所以我正在开发一款应用程序，我让这部分工作了好几天，而且没有任何地方它无缘无故地停止工作......
当我在MainActivity中尝试使用另一个无头片段时，我也遇到了同样的错误，但最终用MainActivity中的内部方法替换了片段，一切都恢复正常。
但是，我不能重写我只需避免使用片段的每一段代码。片段代码如下。
public class IMEIFragment extends Fragment implements ActivityCompat.OnRequestPermissionsResultCallback{
public static final String TAG_IMEI = "IMEILoader";
protected Activity mActivity;
private String RecordedIMEI;
//public static final String CHECK_INTERNET = "network_connection";
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
return null; //Do we need this at all?
}
@Override
public void onAttach(Context context) {
super.onAttach(context);
Activity activity = context instanceof Activity ? (Activity) context : null;
mActivity = activity;
}
//Is this needed?
@SuppressWarnings("deprecation")
@Override
public void onAttach(Activity activity) {
activity = getActivity();
if (isAdded() && activity != null) {
super.onAttach(activity);
}
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) {
mActivity = activity;
}
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setRetainInstance(true);
}
@Override
public void onDetach() {
super.onDetach();
mActivity = null;
}
public String loadIMEI(Context context) {
if (Build.VERSION.SDK_INT >= 23) {
if (ActivityCompat.checkSelfPermission(context, Manifest.permission.READ_PHONE_STATE)
!= PackageManager.PERMISSION_GRANTED) {
// READ_PHONE_STATE permission has not been granted.
requestPermissions(context);
} else {
// READ_PHONE_STATE permission is already been granted.
RecordedIMEI = permissionGrantedActions(context);
}
if (RecordedIMEI != null) {
Log.i("loadIMEIService", "IMEI number returned!");
}
} else {
// READ_PHONE_STATE permission is already been granted.
RecordedIMEI = permissionGrantedActions(context);
}
if (RecordedIMEI != null) {
Log.i("loadIMEIService", "IMEI number returned!");
}
return RecordedIMEI;
}
private void requestPermissions(Context context) {
if (ContextCompat.checkSelfPermission(context, Manifest.permission.READ_PHONE_STATE) != PackageManager.PERMISSION_GRANTED) {
Log.i("loadIMEIService", "READ_PHONE_STATE permission not granted, asking for it...");
// TODO create proper notification content
PermissionHelper.requestPermissions(((PriceActivity) getActivity()),
new String[]{Manifest.permission.READ_PHONE_STATE},
Constants.PERM_REQUEST_PHONE_STATE,
getString(R.string.notify_perm_title),
getString(R.string.notify_perm_body),
R.drawable.ic_security);
}
}
// Callback received when a permissions request has been completed.
@Override
public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) {
boolean isGranted = false;
for (int i = 0; i < grantResults.length; i++)
if (permissions[i].equals(Manifest.permission.READ_PHONE_STATE) && (grantResults[i] == PackageManager.PERMISSION_GRANTED))
isGranted = true;
if (isGranted) {
Context context = getActivity().getApplicationContext();
permissionGrantedActions(context);
}
else
Log.w("loadIMEIService", "READ_PHONE_STATE permission not granted. loadIMEI will not be available.");
}
public String permissionGrantedActions(Context context) {
//Have an object of TelephonyManager
TelephonyManager tm =(TelephonyManager)context.getSystemService(Context.TELEPHONY_SERVICE);
//Get IMEI Number of Phone
String IMEINumber = tm.getDeviceId();
if(IMEINumber != null) {
Log.i("loadIMEIService", "IMEI number recorded!");
}
return IMEINumber;
}
}
错误如下：
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.android.project1, PID: 5498
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.android.project1/com.android.project1.main.MainActivity}: java.lang.IllegalStateException: Fragment IMEIFragment{3e80da7 IMEILoader} not attached to Activity
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.IllegalStateException: Fragment IMEIFragment{3e80da7 IMEILoader} not attached to Activity
at android.app.Fragment.getResources(Fragment.java:805)
at android.app.Fragment.getString(Fragment.java:827)
at com.android.project1.fragments.IMEIFragment.requestPermissions(IMEIFragment.java:107)
at com.android.project1.fragments.IMEIFragment.loadIMEI(IMEIFragment.java:80)
at com.android.project1.main.MainActivity.onCreate(MainActivity.java:108)
at android.app.Activity.performCreate(Activity.java:6237)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
这是我的MainActivity的相关部分：
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mDeviceCode = (TextView) findViewById(R.id.device_code);
// Initializing headless fragment
mFragment =
(IMEIFragment) getFragmentManager()
.findFragmentByTag("IMEILoader");
if (mFragment == null) {
mFragment = new IMEIFragment();
getFragmentManager().beginTransaction()
.add(mFragment, "IMEILoader").commit();
}
if (mFragment != null) {
mNumber = mFragment.loadIMEI(MainActivity.this);
mDeviceCode.setText(Html.fromHtml("<b>IMEI</b>: " + mNumber));
}
我确实有相同的代码工作了一个多星期。谁知道可能是什么问题？
编辑1：错误指向片段
中的requestPermissions答案 0 :(得分：0)
碎片应尽可能自包含。您正从活动
直接调用您的IMEIFragmentfrom functions import doSomething
var = doSomething()
你不能这样做。通过活动中的事务添加片段是异步操作。例如，当 Caused by: java.lang.IllegalStateException: Fragment IMEIFragment{3e80da7 IMEILoader} not attached to Activity
at android.app.Fragment.getResources(Fragment.java:805)
at android.app.Fragment.getString(Fragment.java:827)
at com.android.project1.fragments.IMEIFragment.requestPermissions(IMEIFragment.java:107)
at com.android.project1.fragments.IMEIFragment.loadIMEI(IMEIFragment.java:80)
at com.android.project1.main.MainActivity.onCreate(MainActivity.java:108)
方法完成时，片段未初始化。而且，你无法知道它什么时候被初始化。这就是为什么它应该是自包含的。片段决定何时调用loadIMEI（），而不是活动。
如果确实需要由活动启动，您可以将片段中的回调添加到活动中，例如，
commit()或其他什么。
是的，void onFragmentReady(Fragment f);
应该返回一些东西。如果您的片段根本没有任何用户界面，那么您就不需要它作为片段。