我有一个Android项目，我希望用自定义编写的适配器将Activity转换为ListActivity：
public class MyArrayAdapter extends ArrayAdapter<Coordinate> {
private final Context context;
private final List<Coordinate> values;
public MyArrayAdapter(Context context, List<Coordinate> values) {
super(context, R.layout.table_row, values);
this.context = context;
this.values = values;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View rowView = inflater.inflate(R.layout.table_row, parent, false);
TextView textViewRowId = (TextView) rowView.findViewById(R.id.table_row_id);
TextView textViewLatitude = (TextView) rowView.findViewById(R.id.table_row_latitude);
TextView textViewLongitude = (TextView) rowView.findViewById(R.id.table_row_longitude);
TextView textViewAtitude = (TextView) rowView.findViewById(R.id.table_row_altitude);
textViewRowId.setText(Long.toString(values.get(position).getId()));
textViewLatitude.setText(Double.toString(values.get(position).getLatitude()));
textViewLongitude.setText(Double.toString(values.get(position).getLongitude()));
textViewAtitude.setText(Double.toString(values.get(position).getAltitude()));
return rowView;
}
@Override
public void add(Coordinate object) {
super.add(object);
values.add(object);
}
}
问题在于初始化布局。我不知道首先要初始化/膨胀什么。在onCreate Activity的{{1}}中进行此操作：
public class MainActivity extends ListActivity implements ActionBar.TabListener {
SectionsPagerAdapter mSectionsPagerAdapter;
ViewPager mViewPager;
protected static final int SECTION_MAIN = 1;
protected static final int SECTION_DB_TABLE = 2;
private LocationManager location_manger;
private CoordinatesDataSource coordinates_data_source;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
coordinates_data_source = new CoordinatesDataSource(getApplicationContext());
coordinates_data_source.open();
List<Coordinate> values = coordinates_data_source.getAllCoordinates();
MyArrayAdapter adapter = new MyArrayAdapter(getApplicationContext(), values);
setListAdapter(adapter);
// Set up the action bar.
final ActionBar actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
// Create the adapter that will return a fragment for each of the three
// primary sections of the activity.
mSectionsPagerAdapter = new SectionsPagerAdapter(getFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mSectionsPagerAdapter);
// When swiping between different sections, select the corresponding tab.
// We can also use ActionBar.Tab#select() to do this if we have a reference to the Tab.
mViewPager
.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
@Override
public void onPageSelected(int position) {
actionBar.setSelectedNavigationItem(position);
}
});
// For each of the sections in the app, add a tab to the action bar.
for (int i = 0; i < mSectionsPagerAdapter.getCount(); i++) {
// Create a tab with text corresponding to the page title defined by the adapter.
// Also specify this Activity object, which implements the TabListener
// interface, as the callback (listener) for when this tab is selected.
actionBar.addTab(actionBar.newTab()
.setText(mSectionsPagerAdapter.getPageTitle(i))
.setTabListener(this));
}
MyLocationListener loclist = new MyLocationListener(
this, getApplicationContext(), coordinates_data_source);
location_manger = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
location_manger.requestLocationUpdates(LocationManager.GPS_PROVIDER, 500, 1, loclist);
}
//...
