本文介绍了绘制背景RelativeLayout时发生NullPointerException的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
像这样的愚蠢错误使我发疯，只想为每个视图绘制两种颜色的布局背景，但是我得到了nullPointerException.
A silly mistake like this going me crazy, just want to paint the background of a layout of two colors for each view, but I get a nullPointerException.
XML文件:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<RelativeLayout
android:id="@+id/background_areas"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
....
JAVA文件:
for (int o = 0; o < areas.size(); o++) {
LayoutInflater li_area= (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
final View vArea = li_area.inflate(R.layout.areas_detalles_cpa, null);
RelativeLayout fondo_area = (RelativeLayout)findViewById(R.id.background_areas);
if(o%2==0){
NULLPOINTEREXCEPTION fondo_area.setBackgroundColor(Color.rgb(104, 2, 64));
NULLPOINTEREXCEPTIONfondo_area.setBackgroundColor(Color.rgb(104, 2, 64));
}else{
fondo_area.setBackgroundColor(Color.rgb(197, 5, 120));
}
......
Logcat:
01-31 14:11:47.956: W/System.err(12950): java.lang.NullPointerException
01-31 14:11:47.964: W/System.err(12950): at com.hiberus.campus.cpa.views.AreasEstudiosCPA.cargarListaAreas(AreasEstudiosCPA.java:125)
01-31 14:11:47.964: W/System.err(12950): at com.hiberus.campus.cpa.views.AreasEstudiosCPA$task.onPostExecute(AreasEstudiosCPA.java:200)
01-31 14:11:47.964: W/System.err(12950): at com.hiberus.campus.cpa.views.AreasEstudiosCPA$task.onPostExecute(AreasEstudiosCPA.java:1)
01-31 14:11:47.964: W/System.err(12950): at android.os.AsyncTask.finish(AsyncTask.java:602)
01-31 14:11:47.964: W/System.err(12950): at android.os.AsyncTask.access$600(AsyncTask.java:156)
01-31 14:11:47.964: W/System.err(12950): at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:615)
01-31 14:11:47.964: W/System.err(12950): at android.os.Handler.dispatchMessage(Handler.java:99)
01-31 14:11:47.964: W/System.err(12950): at android.os.Looper.loop(Looper.java:137)
01-31 14:11:47.964: W/System.err(12950): at android.app.ActivityThread.main(ActivityThread.java:4514)
01-31 14:11:47.964: W/System.err(12950): at java.lang.reflect.Method.invokeNative(Native Method)
01-31 14:11:47.964: W/System.err(12950): at java.lang.reflect.Method.invoke(Method.java:511)
01-31 14:11:47.964: W/System.err(12950): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790)
01-31 14:11:47.964: W/System.err(12950): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:557)
01-31 14:11:47.964: W/System.err(12950): at dalvik.system.NativeStart.main(Native Method)
我是否检查了ID，xml文件的名称以及一切似乎都很好，这是发生了吗?
Do I have checked the id, the names of the xml file and everything seems fine, that is happening?
推荐答案
我认为您缺少此部分.使用 vArea.findViewById()而不是仅使用 findViewById()
I think you are missing this part..Use vArea.findViewById() instead of only findViewById()
final View vArea = li_area.inflate(R.layout.areas_detalles_cpa, null);
RelativeLayout fondo_area = (RelativeLayout)vArea.findViewById(R.id.background_areas);
这篇关于绘制背景RelativeLayout时发生NullPointerException的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！