التحكم في "زر" الظهر في الروبوت
https://stackoverflow.com/questions/1265095
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13-09-2019 - |
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أريد الحصول على قيمة بيانات النص من النشاط الفرعي مرة أخرى. وكل شيء على ما يرام. ولكن عندما تم فتح النشاط الفرعي، ثم انقر فوق "استرج" "زر" على الهاتف، فهو رمي خطأ استثناء. لقد وجدت على التحكم في دورة حياة الروبوت الحياة الروبوت المتوخي ولكن من الصعب فهمها. هل يستطيع احد مساعدتي؟ هذا هو رمزي:
public class SBooks extends ListActivity {
private String title_raw;
private SBooksDbAdapter mDbHelper;
private static final int ACTIVITY_SEARCH = 0;
private static final int SEARCH_ID = Menu.FIRST;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.sbooks_list);
mDbHelper = new SBooksDbAdapter(this);
mDbHelper.open();
}
// Create Menu Option
@Override
public boolean onCreateOptionsMenu(Menu menu) {
boolean result = super.onCreateOptionsMenu(menu);
menu.add(0, SEARCH_ID, 0, R.string.menu_search);
return result;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch(item.getItemId()){
case SEARCH_ID:
Intent intent = new Intent(this, SBooksSearch.class);
startActivityForResult(intent, ACTIVITY_SEARCH);
return super.onOptionsItemSelected(item);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent intent){
super.onActivityResult(requestCode, resultCode, intent);
switch(requestCode){
case ACTIVITY_SEARCH:
Bundle bundle = intent.getExtras();
title_raw = bundle.getString(SBooksDbAdapter.KEY_TITLE_RAW);
if(title_raw!=null){
Cursor cursor = mDbHelper.searchData(title_raw);
String[] from = new String[]{ SBooksDbAdapter.KEY_ROWID,
SBooksDbAdapter.KEY_TITLE, SBooksDbAdapter.KEY_LYRICS };
int[] to = new int[]{ R.id.id, R.id.title, R.id.lyrics };
SimpleCursorAdapter adapter =
new SimpleCursorAdapter(this, R.layout.sbooks_row, cursor, from, to );
setListAdapter(adapter);
}
}
}
}
هذا نشاطي الفرعي:
public class SBooksSearch extends Activity {
private EditText mTextSearch;
private Button searchButton;
private SBooksDbAdapter mDbHelper;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.sbooks_search);
mTextSearch = (EditText)findViewById(R.id.text_search);
searchButton = (Button)findViewById(R.id.btn_search);
searchButton.setOnClickListener(new View.OnClickListener(){
public void onClick(View v){
Intent intent = new Intent();
intent.putExtra(SBooksDbAdapter.KEY_TITLE_RAW, mTextSearch.getText().toString());
setResult(RESULT_OK, intent);
finish();
}
});
}
@Override
protected void onSaveInstanceState(Bundle outState){
super.onSaveInstanceState(outState);
}
@Override
protected void onPause(){
super.onPause();
checkState();
}
@Override
protected void onResume(){
super.onResume();
}
private void checkState() {
} }
هذا هو logcat:
08-12 18:44:39.211: WARN/InputManagerService(581): Starting input on non-focused client com.android.internal.view.IInputMethodClient$Stub$Proxy@43719140 (uid=10004 pid=623)
08-12 18:44:39.510: INFO/ActivityManager(581): Displayed activity com.original.sbooks/.SBooks: 4934 ms
08-12 18:44:40.821: WARN/KeyCharacterMap(730): No keyboard for id 0
08-12 18:44:40.821: WARN/KeyCharacterMap(730): Using default keymap: /system/usr/keychars/qwerty.kcm.bin
08-12 18:44:41.412: INFO/ARMAssembler(581): generated scanline__00000177:03515104_00001A01_00000000 [ 64 ipp] (89 ins) at [0x297608:0x29776c] in 952924 ns
08-12 18:44:41.520: INFO/ARMAssembler(581): generated scanline__00000177:03515104_00000A01_00000000 [ 46 ipp] (70 ins) at [0x297798:0x2978b0] in 517061 ns
08-12 18:44:42.171: INFO/ActivityManager(581): Starting activity: Intent { comp={com.original.sbooks/com.original.sbooks.SBooksSearch} }
08-12 18:44:52.196: WARN/ActivityManager(581): Launch timeout has expired, giving up wake lock!
