Как я могу вернуться к видоискателю камеры после съемки?

Question

Я делаю пример камеры на Android, в настоящее время он просто берет снимок и сохраняет его на внутренней памяти устройства. После снимка экран остается замороженным на последнем снимке, и мне нужно выйти из приложения и снова открыть его, чтобы сделать еще одно изображение. Вот мой код:

MainActivity.java:

package com.example.camera; 

import android.app.Activity; 
import android.hardware.Camera; 
import android.hardware.Camera.PictureCallback; 
import android.os.Bundle; 
import android.os.Environment; 
import android.util.Log; 
import android.view.Menu; 
import android.view.Surface; 
import android.view.View; 
import android.widget.FrameLayout; 
import android.widget.Toast; 

import java.io.File; 
import java.io.FileNotFoundException; 
import java.io.FileOutputStream; 
import java.io.IOException; 
import java.text.SimpleDateFormat; 
import java.util.Date; 

public class MainActivity extends Activity 
{ 
    private Camera mCamera; 
    private ShowCamera showCamera; 
    public Camera isCameraAvailable() 
    { 
     Camera camera=null; 
     Log.d("isCameraAvailable","Camera object set to null."); 
     try 
     { 
      camera = Camera.open(); 
      Log.d("isCameraAvailable","Camera opened."); 
     } 
     catch (Exception e) 
     { 
      Log.d("isCameraAvailable",e.toString()); 
     } 
     return camera; 
    } 
    private static File getOutputMediaFile() 
    { 
     File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES),"com.example.camera"); 
     if (!mediaStorageDir.exists()) 
     { 
      if (!mediaStorageDir.mkdirs()) 
      { 
       Log.d("getOutputMediaFile","Failed to create directory."); 
       return null; 
      } 
     } 
     String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date()); 
     File mediaFile; 
     mediaFile = new File(mediaStorageDir.getPath() + File.separator+ "IMG_" + timeStamp + ".jpg"); 
     Log.d("getOutputMediaFile","Filename created."); 
     return mediaFile; 
    } 
    private PictureCallback capturedIt = new PictureCallback() 
    { 
     @Override 
     public void onPictureTaken(byte[] data, Camera camera) 
     { 
      File pictureFile = getOutputMediaFile(); 
      if (pictureFile == null) 
      { 
       Log.d("onPictureTaken","pictureFile=null"); 
       return; 
      } 
      try 
      { 
       FileOutputStream fos = new FileOutputStream(pictureFile); 
       fos.write(data); 
       Log.d("onPictureTaken","File written."); 
       fos.close(); 
       Log.d("onPictureTaken","File closed."); 
       Toast.makeText(MainActivity.this,pictureFile.toString()+" saved!", Toast.LENGTH_LONG).show(); 
       return; 
      } 
      catch (FileNotFoundException e) 
      { 
       Log.e("onPictureTaken",e.toString()); 
      } 
      catch (IOException e) 
      { 
       Log.d("onPictureTaken",e.toString()); 
      } 
     } 
    }; 
    @Override 
    protected void onCreate(Bundle savedInstanceState) 
    { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 
     mCamera = isCameraAvailable(); 
     setCameraDisplayOrientation(this,0,mCamera); 
     Log.d("onCreate","Camera instance taken."); 
     showCamera = new ShowCamera(this, mCamera); 
     FrameLayout preview = (FrameLayout) findViewById(R.id.flCameraPreview); 
     preview.addView(showCamera); 
     Log.d("onCreate","Camera view in initialized"); 
     preview.setOnClickListener(new View.OnClickListener() 
     { 
      @Override 
      public void onClick(View v) 
      { 
       mCamera.takePicture(null, null, capturedIt); 
       Log.d("onClick","Button Clicked."); 
      } 
     }); 
    } 
    @Override 
    public boolean onCreateOptionsMenu(Menu menu) 
    { 
     getMenuInflater().inflate(R.menu.menu_main, menu); 
     return true; 
    } 
    public static void setCameraDisplayOrientation(Activity activity,int cameraId, android.hardware.Camera camera) 
    { 
     android.hardware.Camera.CameraInfo info=new  android.hardware.Camera.CameraInfo(); 
     android.hardware.Camera.getCameraInfo(cameraId,info); 
     int rotation = activity.getWindowManager().getDefaultDisplay().getRotation(); 
     int degrees = 0; 
     switch (rotation) { 
      case Surface.ROTATION_0: degrees = 0; break; 
      case Surface.ROTATION_90: degrees = 90; break; 
      case Surface.ROTATION_180: degrees = 180; break; 
      case Surface.ROTATION_270: degrees = 270; break; 
     } 
     int result; 
     if (info.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) 
     { 
      result = (info.orientation + degrees) % 360; 
      result = (360 - result) % 360; 
     } 
     else 
     { 
      result = (info.orientation - degrees + 360) % 360; 
     } 
     camera.setDisplayOrientation(result); 
    } 
} 

