Java 将可提取资源添加到ListView中

我在assets文件夹中添加了许多图像，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）。

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;
}
}

package com.basil.victor；
导入android.graphics.drawable.drawable；
导入android.os.Bundle；
导入android.support.v4.app.Fragment；
导入android.view.LayoutInflater；
导入android.view.view；
导入android.view.ViewGroup；
导入android.widget.ListView；
导入java.io.IOException；
导入java.io.InputStream；
公共类事件扩展片段{
私有ListView listEvent；
字符串eventname[]={
“姓名”，
“of”，
",，
“活动”，
“是”，
“现在”，
“这里”
};
字符串EventLogonName[]={
“标志”，
“姓名”，
“of”，
“活动”，
“是”，
“现在”，
“这里”
};
可提取[]arr=新的可提取[7]；
字符串事件字幕[]={
“字幕”，
“of”，
",，
“活动”，
“是”，
“现在”，
“这里”
};
@凌驾
创建视图上的公共视图（布局、充气机、视图组容器、，
Bundle savedInstanceState）{
视图=充气机。充气（R.layout.fragment\u事件，空）；
对于（int i=0；i为什么要对图像使用资产文件夹？如果没有必要，则可以对相同的图像使用drawable，将所有图像放在drawable文件夹中，然后

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;
}
}

package com.basil.victor；
导入android.app.Activity；
导入android.graphics.drawable.drawable；
导入android.view.LayoutInflater；
导入android.view.view；
导入android.view.ViewGroup；
导入android.widget.ArrayAdapter；
导入android.widget.ImageView；
导入android.widget.TextView；
公共类事件列表扩展了ArrayAdapter{
私人最终活动背景；
私有最终字符串[]标题；
私人最终int[]横幅；
私有最终字符串[]副标题；
公共事件列表（活动上下文、，
字符串[]标题，int[]横幅，字符串[]副标题）{
超级（上下文、右布局、列表、标题）；
this.context=上下文；
this.title=标题；
this.banner=横幅；
this.subtitle=副标题；
}
@凌驾
公共视图getView（内部位置、视图视图、视图组父视图）{
LayoutInflater充气器=上下文。getLayoutInflater（）；
视图行视图=充气机。充气（R.layout.event_行，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\u subTitle）；
setText（头衔[职位]）；
setImageResource（（横幅[位置]）；
subTitle.setText（副标题[位置]）；
返回行视图；
}
}
像这样做

class MainActivity extends AppCompatActivity {
private ListView listEvent;


String arras[]={
  "Logo",
    "name",
    "of",
    "events",
    "are",
    "present",
    "here"
};
Drawable[] arr=new Drawable[5];
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
            EventList adapter = new EventList(MainActivity.this, arras);
            //ListView lv = (ListView)rootView.
            listEvent=(ListView)findViewById(R.id.listEvent);
            listEvent.setAdapter(adapter);



        }
    }

适配器类是这样的

 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;
}

}
如果您遇到
FileNotFound异常

检查图像是否位于资源中的子文件夹内，并添加适当的路径

检查扩展名的大小写（在我意识到我的图像有一个.JPG（大写）扩展名之前，我很长时间都面临这个问题）

要搜索的最后一个字符串，请检查随机空白

使用视窗夹

ViewHolder通过缓存视图来加快列表视图的加载速度。如果它每次都通过调用findViewById（）来查找视图，则速度会非常慢

    @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;
}

很可能是您没有正确读入它们，导致您传入了一个空数组。您是否在调试器中查看失败的地方？调试器显示：java.io.FileNotFoundException:Logo.jpg但它存在于资产文件夹中调试您的代码以获取异常。可能是由于名称错误或图像不可用导致应用程序崩溃或者，你可以这样做，我将传递一组可绘制id，并在图像视图上设置这些id否我想使用资源。因为我知道如何使用可绘制id，想尝试使用资源是的，它位于子文件夹横幅内。那么@Haran can u的路径是什么？谢谢。图像位于子文件夹内，所以我更改了一个输入流=getContext（）.getAssets（）.open（“banners/”+eventlogoname[i]+.jpg”）；
    @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;
}