將專輯藝術顯示到圖像視圖

Question

我想將專輯封面加載到圖像視圖中，但是我的代碼無法正常工作並出錯，如何解決我的錯誤？請幫助。

ImageView imageView= (ImageView) findViewById(R.id.imageView); 
    Uri sArtworkUri = Uri.parse("/sdcard/Sqlit/AndroidDownloadManager.mp3"); 
    if (sArtworkUri !=null){ 
     MediaMetadataRetriever mData=new MediaMetadataRetriever(); 
     mData.setDataSource(this,sArtworkUri); 


     byte art[]=mData.getEmbeddedPicture(); 
     Bitmap image= BitmapFactory.decodeByteArray(art,0,art.length); 
     imageView.setImageBitmap(image); 

    } 

錯誤

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.andriodtime.net/com.andriodtime.net.MainActivity}: java.lang.NullPointerException 
                   at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2184) 
                   at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233) 
                   at android.app.ActivityThread.access$800(ActivityThread.java:135) 
                   at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196) 
                   at android.os.Handler.dispatchMessage(Handler.java:102) 
                   at android.os.Looper.loop(Looper.java:136) 
                   at android.app.ActivityThread.main(ActivityThread.java:5001) 
                   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:785) 
                   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601) 
                   at dalvik.system.NativeStart.main(Native Method) 
                   Caused by: java.lang.NullPointerException 
                   at com.andriodtime.net.MainActivity.initView(MainActivity.java:91) 
                   at com.andriodtime.net.MainActivity.onCreate(MainActivity.java:35) 

Answer 1

您的應用程序可能沒有權限從SD卡讀取。

你可以在以下權限添加到您的清單 <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

https://developer.android.com/reference/android/Manifest.permission.html#READ_EXTERNAL_STORAGE

注意，那你可能要在運行時要求此權限。