android emulator中的应用程序崩溃

我不熟悉android编程，并尝试构建一个测试应用程序

播放音乐

，但当我尝试在android emulator中运行该应用程序时，我一直遇到这个错误。任何帮助都将不胜感激

01/02 12:25:31: Launching app
$ adb push C:\GPA CALC\playmusic\app\build\outputs\apk\app-debug.apk /data/local/tmp/com.wordpress.mbedo.www.playmusic
$ adb shell pm install -r "/data/local/tmp/com.wordpress.mbedo.www.playmusic"
Success


$ adb shell am start -n "com.wordpress.mbedo.www.playmusic/com.wordpress.mbedo.www.playmusic.MainActivity" -a android.intent.action.MAIN -c android.intent.category.LAUNCHER
Client not ready yet..Waiting for process to come online
Connected to process 2293 on device emulator-5554
W/System: ClassLoader referenced unknown path: /data/app/com.wordpress.mbedo.www.playmusic-2/lib/x86
D/AndroidRuntime: Shutting down VM


                  --------- beginning of crash
E/AndroidRuntime: FATAL EXCEPTION: main
                  Process: com.wordpress.mbedo.www.playmusic, PID: 2293
                  java.lang.RuntimeException: Unable to start activity ComponentInfo{com.wordpress.mbedo.www.playmusic/com.wordpress.mbedo.www.playmusic.MainActivity}: java.lang.SecurityException: Permission Denial: reading com.android.providers.media.MediaProvider uri content://media/external/audio/media from pid=2293, uid=10053 requires android.permission.READ_EXTERNAL_STORAGE, or grantUriPermission()
                      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2646)
                      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707)
                      at android.app.ActivityThread.-wrap12(ActivityThread.java)
                      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460)
                      at android.os.Handler.dispatchMessage(Handler.java:102)
                      at android.os.Looper.loop(Looper.java:154)
                      at android.app.ActivityThread.main(ActivityThread.java:6077)
                      at java.lang.reflect.Method.invoke(Native Method)
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
                   Caused by: java.lang.SecurityException: Permission Denial: reading com.android.providers.media.MediaProvider uri content://media/external/audio/media from pid=2293, uid=10053 requires android.permission.READ_EXTERNAL_STORAGE, or grantUriPermission()
                      at android.os.Parcel.readException(Parcel.java:1683)
                      at android.database.DatabaseUtils.readExceptionFromParcel(DatabaseUtils.java:183)
                      at android.database.DatabaseUtils.readExceptionFromParcel(DatabaseUtils.java:135)
                      at android.content.ContentProviderProxy.query(ContentProviderNative.java:421)
                      at android.content.ContentResolver.query(ContentResolver.java:530)
                      at android.content.ContentResolver.query(ContentResolver.java:472)
                      at com.wordpress.mbedo.www.playmusic.MainActivity.onCreate(MainActivity.java:57)
                      at android.app.Activity.performCreate(Activity.java:6662)
                      at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118)
                      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2599)
                      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707) 
                      at android.app.ActivityThread.-wrap12(ActivityThread.java) 
                      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460) 
                      at android.os.Handler.dispatchMessage(Handler.java:102) 
                      at android.os.Looper.loop(Looper.java:154) 
                      at android.app.ActivityThread.main(ActivityThread.java:6077) 
                      at java.lang.reflect.Method.invoke(Native Method) 
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865) 
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755) 

应用程序已终止。

---

对于6.0以上的android版本，您需要在运行时调用权限，正如您的logcat所显示的，您的应用程序正在尝试访问/读取您的内部存储，但android系统拒绝访问/读取。Android版本>=M中需要该权限。

java.lang.SecurityException:权限拒绝：读取com.android.providers.media.MediaProvider uricontent://media/external/audio/media 从pid=2293开始，uid=10053需要android.permission.READ\u EXTERNAL\u STORAGE

在android应用程序中，您必须请求用户授予访问其存储的权限

            // if android version >= M
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            if (ActivityCompat.checkSelfPermission
                    (this, Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
                requestPermissions(new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, 0);

            }
        }

在获得许可后，您必须处理它：

        @Override
        public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        {
           switch (requestCode) {
            case 0:
                if (grantResults[0] == PackageManager.PERMISSION_GRANTED){
                 // permission granted
                }
                else {
                    //not granted
                }
                break;
           } 
        }  
    }

---

您尚未在清单中添加读取外部存储权限，请确保您已添加读取外部存储的运行时权限，以便能够从android 6.0运行