#Android studioに関する質問です
文字列の検索をするところでエラーが起こります
エラーの内容は以下の通りです
01-29 21:48:09.161 28292-28292/jp.webcrow.momijinc.cinemasrank E/AndroidRuntime: FATAL EXCEPTION: main
Process: jp.webcrow.momijinc.cinemasrank, PID: 28292
java.lang.RuntimeException: Unable to start activity ComponentInfo{jp.webcrow.momijinc.cinemasrank/jp.webcrow.momijinc.cinemasrank.linedelete}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2292)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2341)
at android.app.ActivityThread.access$1000(ActivityThread.java:157)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1290)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5232)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:805)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:621)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at java.lang.String.indexOf(String.java:989)
at jp.webcrow.momijinc.cinemasrank.linedelete.onCreate(linedelete.java:37)
at android.app.Activity.performCreate(Activity.java:5239)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2256)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2341)
at android.app.ActivityThread.access$1000(ActivityThread.java:157)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1290)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5232)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:805)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:621)
at dalvik.system.NativeStart.main(Native Method)
コードは以下の通りです
java
1package jp.webcrow.momijinc.cinemasrank; 2 3import android.content.Context; 4import android.content.Intent; 5import android.content.pm.PackageManager; 6import android.os.Bundle; 7import android.support.v7.app.AppCompatActivity; 8 9import java.io.BufferedReader; 10import java.io.BufferedWriter; 11import java.io.FileInputStream; 12import java.io.FileOutputStream; 13import java.io.IOException; 14import java.io.InputStreamReader; 15import java.io.OutputStreamWriter; 16 17public class linedelete extends AppCompatActivity { 18 19 @Override 20 protected void onCreate(Bundle savedInstanceState) { 21 super.onCreate(savedInstanceState); 22 setContentView(R.layout.activity_linedelete); 23 String copy = ""; 24 // Intent を取得する 25 Intent intent = getIntent(); 26 27 // キーを元にデータを取得する(データがない場合、第2引数の 0 が返る) 28 String search = intent.getStringExtra("s"); 29 try{ 30 Context ctxt = 31 createPackageContext("jp.webcrow.momijinc.cinemasrank", 0); 32 FileInputStream fis = ctxt.openFileInput("data.txt"); 33 BufferedReader reader = 34 new BufferedReader(new InputStreamReader(fis)); 35 String line; 36 while ((line = reader.readLine()) != null) { 37 if (line.indexOf(search) == -1) copy += line + "\n"; 38 } 39 fis.close(); 40 FileOutputStream fos = openFileOutput("data.txt", Context.MODE_PRIVATE); 41 BufferedWriter bufo = new BufferedWriter(new OutputStreamWriter(fos)); 42 bufo.write(copy); 43 bufo.close(); 44 } catch (IOException | PackageManager.NameNotFoundException e) { 45 e.printStackTrace(); 46 } 47 } 48 49} 50
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2016/02/01 18:05