小贝子编程

选择项目后，列表视图中的Spinner下拉示意图



我想知道为什么要拥有listView的layout_height =" wrap_content"会在列表的末端弄乱旋转器。我经历了在下面修复它的不同方法。我希望有人可以解释这种行为，或者指出我缺乏了解视图/UI事件的Android知识。

1）可以在此处视觉上看到问题。

2）更改ListItem属性

android:descendantFocusability="afterDescendants"

我的行为更好，但仍在发生。似乎列表中的项目没有收到事件，因此对我来说，属性更改很有意义。这是一个视频，介绍了旋转器在更新该属性后的行为方式。除了我实际选择一个项目时，一切都很好。

3）设置ListView的Layout_height =" Match_parent"之后，选择项目后似乎消失了。请参阅此处的视频。

活动：

public class SelectorActivity extends Activity {
public static final String TAG = SelectorActivity.class.getSimpleName();
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    Log.v(TAG, "onCreate");
    setContentView(R.layout.activity_selector);
    LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    ListView contents = (ListView) findViewById(R.id.list_view);    
    contents.addHeaderView(new TestView(this));
    contents.addFooterView(new View(this));
    SimpleBaseAdapter listAdapter = new SimpleBaseAdapter(this);
    // LOW RANGE
    LinearLayout lowRange = (LinearLayout) inflater.inflate(R.layout.list_item_edit, null);
    TextView lowRangeText = (TextView) lowRange.findViewById(R.id.text);
    EditText lowRangeEditText = (EditText) lowRange.findViewById(android.R.id.edit);
    // HIGH RANGE
    LinearLayout highRange = (LinearLayout) inflater.inflate(R.layout.list_item_edit, null);
    TextView highRangeText = (TextView) highRange.findViewById(R.id.text);
    EditText highRangeEditText = (EditText) highRange.findViewById(android.R.id.edit);
    // UNITS
    LinearLayout units = (LinearLayout) inflater.inflate(R.layout.list_item_units, null);
    TextView unitsText = (TextView) units.findViewById(android.R.id.text1);
    // SPINNERS
    LinearLayout spinners = (LinearLayout) inflater.inflate(R.layout.list_item_spinners, null);
    Spinner spinner1 = (Spinner) spinners.findViewById(R.id.spinner1);
    Spinner spinner2 = (Spinner) spinners.findViewById(R.id.spinner2);
    Spinner spinner3 = (Spinner) spinners.findViewById(R.id.spinner3);
    DebugAdapterViewListeners.set(spinner1, "spinner1");
    // VIEW SETUP
    lowRangeText.setText("text1");
    highRangeText.setText("text2");
    unitsText.setText("text3");
    // SPINNER SETUP
    String[] massUnits1 = new String[]{"one","two"};
    String[] massUnits2 = new String[]{"three","four"};
    String[] timeUnits = new String[]{"five","six"};
    ArrayAdapter<String> adapt1 = new ArrayAdapter<String>(this, R.layout.spinner_list_item_centered);
    ArrayAdapter<String> adapt2 = new ArrayAdapter<String>(this, R.layout.spinner_list_item_centered);
    ArrayAdapter<String> adapt3 = new ArrayAdapter<String>(this, R.layout.spinner_list_item_centered);
    adapt1.addAll(massUnits1);
    adapt2.addAll(massUnits2);
    adapt3.addAll(timeUnits);
    spinner1.setAdapter(adapt1);
    spinner2.setAdapter(adapt2);
    spinner3.setAdapter(adapt3);
    listAdapter.addView(lowRange);
    listAdapter.addView(highRange);
    listAdapter.addView(units);
    listAdapter.addView(spinners);
    contents.setAdapter(listAdapter);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.selector, menu);
    return false;
}

}

这是SimpleBaseadapter类：

public class SimpleBaseAdapter extends BaseAdapter {
private ArrayList<View> views;
private Context context;
public SimpleBaseAdapter(Context context) {
    this.context = context;
    this.views = new ArrayList<View>();
}
public void addView(View view) {
    this.views.add(view);
}
@Override
public int getCount() {
    return views.size();
}
@Override
public Object getItem(int position) {
    View view = views.get(position);
    if (view instanceof AbsListView) {
        return ((AbsListView)view).getItemAtPosition(position);
    } else if (view instanceof AbsSpinner) {
        return ((AbsSpinner)view).getItemAtPosition(position);
    }  else {
        return null;
    }
}
@Override
public long getItemId(int position) {
    View view = views.get(position);
    if (view instanceof AbsListView) {
        return ((AbsListView)view).getItemIdAtPosition(position);
    } else if (view instanceof AbsSpinner) {
        return ((AbsSpinner)view).getItemIdAtPosition(position);
    }  else {
        return 0;
    }
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
    return views.get(position);
}
}

