我为图片网址设置了gridview ..我无法在网格中看到图片..只显示背景...然后点击网格在下一个屏幕中播放。
我做错了什么？如何实现这个？
提前多多感谢
我的代码
public class act extends Activity { static String uri1="https://i3.ytimg.com/vi/bQaWsVQSLdY/default.jpg"; static String uri2="https://i4.ytimg.com/vi/cJQCniWQdno/mqdefault.jpg"; static String uri3="https://i1.ytimg.com/vi/D8dA4pE5hEY/mqdefault.jpg"; public static String[] urls={uri1,uri2,uri3}; public Bitmap bitmap; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); GridView grd=(GridView)findViewById(R.id.gridView1); grd.setAdapter(new ImageAdapter(this)); grd.setOnItemClickListener(new OnItemClickListener() { public void onItemClick(AdapterView<?> parent,View v,int pos,long id) { Toast.makeText(getBaseContext(),"pic"+(pos+1)+"select ",Toast.LENGTH_SHORT).show(); } }); } public class ImageAdapter extends BaseAdapter { private Context context; private int itemBackground; ImageAdapter(Context c) { context=c; TypedArray a=obtainStyledAttributes(R.styleable.Gallery1); itemBackground=a.getResourceId(R.styleable.Gallery1_android_galleryItemBackground,0); a.recycle(); } public int getCount() { return urls.length; } public Object getItem(int pos) { return pos; } public long getItemId(int pos) { return pos; } public View getView(int pos,View cv,ViewGroup vg) { Bitmap bitmap= DownloadImage( urls[pos] ); ImageView imageview=new ImageView(context); imageview.setImageBitmap(bitmap); return cv; } private Bitmap DownloadImage(String URL) { final String URL1=URL; new Thread() { public void run() { InputStream in = null; Message msg = Message.obtain(); msg.what = 1; try { in = OpenHttpConnection(URL1); Bitmap bitmap = BitmapFactory.decodeStream(in); Bundle b = new Bundle(); b.putParcelable("bitmap", bitmap); msg.setData(b); in.close(); } catch (IOException e1) { // TODO Auto-generated catch block e1.printStackTrace(); } } }.start(); return bitmap; } private InputStream OpenHttpConnection(String urlString) throws IOException { InputStream in = null; int response = -1; URL url = new URL(urlString); URLConnection conn = url.openConnection(); if (!(conn instanceof HttpURLConnection)) throw new IOException("Not an HTTP connection"); try{ HttpURLConnection httpConn = (HttpURLConnection) conn; httpConn.setAllowUserInteraction(false); httpConn.setInstanceFollowRedirects(true); httpConn.setRequestMethod("GET"); httpConn.connect(); response = httpConn.getResponseCode(); if (response == HttpURLConnection.HTTP_OK) { in = httpConn.getInputStream(); } } catch (Exception ex) { throw new IOException("Error connecting"); } return in; } } }
logcat的
E/AndroidRuntime(832): java.lang.NullPointerException E/AndroidRuntime(832): at android.widget.GridView.onMeasure(GridView.java:937) E/AndroidRuntime(832): at android.view.View.measure(View.java:8313) E/AndroidRuntime(832): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138) E/AndroidRuntime(832): at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1017) E/AndroidRuntime(832): at android.widget.LinearLayout.measureVertical(LinearLayout.java:386) E/AndroidRuntime(832): at android.widget.LinearLayout.onMeasure(LinearLayout.java:309) E/AndroidRuntime(832): at android.view.View.measure(View.java:8313) E/AndroidRuntime(832): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138) E/AndroidRuntime(832): at android.widget.FrameLayout.onMeasure(FrameLayout.java:250) E/AndroidRuntime(832): at android.view.View.measure(View.java:8313) E/AndroidRuntime(832): at android.widget.LinearLayout.measureVertical(LinearLayout.java:531) E/AndroidRuntime(832): at android.widget.LinearLayout.onMeasure(LinearLayout.java:309) E/AndroidRuntime(832): at android.view.View.measure(View.java:8313) E/AndroidRuntime(832): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138) E/AndroidRuntime(832): at android.widget.FrameLayout.onMeasure(FrameLayout.java:250) E/AndroidRuntime(832): at android.view.View.measure(View.java:8313) E/AndroidRuntime(832): at android.view.ViewRoot.performTraversals(ViewRoot.java:839) E/AndroidRuntime(832): at android.view.ViewRoot.handleMessage(ViewRoot.java:1859) E/AndroidRuntime(832): at android.os.Handler.dispatchMessage(Handler.java:99) E/AndroidRuntime(832): at android.os.Looper.loop(Looper.java:123) E/AndroidRuntime(832): at android.app.ActivityThread.main(ActivityThread.java:3683) E/AndroidRuntime(832): at java.lang.reflect.Method.invokeNative(Native Method) E/AndroidRuntime(832): at java.lang.reflect.Method.invoke(Method.java:507) E/AndroidRuntime(832): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) E/AndroidRuntime(832): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) E/AndroidRuntime(832): at dalvik.system.NativeStart.main(Native Method)
