@Override
public boolean onOptionsItemSelected(MenuItem item) {
  switch (item.getItemId()) {
        case android.R.id.home: {
                 finish();
            }
            return true;
        }
    ....
}

...
mSearchView.setInputType(EditorInfo.TYPE_CLASS_TEXT
        | EditorInfo.TYPE_TEXT_VARIATION_EMAIL_ADDRESS);
mSearchView.addTextChangedListener(new SearchTextWatcher());
...
private class SearchTextWatcher implements TextWatcher {
    @Override
    public void onTextChanged(CharSequence queryString, int start, int before, int count) {
        if (queryString.equals(mQueryString)) {
            return;
        }
    //当前输入的模糊查询的名称
        mQueryString = queryString.toString();
        if (!mSearchMode) {
            if (!TextUtils.isEmpty(queryString)) {
                setSearchMode(true);
            }
        } else if (mListener != null) {
      //回调通知 PeopleActivity 改变界面
            mListener.onAction(Action.CHANGE_SEARCH_QUERY);
        }
        mClearSearchView.setVisibility(
                TextUtils.isEmpty(queryString) ? View.GONE : View.VISIBLE);
    }
    @Override
    public void afterTextChanged(Editable s) {}
    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {}
}

 @Override
public void onAction(int action) {
    Log.d(TAG,"[onAction]action = " + action);
    /// M: [vcs] @{
    if (mVcsController != null) {
        mVcsController.onActionVcs(action);
    }
    /// @}
    switch (action) {
  ...
  case ActionBarAdapter.Listener.Action.CHANGE_SEARCH_QUERY:
      //获取当前输入的模糊查询姓名
            final String queryString = mActionBarAdapter.getQueryString();
      //显示对应的fragment
            setQueryTextToFragment(queryString);
            updateDebugOptionsVisibility(
                    ENABLE_DEBUG_OPTIONS_HIDDEN_CODE.equals(queryString));
            break;
        default:
            throw new IllegalStateException("Unkonwn ActionBarAdapter action: " + action);
    }
}

private void showQueryTextFragment(String queryString){
    Log.d(TAG, "[showQueryTextFragment]");
    if (!mActionBarAdapter.isSelectionMode()) {
        Log.e(TAG, "[queryString==]"+queryString);
        mActionBarAdapter.setSearchMode(true);
        mActionBarAdapter.setQueryString(queryString);
    }
}

public class QuickContactActivity extends ContactsActivity {
    /**
     * QuickContacts immediately takes up the full screen. All possible information is shown.
     * This value for {@link android.provider.ContactsContract.QuickContact#EXTRA_MODE}
     * should only be used by the Contacts app.
     */
    public static final int MODE_FULLY_EXPANDED = 4;
  //看上面的注释就知道了肯定是跟这个变量有关系， 立刻显示全屏，应当只用于 联系人 app 使用
   @Override
    protected void onCreate(Bundle savedInstanceState) {
        Trace.beginSection("onCreate()");
        super.onCreate(savedInstanceState);
        if (RequestPermissionsActivity.startPermissionActivity(this)) {
            return;
        }
        getWindow().setStatusBarColor(Color.TRANSPARENT);
    //处理Intent传递的参数
        processIntent(getIntent());
    .....
    //Scroller初始化，传递滚动模式
    mScroller.initialize(mMultiShrinkScrollerListener, mExtraMode == MODE_FULLY_EXPANDED);
        // mScroller needs to perform asynchronous measurements after initalize(), therefore
        // we can't mark this as GONE.
        mScroller.setVisibility(View.INVISIBLE);
    ...
  }
  private void processIntent(Intent intent) {
        ...
    //获取传递的EXTRA_MODE，不传默认为large，查看api对应的int值为3，MODE_FULLY_EXPANDED为4， 所以不传递参数或者参数对应值不为4就只显示半屏
        mExtraMode = getIntent().getIntExtra(QuickContact.EXTRA_MODE, QuickContact.MODE_LARGE);
    ...
    }
}

private void gotoContact(){
    Uri personUri = ContentUris.withAppendedId(Contacts.People.CONTENT_URI, 1);
    Intent intent = new Intent();
    intent.setAction(Intent.ACTION_VIEW);
    intent.setData(personUri);
  //这句比较关键
    intent.putExtra(ContactsContract.QuickContact.EXTRA_MODE, 4);
    intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    startActivity(intent);
}