ImageView的setVisibility(0)和空指针异常 [英] ImageView setVisibility(0) and null pointer exception
问题描述
我有2 XML
文件,主文件,其中我有一个的ListView
和其他的地方我提出一些的定制我的的ListView
。
第二个 XML
是在我的自定义使用 ArrayAdapter
。
在第二个 XML
我有一个的ImageView
,我想在某一时刻设置为可见的,但我我得到的空指针异常
,因为我从来没有与 setCurrentView
设置第二 XML
文件,其中是我的的ImageView
。
我试图做到这一点:
ImageView的statusOk =(ImageView的)findViewById(R.id.statusOkImage);
statusOk.setVisibility(0);
你能告诉我怎么解决?
感谢您。
编辑:
下面是更多code:
main.xml中
<?XML版本=1.0编码=UTF-8&GT?;
< LinearLayout中的xmlns:机器人=http://schemas.android.com/apk/res/android
机器人:方向=垂直
机器人:layout_width =FILL_PARENT
机器人:layout_height =FILL_PARENT> < ListView控件
机器人:ID =@ + ID / ListView01
机器人:layout_height =WRAP_CONTENT
机器人:layout_width =FILL_PARENT/>
< / LinearLayout中>
第二个XML:
<?XML版本=1.0编码=UTF-8&GT?;
< LinearLayout中的xmlns:机器人=http://schemas.android.com/apk/res/android
机器人:方向=垂直
机器人:layout_width =FILL_PARENT
机器人:layout_height =FILL_PARENT>< ImageView的
机器人:ID =@ + ID / statusOkImage
机器人:layout_width =WRAP_CONTENT
机器人:layout_height =WRAP_CONTENT
机器人:SRC =@绘制/ STATUS_OK
机器人:知名度=隐形/> < TextView的机器人:ID =@ + ID /名称
机器人:TEXTSIZE =14sp
机器人:文字样式=大胆
机器人:文字颜色=#FFFF00
机器人:layout_width =WRAP_CONTENT
机器人:layout_height =WRAP_CONTENT/>
< TextView的机器人:ID =@ + ID / cityState
机器人:layout_width =WRAP_CONTENT
机器人:layout_height =WRAP_CONTENT/>
< TextView的机器人:ID =@ + ID /手机
机器人:layout_width =WRAP_CONTENT
机器人:layout_height =WRAP_CONTENT/>
< / LinearLayout中>
MainActivity:
公共类TestListActivity延伸活动{
@覆盖
公共无效的onCreate(捆绑savedInstanceState){
super.onCreate(savedInstanceState);
的setContentView(R.layout.main);
ArrayList的<&SearchResult所GT;的SearchResult = GetSearchResults();
最终的ListView LV1 =(ListView控件)findViewById(R.id.ListView01);
lv1.setAdapter(新MyCustomBaseAdapter(这一点,SearchResult所));
}私人的ArrayList<&SearchResult所GT; GetSearchResults(){
ArrayList的<&SearchResult所GT;结果=新的ArrayList<&SearchResult所GT;(); SearchResult所SR1 =新的SearchResult();
SR1 =新的SearchResult();
sr1.setName(弗雷德 - 琼斯);
sr1.setCityState(拉斯维加斯);
sr1.setPhone(612-555-8214);
results.add(SR1);
返回结果;
}
}
自定义适配器:
公共类MyCustomBaseAdapter延伸BaseAdapter {
私有静态的ArrayList<&SearchResult所GT; searchArrayList; 私人LayoutInflater mInflater; 公共MyCustomBaseAdapter(上下文的背景下,ArrayList的<&SearchResult所GT;业绩){
searchArrayList =结果;
mInflater = LayoutInflater.from(上下文);
} 公众诠释的getCount(){
返回searchArrayList.size();
} 公共对象的getItem(INT位置){
返回searchArrayList.get(位置);
} 众长getItemId(INT位置){
返回的位置;
} 公共查看getView(INT位置,查看convertView,父母的ViewGroup){
ViewHolder持有人;
如果(convertView == NULL){
convertView = mInflater.inflate(R.layout.custom_row_view,NULL);
持有人=新ViewHolder();
holder.txtName =(TextView中)convertView.findViewById(R.id.name);
holder.txtCityState =(TextView中)convertView.findViewById(R.id.cityState);
holder.txtPhone =(TextView中)convertView.findViewById(R.id.phone);
convertView.setTag(保持器);
}其他{
支架=(ViewHolder)convertView.getTag();
} mInflater =(LayoutInflater)getSystemService(LAYOUT_INFLATER_SERVICE); 查看查看= mInflater.inflate(R.layout.custom_row_view,NULL); ImageView的statusOk =(ImageView的)view.findViewById(R.id.imageView1);
statusOk.setVisibility(View.VISIBLE);
holder.txtName.setText(searchArrayList.get(位置).getName());
holder.txtCityState.setText(searchArrayList.get(位置).getCityState());
holder.txtPhone.setText(searchArrayList.get(位置).getPhone()); 返回convertView;
} 静态类ViewHolder {
TextView的txtName的;
TextView的txtCityState;
TextView的txtPhone;
}
}
和finnaly资源类为ListView
公共类的SearchResult {
私人字符串名称=;
私人字符串cityState =;
私人字符串电话=; 公共无效setname可以(字符串名称){
this.name =名称;
} 公共字符串的getName(){
返回名称;
} 公共无效setCityState(字符串cityState){
this.cityState = cityState;
} 公共字符串getCityState(){
返回cityState;
} 公共无效setPhone(字符串电话){
this.phone =电话;
} 公共字符串getPhone(){
回电话;
}
}
要设置定义在XML中的知名度来看,则需要抬高的的活动,看来,的setContentView自动去做,因为你是不是在第二个XML调用的setContentView,然后用:
LayoutInflater吹气=(LayoutInflater)getSystemService(Layout_INFLATER_SERVICE);
查看查看= inflater.inflate(R.layout.secondxml,NULL);
,然后找到该视图您的视图:
ImageView的statusOk =(ImageView的)view.findViewById(R.id.statusOkImage);
statusOk.setVisibility(0);
但只会工作的视图对象,它不会影响原来的XML。
I have 2 xml
files, a main file where I have a listView
and the other where I am making some customisations to my listView
.
