Android getActivity（）返回null—第二次打开片段时
当我按下按钮时，Android getActivity（）返回null—第二次打开片段时,android,android-fragments,google-maps-api-3,Android,Android Fragments,Google Maps Api 3,当我按下按钮时，ShowActivities片段被实例化。我第一次按它时，一切正常。这是我在logCat中得到的： 11-16 23:41:12.560 25874-25874/name.company.newapp E/onCreate: getActivity() == null: false 11-16 23:41:12.560 25874-25874/name.company.newapp E/onCreate: Hash: 1036405628 11-16 23:41:12.570 2
ShowActivities11-16 23:41:12.560 25874-25874/name.company.newapp E/onCreate: getActivity() == null: false
11-16 23:41:12.560 25874-25874/name.company.newapp E/onCreate: Hash: 1036405628
11-16 23:41:12.570 25874-25874/name.company.newapp E/onCreateView: getActivity() == null: false
11-16 23:41:12.570 25874-25874/name.company.newapp E/onCreateView: Hash: 1036405628
11-16 23:41:12.630 25874-25874/name.company.newapp E/onConnected: getActivity() == null: false
11-16 23:41:12.630 25874-25874/name.company.newapp E/onConnected: Hash: 1036405628
ShowActivities11-16 23:41:13.890 25874-25874/name.company.newapp E/onCreate: getActivity() == null: false
11-16 23:41:13.890 25874-25874/name.company.newapp E/onCreate: Hash: 252302789
11-16 23:41:13.890 25874-25874/name.company.newapp E/onCreateView: getActivity() == null: false
11-16 23:41:13.890 25874-25874/name.company.newapp E/onCreateView: Hash: 252302789
11-16 23:41:13.900 25874-25874/name.company.newapp E/onConnected: getActivity() == null: true
11-16 23:41:13.900 25874-25874/name.company.newapp E/onConnected: Hash: 1036405628
onConnected public class ShowActivities extends Fragment implements
GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener, LocationListener {
public ShowActivities() {
}
private static GoogleApiClient googleClient;
private Location mLastLocation;
private PendingResult<LocationSettingsResult> result;
private LocationRequest locationRequest;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Log.e("onCreate"," "+(getActivity() == null));
if (googleClient==null) {
googleClient = new GoogleApiClient.Builder(getActivity())
.addApi(LocationServices.API)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.build();
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
super.onCreateView(inflater, container, savedInstanceState);
Log.e("onCreateView"," "+(getActivity() == null));
// Defines the xml file for the fragment
View view = inflater.inflate(R.layout.upload_activity_fragment, container, false);
return view;
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
}
@Override
public void onConnected(Bundle bundle) {
Log.e("onConnected"," "+(getActivity() == null));
locationRequest = LocationRequest.create();
locationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
LocationSettingsRequest.Builder builder = new LocationSettingsRequest.Builder()
.addLocationRequest(locationRequest);
builder.setAlwaysShow(true);
result = LocationServices.SettingsApi.checkLocationSettings(googleClient, builder.build());
if (result != null) {
result.setResultCallback(new ResultCallback<LocationSettingsResult>() {
@Override
public void onResult(LocationSettingsResult locationSettingsResult) {
final Status status = locationSettingsResult.getStatus();
switch (status.getStatusCode()) {
case LocationSettingsStatusCodes.SUCCESS:
// All location settings are satisfied. The client can initialize location
// requests here.
break;
case LocationSettingsStatusCodes.RESOLUTION_REQUIRED:
// Location settings are not satisfied. But could be fixed by showing the user
// a optionsDialog.
try {
// Show the optionsDialog by calling startResolutionForResult(),
// and check the result in onActivityResult().
if (status.hasResolution()) {
status.startResolutionForResult(getActivity(), 1000);
Log.e("location", "Resolution");
}
} catch (IntentSender.SendIntentException e) {
// Ignore the error.
Log.e("location", "Resolution2");
}
break;
case LocationSettingsStatusCodes.SETTINGS_CHANGE_UNAVAILABLE:
// Location settings are not satisfied. However, we have no way to fix the
// settings so we won't show the optionsDialog.
