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我已经在兼容模式下支持Android 4.4到Android 2.2（Foroyo）的应用程序。那么我在Android 4.0.4和Android 2.2（真实设备）上测试它。我的应用在Android 2.2上崩溃。从谷歌街景恢复到我的应用程序在Android 2.2上崩溃
让我解释一下我的场景。我有一个在标签模式下有11个片段的活动。我正在做的是我通过意图从片段执行Google Street视图，如下所示：
Intent streetView = new Intent(android.content.Intent.ACTION_VIEW,
Uri.parse("google.streetview:cbll=" + 40.720032 + ","+ -73.988354 + &cbp=1,99.56,,1,-5.27&mz=21"));
startActivity(streetView);
这是我的MainActivity代码。请参阅我的onCreate()，onStart()，onPause()，onResume()和onDestroy()方法：
public class MainActivity extends SherlockFragmentActivity {
private ArrayList<Class> classes = new ArrayList<Class>();
private Intent intent;
@SuppressWarnings("unchecked")
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
classes.add(OverView.class);
classes.add(LifeStyle.class);
classes.add(RealState.class);
classes.add(Events.class);
classes.add(Deals.class);
classes.add(Popular.class);
classes.add(MetroBusStops.class);
classes.add(Schools.class);
classes.add(Libraries.class);
classes.add(Parks.class);
classes.add(PublicSafety.class);
// Set up the action bar.
final com.actionbarsherlock.app.ActionBar actionBar = getSupportActionBar();
actionBar.setDisplayShowHomeEnabled(false);
actionBar.setDisplayShowTitleEnabled(false);
Tab tab = null;
for (int i = 0; i < classes.size(); i++) {
tab = actionBar
.newTab()
.setText(
getResources().getStringArray(R.array.tabs_names)[i])
.setTabListener(
new TabListener<SherlockFragment>(this, "Tab" + i,
(Class<SherlockFragment>) classes.get(i)));
actionBar.addTab(tab);
}
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
Log.e("onCreate Activty", "Called");
}
@Override
protected void onStart() {
Log.e("onStart Activty", "Called");
super.onStart();
}
@Override
protected void onResume() {
Log.e("onResume Activty", "Called");
super.onResume();
}
@Override
protected void onPause() {
Log.e("onPause Activty", "Called");
super.onPause();
}
@Override
protected void onDestroy() {
Log.e("onDestroy Activty", "Called");
super.onDestroy();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getSupportMenuInflater().inflate(R.menu.main, menu);
return true;
}
public static class TabListener<T extends SherlockFragment> implements
ActionBar.TabListener {
private SherlockFragment mFragment;
private final SherlockFragmentActivity mActivity;
private final String mTag;
private final Class<T> mClass;
/**
* Constructor used each time a new tab is created.
*
* @param activity
* The host Activity, used to instantiate the fragment
* @param tag
* The identifier tag for the fragment
* @param clz
* The fragment's Class, used to instantiate the fragment
*/
public TabListener(SherlockFragmentActivity activity, String tag,
Class<T> clz) {
mActivity = activity;
mTag = tag;
mClass = clz;
}
/* The following are each of the ActionBar.TabListener callbacks */
public void onTabSelected(Tab tab, FragmentTransaction ft) {
// Check if the fragment is already initialized
if (mFragment == null) {
// If not, instantiate and add it to the activity
mFragment = (SherlockFragment) SherlockFragment.instantiate(
mActivity, mClass.getName());
ft.add(android.R.id.content, mFragment, mTag);
} else {
// If it exists, simply attach it in order to show it
ft.attach(mFragment);
}
}
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
if (mFragment != null) {
// Detach the fragment, because another one is being attached
ft.detach(mFragment);
}
}
public void onTabReselected(Tab tab, FragmentTransaction ft) {
// User selected the already selected tab. Usually do nothing.
