파일에서 Java 응용 프로그램 읽기 이름

Question

.txt 파일에서 이름과 성을 Java 응용 프로그램으로 읽는 중 멈추었습니다. 먼저 AssetManager를 사용하여 첫 번째 방법을 시도했지만 입력 할 때 응용 프로그램이 중단됩니다.

두 번째 방법은 inputstream의 함께하지만 난 3 오류를 얻을 :

Description Resource Path Location Type 
ByteArrayOutputStream cannot be resolved to a type MainActivity.java /MyInfo/src/com/example/myinfo line 64 Java Problem 
ByteArrayOutputStream cannot be resolved to a type MainActivity.java /MyInfo/src/com/example/myinfo line 64 Java Problem 
dummytext cannot be resolved or is not a field MainActivity.java /MyInfo/src/com/example/myinfo line 55 Java Problem 

MainActivity.java

package com.example.myinfo; 

import java.io.IOException; 
import java.io.InputStream; 

import android.os.Bundle; 
import android.content.res.AssetManager; 
import android.support.v4.app.Fragment; 
import android.support.v7.app.ActionBarActivity; 
import android.view.LayoutInflater; 
import android.view.Menu; 
import android.view.MenuItem; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.TextView; 

public class MainActivity extends ActionBarActivity { 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 
    /* 
     TextView name = (TextView) findViewById(R.id.name); 
     AssetManager assetManager = getAssets(); 



     InputStream input; 
     try { 

      input = assetManager.open("info.txt"); 

      int size = input.available(); 
      byte[] buffer = new byte[size]; 
      input.read(buffer); 
      input.close(); 

      // byte buffer into a string 
      String text = new String(buffer); 

      nume.setText(text); 
     } catch (IOException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } 

     */ 
     if (savedInstanceState == null) { 
      getSupportFragmentManager().beginTransaction() 
        .add(R.id.container, new PlaceholderFragment()).commit(); 
     } 


     TextView dummytext = (TextView) findViewById(R.id.dummytext); 
     dummytext.setText(readText()); 



    } 

    private String readText() { 
     InputStream inputStream = getResources().openRawResource(R.raw.dummytext); 
     ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream(); 

     int i; 
     try { 
      i = inputStream.read(); 
      while(i!=-1){ 
       byteArrayOutputStream.write(i); 
       i = inputStream.read(); 
      } 
      inputStream.close(); 
     }catch (IOException e){ 
      e.printStackTrace(); 
     } 
     return byteArrayOutputStream.toString(); 

     } 

    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 

     // Inflate the menu; this adds items to the action bar if it is present. 
     getMenuInflater().inflate(R.menu.main, menu); 
     return true; 
    } 

    @Override 
    public boolean onOptionsItemSelected(MenuItem item) { 
     // Handle action bar item clicks here. The action bar will 
     // automatically handle clicks on the Home/Up button, so long 
     // as you specify a parent activity in AndroidManifest.xml. 
     int id = item.getItemId(); 
     if (id == R.id.action_settings) { 
      return true; 
     } 
     return super.onOptionsItemSelected(item); 
    } 

    /** 
    * A placeholder fragment containing a simple view. 
    */ 
    public static class PlaceholderFragment extends Fragment { 



     public PlaceholderFragment() { 
     } 

     @Override 
     public View onCreateView(LayoutInflater inflater, ViewGroup container, 
       Bundle savedInstanceState) { 
      View rootView = inflater.inflate(R.layout.fragment_main, container, 
        false); 

      return rootView; 
     } 
    } 


} 

을 내 XML은 이것이다 :

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:paddingBottom="@dimen/activity_vertical_margin" 
    android:paddingLeft="@dimen/activity_horizontal_margin" 
    android:paddingRight="@dimen/activity_horizontal_margin" 
    android:paddingTop="@dimen/activity_vertical_margin" 
    tools:context="com.example.myinfo.MainActivity$PlaceholderFragment" > 

    <Button 
     android:id="@+id/button1" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignParentBottom="true" 
     android:layout_centerHorizontal="true" 
     android:layout_marginBottom="87dp" 
     android:text="Adauga Fisier" /> 

    <TextView 
     android:id="@+id/dummytext" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignLeft="@+id/nume" 
     android:layout_below="@+id/nume" 
     android:layout_marginTop="29dp" 
     android:text="Prenume" 
     android:textAppearance="?android:attr/textAppearanceLarge" /> 

    <TextView 
     android:id="@+id/name" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignParentTop="true" 
     android:layout_alignRight="@+id/button1" 
     android:layout_marginRight="14dp" 
     android:layout_marginTop="65dp" 
     android:textAppearance="?android:attr/textAppearanceLarge" /> 

</RelativeLayout> 

그렇게하지 내가 뭘 잘못했는지 이해해. 코멘트에있는 코드를 실행하면 Logcat NullPointerException에 들어간 것을 알 수 있습니다.

