Android GridView没有在LongItemTouchListener上触发项目不可见

我们有一个GridView，其中有一堆项目，以至于用户需要向下滚动才能看到它们。 GridView中的每个项目都由一个Textview和一个Webview组成，并附带一些事件。
问题：OnItemLongClickListener不会在首次创建Activity时看不到的项目（您需要向下滚动以查看）。Android GridView没有在LongItemTouchListener上触发项目不可见

相关代码：

活动 -

public class MyCoursesActivity extends ActivityBase implements ILoginListener, IUpdateListener, OnDragListener { 

private ArrayList<Course> myCoursesList = new ArrayList<Course>(); 
private int draggedIndex = -1; 
CoursesListAdapter coursesAdapter = new CoursesListAdapter(MyCoursesActivity.this, myCoursesList); 

MyCourseAdapter mca = new MyCourseAdapter(); 

private void Load() throws ParseException 
{ 
    myCoursesList = mca.Load(); 

    coursesAdapter = new CoursesListAdapter(MyCoursesActivity.this, myCoursesList); 
    final GridView gv = (GridView) findViewById(R.id.mycourses_Grid); 
    gv.setAdapter(coursesAdapter); 

    gv.setOnItemLongClickListener(new OnItemLongClickListener() { 

     public boolean onItemLongClick(AdapterView gridView, View view, 
       int position, long row) { 
      view = gridView.getChildAt(position); 
      ClipData.Item item = new ClipData.Item(""); 
      ClipData clipData = new ClipData("", 
        new String[] { ClipDescription.MIMETYPE_TEXT_PLAIN }, item); 

      view.startDrag(clipData, new View.DragShadowBuilder(view), null, 0); 
      View trashCan = findViewById(R.id.trash_can); 
      trashCan.setVisibility(View.VISIBLE); 
      trashCan.setOnDragListener(MyCoursesActivity.this); 

      draggedIndex = position; 
      return true; 
     } 
    });    
} 


public boolean onDrag(View view, DragEvent dragEvent) { 
    switch (dragEvent.getAction()) { 
    case DragEvent.ACTION_DRAG_STARTED: 
     if (view.getId() == R.id.trash_can) { 
      view.animate().scaleX(1.0f); 
      view.animate().scaleY(1.0f); 
      return true; 
     } else 
     if (dragEvent.getClipDescription().hasMimeType(
       ClipDescription.MIMETYPE_TEXT_PLAIN)) { 
      return true; 

     } else { 
      return false; 
     } 
    case DragEvent.ACTION_DRAG_ENTERED: 
     if (view.getId() == R.id.trash_can) { 
      view.animate().scaleX(1.5f); 
      view.animate().scaleY(1.5f); 
     } 
     return true; 
    case DragEvent.ACTION_DRAG_EXITED: 
     if (view.getId() == R.id.trash_can) { 
      view.animate().scaleX(1.0f); 
      view.animate().scaleY(1.0f); 
     } 
     view.invalidate(); 
     return true; 
    case DragEvent.ACTION_DRAG_LOCATION: 
     return true; 
    case DragEvent.ACTION_DROP: 
     if (view.getId() == R.id.trash_can) { 
         //do stuff 
     } 
     coursesAdapter.notifyDataSetChanged();   
    case DragEvent.ACTION_DRAG_ENDED: 
     // Hide the trash can 
     new Handler().postDelayed(new Runnable() { 

      @Override 
      public void run() { 
       findViewById(R.id.trash_can).setVisibility(View.INVISIBLE); 
      } 
     }, 1000l); 
     if (view.getId() == R.id.trash_can) { 
      view.animate().scaleX(1.0f); 
      view.animate().scaleY(1.0f); 
     } else { 
      view.setVisibility(View.VISIBLE); 
     } 
     // remove drag listeners 
     view.setOnDragListener(null); 
     return true; 

    } 
    return false; 
} 

}

GridView控件适配器 -

public class CoursesListAdapter extends BaseAdapter { 

private Context context; 
private ArrayList<Course> courses; 

public CoursesListAdapter(Context context, ArrayList<Course> courses){ 
    this.context = context; 
    this.courses = courses; 
} 

