由网友(日落黄昏时)分享简介:我得到的errror:显示java.lang.NullPointerException:需要的println消息时使用该梅索德: lst_info =新的HashMap<字符串,字符串>();SystemDatabaseHandler分贝=新SystemDatabaseHandler(getApplica...![Java 混淆工具 ProGuard 之初体验](https://p.xsw88.cn/allimgs/daicuo/20230907/5959.png)
我得到的errror:显示java.lang.NullPointerException:需要的println消息时使用该梅索德:
lst_info =新的HashMap<字符串,字符串>();SystemDatabaseHandler分贝=新SystemDatabaseHandler(getApplicationContext());lst_info = db.getLstInfo(SQL_ID);
SystemDatabaseHandler:
公开的HashMap<字符串,字符串> getLstInfo(INT ID){ HashMap的<字符串,字符串> lst_temp; lst_temp =新的HashMap<字符串,字符串>(); 字符串selectQuery =SELECT * FROM dkr_lst_lst WHERE lst_id =+ ID; SQLiteDatabase分贝= this.getWritableDatabase(); 光标光标= db.rawQuery(selectQuery,NULL); 如果(cursor.moveToFirst()){ 做{ Log.d(SQL_ID,cursor.getString(0)); lst_temp.put(SQL_ID,cursor.getString(0)); }而(cursor.moveToNext()); } cursor.close(); db.close(); 返回lst_temp;}
Log.d(SQL_ID,cursor.getString(0));返回我:
11月7日至12日:56:05.603:D / SQL_ID(13783):1。
日志猫:
11月7日至12日:56:05.613:D /数据库(13783):dbclose():PATH = /data/data/de.bodprod.dkr/databases/dkr,手柄= 0x4301a811月7日至12日:56:05.613:D / AndroidRuntime(13783):关闭VM11月7日至12日:56:05.613:W / dalvikvm(13783):主题ID = 1:螺纹未捕获的异常(组= 0x4001d5a0)退出11月7日至12日:56:05.623:E / AndroidRuntime(13783):致命异常:主要11月7日至12日:56:05.623:E / AndroidRuntime(13783):了java.lang.RuntimeException:无法启动活动ComponentInfo {de.bodprod.dkr / de.bodprod.dkr.BosLstDetailMap}:显示java.lang.NullPointerException:的println需要一个消息11月7日至12日:56:05.623:E / AndroidRuntime(13783):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1872)11月7日至12日:56:05.623:E / AndroidRuntime(13783):在android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1893)11月7日至12日:56:05.623:E / AndroidRuntime(13783):在android.app.ActivityThread.access $ 1500(ActivityThread.java:135)11月7日至12日:56:05.623:E / AndroidRuntime(13783):在android.app.ActivityThread $ H.handleMessage(ActivityThread.java:1054)11月7日至12日:56:05.623:E / AndroidRuntime(13783):在android.os.Handler.dispatchMessage(Handler.java:99)11月7日至12日:56:05.623:E / AndroidRuntime(13783):在android.os.Looper.loop(Looper.java:150)11月7日至12日:56:05.623:E / AndroidRuntime(13783):在android.app.ActivityThread.main(ActivityThread.java:4385)11月7日至12日:56:05.623:E / AndroidRuntime(13783):在java.lang.reflect.Method.invokeNative(本机方法)11月7日至12日:56:05.623:E / AndroidRuntime(13783):在java.lang.reflect.Method.invoke(Method.java:507)11月7日至12日:56:05.623:E / AndroidRuntime(13783):在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:849)11月7日至12日:56:05.623:E / AndroidRuntime(13783):在com.android.internal.os.ZygoteInit.main(ZygoteInit.java:607)11月7日至12日:56:05.623:E / AndroidRuntime(13783):在dalvik.system.NativeStart.main(本机方法)11月7日至12日:56:05.623:E / AndroidRuntime(13783):显示java.lang.NullPointerException:由引起的println需要一个消息11月7日至12日:56:05.623:E / AndroidRuntime(13783):在android.util.Log.println_native(本机方法)11月7日至12日:56:05.623:E / AndroidRuntime(13783):在android.util.Log.d(Log.java:137)11月7日至12日:56:05.623:E / AndroidRuntime(13783):在de.bodprod.dkr.BosLstDetailMap.onCreate(BosLstDetailMap.java:43)11月7日至12日:56:05.623:E / AndroidRuntime(13783):在android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1072)11月7日至12日:56:05.623:E / AndroidRuntime(13783):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1836)11月7日至12日:56:05.623:E / AndroidRuntime(13783):... 11个11月7日至12日:56:07.495:D /过程(13783):killProcess,PID = 13783
![Java 混淆工具 ProGuard 之初体验](https://p.xsw88.cn/allimgs/daicuo/20230907/5959.png)
解决方案
也许当你做
Log.d(SQL_ID,cursor.getString(0));
cursor.getString(0)返回null,然后崩溃。
试着做:
如果(cursor.getString(0)!= NULL){ Log.d(SQL_ID,cursor.getString(0));}
否则我们展示de.bodprod.dkr.BosLstDetailMap.onCreate(BosLstDetailMap.java:43)
