Android ViewPager，cameraview中沒有顯示

我試圖創建一個應用程序有3個片段，我用viewpager掃描它們。
第一個是列表，第二個應該是相機，第三個是列表。
滑動工作，但當我到第二個片段時，cameraPreview是黑色的。

我沒有得到崩潰或不同的東西的堆棧跟蹤。
我已經創建了這個應用程序的一部分，但沒有刷過，它確實工作。我在新應用程序中再次設置它時沒有更改片段，我只將android.app.Fragment的導入更改爲android.support.v4.app.Fragment。Android ViewPager，cameraview中沒有顯示

這個例子，我才用它來創建應用程序：
ViewPager with multiple Fragments and Layout files - How To
煤礦是沒有什麼不同的是，我想說感謝Haxor了很好的解釋，這真的幫助了我。我不能給予好評這些事，所以我會感謝你這種方式:)

MainActivity.class：

import android.support.v4.app.Fragment; 
import android.support.v4.app.FragmentActivity; 
import android.os.Bundle; 
import android.support.v4.app.FragmentManager; 
import android.support.v4.app.FragmentPagerAdapter; 
import android.support.v4.view.ViewPager; 
import android.view.Menu; 
import android.view.MenuItem; 
import android.view.SurfaceView; 
import android.view.View; 
import android.widget.LinearLayout; 


public class MainActivity extends FragmentActivity { 

LinearLayout ButtonBar; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
    ViewPager pager = (ViewPager) findViewById(R.id.viewPager); 
    pager.setAdapter(new MyPagerAdapter(getSupportFragmentManager())); 
} 


private class MyPagerAdapter extends FragmentPagerAdapter { 

    public MyPagerAdapter(FragmentManager fm) { 
     super(fm); 
    } 

    @Override 
    public Fragment getItem(int pos) { 
     switch(pos) { 
      case 0: 
       return FirstFragment.newInstance("FirstFragment, Instance 1"); 
      case 1: 
       return SecondFragment.newInstance("SecondFragment, Instance 1"); 
      case 2: 
       return ThirdFragment.newInstance("ThirdFragment, Instance 1"); 
      default: 
       return ThirdFragment.newInstance("ThirdFragment, Default"); 
     } 
    } 

    @Override 
    public int getCount() { 
     return 3; 
    } 
} 
}

activity_main.xml中

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
xmlns:tools="http://schemas.android.com/tools" 
android:layout_width="wrap_content" 
android:layout_height="wrap_content" 
tools:context=".MainActivity" 
android:background="#ffff"> 

<android.support.v4.view.ViewPager 
    android:id="@+id/viewPager" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent"/> 
</RelativeLayout>

二fragment.class：

import android.graphics.Bitmap; 
import android.graphics.BitmapFactory; 
import android.hardware.Camera; 
import android.os.Build; 
import android.os.Bundle; 
import android.support.v4.app.Fragment; 
import android.util.Log; 
import android.view.LayoutInflater; 
import android.view.SurfaceHolder; 
import android.view.SurfaceView; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.ImageButton; 
import android.widget.LinearLayout; 
import android.widget.TextView; 

import java.io.IOException; 
import java.io.OutputStream; 

/** 
* Created by Gebruiker on 29-10-2014. 
*/ 
public class SecondFragment extends Fragment { 

View rootView; 
ImageButton cameraShootButton; 
ImageButton cameraChangeButton; 
Boolean switching = false; 
View.OnClickListener tapper = null; 
SurfaceView cameraPreview = null; 
SurfaceHolder cameraPreviewHolder = null; 
Camera camera = null; 
boolean inPreview = false; 
boolean cameraConfigured = false; 
Integer currentCamera; 

public static SecondFragment newInstance(String text) { 

    SecondFragment f = new SecondFragment(); 
    Bundle b = new Bundle(); 
    b.putString("msg", text); 

    f.setArguments(b); 

    return f; 
} 

@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 
    rootView = inflater.inflate(R.layout.second_frag, container, false); 


    cameraShootButton = (ImageButton) rootView.findViewById(R.id.captureB); 
    cameraChangeButton = (ImageButton) rootView.findViewById(R.id.changeCameraB); 
    cameraPreview = (SurfaceView) rootView.findViewById(R.id.cameraView); 

    cameraPreviewHolder = cameraPreview.getHolder(); 
    cameraPreviewHolder.addCallback(surfaceCallback); 
    cameraPreviewHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); 


    tapper = new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      if (v.getId() == R.id.captureB) { 
       camera.takePicture(ShutterCallback, PictureCallbackRaw, null, PictureCallbackJpeg); 
      } else if (v.getId() == R.id.changeCameraB) { 
       if (switching == true){ 
        return; 
       } 
       changeCamera(); 
      } 
     } 
    }; 

    cameraShootButton.setOnClickListener(tapper); 
    cameraChangeButton.setOnClickListener(tapper); 
    return rootView; 
} 