<@Override getCount etc.> 

@Override 
public View getView(int position, View convertView, ViewGroup parentView) { 
    final Course course = (Course) getItem(position); 

    LayoutInflater inflater = LayoutInflater.from(context); 
    convertView = inflater.inflate(R.layout.course_view, parentView, false); 


    if(context instanceof OnDragListener){ 
     convertView.setTag(course); 
     convertView.setOnDragListener((OnDragListener) context); 
    } 

    TextView title = (TextView) convertView.findViewById(R.id.courseview_titleTv); 
    title.setText(course.getTitle()); 

    WebView wv = (WebView) convertView.findViewById(R.id.courseview_imageWv); 

    wv.setOnTouchListener(new OnTouchListener(){ 

     @Override 
     public boolean onTouch(View arg0, MotionEvent event) { 
      if(event.getAction() == MotionEvent.ACTION_UP){ 
       Intent myIntent = new Intent(context, CourseDetailsActivity.class); 
       myIntent.putExtra("Course", course); 
       context.startActivity(myIntent); 
       return true; 
      } 
      return false; 
     } 

    }); 

    convertView.setOnClickListener(new OnClickListener() { 

     @Override 
     public void onClick(View v) { 
      Intent myIntent = new Intent(context, CourseDetailsActivity.class); 
      myIntent.putExtra("Course", course); 
      context.startActivity(myIntent);  
     } 
    }); 

    return convertView; 
} 

}

任何想法？谢谢。

编辑：试图把ImageViews而不是WebViews和似乎没有问题的事件了。我们尝试了一个固定的drawable。我们试图让webview的实际内容显示在自己的项目中的ImageView中，以简化故障排除。这是迄今为止的代码。该ImageView的不显示任何图像（例如，谷歌涂鸦）

的WebView到的ImageView -

final WebView mWeb = (WebView) findViewById(R.id.webView1); 
    //final WebView mWeb = new WebView(this); 
    final ImageView imgView = (ImageView) findViewById(R.id.imageView1); 

    mWeb.setInitialScale(100); 

    mWeb.setWebViewClient(new WebViewClient() { 
public void onPageFinished(WebView v, String url){ 
    Picture picture = mWeb.capturePicture(); 

    Bitmap bitmap = Bitmap.createBitmap(picture.getWidth(), picture.getHeight(), Bitmap.Config.ARGB_8888); 
    final Canvas c =new Canvas(bitmap); 
    picture.draw(c); 

    imgView.setMinimumWidth(bitmap.getWidth()); 
    imgView.setMinimumHeight(bitmap.getHeight()); 
    imgView.setImageBitmap(bitmap); 
    imgView.setVisibility(View.VISIBLE); 

} 
}); 

mWeb.loadUrl("http://www.google.com");

来源

2013-07-08 Sphaso

OMG！ 'GridView'内的'Webview' !!!!!休斯顿，我们有一个问题。 –

@ M-WaJeEh你能介绍一下吗？有什么问题？ – Sphaso

它只是'WebView'是一个非常沉重的组件，不应该在'ListView'或'GridView'中使用。我认为你有一些书签类应用程序欠发达。所以相反，我能想到的是，您应该从'WebView'生成位图，并在'GridView'内显示这些位图而不是整个'WebView'。它很容易从WebView生成位图，例如请参阅这个http：// stackoverflow。com/questions/10009265/rendering-android-webview-to-bitmap-html5-javascript-callback-issue –

这是我做到了，这是为我工作：

package com.test.progress; 

import android.graphics.Bitmap; 
import android.graphics.Canvas; 
import android.graphics.Picture; 
import android.os.Bundle; 
import android.support.v4.app.FragmentActivity; 
import android.view.View; 
import android.webkit.WebView; 
import android.webkit.WebViewClient; 
import android.widget.ImageView; 

public class MainActivity extends FragmentActivity { 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 

    final WebView mWeb = (WebView) findViewById(R.id.webView1); 
    // final WebView mWeb = new WebView(this); 
    final ImageView imgView = (ImageView) findViewById(R.id.imageView1); 

    mWeb.setInitialScale(100); 

    mWeb.setWebViewClient(new WebViewClient() { 
     public void onPageFinished(WebView v, String url) { 
      v.postDelayed(new Runnable() { 

