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我有两个.java文件:Read.java
和Save.java
。当我尝试启动我的应用程序时,我得到一个NullPointerException
。 logcat的条目指两个java.lang.NullPointerException与光标
Cursor cu = cr.query(URI, null, null, null, null);
和
rc.Cont(destination.getAbsolutePath());
作为NullPointerException异常的原因。
但是,我已经尝试Read.java
分开,它的工作正常,因为我除了。我想,这是来自另一个班级的打来的麻烦。感谢帮助。
- Read.java
public class ReadCon(String destination) {
`...`
public void Cont(String destination) {
ContentResolver cr = getContentResolver();
Cursor cu = cr.query(URI, null, null, null, null);
...
}
}
- Save.java
public class SaveEnd extends Activity {
File destination;
Fonctions f = new Fonctions();
//creerDossier return type is File
destination = f.creerDossier(2, Save.pathsList[i]);
ReadCon rc = new ReadCon();
rc.Cont(destination.getAbsolutePath());
}
这是堆栈跟踪:
java.lang.NullPointerException
at android.content.ContextWrapper.getContentResolver(ContextWrapper.java:91)
at projet.sarelo.ReadContacts.SaveContacts(Read.java:134)
at projet.sarelo.SaveEnd.onStart(Save.java:75)
at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1132)
at android.app.Activity.performStart(Activity.java:4320)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1709)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1752)
at android.app.ActivityThread.access$1500(ActivityThread.java:123)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:993)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:126)
at android.app.ActivityThread.main(ActivityThread.java:3997)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:491)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:841)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:599)
at dalvik.system.NativeStart.main(Native Method)
发布堆栈跟踪 – Jack
正如Jack所说,发布堆栈跟踪。有一些代码丢失了,所以很难说,但是在调用getAbsolutePath()之前,你实例化了什么是“目的地”? – hooked82
@ hooked82目标是一个File实例。 –