我在assets文件夹中添加了许多图像,并希望从那里获取这些图像并将其添加到ListView中。 当我执行应用程序时,一切都很完美,但listview的图像容器显示为空白(透明)。 Output
Java文件:
package com.basil.victor;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ListView;
import java.io.IOException;
import java.io.InputStream;
public class Events extends Fragment {
private ListView listEvent;
String eventname[]={
"Name",
"of",
"the",
"events",
"are",
"present",
"here"
};
String eventlogoname[]={
"Logo",
"name",
"of",
"events",
"are",
"present",
"here"
};
Drawable[] arr=new Drawable[7];
String eventsubtitle []={
"Subtitles",
"of",
"the",
"events",
"are",
"present",
"here"
};
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_events, null);
for(int i=0;i<7;i++) {
try {
InputStream stream = getContext().getAssets().open(eventlogoname[i] + ".jpg");
Drawable el = Drawable.createFromStream(stream, null);
arr[i] = el;
} catch (IOException e) {
e.printStackTrace();
}
}
EventList adapter = new
EventList(getActivity(), eventname, arr, eventsubtitle);
//ListView lv = (ListView)rootView.
listEvent=(ListView)view.findViewById(R.id.listEvent);
listEvent.setAdapter(adapter);
return view;
}
}
ListView适配器:
package com.basil.victor;
import android.app.Activity;
import android.graphics.drawable.Drawable;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;
public class EventList extends ArrayAdapter<String>{
private final Activity context;
private final String[] title;
private final Drawable[] banner;
private final String[] subtitle;
public EventList(Activity context,
String[] title, Drawable[] banner, String[] subtitle) {
super(context, R.layout.list_single, title);
this.context = context;
this.title = title;
this.banner = banner;
this.subtitle = subtitle;
}
@Override
public View getView(int position, View view, ViewGroup parent) {
LayoutInflater inflater = context.getLayoutInflater();
View rowView= inflater.inflate(R.layout.event_row, null, true);
TextView txtTitle = (TextView) rowView.findViewById(R.id.event_title);
ImageView imageView = (ImageView) rowView.findViewById(R.id.event_banner);
TextView subTitle = (TextView) rowView.findViewById(R.id.event_subtitle);
txtTitle.setText(title[position]);
imageView.setImageDrawable(banner[position]);
subTitle.setText(subtitle[position]);
return rowView;
}
}
答案 0 :(得分:1)
如果您收到FileNotFound Exception
,
检查图片是否在资源中的子文件夹内,并添加相应的路径
检查扩展的情况(在我意识到我的图像有.JPG(大写)扩展名之前我已经遇到这个问题了很长时间)
正在搜索的最后一个字符串,检查随机空格
答案 1 :(得分:0)
为什么要为图像使用资产文件夹?如果没有必要那么你可以使用drawable将所有图像放在drawable文件夹和
中package com.basil.victor;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ListView;
import java.io.IOException;
import java.io.InputStream;
public class Events extends Fragment {
private ListView listEvent;
String eventname[]={
"Name",
"of",
"the",
"events",
"are",
"present",
"here"
};
int[] arr=new int[7];
String eventsubtitle []={
"Subtitles",
"of",
"the",
"events",
"are",
"present",
"here"
};
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_events, null);
arr[]={
R.drawable.Logo,
R.drawable.name,
R.drawable.of,
R.drawable.events,
R.drawable.are,
R.drawable.present,
R.drawable.here
};
EventList adapter = new
EventList(getActivity(), eventname, arr, eventsubtitle);
//ListView lv = (ListView)rootView.
listEvent=(ListView)view.findViewById(R.id.listEvent);
listEvent.setAdapter(adapter);
return view;
}
}
适配器:
package com.basil.victor;
import android.app.Activity;
import android.graphics.drawable.Drawable;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;
public class EventList extends ArrayAdapter<String>{
private final Activity context;
private final String[] title;
private final int[] banner;
private final String[] subtitle;
public EventList(Activity context,
String[] title, int[] banner, String[] subtitle) {
super(context, R.layout.list_single, title);
this.context = context;
this.title = title;
this.banner = banner;
this.subtitle = subtitle;
}
@Override
public View getView(int position, View view, ViewGroup parent) {
LayoutInflater inflater = context.getLayoutInflater();
View rowView= inflater.inflate(R.layout.event_row, null, true);
TextView txtTitle = (TextView) rowView.findViewById(R.id.event_title);
ImageView imageView = (ImageView) rowView.findViewById(R.id.event_banner);
TextView subTitle = (TextView) rowView.findViewById(R.id.event_subtitle);
txtTitle.setText(title[position]);
imageView.setImageResource((banner[position]);
subTitle.setText(subtitle[position]);
return rowView;
}
}
答案 2 :(得分:0)
这样做
public class EventList extends BaseAdapter {
LayoutInflater inflater;
private final Activity context;
String arras[];
public EventList(Activity context,String[] arras) {
super();
this.context = context;
this.arras = arras;
inflater = (LayoutInflater) this.context
.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
}
@Override
public int getCount() {
return arras.length;
}
@Override
public Object getItem(int position) {
return arras.length;
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View myView, ViewGroup parent) {
if (myView == null) {
myView = inflater.inflate(R.layout.event_row, null, true);
}
ImageView imageView = (ImageView) myView.findViewById(R.id.event_banner);
try {
InputStream stream = context.getAssets().open(arras[position] + ".jpg");
Drawable el = Drawable.createFromStream(stream, null);
imageView.setImageDrawable(el);
} catch (IOException e) {
e.printStackTrace();
}
return myView;
}
适配器类就像这样
{{1}}
}
答案 3 :(得分:0)
使用ViewHolder
ViewHolder通过缓存视图使列表视图加载更快。如果每次通过调用findViewById()来查看视图,它将会非常慢。
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View v = convertView;
ViewHolder holder; // to reference the child views for later actions
if (v == null) {
LayoutInflater vi =
(LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
v = vi.inflate(R.layout.mainrow, null);
// cache view fields into the holder
holder = new ViewHolder();
holder.ImageView = (ImageView) v.findViewById(R.id.event_banner);
// associate the holder with the view for later lookup
v.setTag(holder);
} else {
// view already exists, get the holder instance from the view
holder = (ViewHolder) v.getTag();
}
// no local variables with findViewById here
// use holder.ImageView where you were
// using the local variable nameText before
try {
InputStream stream = context.getAssets().open(arras[position] + ".jpg");
Drawable el = Drawable.createFromStream(stream, null);
holder.ImageView.setImageDrawable(el);
} catch (IOException e) {
e.printStackTrace();
}
return v;
}
// somewhere else in your class definition
static class ViewHolder {
ImageView imageView;
}