}
}
@Override
public void onBackPressed() {
finish();
overridePendingTransition(R.anim.slide_in_left, R.anim.slide_out_right);
}
}
测试在Android 4.0.4
它的工作就好了。这是我的活动生命周期的MainActivity的日志，我在其中制作标签和片段。
虽然开始我的第一次活动：
onCreate Activty Called
onStart Activty Called
onResume Activty Called
通过intent启动谷歌街景某些片段
onPause Activty Called
通过BackKey出版社
onStart Activty Called
onResume Activty Called
关闭街景视图后在Android 2.2上测试
我在Android 2.2中做了同样的事情，但在这里活动的生命周期有些不同。这是我的活动生命周期日志
第一次开始我的活动。
onCreate Activty Called
onStart Activty Called
onResume Activty Called
通过intent启动谷歌街景某些片段
onPause Activty Called
通过BackKey出版社
onCreate Activty Called (Look this. Why is it called here again? This is Odd behaviour)
onStart Activty Called
onResume Activty Called
它也重新创建我的全部活动，包括标签和片段关闭街景视图后。它看起来重新启动我的应用程序现在，如果我点击任何选项卡，它只是崩溃，并给出空指针异常。
这里是logcat的
01-17 12:53:18.968: E/AndroidRuntime(2596): FATAL EXCEPTION: main
01-17 12:53:18.968: E/AndroidRuntime(2596): java.lang.NullPointerException
01-17 12:53:18.968: E/AndroidRuntime(2596): at fragment.populor.Popular.onCreateView(Popular.java:72)
01-17 12:53:18.968: E/AndroidRuntime(2596): at android.support.v4.app.Fragment.performCreateView(Fragment.java:1500)
01-17 12:53:18.968: E/AndroidRuntime(2596): at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:927)
01-17 12:53:18.968: E/AndroidRuntime(2596): at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1104)
01-17 12:53:18.968: E/AndroidRuntime(2596): at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
01-17 12:53:18.968: E/AndroidRuntime(2596): at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1467)
01-17 12:53:18.968: E/AndroidRuntime(2596): at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:440)
01-17 12:53:18.968: E/AndroidRuntime(2596): at android.os.Handler.handleCallback(Handler.java:587)
01-17 12:53:18.968: E/AndroidRuntime(2596): at android.os.Handler.dispatchMessage(Handler.java:92)
01-17 12:53:18.968: E/AndroidRuntime(2596): at android.os.Looper.loop(Looper.java:123)
01-17 12:53:18.968: E/AndroidRuntime(2596): at android.app.ActivityThread.main(ActivityThread.java:4627)
01-17 12:53:18.968: E/AndroidRuntime(2596): at java.lang.reflect.Method.invokeNative(Native Method)
01-17 12:53:18.968: E/AndroidRuntime(2596): at java.lang.reflect.Method.invoke(Method.java:521)
01-17 12:53:18.968: E/AndroidRuntime(2596): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
01-17 12:53:18.968: E/AndroidRuntime(2596): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
01-17 12:53:18.968: E/AndroidRuntime(2596): at dalvik.system.NativeStart.main(Native Method)
这里是我的片段代码：
public class Popular extends SherlockFragment implements OnClickListener,
OnItemClickListener {
public Popular() {
}
private View v;
private ListView listView;
private RelativeLayout rel_list, rel_map;
private Button btnList, btnMap;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
if (v != null) {
ViewGroup parent = (ViewGroup) v.getParent();
if (parent != null)
parent.removeView(v);
}
try {
v = inflater.inflate(R.layout.populor_fragment, container, false);
} catch (InflateException e) {
}
listView = (ListView) v.findViewById(R.id.listView1);
rel_list = (RelativeLayout) v.findViewById(R.id.rel_list);
rel_map = (RelativeLayout) v.findViewById(R.id.rel_map);
btnList = (Button) v.findViewById(R.id.btnList);
btnMap = (Button) v.findViewById(R.id.btnMap);
listView.setAdapter(new MyListAdapter());
return v;
}
@Override
public void onStart() {
super.onStart();
btnList.setOnClickListener(this);
btnMap.setOnClickListener(this);
listView.setOnItemClickListener(this);
}
private class MyListAdapter extends BaseAdapter {
@Override
public int getCount() {
return listItems.size();
}
@Override
public Object getItem(int position) {
return position;
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater = (LayoutInflater) getActivity()
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View rowView = inflater.inflate(R.layout.populor_list_items,
parent, false);
TextView txtCategoryName = (TextView) rowView
.findViewById(R.id.txtCategory);
txtCategoryName.setText(listItems.get(position));
return rowView;
}
}
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int arg2,
long arg3) {
// Clear All previous items colors
for (int j = 0; j < adapterView.getChildCount(); j++)
adapterView.getChildAt(j).setBackgroundColor(Color.TRANSPARENT);
// change the background color of the selected element
view.setBackgroundColor(Color.LTGRAY);
showStreetView();
}
private void showStreetView() {
Intent streetView = new Intent(android.content.Intent.ACTION_VIEW,
Uri.parse("google.streetview:cbll=" + 40.720032 + ","
+ -73.988354 + "&cbp=1,99.56,,1,-5.27&mz=21"));
startActivity(streetView);
}
}
难道我做错了我的片段onCreateView()。如果是这样，为什么它在Android 4.0.4上正常工作？
热门课程中的第72行是什么？谢谢。 – fasteque
其listView =（ListView）v.findViewById（R.id.listView1）;但为什么这是第一次没有变为空。 –