I get the errror: java.lang.NullPointerException: println needs a message when use this methode:
lst_info = new HashMap<String, String>();
SystemDatabaseHandler db = new SystemDatabaseHandler(getApplicationContext());
lst_info = db.getLstInfo(sql_id);
SystemDatabaseHandler:
public HashMap<String , String> getLstInfo(int id){
HashMap<String , String> lst_temp;
lst_temp = new HashMap<String , String>();
String selectQuery = "SELECT * FROM dkr_lst_lst WHERE lst_id = " + id;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
if (cursor.moveToFirst()) {
do {
Log.d("sql_id", cursor.getString(0));
lst_temp.put("sql_id", cursor.getString(0));
}while (cursor.moveToNext());
}
cursor.close();
db.close();
return lst_temp;
}
Log.d("sql_id", cursor.getString(0)); returns me:
07-12 11:56:05.603: D/sql_id(13783): 1
The Log Cat:
07-12 11:56:05.613: D/Database(13783): dbclose(): path = /data/data/de.bodprod.dkr/databases/dkr, handle = 0x4301a8
07-12 11:56:05.613: D/AndroidRuntime(13783): Shutting down VM
07-12 11:56:05.613: W/dalvikvm(13783): threadid=1: thread exiting with uncaught exception (group=0x4001d5a0)
07-12 11:56:05.623: E/AndroidRuntime(13783): FATAL EXCEPTION: main
07-12 11:56:05.623: E/AndroidRuntime(13783): java.lang.RuntimeException: Unable to start activity ComponentInfo{de.bodprod.dkr/de.bodprod.dkr.BosLstDetailMap}: java.lang.NullPointerException: println needs a message
07-12 11:56:05.623: E/AndroidRuntime(13783): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1872)
07-12 11:56:05.623: E/AndroidRuntime(13783): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1893)
07-12 11:56:05.623: E/AndroidRuntime(13783): at android.app.ActivityThread.access$1500(ActivityThread.java:135)
07-12 11:56:05.623: E/AndroidRuntime(13783): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1054)
07-12 11:56:05.623: E/AndroidRuntime(13783): at android.os.Handler.dispatchMessage(Handler.java:99)
07-12 11:56:05.623: E/AndroidRuntime(13783): at android.os.Looper.loop(Looper.java:150)
07-12 11:56:05.623: E/AndroidRuntime(13783): at android.app.ActivityThread.main(ActivityThread.java:4385)
07-12 11:56:05.623: E/AndroidRuntime(13783): at java.lang.reflect.Method.invokeNative(Native Method)
07-12 11:56:05.623: E/AndroidRuntime(13783): at java.lang.reflect.Method.invoke(Method.java:507)
07-12 11:56:05.623: E/AndroidRuntime(13783): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:849)
07-12 11:56:05.623: E/AndroidRuntime(13783): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:607)
07-12 11:56:05.623: E/AndroidRuntime(13783): at dalvik.system.NativeStart.main(Native Method)
07-12 11:56:05.623: E/AndroidRuntime(13783): Caused by: java.lang.NullPointerException: println needs a message
07-12 11:56:05.623: E/AndroidRuntime(13783): at android.util.Log.println_native(Native Method)
07-12 11:56:05.623: E/AndroidRuntime(13783): at android.util.Log.d(Log.java:137)
07-12 11:56:05.623: E/AndroidRuntime(13783): at de.bodprod.dkr.BosLstDetailMap.onCreate(BosLstDetailMap.java:43)
07-12 11:56:05.623: E/AndroidRuntime(13783): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1072)
07-12 11:56:05.623: E/AndroidRuntime(13783): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1836)
07-12 11:56:05.623: E/AndroidRuntime(13783): ... 11 more
07-12 11:56:07.495: D/Process(13783): killProcess, pid=13783
解决方案
Maybe when you do
Log.d("sql_id", cursor.getString(0));
cursor.getString(0) return null, and then it crash.
Try to do :
if(cursor.getString(0) != null) {
Log.d("sql_id", cursor.getString(0));
}
Else show us de.bodprod.dkr.BosLstDetailMap.onCreate(BosLstDetailMap.java:43)
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