Java 为视频视图提供视频路径时出现空指针异常错误

当给我的视频视图提供视频路径时，我遇到了一个

NullPointerException

错误，导致我的应用程序在开始时崩溃。 我已经使用了

setVideoURI（）

和

setVideoPath（）

方法，但我仍然面临这个问题！ 这是我的密码：

MainActivity.java:

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.VideoView;


public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        VideoView videoView = (VideoView) findViewById(R.id.video);

        videoView.setVideoPath("android.resource://" + getPackageName() + "/" + R.raw.video);
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
}

    <?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <VideoView
        android:id="@+id/video"
        android:layout_width="566dp"
        android:layout_height="230dp"
        tools:layout_editor_absoluteX="0dp"
        tools:layout_editor_absoluteY="0dp" />
</android.support.constraint.ConstraintLayout>

    06-09 01:31:02.898 15912-15912/com.example.avail.video E/dalvikvm: Could not find class 'android.graphics.drawable.RippleDrawable', referenced from method android.support.v7.widget.AppCompatImageHelper.hasOverlappingRendering
06-09 01:31:02.948 15912-15912/com.example.avail.video E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.avail.video, PID: 15912
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.avail.video/com.example.avail.video.MainActivity}: java.lang.NullPointerException
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2198)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2257)
        at android.app.ActivityThread.access$800(ActivityThread.java:139)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1210)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:136)
        at android.app.ActivityThread.main(ActivityThread.java:5097)
        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.example.avail.video.MainActivity.onCreate(MainActivity.java:14)
        at android.app.Activity.performCreate(Activity.java:5248)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1110)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2162)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2257) 
        at android.app.ActivityThread.access$800(ActivityThread.java:139) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1210) 
        at android.os.Handler.dispatchMessage(Handler.java:102) 
        at android.os.Looper.loop(Looper.java:136) 
        at android.app.ActivityThread.main(ActivityThread.java:5097) 
        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) 

activity\u main.xml:

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.VideoView;


public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        VideoView videoView = (VideoView) findViewById(R.id.video);

        videoView.setVideoPath("android.resource://" + getPackageName() + "/" + R.raw.video);
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
}

    <?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <VideoView
        android:id="@+id/video"
        android:layout_width="566dp"
        android:layout_height="230dp"
        tools:layout_editor_absoluteX="0dp"
        tools:layout_editor_absoluteY="0dp" />
</android.support.constraint.ConstraintLayout>

    06-09 01:31:02.898 15912-15912/com.example.avail.video E/dalvikvm: Could not find class 'android.graphics.drawable.RippleDrawable', referenced from method android.support.v7.widget.AppCompatImageHelper.hasOverlappingRendering
06-09 01:31:02.948 15912-15912/com.example.avail.video E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.avail.video, PID: 15912
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.avail.video/com.example.avail.video.MainActivity}: java.lang.NullPointerException
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2198)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2257)
        at android.app.ActivityThread.access$800(ActivityThread.java:139)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1210)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:136)
        at android.app.ActivityThread.main(ActivityThread.java:5097)
        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.example.avail.video.MainActivity.onCreate(MainActivity.java:14)
        at android.app.Activity.performCreate(Activity.java:5248)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1110)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2162)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2257) 
        at android.app.ActivityThread.access$800(ActivityThread.java:139) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1210) 
        at android.os.Handler.dispatchMessage(Handler.java:102) 
        at android.os.Looper.loop(Looper.java:136) 
        at android.app.ActivityThread.main(ActivityThread.java:5097) 
        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) 

---

任何帮助都将非常感激

调用方法的顺序不正确。应该是这样的：

protected void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
   setContentView(R.layout.activity_main);

   VideoView videoView = (VideoView) findViewById(R.id.video);
   videoView.setVideoPath("android.resource://" + getPackageName() + "/" + R.raw.video);
}

可能重复的