我在stackoverflow和其他网站上查看了许多与我类似的问题，但未能找到解决我问题的方法。我已请求正确的权限，但仍然出现此错误。起初我以为是因为我在使用AVD，但是即使在使用电话时，我仍然会收到此错误。
主要活动：
package com.example.vishal.textfacialprocessing;
import android.app.Activity;
import android.content.Context;
import android.content.res.Configuration;
import android.hardware.Camera;
import android.os.Bundle;
import android.util.Log;
import android.view.Display;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.FrameLayout;
import android.widget.Toast;
import com.qualcomm.snapdragon.sdk.face.FaceData;
import com.qualcomm.snapdragon.sdk.face.FacialProcessing;
public class MainActivity extends Activity implements Camera.PreviewCallback {
Camera mCamera = null;
CameraPreview preview;
private CameraPreview mPreview = null;
private int cameraside = 1;
private int Front_Camera_Index = 1;
private int Back_Camera_Index = 0;
private static boolean switchCamera;
private boolean _qcSDKEnabled;
FacialProcessing faceProc;
Display display;
private int displayAngle;
private int numFaces;
FaceData[] faceArray = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final Button switchCameraButton = (Button)
findViewById(R.id.switchCamera);
switchCameraButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (cameraside == 1) {
cameraside = 0;
} else {
cameraside = 1;
}
}
});
setCamera();
}
public void setCamera ()
{
mCamera = Camera.open(cameraside);
mPreview = new CameraPreview(MainActivity.this,mCamera);
FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview);
preview.addView(mPreview);
mCamera.setPreviewCallback(MainActivity.this);
_qcSDKEnabled = FacialProcessing.isFeatureSupported(FacialProcessing.FEATURE_LIST.FEATURE_FACIAL_PROCESSING);
}
}
CameraPreview：
package com.example.vishal.textfacialprocessing;
import android.content.Context;
import android.hardware.Camera;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.ViewGroup;
import com.qualcomm.snapdragon.sdk.face.FacialProcessing;
import java.io.IOException;
public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
private SurfaceHolder mHolder;
private Camera cameraObj;
public CameraPreview(Context context, Camera camera) {
super(context);
cameraObj = camera;
// Install a urfaceHolder.Callback so we get notified when the
// underlying surface is created and destroyed.
mHolder = getHolder();
mHolder.addCallback(this);
// deprecated setting, but required on Android versions prior to 3.0
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
public void surfaceCreated(SurfaceHolder holder) {
// SurfaceHolder jholder = holder;
// The Surface has been created, now tell the camera where to draw the preview.
try {
cameraObj.setPreviewDisplay(holder);
cameraObj.startPreview();
} catch (IOException e) {
}
}
public void surfaceDestroyed(SurfaceHolder holder) {
// empty. Take care of releasing the Camera preview in your activity.
}
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
// If your preview can change or rotate, take care of those events here.
// Make sure to stop the preview before resizing or reformatting it.
if (mHolder.getSurface() == null){
// preview surface does not exist
return;
}
// stop preview before making changes
try {
cameraObj.stopPreview();
} catch (Exception e){
// ignore: tried to stop a non-existent preview
}
// set preview size and make any resize, rotate or
// reformatting changes here
// start preview with new settings
try {
cameraObj.setPreviewDisplay(mHolder);
cameraObj.startPreview();
} catch (Exception e){
}
}
}
表现：
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme" >
<activity
android:name=".MainActivity" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
逻辑：
01-02 14:27:35.261 10635-10635/com.example.vishal.textfacialprocessing E/Typeface: SANS_LOC file not found.
01-02 14:27:35.321 10635-10635/com.example.vishal.textfacialprocessing E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.vishal.textfacialprocessing, PID: 10635
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.vishal.textfacialprocessing/com.example.vishal.textfacialprocessing.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.hardware.Camera.release()' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2411)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2474)
at android.app.ActivityThread.access$800(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1359)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:155)
at android.app.ActivityThread.main(ActivityThread.java:5696)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1029)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:824)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.hardware.Camera.release()' on a null object reference
at com.example.vishal.textfacialprocessing.MainActivity.getCameraInstance(MainActivity.java:156)
at com.example.vishal.textfacialprocessing.MainActivity.onResume(MainActivity.java:58)
at com.example.vishal.textfacialprocessing.MainActivity.onCreate(MainActivity.java:50)
at android.app.Activity.performCreate(Activity.java:5958)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1129)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2364)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2474)
at android.app.ActivityThread.access$800(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1359)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:155)
at android.app.ActivityThread.main(ActivityThread.java:5696)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1029)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:824)
最佳答案
您好Vishal您需要在清单文件中添加以下权限
<uses-permission android:name="android.permission.CAMERA" />
如果您使用的是Android M权限模型，则首先需要检查应用程序在运行时是否具有此权限，并且必须在运行时提示用户输入此权限。您在清单上定义的权限不会在安装时自动授予。
if (checkSelfPermission(Manifest.permission.CAMERA)
!= PackageManager.PERMISSION_GRANTED) {
requestPermissions(new String[]{Manifest.permission.CAMERA},
MY_REQUEST_CODE);
}
您需要为对话框结果提供一个回调：
@Override
public void onRequestPermissionResult(int requestCode, String[] permissions, int[] grantResults) {
if (requestCode == MY_REQUEST__CODE) {
if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
// Now user should be able to use camera
}
else {
// Your app will not have this permission. Turn off all functions
// that require this permission or it will force close like your
// original question
}
}
}
关于java - Java RuntimeException“无法连接到摄像头服务”，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/34569733/