로그 캣 :

04-07 10:06:11.298: I/dalvikvm(275): Could not find method android.content.pm.PackageManager.getActivityLogo, referenced from method android.support.v7.internal.widget.ActionBarView.<init> 
04-07 10:06:11.298: W/dalvikvm(275): VFY: unable to resolve virtual method 318: Landroid/content/pm/PackageManager;.getActivityLogo (Landroid/content/ComponentName;)Landroid/graphics/drawable/Drawable; 
04-07 10:06:11.298: D/dalvikvm(275): VFY: replacing opcode 0x6e at 0x008b 
04-07 10:06:11.308: I/dalvikvm(275): Could not find method android.content.pm.ApplicationInfo.loadLogo, referenced from method android.support.v7.internal.widget.ActionBarView.<init> 
04-07 10:06:11.308: W/dalvikvm(275): VFY: unable to resolve virtual method 314: Landroid/content/pm/ApplicationInfo;.loadLogo (Landroid/content/pm/PackageManager;)Landroid/graphics/drawable/Drawable; 
04-07 10:06:11.308: D/dalvikvm(275): VFY: replacing opcode 0x6e at 0x0099 
04-07 10:06:11.318: D/dalvikvm(275): VFY: dead code 0x008e-0092 in Landroid/support/v7/internal/widget/ActionBarView;.<init> (Landroid/content/Context;Landroid/util/AttributeSet;)V 
04-07 10:06:11.318: D/dalvikvm(275): VFY: dead code 0x009c-00a0 in Landroid/support/v7/internal/widget/ActionBarView;.<init> (Landroid/content/Context;Landroid/util/AttributeSet;)V 
04-07 10:06:11.488: D/AndroidRuntime(275): Shutting down VM 
04-07 10:06:11.488: W/dalvikvm(275): threadid=1: thread exiting with uncaught exception (group=0x4001d800) 
04-07 10:06:11.498: E/AndroidRuntime(275): FATAL EXCEPTION: main 
04-07 10:06:11.498: E/AndroidRuntime(275): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.myinfo/com.example.myinfo.MainActivity}: java.lang.NullPointerException 
04-07 10:06:11.498: E/AndroidRuntime(275): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663) 
04-07 10:06:11.498: E/AndroidRuntime(275): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679) 
04-07 10:06:11.498: E/AndroidRuntime(275): at android.app.ActivityThread.access$2300(ActivityThread.java:125) 
04-07 10:06:11.498: E/AndroidRuntime(275): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033) 
04-07 10:06:11.498: E/AndroidRuntime(275): at android.os.Handler.dispatchMessage(Handler.java:99) 
04-07 10:06:11.498: E/AndroidRuntime(275): at android.os.Looper.loop(Looper.java:123) 
04-07 10:06:11.498: E/AndroidRuntime(275): at android.app.ActivityThread.main(ActivityThread.java:4627) 
04-07 10:06:11.498: E/AndroidRuntime(275): at java.lang.reflect.Method.invokeNative(Native Method) 
04-07 10:06:11.498: E/AndroidRuntime(275): at java.lang.reflect.Method.invoke(Method.java:521) 
04-07 10:06:11.498: E/AndroidRuntime(275): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 
04-07 10:06:11.498: E/AndroidRuntime(275): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 
04-07 10:06:11.498: E/AndroidRuntime(275): at dalvik.system.NativeStart.main(Native Method) 
04-07 10:06:11.498: E/AndroidRuntime(275): Caused by: java.lang.NullPointerException 
04-07 10:06:11.498: E/AndroidRuntime(275): at com.example.myinfo.MainActivity.onCreate(MainActivity.java:42) 
04-07 10:06:11.498: E/AndroidRuntime(275): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 
04-07 10:06:11.498: E/AndroidRuntime(275): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627) 
04-07 10:06:11.498: E/AndroidRuntime(275): ... 11 more 
04-07 10:06:18.688: I/Process(275): Sending signal. PID: 275 SIG: 9 

Answer 1

사용이 코드이 코드는 자산 관리자에서 파일에 대한 InputStream를 열고 파일 내용의 크기를 얻을이 크기 바이트 버퍼를 할당하고 파일을 읽을

`InputStream input; 
AssetManager assetManager = getAssets(); 
    try { 
    input = assetManager.open("helloworld.txt"); 

    int size = input.available(); 
    byte[] buffer = new byte[size]; 
    input.read(buffer); 
    input.close(); 

    // byte buffer into a string 
    String text = new String(buffer); 

    dummytext.setText(text); 
    } catch (IOException e) { 
     e.printStackTrace(); 
    } 
` 

이 버퍼 다음에 버퍼에서 새 문자열을 만들고이 문자열을 텍스트 뷰로 설정하십시오.