我无法从.txt文件中读取数据。当我运行应用程序时,我收到一条错误消息并且应用程序崩溃,我怀疑这与读取文本文件或将其从InputStream转换为扫描程序有关。我有以下代码:
FileExaminer a = new FileExaminer();
FileExaminer b = new FileExaminer();
FileExaminer c = new FileExaminer();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
try{
readFile.runMethods();
} catch (Exception e) {
System.out.println("Error in Main");
}
}
public InputStream input;
public Scanner file;
AssetManager assetManager = getAssets();
public String a, b, c;
public void runMethods() {
openFile();
readFile();
closeFile();
}
public void openFile() {
try{
input = getAssets().open("numbers.txt");
file = new Scanner(input);
} catch(Exception e) {
System.out.println("error");
}
}
public void readFile() {
while (file.hasNext()) {
a = file.next();
b = file.next();
c = file.next();
System.out.printf("%s %s %s/n", a,b,c);
}
}
public void closeFile() {
file.close();
}
我的错误日志是这样的:
07-01 02:10:05.113: D/AndroidRuntime(2174): Shutting down VM
07-01 02:10:05.173: W/dalvikvm(2174): threadid=1: thread exiting with uncaught exception (group=0xb1cf6b20)
07-01 02:10:05.213: E/AndroidRuntime(2174): FATAL EXCEPTION: main
07-01 02:10:05.213: E/AndroidRuntime(2174): Process: com.aghgb.pokedex, PID: 2174
07-01 02:10:05.213: E/AndroidRuntime(2174): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.aghgb.pokedex/com.aghgb.pokedex.Main}: java.lang.NullPointerException
07-01 02:10:05.213: E/AndroidRuntime(2174): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2121)
07-01 02:10:05.213: E/AndroidRuntime(2174): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
07-01 02:10:05.213: E/AndroidRuntime(2174): at android.app.ActivityThread.access$800(ActivityThread.java:135)
07-01 02:10:05.213: E/AndroidRuntime(2174): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
07-01 02:10:05.213: E/AndroidRuntime(2174): at android.os.Handler.dispatchMessage(Handler.java:102)
07-01 02:10:05.213: E/AndroidRuntime(2174): at android.os.Looper.loop(Looper.java:136)
07-01 02:10:05.213: E/AndroidRuntime(2174): at android.app.ActivityThread.main(ActivityThread.java:5017)
07-01 02:10:05.213: E/AndroidRuntime(2174): at java.lang.reflect.Method.invokeNative(Native Method)
07-01 02:10:05.213: E/AndroidRuntime(2174): at java.lang.reflect.Method.invoke(Method.java:515)
07-01 02:10:05.213: E/AndroidRuntime(2174): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
07-01 02:10:05.213: E/AndroidRuntime(2174): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
07-01 02:10:05.213: E/AndroidRuntime(2174): at dalvik.system.NativeStart.main(Native Method)
07-01 02:10:05.213: E/AndroidRuntime(2174): Caused by: java.lang.NullPointerException
07-01 02:10:05.213: E/AndroidRuntime(2174): at android.content.ContextWrapper.getAssets(ContextWrapper.java:83)
07-01 02:10:05.213: E/AndroidRuntime(2174): at com.aghgb.pokedex.FileExaminer.<init>(FileExaminer.java:13)
07-01 02:10:05.213: E/AndroidRuntime(2174): at com.aghgb.pokedex.Main.<init>(Main.java:7)
07-01 02:10:05.213: E/AndroidRuntime(2174): at java.lang.Class.newInstanceImpl(Native Method)
07-01 02:10:05.213: E/AndroidRuntime(2174): at java.lang.Class.newInstance(Class.java:1208)
07-01 02:10:05.213: E/AndroidRuntime(2174): at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
07-01 02:10:05.213: E/AndroidRuntime(2174): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2112)
07-01 02:10:05.213: E/AndroidRuntime(2174): ... 11 more
提前致谢。
答案 0 :(得分:1)
经过几个小时的研究和反复试验后,我想出了这个:
try {
file = new Scanner(getResources().openRawResource(R.raw.pokemon_data));
System.out.println("File Scanned");
// do reading, usually loop until end of file reading
while (file.hasNext()) {
a = file.next();
b = file.next();
c = file.next();
System.out.printf("%s %s %s\n", a, b, c);
}
} catch (Exception e) {
System.out.println("Error opening/reading file");
} finally {
if (file != null) {
file.close();
}
}
此代码用于打印已存储在列中的文本文件,只要文件位于原始文件夹中,该代码就可以正常工作。在while循环中添加更多变量将增加显示的列数。
答案 1 :(得分:0)
要读取.text文件,您可以使用以下方法:
try {
txtFileRead("filename.txt");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
public List<String> txtFileRead(String filename) throws IOException {
List<String> readData = new ArrayList<String>();
AssetManager assets = context.getAssets();
BufferedReader reader = new BufferedReader(new InputStreamReader(assets.open(filename)));
while(true) {
String line = reader.readLine();
if(line == null) {
break;
}
lines.add(line);
}
return lines;
}
in txtFileRead()
我正在阅读文本文件并将读取的数据添加到列表中。