title: unable to open trace file
body: <p>I want to test the performance of my app . I have started it with simple application and try to put traceview but its suddenly fail on my android phone with force to close. Please guide me how can i set my code propley for simple android app to get hands dirt with Trace view</p>
  
  <p>Here is the code 
  package test.check;</p>
  
  <pre><code>import android.app.Activity;
  import android.os.Bundle;
  import android.os.Debug;
  
  public class tracev extends Activity {
      /** Called when the activity is first created. */
      @Override
      public void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          Debug.startMethodTracing("traceview");
          setContentView(R.layout.main);
      }
      @Override
      protected void onStop() {
          Debug.stopMethodTracing();
          super.onStop();
      }
  }
  </code></pre>
  
  <p>Here is the manifest file </p>
  
  <pre><code> &lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;manifest xmlns:android="http://schemas.android.com/apk/res/android"
        package="test.check"
        android:versionCode="1"
        android:versionName="1.0"&gt;
      &lt;uses-sdk android:minSdkVersion="4" /&gt;
  
      &lt;application android:icon="@drawable/icon" android:label="@string/app_name"&gt;
          &lt;activity android:name=".tracev"
                    android:label="@string/app_name"&gt;
              &lt;intent-filter&gt;
                  &lt;action android:name="android.intent.action.MAIN" /&gt;
                  &lt;category android:name="android.intent.category.LAUNCHER" /&gt;
              &lt;/intent-filter&gt;
          &lt;/activity&gt;
  
      &lt;/application&gt;
      &lt;uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /&gt;
  &lt;/manifest&gt;
  </code></pre>
  
  <p>I have also added </p>
  
  <pre><code>&lt;uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /&gt;
  </code></pre>
  
  <p>but its not working . I think its becasue of this line in the logcat but i am not sure how  to deal with it </p>
  
  <pre><code>05-20 23:39:43.913: ERROR/dalvikvm(11673): Unable to open trace file '/sdcard/traceview.trace': Permission denied
  </code></pre>
  
  <p>Logcat</p>
  
  <pre><code>05-20 23:39:43.903: DEBUG/dalvikvm(11673): +++ active profiler count now 1
  05-20 23:39:43.913: INFO/dalvikvm(11673): TRACE STARTED: '/sdcard/traceview.trace' 8192KB
  05-20 23:39:43.913: ERROR/dalvikvm(11673): Unable to open trace file '/sdcard/traceview.trace': Permission denied
  05-20 23:39:43.913: DEBUG/dalvikvm(11673): +++ active profiler count now 0
  05-20 23:39:43.913: DEBUG/AndroidRuntime(11673): Shutting down VM
  05-20 23:39:43.913: WARN/dalvikvm(11673): threadid=3: thread exiting with uncaught exception (group=0x4001e390)
  05-20 23:39:43.913: ERROR/AndroidRuntime(11673): Uncaught handler: thread main exiting due to uncaught exception
  05-20 23:39:43.983: ERROR/AndroidRuntime(11673): java.lang.RuntimeException: Unable to start activity ComponentInfo{test.check/test.check.tracev}: java.lang.RuntimeException: file open failed
  05-20 23:39:43.983: ERROR/AndroidRuntime(11673):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2596)
  05-20 23:39:43.983: ERROR/AndroidRuntime(11673):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2621)
  05-20 23:39:43.983: ERROR/AndroidRuntime(11673):     at android.app.ActivityThread.access$2200(ActivityThread.java:126)
  05-20 23:39:43.983: ERROR/AndroidRuntime(11673):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1932)
  05-20 23:39:43.983: ERROR/AndroidRuntime(11673):     at android.os.Handler.dispatchMessage(Handler.java:99)
  05-20 23:39:43.983: ERROR/AndroidRuntime(11673):     at android.os.Looper.loop(Looper.java:123)
  05-20 23:39:43.983: ERROR/AndroidRuntime(11673):     at android.app.ActivityThread.main(ActivityThread.java:4595)
  05-20 23:39:43.983: ERROR/AndroidRuntime(11673):     at java.lang.reflect.Method.invokeNative(Native Method)
  05-20 23:39:43.983: ERROR/AndroidRuntime(11673):     at java.lang.reflect.Method.invoke(Method.java:521)
  05-20 23:39:43.983: ERROR/AndroidRuntime(11673):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
  05-20 23:39:43.983: ERROR/AndroidRuntime(11673):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
  05-20 23:39:43.983: ERROR/AndroidRuntime(11673):     at dalvik.system.NativeStart.main(Native Method)
  05-20 23:39:43.983: ERROR/AndroidRuntime(11673): Caused by: java.lang.RuntimeException: file open failed
  05-20 23:39:43.983: ERROR/AndroidRuntime(11673):     at dalvik.system.VMDebug.startMethodTracing(Native Method)
  05-20 23:39:43.983: ERROR/AndroidRuntime(11673):     at dalvik.system.VMDebug.startMethodTracing(VMDebug.java:156)
  05-20 23:39:43.983: ERROR/AndroidRuntime(11673):     at android.os.Debug.startMethodTracing(Debug.java:443)
  05-20 23:39:43.983: ERROR/AndroidRuntime(11673):     at android.os.Debug.startMethodTracing(Debug.java:391)
  05-20 23:39:43.983: ERROR/AndroidRuntime(11673):     at test.check.tracev.onCreate(tracev.java:12)
  05-20 23:39:43.983: ERROR/AndroidRuntime(11673):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
  05-20 23:39:43.983: ERROR/AndroidRuntime(11673):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2544)
  05-20 23:39:43.983: ERROR/AndroidRuntime(11673):     ... 11 more
  05-20 23:39:44.013: INFO/Process(94): Sending signal. PID: 11673 SIG: 3
  05-20 23:39:44.013: INFO/dalvikvm(11673): threadid=7: reacting to signal 3
  05-20 23:39:44.023: INFO/dalvikvm(11673): Wrote stack trace to '/data/anr/traces.txt'
  05-20 23:39:51.213: DEBUG/KeyguardViewMediator(94): pokeWakelock(15000)
  05-20 23:39:51.213: INFO/HtcLockScreen(94): Press Menu key to unlock screen
  </code></pre>
  
  <p>I am wondering about one point there is nothing in the sdcard and in front of it there is no device selected . May be it can be the cause of error , here is the picture 
  <img src="https://i.stack.imgur.com/fzbYw.png" alt="enter image description here"></p>