答案 0 :(得分：2)
尝试用此替换getView()并让我知道结果：
public class ImageAdapter extends BaseAdapter
{
private Context context;
private int itemBackground;
public ImageLoader imageLoader;
ImageAdapter(Context c)
{
context=c;
TypedArray a=obtainStyledAttributes(R.styleable.Gallery1);
itemBackground=a.getResourceId(R.styleable.Gallery1_android_galleryItemBackground,0);
a.recycle();
imageLoader=new ImageLoader(context);
}
public int getCount()
{
return urls.length;
}
public Object getItem(int pos)
{
return pos;
}
public long getItemId(int pos)
{
return pos;
}
public View getView(int position, View convertView, ViewGroup parent)
{
ImageView imageView;
if (convertView == null) {
imageView = new ImageView(context);
imageView.setLayoutParams(new GridView.LayoutParams(85, 85));
imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
imageView.setPadding(2, 2, 2, 2);
} else {
imageView = (ImageView) convertView;
}
imageLoader.DisplayImage(urls[position], imageView)
return imageView;
}
}
答案 1 :(得分：1)
这是我试过的代码..图像正在显示..您可以根据需要自定义网格视图。您只需将以下代码复制并粘贴到您的活动中即可尝试..
public class MainActivity extends Activity {
static String uri1="http://i3.ytimg.com/vi/bQaWsVQSLdY/default.jpg";
static String uri2="http://i4.ytimg.com/vi/cJQCniWQdno/mqdefault.jpg";
static String uri3="http://i1.ytimg.com/vi/D8dA4pE5hEY/mqdefault.jpg";
public static String[] urls={uri1,uri2,uri3};
// public Bitmap bitmap;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
GridView grd=(GridView)findViewById(R.id.gridview1);
grd.setAdapter(new ImageAdapter(this));
}
public class ImageAdapter extends BaseAdapter
{
private Context context;
private int itemBackground;
ImageAdapter(Context c)
{
context=c;
}
public int getCount()
{
return urls.length;
}
public Object getItem(int pos)
{
return pos;
}
public long getItemId(int pos)
{
return pos;
}
private Bitmap DownloadImage(String URL)
{
String URL1=URL;
Bitmap bitmap = null;
// new Thread()
// {
// public void run()
// {
InputStream in = null;
Message msg = Message.obtain();
msg.what = 1;
try {
in = OpenHttpConnection(URL1);
bitmap = BitmapFactory.decodeStream(in);
Bundle b = new Bundle();
b.putParcelable("bitmap", bitmap);
msg.setData(b);
in.close();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
// }
// }.start();
return bitmap;
}
private InputStream OpenHttpConnection(String urlString)
throws IOException
{
// System.out.println("Insdie conn");
InputStream in = null;
int response = -1;
URL url = new URL(urlString);
URLConnection conn = url.openConnection();
if (!(conn instanceof HttpURLConnection))
throw new IOException("Not an HTTP connection");
try{
// System.out.println("Inside try");
HttpURLConnection httpConn = (HttpURLConnection) conn;
httpConn.setAllowUserInteraction(false);
httpConn.setInstanceFollowRedirects(true);
// httpConn.setRequestMethod("GET");
httpConn.connect();
response = httpConn.getResponseCode();
// System.out.println("res="+response);
// System.out.println("cccccc="+HttpURLConnection.HTTP_OK);
if (response == HttpURLConnection.HTTP_OK)
{
// System.out.println("Inside if");
in = httpConn.getInputStream();
}
}
catch (Exception ex)
{
throw new IOException("Error connecting");
}
return in;
}
@Override
public View getView(int position, View cv, ViewGroup parent)
{
ImageView imageview = null;
// System.out.println("vvvv="+urls[position]);
Bitmap bitmap= DownloadImage( urls[position] );
// TODO Auto-generated method stub
if(cv == null)
{
// cv=LayoutInflater.from(parent.getContext()).inflate(R.layout.gridviewitem, null);
imageview = new ImageView(context);
}
else
{
imageview = (ImageView) cv;
}
imageview.setImageBitmap(bitmap);
return imageview;
}
}
答案 2 :(得分：0)
此GridView ImageLoading {{1}}
编辑：
你的代码注意到了错误。但你想要从服务器显示图像（在线它不在你的应用程序资源或sdcard，画廊等..）这就是为什么它没有在你的GridView中显示。所以，你必须从服务器下载图像。之后你必须在GridView中显示它们。我已经给你链接上面如何下载图像并在GridView中显示它们。