       @Override 
       public void run() { 
        Picture picture = mWeb.capturePicture(); 

        Bitmap bitmap = Bitmap.createBitmap(picture.getWidth(), 
          picture.getHeight(), Bitmap.Config.ARGB_8888); 
        final Canvas c = new Canvas(bitmap); 
        picture.draw(c); 

        imgView.setMinimumWidth(bitmap.getWidth()); 
        imgView.setMinimumHeight(bitmap.getHeight()); 
        imgView.setImageBitmap(bitmap); 
        imgView.setVisibility(View.VISIBLE); 
       } 
      }, 100); 
     } 
    }); 

    mWeb.loadUrl("http://www.google.com"); 
} 
}

XML布局：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
xmlns:tools="http://schemas.android.com/tools" 
android:id="@+id/frage" 
android:layout_width="match_parent" 
android:layout_height="match_parent" 
android:orientation="vertical" > 

<WebView 
    android:id="@+id/webView1" 
    android:layout_width="match_parent" 
    android:layout_height="0dp" 
    android:layout_weight="1" /> 

<ImageView 
    android:id="@+id/imageView1" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:src="@drawable/ic_launcher" /> 

</LinearLayout>

不要忘了补充：

<uses-permission android:name="android.permission.INTERNET" />

更新1：

看来WebView必须是可见的用户捕捉到的图片，这里是可以正常使用一个愚蠢的解决方案。

NOTE：切勿将位图存储在内存中，就像我在下面的示例中所做的那样。有很好的库可用于缓存目的，使用它们。

package com.vj.test; 

import java.net.URI; 
import java.util.ArrayList; 
import java.util.HashMap; 
import java.util.List; 
import java.util.Map; 
import java.util.Map.Entry; 

import android.app.Activity; 
import android.graphics.Bitmap; 
import android.graphics.Canvas; 
import android.graphics.Picture; 
import android.os.Bundle; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 
import android.webkit.WebView; 
import android.webkit.WebViewClient; 
import android.widget.ArrayAdapter; 
import android.widget.GridView; 
import android.widget.ImageView; 
import android.widget.TextView; 

public class MainActivity extends Activity { 
ArrayAdapter<Data> mAdapter; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
    GridView gv = (GridView) findViewById(R.id.gridView1); 
    final List<Data> data = new ArrayList<Data>(); 
    try { 
     data.add(new Data(new URI("http://www.google.com"))); 
     data.add(new Data(new URI("http://www.yahoo.com"))); 
     data.add(new Data(new URI("http://www.facebook.com"))); 
     data.add(new Data(new URI("http://www.google.com"))); 
     data.add(new Data(new URI("http://www.google.com"))); 
     data.add(new Data(new URI("http://www.google.com"))); 
    } catch (Exception e) { 
    } 
    mAdapter = new ArrayAdapter<Data>(this, R.layout.cell, R.id.url, data) { 
     private Map<URI, Boolean> loadingUrls = new HashMap<URI, Boolean>(); 
     private boolean loadingStarted = false; 

     @Override 
     public View getView(int position, View convertView, ViewGroup parent) { 
      if (convertView == null) { 
       convertView = LayoutInflater.from(MainActivity.this) 
         .inflate(R.layout.cell, null); 
      } 
      Data d = getItem(position); 
      ImageView imageView = (ImageView) convertView 
        .findViewById(R.id.bitmap); 
      if (d.bm == null) { 
       convertView.findViewById(R.id.progress).setVisibility(
         View.VISIBLE); 
       imageView.setImageBitmap(null); 
       loadBitmap(d); 
      } else { 
       imageView.setImageBitmap(d.bm); 
       convertView.findViewById(R.id.progress).setVisibility(
         View.GONE); 

