Android 为什么图像不显示在列表视图中?
这是密码 图像未显示在列表视图中如何解决此问题?我将uri值设置为位图。那么问题出在哪里?更改了数组并解决了错误,但静态图像未显示在列表视图中。 MainActivity.javaAndroid 为什么图像不显示在列表视图中?,android,Android,这是密码 图像未显示在列表视图中如何解决此问题?我将uri值设置为位图。那么问题出在哪里?更改了数组并解决了错误,但静态图像未显示在列表视图中。 MainActivity.java public class MainActivity extends Activity { ListView lv; Context context; ArrayList prgmName; Bitmap bitmap; //bitmap=getBitmapFromUrl("h
public class MainActivity extends Activity {
ListView lv;
Context context;
ArrayList prgmName;
Bitmap bitmap;
//bitmap=getBitmapFromUrl("http://content6.flixster.com/movie/11/17/75/11177548_pro.jpg");
public static String [] prgmNameList={"Let Us C","c++","JAVA","Jsp","Microsoft .Net","Android","PHP","Jquery","JavaScript"};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
bitmap=getBitmapFromUrl("http://content6.flixster.com/movie/11/17/75/11177548_pro.jpg");
context=this;
Bitmap [] prgmImages ={bitmap,bitmap,bitmap,bitmap,bitmap,bitmap,bitmap,bitmap,bitmap};
lv=(ListView) findViewById(R.id.listView);
lv.setAdapter(new CustomAdapter(this, prgmNameList,prgmImages));
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
private Bitmap getBitmapFromUrl(String src) {
// TODO Auto-generated method stub
try {
URL url =new URL(src);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setDoInput(true);
connection.connect();
InputStream input=connection.getInputStream();
Bitmap mybiBitmap=BitmapFactory.decodeStream(input);
return mybiBitmap;
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
return null;
}
}
}
CustomAdapter.java
public class CustomAdapter extends BaseAdapter{
String [] result;
Context context;
Bitmap[] imageId;
private static LayoutInflater inflater=null;
public CustomAdapter(MainActivity mainActivity, String[] prgmNameList, Bitmap[] prgmImages) {
// TODO Auto-generated constructor stub
result=prgmNameList;
context=mainActivity;
imageId=prgmImages;
inflater = ( LayoutInflater )context.
getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return result.length;
}
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return position;
}
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
public class Holder
{
TextView tv;
ImageView img;
}
@Override
public View getView(final int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
Holder holder=new Holder();
View rowView;
rowView = inflater.inflate(R.layout.list_item, null);
holder.tv=(TextView) rowView.findViewById(R.id.textView1);
holder.img=(ImageView) rowView.findViewById(R.id.imageView1);
// holder.tv.setText(result[position]);
// holder.img.setImageBitmap(imageId[position]);
if(result != null && result.length > position)
{
holder.tv.setText(result[position]);
}
if(imageId != null && imageId.length > 0)
{
holder.img.setImageBitmap(imageId[0]);
}
rowView.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Toast.makeText(context, "You Clicked "+result[position], Toast.LENGTH_LONG).show();
}
});
return rowView;
}
}
activity_main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="25dp"
android:textStyle="bold"
android:text=" Your Theaters..." />
<ListView
android:id="@+id/listView"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
</ListView>
</LinearLayout>
list_item.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal" >
<ImageView
android:id="@+id/imageView1"
android:layout_gravity="center"
android:layout_width="48dp"
android:layout_height="48dp"
android:src="@drawable/ic_launcher" />
<TextView
android:id="@+id/textView1"
android:layout_gravity="center"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="25dp"
android:text="TextView" />
</LinearLayout>
这可能是因为在位图加载并保存到数组之前,需要调用适配器。下载图像需要一些时间,并且适配器没有等待图像。请参见此示例,它正在使用映像加载程序:日志中是否存在NetworkOnMainThreadException 从onCreate调用getBitmapFromUrl时,您正在主线程上下载位图。在您的情况下,它将无声地失败,因为您正在捕获异常,但您将得到一个空结果 由于从网络加载图像非常常见,所以有很多库可以处理这个问题,更像是为您提供缓存,例如。
或者也发布您的xml布局列表项目文件。检查日志您是否收到任何错误您是否在清单中添加了权限?当位图已下载时,您需要在适配器中调用notifyDataSetChanged。但在本例中,url包含xml文件,但在我的示例中,url不包含xml文件,因此如何解析此文件?我的url是,你不需要解析。只需输入适配器的getView:imageLoader.DisplayImage,thumb_image;如何解析我的url?我得到了空指针异常,因为这个url没有节点名?我正在分析这个url,因为我想要电影的名称和电影的图像,我如何才能做到这一点?