08-12 18:44:52.279: WARN/ActivityManager(581): Activity idle timeout for HistoryRecord{436bfc80 {com.original.sbooks/com.original.sbooks.SBooksSearch}}
08-12 18:44:57.350: DEBUG/dalvikvm(620): GC freed 4103 objects / 231808 bytes in 75ms
08-12 18:45:05.130: DEBUG/dalvikvm(649): GC freed 2604 objects / 150112 bytes in 88ms
08-12 18:45:10.120: DEBUG/dalvikvm(623): GC freed 2750 objects / 149592 bytes in 71ms
08-12 18:45:11.920: INFO/ActivityManager(581): Displayed activity com.original.sbooks/.SBooksSearch: 29748 ms
08-12 18:45:17.263: WARN/ActivityManager(581): Activity pause timeout for HistoryRecord{436bfc80 {com.original.sbooks/com.original.sbooks.SBooksSearch}}
08-12 18:45:26.762: WARN/ActivityManager(581): Launch timeout has expired, giving up wake lock!
08-12 18:45:27.272: WARN/ActivityManager(581): Activity idle timeout for HistoryRecord{435a7760 {com.original.sbooks/com.original.sbooks.SBooks}}
08-12 18:46:04.905: DEBUG/AndroidRuntime(730): Shutting down VM
08-12 18:46:04.905: WARN/dalvikvm(730): threadid=3: thread exiting with uncaught exception (group=0x4000fe70)
08-12 18:46:04.905: ERROR/AndroidRuntime(730): Uncaught handler: thread main exiting due to uncaught exception
08-12 18:46:04.991: ERROR/AndroidRuntime(730): java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=0, result=0, data=null} to activity {com.original.sbooks/com.original.sbooks.SBooks}: java.lang.NullPointerException
08-12 18:46:04.991: ERROR/AndroidRuntime(730): at android.app.ActivityThread.deliverResults(ActivityThread.java:3005)
08-12 18:46:04.991: ERROR/AndroidRuntime(730): at android.app.ActivityThread.handleSendResult(ActivityThread.java:3047)
08-12 18:46:04.991: ERROR/AndroidRuntime(730): at android.app.ActivityThread.access$2300(ActivityThread.java:112)
08-12 18:46:04.991: ERROR/AndroidRuntime(730): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1721)
08-12 18:46:04.991: ERROR/AndroidRuntime(730): at android.os.Handler.dispatchMessage(Handler.java:99)
08-12 18:46:04.991: ERROR/AndroidRuntime(730): at android.os.Looper.loop(Looper.java:123)
08-12 18:46:04.991: ERROR/AndroidRuntime(730): at android.app.ActivityThread.main(ActivityThread.java:3948)
08-12 18:46:04.991: ERROR/AndroidRuntime(730): at java.lang.reflect.Method.invokeNative(Native Method)
08-12 18:46:04.991: ERROR/AndroidRuntime(730): at java.lang.reflect.Method.invoke(Method.java:521)
08-12 18:46:04.991: ERROR/AndroidRuntime(730): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:782)
08-12 18:46:04.991: ERROR/AndroidRuntime(730): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:540)
08-12 18:46:04.991: ERROR/AndroidRuntime(730): at dalvik.system.NativeStart.main(Native Method)
08-12 18:46:04.991: ERROR/AndroidRuntime(730): Caused by: java.lang.NullPointerException
08-12 18:46:04.991: ERROR/AndroidRuntime(730): at com.original.sbooks.SBooks.onActivityResult(SBooks.java:111)
08-12 18:46:04.991: ERROR/AndroidRuntime(730): at android.app.Activity.dispatchActivityResult(Activity.java:3595)
08-12 18:46:04.991: ERROR/AndroidRuntime(730): at android.app.ActivityThread.deliverResults(ActivityThread.java:3001)
المحلول
أعتقد أن NATE صحيح حول NPE في Intent.getExtras ().
يجب أن تتحقق من قيمة رمز النتيجة قبل أن تفعل أي شيء. قد ترغب أيضا في التحقق للتأكد من النمو. Hasextra (SOTKSDBADAPTER.KEY_TITLE_RAW) قبل أن تحصل على هذه القيمة. لذلك، شيء مثل هذا:
switch(requestCode){
case ACTIVITY_SEARCH:
if (resultCode == RESULT_OK && intent.hasExtra(SBooksDbAdapter.KEY_TITLE_RAW)) {
title_raw = intent.getStringExtra(SBooksDbAdapter.KEY_TITLE_RAW);
... do all that other stuff ...
}
}
نصائح أخرى
حاول وضع بعض تسجيل الدخول إلى طريقة onactivityResult (...) لنشاطك الرئيسي. قد يمنحك الزر "الخلفي" من Subactivity رمز نتيجة نتيجة نتيجة النتيجة، ويمكن أن يكون النية فارغا في هذه الحالة. لذلك سوف تحصل على NPE في
حزمة Bundle = intent.getextras ()؛
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