Android Hochladen Kamera Bild, Video Server mit Progress Bar

Question

Source code and project link description here

den Fehler Facing, weiß nicht, wie sie zu beheben - ich bin immer Fehler auf MainActivity.java und UploadActivity.java.I haben viele Arbeit um und nichts versucht

hilft

09-20 18:06:37.279 21398-21398/info.androidhive.camerafileupload E/AndroidRuntime: FATAL EXCEPTION: main 
                       Process: info.androidhive.camerafileupload, PID: 21398 
                       java.lang.RuntimeException: Unable to start activity ComponentInfo{info.androidhive.camerafileupload/info.androidhive.camerafileupload.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.app.ActionBar.setBackgroundDrawable(android.graphics.drawable.Drawable)' on a null object reference 
                        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416) 
                        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476) 
                        at android.app.ActivityThread.-wrap11(ActivityThread.java) 
                        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344) 
                        at android.os.Handler.dispatchMessage(Handler.java:102) 
                        at android.os.Looper.loop(Looper.java:148) 
                        at android.app.ActivityThread.main(ActivityThread.java:5417) 
                        at java.lang.reflect.Method.invoke(Native Method) 
                        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
                        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
                       Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.app.ActionBar.setBackgroundDrawable(android.graphics.drawable.Drawable)' on a null object reference 
                        at info.androidhive.camerafileupload.MainActivity.onCreate(MainActivity.java:46) 
                        at android.app.Activity.performCreate(Activity.java:6237) 
                        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107) 
                        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369) 
                        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)  
                        at android.app.ActivityThread.-wrap11(ActivityThread.java)  
                        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)  
                        at android.os.Handler.dispatchMessage(Handler.java:102)  
                        at android.os.Looper.loop(Looper.java:148)  
                        at android.app.ActivityThread.main(ActivityThread.java:5417)  
                        at java.lang.reflect.Method.invoke(Native Method)  
                        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)  
                        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)  

Answer 1

Ihre Fehler-Stack-Trace sagt Ihnen:

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.app.ActionBar.setBackgroundDrawable(android.graphics.drawable.Drawable)' on a null object reference 

Also das Problem ist, dass, wenn Sie tun:

getActionBar().setBackgroundDrawable(new ColorDrawable(Color.parseColor(getResources().getString(R.color.action_bar)))); 

Der Aufruf von getActionBar() gibt null zurück.

Es gibt eine Reihe von Gründen, warum getActionBar() null zurück könnte, aber die häufigste ist, dass Sie

getSupportActionBar() 

statt

getActionBar() 

Aufruf sollte also versuchen, alle Instanzen zu ersetzen von "getActionBar()" in Ihrem Code mit "getSupportActionBar()"