Android 无法从一次创建MainActivity开始操作\u视频\u捕获

我是Android新手。我需要写一个简单的应用程序，将打开相机，应该显示视频从相机和一些无线参数（RSSI）。为了从照相机中获取流，我尝试使用MainActivity的ACTION\u VIDEO\u CAPTURE from onCreate（）方法。我在MAC上的Android Studio的模拟器上尝试这个，因为我没有Android mobile。但应用程序正在崩溃。下面是代码（我没有在下面的代码中键入所有导入）

MainActivity.java:

package com.example.myapplication;

public class MainActivity extends AppCompatActivity {

    private static final String TAG = "MainActivity";
    private static final int VIDEO_CAPTURE = 1;

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

        TextView wifiTextView = (TextView) findViewById(R.id.wifi_text);

        WifiManager wifiManager = (WifiManager) getApplicationContext().getSystemService(Context.WIFI_SERVICE);
        WifiInfo wifiInfo = wifiManager.getConnectionInfo();
        int rssi = wifiManager.getConnectionInfo().getRssi();
        wifiTextView.setTextColor(Color.WHITE);
        wifiTextView.setText(Integer.toString(rssi));

        Log.d(TAG, "Has Camera : " + hasCamera());

        Intent intent = new Intent(MediaStore.ACTION_VIDEO_CAPTURE);
        startActivityForResult(intent, VIDEO_CAPTURE);
    }

    private boolean hasCamera() {
        if(getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA_FRONT)) {
            return true;
        }
        else {
            return false;
        }
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data){
        super.onActivityResult(requestCode, resultCode, data);

        if(requestCode == VIDEO_CAPTURE) {
            if(resultCode == RESULT_OK) {
                Log.d(TAG, "Got data here from Camera");
            }
        }
    }
}

布局：

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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/videoView"
        android:layout_height="match_parent"
        android:layout_width="match_parent" />

    <TextView
        android:id="@+id/wifi_text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

---

有人能帮我解决这个问题吗。

看来您确实包含了许可，但忘记了请求许可。包括摄像头访问在内的危险权限要求在运行时允许用户访问

错误明确说明了原因：`java.lang.SecurityException:权限拒绝

首先检查您的应用程序是否具有所需的权限：

然后，如果您没有所需的权限：

---

另外，请不要忘记仔细阅读：。

如果没有崩溃日志，将很难调试，请包括日志。由于我正在emulator上运行，因此不确定如何获取该日志。应用程序正在关闭并返回主页。在Android studio的run或Logcat选项卡中，崩溃日志应标记为红色文本。谢谢。我已经附上了坠机日志。您的清单文件中是否包含了摄像头权限？谢谢Thundercook。这就是原因。但似乎即使我从清单中删除“”，它也开始工作了。

<uses-permission android:name="android.permission.CAMERA" />
    <uses-feature android:name="android.hardware.camera" android:required="false" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.RECORD_AUDIO" />

2020-05-28 13:48:03.782 6531-6531/? E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.myapplication, PID: 6531
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.myapplication/com.example.myapplication.MainActivity}: java.lang.SecurityException: Permission Denial: starting Intent { act=android.media.action.VIDEO_CAPTURE cmp=com.android.camera2/com.android.camera.VideoCamera } from ProcessRecord{ad7c2be 6531:com.example.myapplication/u0a149} (pid=6531, uid=10149) with revoked permission android.permission.CAMERA
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3341)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3485)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2045)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:223)
        at android.app.ActivityThread.main(ActivityThread.java:7478)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:549)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:941)
     Caused by: java.lang.SecurityException: Permission Denial: starting Intent { act=android.media.action.VIDEO_CAPTURE cmp=com.android.camera2/com.android.camera.VideoCamera } from ProcessRecord{ad7c2be 6531:com.example.myapplication/u0a149} (pid=6531, uid=10149) with revoked permission android.permission.CAMERA
        at android.os.Parcel.createExceptionOrNull(Parcel.java:2285)
        at android.os.Parcel.createException(Parcel.java:2269)
        at android.os.Parcel.readException(Parcel.java:2252)
        at android.os.Parcel.readException(Parcel.java:2194)
        at android.app.IActivityTaskManager$Stub$Proxy.startActivity(IActivityTaskManager.java:3722)
        at android.app.Instrumentation.execStartActivity(Instrumentation.java:1723)
        at android.app.Activity.startActivityForResult(Activity.java:5323)
        at androidx.fragment.app.FragmentActivity.startActivityForResult(FragmentActivity.java:676)
        at android.app.Activity.startActivityForResult(Activity.java:5281)
        at androidx.fragment.app.FragmentActivity.startActivityForResult(FragmentActivity.java:663)
        at com.example.myapplication.MainActivity.onCreate(MainActivity.java:45)
        at android.app.Activity.performCreate(Activity.java:7989)
        at android.app.Activity.performCreate(Activity.java:7978)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1309)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3316)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3485) 
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83) 
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) 
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2045) 
        at android.os.Handler.dispatchMessage(Handler.java:106) 
        at android.os.Looper.loop(Looper.java:223) 
        at android.app.ActivityThread.main(ActivityThread.java:7478) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:549) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:941) 
     Caused by: android.os.RemoteException: Remote stack trace:
        at com.android.server.wm.ActivityStackSupervisor.checkStartAnyActivityPermission(ActivityStackSupervisor.java:1034)
        at com.android.server.wm.ActivityStarter.executeRequest(ActivityStarter.java:969)
        at com.android.server.wm.ActivityStarter.execute(ActivityStarter.java:640)
        at com.android.server.wm.ActivityTaskManagerService.startActivityAsUser(ActivityTaskManagerService.java:1095)
        at com.android.server.wm.ActivityTaskManagerService.startActivityAsUser(ActivityTaskManagerService.java:1067)