本文介绍了空指针异常ContextWrapper的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我有一类称为FileGeneration扩展活动 在FileGeneration我有一个名为方法
I have a class called FileGeneration that extends Activity In FileGeneration I have a method called
protected OutputStream openAndWriteFile() { // Set the Context-mode int cxt = Context.MODE_PRIVATE; // Check if we are not going to clear the file and the file exists if (!clearFile && (new File(this.fileName)).exists()) { // Append to the file cxt = Context.MODE_APPEND; } // Try to open the file to write to try { // Open the File using the Context this.os = openFileOutput(this.fileName, cxt); } catch (FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } // Return the OutputStream return this.os; }和我得到的logcat这个输出
And I get this output in Logcat
06-08 15:31:43.733: ERROR/AndroidRuntime(2850): java.lang.NullPointerException 06-08 15:31:43.733: ERROR/AndroidRuntime(2850): at android.content.ContextWrapper.openFileOutput(ContextWrapper.java:158) 06-08 15:31:43.733: ERROR/AndroidRuntime(2850): at android.content.ContextWrapper.openFileOutput(ContextWrapper.java:158) 06-08 15:31:43.733: ERROR/AndroidRuntime(2850): at dataconnection.FileGeneration.openAndWriteFile(FileGeneration.java:278)
278线的类
Line 278 in the class is
this.os = openFileOutput(this.fileName, cxt);
但是,当我刚刚与paramters打印方法在logcat中,它说
But when I just print the method with the paramters out in Logcat it says
openFileOutput(Preferences.xml, 1);
该文件不存在,但openFileOutput表示,将创建它,如果它不存在
The file does not exist, but openFileOutput says it will create it, if it does not exist
什么是错的?
推荐答案我解决了这个问题,(新ContextWrapper(CTX))。openFileOutput(this.fileName,CXT)
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空指针异常ContextWrapper
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