Question

我在android中使用Master Detail Flow模板。我想在应用程序启动时以编程方式访问列表中的项目，以便设置字体大小和那里的TextViews的颜色。如果我在onResume（ItemListActivity或ItemListFragment）中编码，则ListView不为null，但3 TextViews（ListView的子项）为空。

public void updateActivity( )
{
 ViewGroup leftPane = ( ViewGroup ) findViewById( R.id.item_list );
 FrameLayout frameLayout = ( FrameLayout ) leftPane.getChildAt( 0 );
 FrameLayout frameLayout2 = ( FrameLayout ) frameLayout.getChildAt( 1 );
 ListView listView = ( ListView ) frameLayout2.getChildAt( 1 );  // listView NOT null
 TextView item0 = ( TextView ) listView.getChildAt( 0 ); // item0 is NULL !!!!!
}

我在ItemListActivity中提出了这个代码作为（脏）修复，我不确定它是否会一直工作并且与设备无关：

public View onCreateView( String name, Context context, AttributeSet attrs ) 
{
 // started is an int instance variable, initialized at 0
 Log.w( "MA", "Inside Activity:onCreateView, started =  " + started ); 
 // if started <= 40 ==> item0 is NULL inside updateActivity 
 if( started == 41) // ==> item0 NOT null inside updateActivity 
   updateActivity( );
 started++;
 return super.onCreateView( name, context, attrs );
}

这有效但我正在寻找一个（更好）更好的解决方案;这是LogCat中的输出（它确实停在48）：

似乎涉及各种生命周期方法的交错执行。必须有一种在方法内编码的方法，该方法保证在该方法执行之前已经实例化了所有的视图;我试图从Activity，FragmentActivity，ListFragment和Fragment类中覆盖很多方法;到目前为止没有运气，TextViews（ListView的子节点）在所有这些方法中都是NULL。顺便说一句，其他TextViews在启动时仍为NULL等于41，第二个在启动时等于43时变为NOT null，而当启动时等于45时第三个变为NOT null。任何的想法？谢谢你的帮助。

......
05-16 19:27:36.460: W/MA(3155): Inside Activity:onCreateView, started =  37
05-16 19:27:36.460: W/MA(3155): Inside Activity:onCreateView, started =  38
05-16 19:27:36.460: W/MA(3155): Inside ItemListActivity:onResume
05-16 19:27:36.460: W/MA(3155): Inside ItemListFragment:onResume
05-16 19:27:36.484: W/MA(3155): Inside Activity:onCreateView, started =  39
05-16 19:27:36.484: W/MA(3155): Inside Activity:onCreateView, started =  40
05-16 19:27:36.632: W/MA(3155): Inside Activity:onCreateView, started =  41
05-16 19:27:36.632: W/MA(3155): Inside checkActivity
05-16 19:27:36.632: W/MA(3155): Inside Activity:onCreateView, started =  42
05-16 19:27:36.640: W/MA(3155): Inside Activity:onCreateView, started =  43
05-16 19:27:36.640: W/MA(3155): Inside Activity:onCreateView, started =  44
05-16 19:27:36.648: W/MA(3155): Inside Activity:onCreateView, started =  45
05-16 19:27:36.656: W/MA(3155): Inside Activity:onCreateView, started =  46
05-16 19:27:36.742: W/MA(3155): Inside Activity:onCreateView, started =  47
05-16 19:27:36.742: W/MA(3155): Inside Activity:onCreateView, started =  48

Answer 1

要实现此目的，您必须实现自定义适配器。从您的onCreate活动中创建CustomAdapter的对象，并在list of data中传递constructor。

在CustomAdapter内，你必须在每行的膨胀布局中覆盖getView()（在这里哟）你必须为findViewById(id)调用textView()并根据你的数据setFont()的{{1}}和setColor()。

Master Detail Flow模板中的TextView null

1 个答案: