java - Audio start recording has stopped - not working -

even tried possible solutions find, couldnt solve problem. want make guitar tuner. when execute,getting message; "my application has stopped". think problem here "audio.startrecording();" when remove lane dont stopped message. tried api 15,25 versions app , virtual device phone. can u me guys problem?

here code:

package com.xxx.myapplication; import android.support.v7.app.appcompatactivity; import android.os.bundle; import android.app.activity; import android.media.audioformat; import android.media.audiorecord; import android.media.mediarecorder;  public class mainactivity extends appcompatactivity {     private static final int samplerate = 44100;     private audiorecord audio;     private int buffersize;     private double lastlevel = 0;      @override     protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_main);      }      protected void onresume() {         super.onresume();         buffersize = audiorecord                 .getminbuffersize(samplerate, audioformat.channel_in_mono,                     audioformat.encoding_pcm_16bit);         audio = new audiorecord(mediarecorder.audiosource.mic, samplerate,                 audioformat.channel_in_mono,                 audioformat.encoding_pcm_16bit, buffersize);          audio.startrecording();         short[] buffer = new short[buffersize];         int bufferreadresult = audio.read(buffer, 0, buffersize);     }  } 

manifest:

<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.xxx.myapplication" >  <application     android:allowbackup="true"     android:icon="@mipmap/ic_launcher"     android:label="@string/app_name"         android:roundicon="@mipmap/ic_launcher_round"         android:supportsrtl="true"         android:theme="@style/apptheme" >         <activity android:name=".mainactivity" >             <intent-filter>                 <action android:name="android.intent.action.main" />                  <category android:name="android.intent.category.launcher" />             </intent-filter>         </activity>     </application>     <uses-permission android:name="android.permission.record_audio"/> </manifest>