关于Android的错误：Permission Denial: 。。。.READ_EXTERNAL_STORAGE, or grantUriPermission(

Question

这是错误代码 ，在虚拟机运行时崩溃，

    E/AndroidRuntime: FATAL EXCEPTION: main
              Process: com.add.mp3list, PID: 7193
              java.lang.RuntimeException: Unable to start activity ComponentInfo{com.add.mp3list/com.add.mp3list.MainActivity}: java.lang.SecurityException: Permission Denial: reading com.android.providers.media.MediaProvider uri content://media/external/audio/media from pid=7193, uid=10090 requires android.permission.READ_EXTERNAL_STORAGE, or grantUriPermission()
                  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2817)
                  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2892)
                  at android.app.ActivityThread.-wrap11(Unknown Source:0)
                  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1593)
                  at android.os.Handler.dispatchMessage(Handler.java:105)
                  at android.os.Looper.loop(Looper.java:164)
                  at android.app.ActivityThread.main(ActivityThread.java:6541)
                  at java.lang.reflect.Method.invoke(Native Method)
                  at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)
               Caused by: java.lang.SecurityException: Permission Denial: reading com.android.providers.media.MediaProvider uri content://media/external/audio/media from pid=7193, uid=10090 requires android.permission.READ_EXTERNAL_STORAGE, or grantUriPermission()
                  at android.os.Parcel.readException(Parcel.java:1942)
                  at android.database.DatabaseUtils.readExceptionFromParcel(DatabaseUtils.java:183)
                  at android.database.DatabaseUtils.readExceptionFromParcel(DatabaseUtils.java:135)
                  at android.content.ContentProviderProxy.query(ContentProviderNative.java:418)
                  at android.content.ContentResolver.query(ContentResolver.java:754)
                  at android.content.ContentResolver.query(ContentResolver.java:704)
                  at android.content.ContentResolver.query(ContentResolver.java:662)
                  at com.add.mp3list.MusicList.getMusicData(MusicList.java:26)
                  at com.add.mp3list.MainActivity.onCreate(MainActivity.java:21)
                  at android.app.Activity.performCreate(Activity.java:6975)
                  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1213)
                  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2770)
                  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2892) 
                  at android.app.ActivityThread.-wrap11(Unknown Source:0) 
                  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1593) 
                  at android.os.Handler.dispatchMessage(Handler.java:105) 
                  at android.os.Looper.loop(Looper.java:164) 
                  at android.app.ActivityThread.main(ActivityThread.java:6541) 
                  at java.lang.reflect.Method.invoke(Native Method) 
                  at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240) 
                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767) 

Application terminated.

Answer 1

1.首先检查你在AndroidManifest.xml中，是否已经配置了android.permission.READ_EXTERNAL_STORAGE这个权限， 没有的话加上下面这个：

 <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

2.然后查看你的SDK是不是大于23，如果大于23还需要动态申请权限：

 if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
     requestPermissions(needPermissions, PERMISSON_REQUESTCODE);
 }

needPermissions是你要申请的权限，PERMISSON_REQUESTCODE 是请求码自己定义用于回调的；具体·的你可以查下Android6.0动态权限了解。

3.确保权限获取后再次执行你后面的操作。