break;
}
}
});
}
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if ((resultCode == Activity.RESULT_OK) && (requestCode == 1000)) {
mLastLocation = LocationServices.FusedLocationApi.getLastLocation(googleClient);
}
}
@Override
public void onConnectionSuspended(int i) {
}
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
}
@Override
public void onLocationChanged(Location location) {
Log.e("location", "finally");
}
@Override
public void onResume() {
super.onResume();
}
@Override
public void onPause() {
super.onPause();
if (googleClient!=null) {
googleClient = null;
}
}
}
公共类ShowActivities扩展片段实现
GoogleAppClient.ConnectionCallbacks，GoogleAppClient.OnConnectionFailedListener，LocationListener{
公众展览活动（）{
}
私有静态谷歌客户端；
私人场所；
私人结果；
私人位置请求位置请求；
@凌驾
创建时的公共void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
Log.e（“onCreate”，“+（getActivity（）==null））；
if（googleClient==null）{
googleClient=新的GoogleAppClient.Builder（getActivity（））
.addApi（LocationServices.API）
.addConnectionCallbacks（此）
.addOnConnectionFailedListener（此）
.build（）；
}
}
@凌驾
创建视图上的公共视图（布局、充气机、视图组容器、，
Bundle savedInstanceState）{
super.onCreateView（充气机、容器、保存状态）；
Log.e（“onCreateView”，“”+（getActivity（）==null））；
//定义片段的xml文件
视图=充气机。充气（R.layout.upload\u activity\u片段，容器，false）；
返回视图；
}
@凌驾
已创建视图上的公共void（视图，捆绑保存状态）{
}
@凌驾
未连接的公共空间（捆绑包）{
Log.e（“onConnected”，“”+（getActivity（）==null））；
locationRequest=locationRequest.create（）；
locationRequest.setPriority（locationRequest.PRIORITY\u高精度）；
LocationSettingsRequest.Builder=新建LocationSettingsRequest.Builder（）
.addLocationRequest（locationRequest）；
builder.setAlwaysShow（true）；
结果=LocationServices.SettingsApi.checkLocationSettings（googleClient，builder.build（））；
如果（结果！=null）{
result.setResultCallback（新的ResultCallback（）{
@凌驾
公共无效onResult（LocationSettingsResult LocationSettingsResult）{
最终状态状态=locationSettingsResult.getStatus（）；
开关（status.getStatusCode（））{
案例位置设置StatusCodes.SUCCESS：
//满足所有位置设置。客户端可以初始化位置
//请求在这里。
打破
案例位置设置StatusCodes.RESOLUTION_要求：
//不满足位置设置。但可以通过显示用户来修复
//选项对话框。
试一试{
//通过调用startResolutionForResult（）显示选项对话框，
//并在onActivityResult（）中检查结果。
if（status.hasResolution（））{
status.startResolutionForResult（getActivity（），1000）；
Log.e（“位置”、“决议”）；
}
}catch（IntentSender.sendtintentexe）{
//忽略错误。
日志e（“位置”、“决议2”）；
}
打破
案例位置设置StatusCodes.SETTINGS\u CHANGE\u不可用：
//位置设置不满意。但是，我们无法修复此问题
//设置，因此我们不会显示选项对话框。
打破
}
}
});
}
}
@凌驾
ActivityResult上的公共void（int请求代码、int结果代码、意图数据）{
super.onActivityResult（请求代码、结果代码、数据）；
if（（resultCode==Activity.RESULT_OK）&&（requestCode==1000））{
mLastLocation=LocationServices.FusedLocationApi.getLastLocation（谷歌客户端）；
}
}
@凌驾
公共空间连接暂停（int i）{
}
@凌驾
公共无效onConnectionFailed（ConnectionResult ConnectionResult）{
}
@凌驾
已更改位置上的公共无效（位置）{
Log.e（“位置”、“最终”）；
}
@凌驾
恢复时公开作废（）{
super.onResume（）；
}
@凌驾
公共无效暂停（）{
super.onPause（）；
if（googleClient！=null）{
googleClient=null；
}
}
}
这个问题解决了。我修改了onPause，使googleClient在退出片段后为null 首先尝试通过标记在占位符中获取片段实例，如果没有先前的输入，则创建一个实例
Fragment ShowActivities = getFragmentManager().getFragmentByTag(YOUR_TAG);
if (showActivities == null) {
showActivities = new ShowActivities();
getFragmentManager().beginTransaction()
.replace(R.id.your_placeholder, showActivities, YOUR_TAG)
.addToBackStack(null)
.commit();
}
首先尝试通过标记在占位符中获取片段实例，如果没有以前的实例，则创建一个实例
Fragment ShowActivities = getFragmentManager().getFragmentByTag(YOUR_TAG);
if (showActivities == null) {
showActivities = new ShowActivities();
getFragmentManager().beginTransaction()
.replace(R.id.your_placeholder, showActivities, YOUR_TAG)
.addToBackStack(null)
.commit();
}
client = new NightAssetRestClient(getActivity());
locationQueries = new LocationQueries(getActivity());
if (googleClient==null) {
googleClient = new GoogleApiClient.Builder(getActivity())
.addApi(LocationServices.API)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.build();
}