@Override 
public void onResume() { 
    super.onResume(); 
    camera = getCamera("back"); 
    currentCamera = 1; 
    startPreview(); 
} 

@Override 
public void onPause() { 
    if (inPreview) { 
     camera.stopPreview(); 
    } 
    camera.release(); 
    camera = null; 
    inPreview = false; 

    super.onPause(); 
} 

private Camera.Size getBestPreviewSize(int width, int height, 
             Camera.Parameters parameters) { 
    Camera.Size result = null; 

    for (Camera.Size size : parameters.getSupportedPreviewSizes()) { 
     if (size.width <= width && size.height <= height) { 
      if (result == null) { 
       result = size; 
      } else { 
       int resultArea = result.width * result.height; 
       int newArea = size.width * size.height; 

       if (newArea > resultArea) { 
        result = size; 
       } 
      } 
     } 
    } 

    return (result); 
} 

private void initPreview(int width, int height) { 
    if (camera != null && cameraPreviewHolder.getSurface() != null) { 
     try { 
      camera.setPreviewDisplay(cameraPreviewHolder); 
     } catch (Throwable t) { 
      Log.e("PreviewDemo-surfaceCallback", 
        "Exception in setPreviewDisplay()", t); 
     } 

     if (!cameraConfigured) { 
      Camera.Parameters parameters = camera.getParameters(); 
      Log.v("CAMERA", parameters.toString()); 
      Camera.Size size = getBestPreviewSize(width, height, 
        parameters); 

      if (size != null) { 
       Log.v("CameraPreviewHeight", ""+cameraPreview.getMeasuredHeight()); 
       Log.v("CameraRES", size.width + " " + size.height); 
       parameters.setPreviewSize(size.width, size.height); 
       camera.setParameters(parameters); 
       cameraConfigured = true; 
      } 
     } 
    } 
} 

private void startPreview() { 
    if (cameraConfigured && camera != null) { 
     camera.startPreview(); 
     inPreview = true; 
     camera.setDisplayOrientation(90); 
     if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH_MR1) { 
      camera.enableShutterSound(false); 
     } 
    } 
} 

private void changeCamera() { 
    switching = true; 
    if (inPreview) { 
     camera.stopPreview(); 
     camera.setPreviewCallback(null); 
    } 
    camera.release(); 
    camera = null; 
    inPreview = false; 
    if (currentCamera==1){ 
     camera = getCamera("front"); 
     currentCamera =2; 
    } 
    else{ 
     camera = getCamera("back"); 
     currentCamera = 1; 
    } 
    camera.setDisplayOrientation(90); 
    try { 
     camera.setPreviewDisplay(cameraPreviewHolder); 
     cameraPreviewHolder.addCallback(surfaceCallback); 
     camera.startPreview(); 
    } catch (IOException e) { 
     e.printStackTrace(); 
    } 

    inPreview = true; 

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH_MR1) { 
     camera.enableShutterSound(false); 
    } 
    switching = false; 

} 

SurfaceHolder.Callback surfaceCallback = new SurfaceHolder.Callback() { 
    public void surfaceCreated(SurfaceHolder holder) { 
     // no-op -- wait until surfaceChanged() 
    } 

    public void surfaceChanged(SurfaceHolder holder, 
           int format, int width, 
           int height) { 
     initPreview(width, height); 
     startPreview(); 
    } 

    public void surfaceDestroyed(SurfaceHolder holder) { 
     // no-op 
    } 
}; 

Camera.ShutterCallback ShutterCallback = new Camera.ShutterCallback() { 
    public void surfaceCreated(SurfaceHolder holder) { 
     // no-op -- wait until surfaceChanged() 
    } 

    public void surfaceChanged(SurfaceHolder holder, 
           int format, int width, 
           int height) { 
     initPreview(width, height); 
     startPreview(); 
    } 

    public void surfaceDestroyed(SurfaceHolder holder) { 
     // no-op 
    } 

    @Override 
    public void onShutter() { 

    } 
}; 