活动布局：

<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:background="@color/green_1"
    android:orientation="vertical"
    >
    <ListView
        android:id="@+id/list_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" 
        android:headerDividersEnabled="true"
        android:footerDividersEnabled="true"        
        android:dividerHeight="0.5sp"
        android:divider="@color/black"
        android:clipToPadding="false"
        android:layout_marginTop="18sp"
        android:layout_marginBottom="18sp"
          />
</LinearLayout>

编辑列表项目布局：

<?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" 
    android:padding="@dimen/row_padding"
        android:background="@android:color/white"
    >
    <TextView 
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/text"
            android:layout_weight="50"
        android:gravity="top"
        android:textSize="@dimen/font_size_standard"
      android:textColor="@drawable/selector_row_item_detail_text"
      />
    <EditText
            android:layout_width="0dip"
        android:layout_height="wrap_content"
        android:id="@android:id/edit"
        android:layout_weight="50"
        android:inputType="number"
        android:gravity="right"
        />
</LinearLayout>

旋转器行项目布局：

<?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:id="@+id/spinner_container"
        android:orientation="horizontal"
        android:background="@android:color/white"
        android:paddingTop="@dimen/header_row_padding_vertical"

        >
            <Spinner
              android:layout_width="0dip"
                android:layout_height="wrap_content"
                android:layout_weight="33"
                android:id="@+id/spinner1"
                android:gravity="center"
                android:spinnerMode="dropdown"
                />
            <Spinner
              android:layout_width="0dip"
                android:layout_height="wrap_content"
                android:layout_weight="33"
                android:id="@+id/spinner2"
                android:gravity="center"
                android:spinnerMode="dialog"
                />
            <Spinner
              android:layout_width="0dip"
                android:layout_height="wrap_content"
                android:layout_weight="33"
                android:id="@+id/spinner3"
                android:gravity="center"
                android:spinnerMode="dialog"
                />
        </LinearLayout>

您面临的问题是旋转器的基本行为，因此需要修改的旋转器。这是针对初始IE的微调器的代码。默认情况下，可视化是"选择项目"（如果在.xml中声明的提示如android:prompt="@string/Select Item"中的提示）＆amp;下拉访视图与原始旋转器的大小相同。此修改后的旋转器的限制是，如果项目为空，则不会显示提示。

将新类称为NoDefaultSpinner.java＆amp;在该副本中，粘贴此代码

public class NoDefaultSpinner extends Spinner {
    public NoDefaultSpinner(Context context) {
        super(context);
    }
    public NoDefaultSpinner(Context context, AttributeSet attrs) {
        super(context, attrs);
    }
    public NoDefaultSpinner(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }
    @Override
    public void setAdapter(SpinnerAdapter orig ) {
        final SpinnerAdapter adapter = newProxy(orig);
        super.setAdapter(adapter);
        try {
            final Method m = AdapterView.class.getDeclaredMethod(
                               "setNextSelectedPositionInt",int.class);
            m.setAccessible(true);
            m.invoke(this,-1);
            final Method n = AdapterView.class.getDeclaredMethod(
                               "setSelectedPositionInt",int.class);
            n.setAccessible(true);
            n.invoke(this,-1);
        } 
        catch( Exception e ) {
            throw new RuntimeException(e);
        }
    }
    protected SpinnerAdapter newProxy(SpinnerAdapter obj) {
        return (SpinnerAdapter) java.lang.reflect.Proxy.newProxyInstance(
                obj.getClass().getClassLoader(),
                new Class[]{SpinnerAdapter.class},
                new SpinnerAdapterProxy(obj));
    }

    /**
     * Intercepts getView() to display the prompt if position < 0
     */
    protected class SpinnerAdapterProxy implements InvocationHandler {
        protected SpinnerAdapter obj;
        protected Method getView;

        protected SpinnerAdapterProxy(SpinnerAdapter obj) {
            this.obj = obj;
            try {
                this.getView = SpinnerAdapter.class.getMethod(
                                 "getView",int.class,View.class,ViewGroup.class);
            } 
            catch( Exception e ) {
                throw new RuntimeException(e);
            }
        }
        public Object invoke(Object proxy, Method m, Object[] args) throws Throwable {
            try {
                return m.equals(getView) && 
                       (Integer)(args[0])<0 ? 
                         getView((Integer)args[0],(View)args[1],(ViewGroup)args[2]) : 
                         m.invoke(obj, args);
            } 
            catch (InvocationTargetException e) {
                throw e.getTargetException();
            } 
            catch (Exception e) {
                throw new RuntimeException(e);
            }
        }
        protected View getView(int position, View convertView, ViewGroup parent) 
          throws IllegalAccessException {
            if( position<0 ) {
                final TextView v = 
                  (TextView) ((LayoutInflater)getContext().getSystemService(
                    Context.LAYOUT_INFLATER_SERVICE)).inflate(
                      android.R.layout.simple_spinner_item,parent,false);
                v.setText(getPrompt());
                return v;
            }
            return obj.getView(position,convertView,parent);
        }
    }
}