在带有列表的片段中我只有这个：
<?xml version="1.0" encoding="utf-8"?>
<ListView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/list"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
</ListView>
有了这段代码，我会收到以下错误：
8782 AndroidRuntime E FATAL EXCEPTION: main
8782 AndroidRuntime E Process: pl.patryk, PID: 8782
8782 AndroidRuntime E java.lang.RuntimeException: Unable to start activity ComponentInfo{pl.patryk/pl.patryk.MainActivity}: java.lang.RuntimeException: Your content mu
st have a ListView whose id attribute is 'android.R.id.list'
8782 AndroidRuntime E at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2215)
8782 AndroidRuntime E at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2265)
8782 AndroidRuntime E at android.app.ActivityThread.access$800(ActivityThread.java:145)
8782 AndroidRuntime E at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1206)
8782 AndroidRuntime E at android.os.Handler.dispatchMessage(Handler.java:102)
8782 AndroidRuntime E at android.os.Looper.loop(Looper.java:136)
8782 AndroidRuntime E at android.app.ActivityThread.main(ActivityThread.java:5144)
8782 AndroidRuntime E at java.lang.reflect.Method.invokeNative(Native Method)
8782 AndroidRuntime E at java.lang.reflect.Method.invoke(Method.java:515)
8782 AndroidRuntime E at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:795)
8782 AndroidRuntime E at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:611)
8782 AndroidRuntime E at dalvik.system.NativeStart.main(Native Method)
8782 AndroidRuntime E Caused by: java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'
8782 AndroidRuntime E at android.app.ListActivity.onContentChanged(ListActivity.java:243)
8782 AndroidRuntime E at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:346)
8782 AndroidRuntime E at android.app.Activity.setContentView(Activity.java:1929)
8782 AndroidRuntime E at pl.patryk.MainActivity.onCreate(MainActivity.java:48)
8782 AndroidRuntime E at android.app.Activity.performCreate(Activity.java:5231)
8782 AndroidRuntime E at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
8782 AndroidRuntime E at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2169)
8782 AndroidRuntime E ... 11 more
如果我移动setContentView(R.layout.activity_main);，我会得到以下内容：
8941 AndroidRuntime E FATAL EXCEPTION: main
8941 AndroidRuntime E Process: pl.patryk, PID: 8941
8941 AndroidRuntime E java.lang.RuntimeException: Unable to start activity ComponentInfo{pl.patryk/pl.patryk.MainActivity}: java.lang.NullPointerException
8941 AndroidRuntime E at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2215)
8941 AndroidRuntime E at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2265)
8941 AndroidRuntime E at android.app.ActivityThread.access$800(ActivityThread.java:145)
8941 AndroidRuntime E at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1206)
8941 AndroidRuntime E at android.os.Handler.dispatchMessage(Handler.java:102)
8941 AndroidRuntime E at android.os.Looper.loop(Looper.java:136)
8941 AndroidRuntime E at android.app.ActivityThread.main(ActivityThread.java:5144)
8941 AndroidRuntime E at java.lang.reflect.Method.invokeNative(Native Method)
8941 AndroidRuntime E at java.lang.reflect.Method.invoke(Method.java:515)
8941 AndroidRuntime E at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:795)
8941 AndroidRuntime E at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:611)
8941 AndroidRuntime E at dalvik.system.NativeStart.main(Native Method)
8941 AndroidRuntime E Caused by: java.lang.NullPointerException
8941 AndroidRuntime E at pl.patryk.MainActivity.onCreate(MainActivity.java:67)
修改
要明确：
我的activity_main.xml没有ListView。我有2个片段是我的标签，在一个（第二个标签）中我有上面添加的ListView。
所以我的布局：
activity_main
fragment_main
fragment_table_points
table_row
activity_main是主要布局，fragment_main是第一个标签，fragment_table_points第二个标签，table_row是适配器的布局。
答案 0 :(得分：3)
它是null，因为ListView id应该来自ListView的默认android id，而不是创建它的新id，因此给你这个错误：
Your content must have a ListView whose id attribute is 'android.R.id.list'
<强>问题：
android:id="@+id/list"
<强>溶液
更改id以匹配ListActivity的android listview id
<?xml version="1.0" encoding="utf-8"?>
<ListView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@android:id/list"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
</ListView>
答案 1 :(得分：0)
Rod_Algonquin提供了very good answer above，以便ListAdapter使用Activity。我需要将其与Fragment一起使用，因此我需要将Fragment类扩展为ListFragment并实现所需的方法。
public static class MyListFragment extends ListFragment{
/**
* The fragment argument representing the section number for this fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";
/**
* Returns a new instance of this fragment for the given section number.
*/
public static MyListFragment newInstance(int sectionNumber) {
MyListFragment fragment = new MyListFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
public MyListFragment(){}
@Override
public View onCreateView(
LayoutInflater inflater,
ViewGroup container,
Bundle savedInstanceState) {
int current_section = getArguments().getInt(ARG_SECTION_NUMBER);
int current_layout;
switch (current_section) {
case SECTION_MAIN:
current_layout = R.layout.fragment_main;
break;
default:
current_layout = R.layout.fragment_other;
break;
}
View rootView = inflater.inflate(current_layout, container, false);
return rootView;
}
}