Camera.PictureCallback PictureCallbackRaw = new Camera.PictureCallback() { 
    public void surfaceCreated(SurfaceHolder holder) { 
     // no-op -- wait until surfaceChanged() 
    } 

    public void surfaceChanged(SurfaceHolder holder, 
           int format, int width, 
           int height) { 
     initPreview(width, height); 
     startPreview(); 
    } 

    public void surfaceDestroyed(SurfaceHolder holder) { 
     // no-op 
    } 

    @Override 
    public void onPictureTaken(byte[] data, Camera camera) { 

    } 
}; 

Camera.PictureCallback PictureCallbackJpeg = new Camera.PictureCallback() { 
    public void surfaceCreated(SurfaceHolder holder) { 
     // no-op -- wait until surfaceChanged() 
    } 

    public void surfaceChanged(SurfaceHolder holder, 
           int format, int width, 
           int height) { 
     initPreview(width, height); 
     startPreview(); 
    } 

    public void surfaceDestroyed(SurfaceHolder holder) { 
     // no-op 
    } 

    @Override 
    public void onPictureTaken(byte[] byteData, Camera camera) { 
     BitmapFactory.Options options = new BitmapFactory.Options(); 
     options.inSampleSize = 5; 
     OutputStream bos = null; 
     Bitmap m = BitmapFactory.decodeByteArray(byteData, 0, byteData.length, options); 

     //m.compress(Bitmap.CompressFormat.PNG, 75, bos); 
     //Log.v("CAPTURED", ""+bos); 
    } 
}; 

private Camera getCamera(String getCamera) { 
    int cameraCount = 0; 
    Camera cam = null; 
    Camera.CameraInfo cameraInfo = new Camera.CameraInfo(); 
    cameraCount = Camera.getNumberOfCameras(); 
    for (int camIdx = 0; camIdx < cameraCount; camIdx++) { 
     Camera.getCameraInfo(camIdx, cameraInfo); 
     if ((cameraInfo.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) && (getCamera == "front")) { 
      try { 
       cam = Camera.open(camIdx); 
      } catch (RuntimeException e) { 
       Log.e("TEST", "Camera failed to open: " + e.getLocalizedMessage()); 
      } 
     } 
     else if ((cameraInfo.facing == Camera.CameraInfo.CAMERA_FACING_BACK) && (getCamera == "back")) { 
      try { 
       cam = Camera.open(camIdx); 
      } catch (RuntimeException e) { 
       Log.e("TEST", "Camera failed to open: " + e.getLocalizedMessage()); 
      } 
     } 
    } 
    return cam; 
} 


}

second_frag.xml

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
android:layout_width="match_parent" 
android:layout_height="match_parent"> 

<android.view.SurfaceView 
    android:id="@+id/cameraView" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" /> 

<LinearLayout 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:orientation="horizontal" 
    android:layout_alignParentBottom="true"> 

    <LinearLayout 
     android:layout_width="0dp" 
     android:layout_height="wrap_content" 
     android:layout_weight="1" 
     android:gravity="center"> 

     <ImageButton 
      android:id="@+id/flitserB" 
      android:layout_width="30dp" 
      android:layout_height="70dp" 
      android:scaleType="fitCenter" 
      android:src="@drawable/flash" 
      android:background="@null"/> 
    </LinearLayout> 

    <LinearLayout 
     android:layout_width="0dp" 
     android:layout_height="wrap_content" 
     android:layout_weight="1" 
     android:gravity="center"> 
     <ImageButton 
      android:id="@+id/captureB" 
      android:layout_width="70dp" 
      android:layout_height="70dp" 
      android:scaleType="fitCenter" 
      android:src="@drawable/camerashoot" 
      android:background="@null"/> 
    </LinearLayout> 

    <LinearLayout 
     android:layout_width="0dp" 
     android:layout_height="wrap_content" 
     android:layout_weight="1" 
     android:gravity="center"> 
     <ImageButton 
      android:id="@+id/changeCameraB" 
      android:layout_width="30dp" 
      android:layout_height="70dp" 
      android:scaleType="fitCenter" 
      android:src="@drawable/camerachange" 
      android:background="@null"/> 

    </LinearLayout> 

</LinearLayout> 


</RelativeLayout>

來源

2014-10-29 Joris Coenen

是否在viewpager之外的工作？ – nadavfima 2014-10-29 13:56:45

也許你忘了相機權限添加到AndroidManifest.xml中：

<uses-permission android:name="android.permission.CAMERA" />

看到： http://developer.android.com/reference/android/hardware/Camera.html

來源

2014-10-29 13:55:26 wpiwonski

我真的可以在自己的頭上打我自己，那是我的問題，我已經在尋找2個小時了......謝謝大家回覆並查看我的文章 – 2014-10-29 13:59:26

Android ViewPager，cameraview中沒有顯示

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