在旋转器行项目中布局将旋转器的类型更改为 <com.example.appname.NoDefaultSpinner 

        <com.example.appname.NoDefaultSpinner
          android:layout_width="0dip"
            android:layout_height="wrap_content"
            android:layout_weight="33"
            android:id="@+id/spinner1"
            android:gravity="center"
            android:spinnerMode="dropdown"
            />
        <com.example.appname.NoDefaultSpinner
          android:layout_width="0dip"
            android:layout_height="wrap_content"
            android:layout_weight="33"
            android:id="@+id/spinner2"
            android:gravity="center"
            android:spinnerMode="dialog"
            />
        <com.example.appname.NoDefaultSpinner
          android:layout_width="0dip"
            android:layout_height="wrap_content"
            android:layout_weight="33"
            android:id="@+id/spinner3"
            android:gravity="center"
            android:spinnerMode="dialog"
            />

活动：将旋转器的类型更改为NodeFaultSpinner，如This 

public class SelectorActivity extends Activity {
public static final String TAG = SelectorActivity.class.getSimpleName();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Log.v(TAG, "onCreate");
setContentView(R.layout.activity_selector);
LayoutInflater inflater = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
ListView contents = (ListView) findViewById(R.id.list_view);    
contents.addHeaderView(new TestView(this));
contents.addFooterView(new View(this));
SimpleBaseAdapter listAdapter = new SimpleBaseAdapter(this);
// LOW RANGE
LinearLayout lowRange = (LinearLayout) inflater.inflate(R.layout.list_item_edit, null);
TextView lowRangeText = (TextView) lowRange.findViewById(R.id.text);
EditText lowRangeEditText = (EditText) lowRange.findViewById(android.R.id.edit);
// HIGH RANGE
LinearLayout highRange = (LinearLayout) inflater.inflate(R.layout.list_item_edit, null);
TextView highRangeText = (TextView) highRange.findViewById(R.id.text);
EditText highRangeEditText = (EditText) highRange.findViewById(android.R.id.edit);
// UNITS
LinearLayout units = (LinearLayout) inflater.inflate(R.layout.list_item_units, null);
TextView unitsText = (TextView) units.findViewById(android.R.id.text1);
// SPINNERS
LinearLayout spinners = (LinearLayout) inflater.inflate(R.layout.list_item_spinners, null);
NoDefaultSpinner spinner1 = (NoDefaultSpinner) spinners.findViewById(R.id.spinner1);
NoDefaultSpinner spinner2 = (NoDefaultSpinner) spinners.findViewById(R.id.spinner2);
NoDefaultSpinner spinner3 = (NoDefaultSpinner) spinners.findViewById(R.id.spinner3);
DebugAdapterViewListeners.set(spinner1, "spinner1");
// VIEW SETUP
lowRangeText.setText("text1");
highRangeText.setText("text2");
unitsText.setText("text3");
// SPINNER SETUP
String[] massUnits1 = new String[]{"one","two"};
String[] massUnits2 = new String[]{"three","four"};
String[] timeUnits = new String[]{"five","six"};
ArrayAdapter<String> adapt1 = new ArrayAdapter<String>(this, R.layout.spinner_list_item_centered);
ArrayAdapter<String> adapt2 = new ArrayAdapter<String>(this, R.layout.spinner_list_item_centered);
ArrayAdapter<String> adapt3 = new ArrayAdapter<String>(this, R.layout.spinner_list_item_centered);
adapt1.addAll(massUnits1);
adapt2.addAll(massUnits2);
adapt3.addAll(timeUnits);
spinner1.setAdapter(adapt1);
spinner2.setAdapter(adapt2);
spinner3.setAdapter(adapt3);
listAdapter.addView(lowRange);
listAdapter.addView(highRange);
listAdapter.addView(units);
listAdapter.addView(spinners);
contents.setAdapter(listAdapter);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.selector, menu);
return false;
}

此解决方案依靠反射来调用AdapterView.setNextSelectedPositionInt()和AdapterView.setSelectedPositionInt()，＆amp;在API 4上成功运行至API19。

您应该扩展SpinnerAdapter而不是baseadapter。它具有GetDropdownView（）和GetView（），我相信它可以在内部处理一些特殊情况。我正在以Android 4.2的类似布局扩展此适配器，但我看不到您遇到的问题。

我会猜测，getDropdownView（）如何处理将视图附加到root的差异将解释此差异，但我没有查看代码来检查此

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