      } 
      TextView tv = (TextView) convertView.findViewById(R.id.url); 
      tv.setText(d.url.getHost() + ""); 
      return convertView; 
     } 

     private void loadBitmap(final Data d) { 
      synchronized (loadingUrls) { 
       if (loadingUrls.containsKey(d.url)) { 
        return; 
       } 
       loadingUrls.put(d.url, false); 
      } 

      if (loadingStarted) { 
       return; 
      } 
      loadingStarted = true; 
      final WebView mWeb = (WebView) findViewById(R.id.laodingWebView); 
      mWeb.setDrawingCacheEnabled(true); 
      mWeb.setInitialScale(100); 
      mWeb.setWebViewClient(new WebViewClient() { 
       public void onPageFinished(WebView v, final String url) { 
        v.postDelayed(new Runnable() { 

         @Override 
         public void run() { 
          Picture picture = mWeb.capturePicture(); 
          Bitmap bitmap = Bitmap.createBitmap(100, 100, 
            Bitmap.Config.ARGB_8888); 
          final Canvas c = new Canvas(bitmap); 
          picture.draw(c); 
          URI nextUrl = null; 
          // d.bm = bitmap; 
          synchronized (loadingUrls) { 
           loadingUrls.put((URI) mWeb.getTag(), true); 
          } 
          updateAllSimilar((URI) mWeb.getTag(), bitmap); 
          mAdapter.notifyDataSetChanged(); 
          for (Entry<URI, Boolean> s : loadingUrls 
            .entrySet()) { 
           if (!s.getValue()) { 
            nextUrl = s.getKey();break; 
           } 
          } 

          if (nextUrl != null) { 
           loadNext(mWeb, nextUrl); 
          } else { 
           mWeb.setVisibility(View.GONE); 
          } 
         } 
        }, 50); 
       } 
      }); 
      URI url = null; 
      for (Entry<URI, Boolean> s : loadingUrls.entrySet()) { 
       if (!s.getValue()) { 
        url = s.getKey();break; 
       } 
      } 
      if (url != null) { 
       loadNext(mWeb, url); 
      } 
     } 

     private void updateAllSimilar(URI url, Bitmap bm) { 
      synchronized (data) { 
       for (Data d : data) { 
        if (d.url.equals(url)) { 
         d.bm = bm; 
        } 
       } 
      } 
     } 

     private void loadNext(WebView mWeb, URI url) { 
      mWeb.loadUrl(url.toString()); 
      mWeb.setTag(url); 
     } 
    }; 
    gv.setAdapter(mAdapter); 
} 

static class Data { 
    Bitmap bm;// don't ever do this, Use cache libraries instead 
    URI url; 

    public Data(URI uri) { 
     this.url = uri; 
    } 
} 
}

activity_main.xml中

<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" 
tools:context=".MainActivity" > 

<GridView 
    android:id="@+id/gridView1" 
    android:layout_width="match_parent" 
    android:layout_height="0dp" 
    android:layout_weight="1" 
    android:numColumns="2" > 
</GridView> 

<WebView 
    android:id="@+id/laodingWebView" 
    android:layout_width="match_parent" 
    android:layout_height="1px" /> 

</LinearLayout>

cell.xml

<?xml version="1.0" encoding="utf-8"?> 
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android" 
android:layout_width="match_parent" 
android:layout_height="wrap_content" > 

<LinearLayout 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:orientation="vertical" > 

    <ImageView 
     android:id="@+id/bitmap" 
     android:layout_width="match_parent" 
     android:layout_height="80dp" 
     android:scaleType="fitCenter" /> 

    <TextView 
     android:id="@+id/url" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:gravity="center_horizontal" 
     android:maxLines="1" 
     android:singleLine="true" /> 
</LinearLayout> 

<ProgressBar 
    android:id="@+id/progress" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" /> 

</FrameLayout>

来源

2013-07-09 07:30:53

这很好，谢谢。但是，当我用“最终的WebView mWeb =新的WebView（this）”实例化WebView时，它不起作用;“ （它给出了宽度和高度<0例外）。所以我只是把WebView放在GridVew中，就像你说我不应该显示ImageView ...？有什么不同？ – Sphaso

检查更新1.你会明白。 –

并请适当更新您的问题的标题。 –

Android GridView没有在LongItemTouchListener上触发项目不可见

回答

相关问题