sharedPref.getInt("Drink", 0);
if(drinkCount > 0)
{
for(int i = 1; i <= drinkCount; i++){
String path = getExternalFilesDir(null) + "/drinkObject" + i + ".ser";
drinkPhotoPaths.add(path);
}
}
gridview.setAdapter(new drinkSaleLayoutAdapter(this, drinkPhotoPaths));
gridview.setOnItemClickListener(new AdapterView.OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View v,
int position, long id) {
//Create an Intent to start the ImageViewActivity
Intent intent = new Intent(drinkSaleList.this,
SaleActivity.class);
Toast.makeText(drinkSaleList.this, "You clicked " + position + "and Id is " + id, Toast.LENGTH_SHORT).show();
// Add the ID of the thumbnail to display as an Intent Extra
// intent.putExtra(EXTRA_RES_ID, (int) id);
// Start the ImageViewActivity
// startActivity(intent);
}
});
}
public class drinkSaleLayoutAdapter extends BaseAdapter {
private Context mContext;
private List<String> mPhotoPaths;
public drinkSaleLayoutAdapter(Context c, List<String> photoPaths){
mContext = c;
mPhotoPaths = photoPaths;
}
public int getCount(){
int x = mPhotoPaths.size();
return mPhotoPaths.size();
}
public Object getItem(int position){
return mPhotoPaths.get(position);
}
public long getItemId(int position){
return position;
}
public View getView(int position, View convertView, ViewGroup parent){
ImageView imageView;
if(convertView == null){
imageView = new ImageView(mContext);
imageView.setLayoutParams(new GridView.LayoutParams(100, 100));
imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
imageView.setPadding(8,8,8,8);
}
else{
imageView = (ImageView) convertView;
}
FileInputStream fis = null;
try {
fis = new FileInputStream(mPhotoPaths.get(position));
} catch (FileNotFoundException e) {
e.printStackTrace();
}
Bitmap bm = BitmapFactory.decodeStream(fis);
imageView.setImageBitmap(bm);
return imageView;
}
}
公共类drinkSaleList扩展活动{
private ArrayList drinkPhotoPaths=new ArrayList();
@凌驾
创建时受保护的void(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(右布局、活动、饮料、销售、列表);
GridView GridView=(GridView)findViewById(R.id.GridView);
SharedReferences SharedReferences=PreferenceManager.GetDefaultSharedReferences(getApplicationContext());
int drinkCount=sharedPref.getInt(“饮料”,0);
如果(drinkCount>0)
{
对于(int i=1;i代码似乎是正确的,但缺少一行非常重要。在getView()
函数中,在else
条件中,您将convertView
分配给imageView实例,但实际上convertView
未膨胀或未初始化
您需要更改代码,如下所示:
if(convertView == null){
imageView = new ImageView(mContext);
imageView.setLayoutParams(new GridView.LayoutParams(100, 100));
imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
imageView.setPadding(8,8,8,8);
convertView = imageView;
}
else{
imageView = (ImageView) convertView;
}
我希望通过更改代码,它应该可以工作。您没有设置convertView
,因此它会变为空。首先您必须设置convertView
。
你应该试试这个
public View getView(int position, View convertView, ViewGroup parent){
ViewHolder viewHolder;
if(convertView == null){
LayoutInflater inflater = mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.your_view, null); // you need one xml file which has parent layout to hold imageview
viewHolder = new ViewHolder;
viewHolder.linearLayout = converView.findViewById(R.id.linearLayout); //your parent layout id which is defined in xml file
viewHolder.imageView = new ImageView(mContext);
viewHolder.imageView.setLayoutParams(new GridView.LayoutParams(100, 100));
viewHolder.imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
viewHolder.imageView.setPadding(8,8,8,8);
viewHolder.linearLayout.addView(viewHolder.imageView); // add imageview on layout
convertView.setTag(viewHolder);
}
else{
viewHolder = (ViewHolder) convertView.getTag();
}
FileInputStream fis = null;
try {
fis = new FileInputStream(mPhotoPaths.get(position));
} catch (FileNotFoundException e) {
e.printStackTrace();
}
Bitmap bm = BitmapFactory.decodeStream(fis);
viewHolder.imageView.setImageBitmap(bm);
return convertView;
}
private static class ViewHolder
{
LinearLayout linearLayout;
ImageView imageView;
}
这是xml文件
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"'
android:id="@+id/linearLayout""
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
</LinearLayout>
我可以理解其中的想法,但我过去是根据Google如何使用SimpleAdapter实现的,其中getView()返回args和mResource,然后使用createViewFromResource()使用视图创建列表返回和显示的地方。我知道这很有效。你这样做的方式,idk。也许所有的路都通向罗马。我相信谷歌代码和我的代码之间的区别在于,你不能在运行时将图片添加到资源文件夹中。因为我的程序使用相机*即在运行时获取图片)并且必须保存它们以备将来使用,我相信该方法对我来说不是一个选项,否则这样做会很麻烦。但我希望我没有错。它只是一个有名称的方法。变量、相机图片、游标都可以在那里工作。因为两者都有视图参数,尽管getView()方法理论上应该可以工作。您正在getView()中返回imageview。这是错误的。您需要分配convertview并返回convertview。您还不了解这一概念。请不要复制粘贴。感谢您的回复。我现在正在尝试实现此代码(处理它给出的一些错误/xml)。但是,我只想补充一点,我在getView的第一行设置了一个断点,该断点从未被触发。该解决方案是否应该至少调用getView()的第一行才能工作?您必须定义一个xml
文件请参见getView()中的编辑代码和注释
methods