title: Why my activity has not started up?
body: <p>I am using implicit way to start an <code>Activity</code>. But when it runs, LogCat shows me <code>can not find the Activity</code>.<p>
  here is my declare of <code>&lt;intent-filter&gt;</code>:<br></p>
  
  <pre><code>    &lt;activity android:name=".GroupEditActivity"&gt;
          &lt;intent-filter&gt;
              &lt;action android:name="android.intent.action.EDIT"&gt;&lt;/action&gt;
              &lt;data mimeType="vnd.android.cursor.item/group"&gt;&lt;/data&gt;
              &lt;category android:name="android.intent.category.DEFAULT"&gt;&lt;/category&gt;
          &lt;/intent-filter&gt;
      &lt;/activity&gt;
  </code></pre>
  
  <p>Here is the code to start <code>Activity</code>:<br></p>
  
  <pre><code>Intent intent = new Intent(Intent.ACTION_EDIT);
  intent.setType(Groups.CONTENT_ITEM_TYPE);
  startActivity(intent);
  </code></pre>
  
  <p>Reference said if I set the type and action the same as <code>Intent-filter</code>, them my <code>Activity</code> can start up. But when I only set action in <code>Intent</code>, it still can start the <code>Activity</code> which <code>Intent-filter</code> contains mimetype. So I totally lost.<p>
  <a href="https://developer.android.com/guide/topics/intents/intents-filters.html#ifs" rel="nofollow">here</a> is what i find in official website:<br>
  Thanks</p>
  
  <p><p></p>
  
  <h3>logcat details:</h3>
  
  <p><em><strong>android.content.ActivityNotFoundException: No Activity found to handle Intent { act=android.intent.action.EDITtyp=vnd.android.cursor.item/group }</em></strong></p>
  
  <p>And I can sure the type and action in java and xml are the same.<p></p>
  
  <p>I solve the problem myself. The error is cause by <code>&lt;data mimeType</code>. I forgot to add android here. So if change to <code>&lt;data android:mimeType</code>, then everything works fine. But why it doesn't report a exception before, does mimeType is also legal?</p>