The second xml
is used on my Custom ArrayAdapter
.
In the second xml
i have a ImageView
which I would like to set to visible at one moment but I am getting the null pointer exception
because i am never setting with setCurrentView
the second xml
file where is my ImageView
.
I am trying to do this:
ImageView statusOk=(ImageView)findViewById(R.id.statusOkImage);
statusOk.setVisibility(0);
Could you please tell me how to resolve that?
Thank you.
Edit:
Here is more code:
main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<ListView
android:id="@+id/ListView01"
android:layout_height="wrap_content"
android:layout_width="fill_parent"/>
</LinearLayout>
Second xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<ImageView
android:id="@+id/statusOkImage"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/status_ok"
android:visibility="invisible"/>
<TextView android:id="@+id/name"
android:textSize="14sp"
android:textStyle="bold"
android:textColor="#FFFF00"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<TextView android:id="@+id/cityState"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<TextView android:id="@+id/phone"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
</LinearLayout>
MainActivity:
public class TestListActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
ArrayList<SearchResults> searchResults = GetSearchResults();
final ListView lv1 = (ListView) findViewById(R.id.ListView01);
lv1.setAdapter(new MyCustomBaseAdapter(this, searchResults));
}
private ArrayList<SearchResults> GetSearchResults(){
ArrayList<SearchResults> results = new ArrayList<SearchResults>();
SearchResults sr1 = new SearchResults();
sr1 = new SearchResults();
sr1.setName("Fred Jones");
sr1.setCityState("Las Vegas, NV");
sr1.setPhone("612-555-8214");
results.add(sr1);
return results;
}
}
custom Adapter:
public class MyCustomBaseAdapter extends BaseAdapter {
private static ArrayList<SearchResults> searchArrayList;
private LayoutInflater mInflater;
public MyCustomBaseAdapter(Context context, ArrayList<SearchResults> results) {
searchArrayList = results;
mInflater = LayoutInflater.from(context);
}
public int getCount() {
return searchArrayList.size();
}
public Object getItem(int position) {
return searchArrayList.get(position);
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if (convertView == null) {
convertView = mInflater.inflate(R.layout.custom_row_view, null);
holder = new ViewHolder();
holder.txtName = (TextView) convertView.findViewById(R.id.name);
holder.txtCityState = (TextView) convertView.findViewById(R.id.cityState);
holder.txtPhone = (TextView) convertView.findViewById(R.id.phone);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
mInflater=(LayoutInflater)getSystemService(LAYOUT_INFLATER_SERVICE);
View view=mInflater.inflate(R.layout.custom_row_view, null);
ImageView statusOk=(ImageView)view.findViewById(R.id.imageView1);
statusOk.setVisibility(View.VISIBLE);
holder.txtName.setText(searchArrayList.get(position).getName());
holder.txtCityState.setText(searchArrayList.get(position).getCityState());
holder.txtPhone.setText(searchArrayList.get(position).getPhone());
return convertView;
}
static class ViewHolder {
TextView txtName;
TextView txtCityState;
TextView txtPhone;
}
}
And finnaly the resource class for the listView
public class SearchResults {
private String name = "";
private String cityState = "";
private String phone = "";
public void setName(String name) {
this.name = name;
}
public String getName() {
return name;
}
public void setCityState(String cityState) {
this.cityState = cityState;
}
public String getCityState() {
return cityState;
}
public void setPhone(String phone) {
this.phone = phone;
}
public String getPhone() {
return phone;
}
}
To set visibility view defined in xml, you need to inflate that view in activity, setContentView do it automatically, and as you are not invoking setContentView on second xml, then use:
LayoutInflater inflater=(LayoutInflater)getSystemService(Layout_INFLATER_SERVICE);
View view=inflater.inflate(R.layout.secondxml, null);
and then find your view from that view:
ImageView statusOk=(ImageView)view.findViewById(R.id.statusOkImage);
statusOk.setVisibility(0);
but it will work only for view object, it does not affect original xml.
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