ShowCamera.java:

package com.example.camera; 

import android.content.Context; 
import android.hardware.Camera; 
import android.util.Log; 
import android.view.SurfaceHolder; 
import android.view.SurfaceView; 

import java.io.IOException; 

public class ShowCamera extends SurfaceView implements  SurfaceHolder.Callback 
{ 
    private SurfaceHolder holdMe; 
    private Camera mCamera; 
    public ShowCamera(Context context,Camera camera) 
    { 
     super(context); 
     this.mCamera = camera; 
     this.holdMe = getHolder(); 
     this.holdMe.addCallback(this); 
     this.holdMe.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); 
    } 
    @Override 
    public void surfaceChanged(SurfaceHolder surfaceHolder, int format,int width, int height) 
    { 
     try 
     { 
      mCamera.setPreviewDisplay(surfaceHolder); 
      mCamera.startPreview(); 
     } 
     catch (Exception e) 
     { 
      Log.d("surfaceChanged",e.toString()); 
     } 
    } 
    @Override 
    public void surfaceCreated(SurfaceHolder holder) 
    { 
     try 
     { 
      mCamera.setPreviewDisplay(holder); 
      mCamera.startPreview(); 
     } 
     catch (IOException e) 
     { 
      Log.e("surfaceCreated",e.toString()); 
     } 
    } 
    @Override 
    public void surfaceDestroyed(SurfaceHolder surfaceHolder) 
    { 
     mCamera.stopPreview(); 
     mCamera.release(); 
    } 
} 

После съемки и сохранения его в памяти, если я один раз нажмите на экран более, приложение выйдет из строя.

Answer 1

У вас есть stopPreview in surfaceDestroyed. но когда он возвращается. вы должны перезапустить камеру в режиме onResume. который отсутствует

public void onResume() 
{ 
    mCamera = getCameraInstance(); // i have created this i 
                // static method here 
    //mCamera.setPreviewCallback(previewCallback);//it depends on you need 
    try 
    { 
     mCamera.setPreviewDisplay(mHolder); 

     mCamera.startPreview(); 
    } 
    catch (IOException ioexception) 
    { 
     Log.e("MyCamera", 
       (new StringBuilder()).append("PreviewDisplay Error => ") 
         .append(ioexception.getMessage()).toString()); 
    } 

} 

И

public static Camera getCameraInstance() 
    { 
     Camera camera1; 
     try 
     { 
      if (android.os.Build.VERSION.SDK_INT >= 9) 
      { 
       return Camera.open(cameraId); 
      } 
      camera1 = Camera.open(); 
     } 
     catch (Exception exception) 
     { 
      Log.e("NightVision", 
        (new StringBuilder()).append("ErrorCameraInit: ") 
          .append(exception.getMessage()).toString()); 
      return null; 
     } 
     return camera1; 
    }