android – 活动恢复时相机预览屏幕黑屏

我一直试图让我的应用程序上的相机部分工作大约一个星期,并且在最终修复了一个错误之后,它创建了一个新的.

当我恢复活动时,预览不起作用,录制功能也不起作用.通过查看Logcat,我发现我的Camera对象等于null,我找不到它来重新创建它.

我的创造

@H_27_11@mCamera = getCameraInstance(); // Create preView view and set it as the content of our activity. mPreview = new CameraPreview(this,mCamera); preview = (FrameLayout) findViewById(R.id.previewer); preview.addView(mPreview);

获取相机实例方法

private Camera getCameraInstance() { 

        Camera c = null;     
        try {     
            //c = Camera.open(); // attempt to get a Camera instance    
             c = this.open(); // attempt to get a Camera instance    
        } catch (Exception E) {     
            // Camera is not available (in use or does not exist)    
        }     
        Log.i("TEST getCameraInstance","" + c);     
        return c; // returns null if camera is unavailable          
}

我的暂停

protected void onPause() {

        super.onPause();      
        try {     
            // release the camera immediately on pause event     
            // releaseCamera();    
            mCamera.stopPreview();      
            mCamera.setPreviewCallBACk(null);    
            mCamera.release();     
            mCamera = null;     
        } catch (Exception E) {       
            e.printStackTrace();    
        }    
}

我的简历

protected void onResume() {

        super.onResume();       
        try {       
            mCamera = Camera.open();      
            mCamera = getCameraInstance();     
            Log.i("TEST onresume","onResume Runing");      
            Log.i("TEST onresume","camera "  + mCamera);       
            mCamera.setPreviewCallBACk(null);      
            Log.i("TEST onresume","camera "  + mCamera);      
            //mCamera = getCameraInstance();      
            Log.i("TEST onresume","camera "  + mCamera);    
            // mCamera.setPreviewCallBACk(null);     
            mPreview = new CameraPreview(MainRecordScreen.this,mCamera);// set preview      
            Log.i("TEST onresume","camera "  + mCamera);                                                                               
            preview.addView(mPreview);     
            Log.i("TEST onresume","camera "  + mCamera);    
            mCamera.startPreview();              
        } catch (Exception E) {      
            Log.d(tag,"Error starTing camera preview: " + e.getmessage());    
        }      
        Log.i("TEST onresume","camera "  + mCamera);    
}

我的LogCat

06-19 06:38:40.223: E/AndroidRuntime(16702): FATAL EXCEPTION: main
06-19 06:38:40.223: E/AndroidRuntime(16702): java.lang.NullPointerException
06-19 06:38:40.223: E/AndroidRuntime(16702):    at com.plcd.test.MainRecordScreen.prepareVideoRecorder(MainRecordScreen.java:198)
06-19 06:38:40.223: E/AndroidRuntime(16702):    at com.plcd.test.MainRecordScreen.access$7(MainRecordScreen.java:193)
06-19 06:38:40.223: E/AndroidRuntime(16702):    at com.plcd.test.MainRecordScreen$3.onClick(MainRecordScreen.java:115)
06-19 06:38:40.223: E/AndroidRuntime(16702):    at android.view.View.performClick(View.java:3511)
06-19 06:38:40.223: E/AndroidRuntime(16702):    at android.view.View$PerformClick.run(View.java:14105)
06-19 06:38:40.223: E/AndroidRuntime(16702):    at android.os.Handler.handleCallBACk(Handler.java:605)
06-19 06:38:40.223: E/AndroidRuntime(16702):    at android.os.Handler.dispatchmessage(Handler.java:92)
06-19 06:38:40.223: E/AndroidRuntime(16702):    at android.os.Looper.loop(Looper.java:137)
06-19 06:38:40.223: E/AndroidRuntime(16702):    at android.app.ActivityThread.main(ActivityThread.java:4424)
06-19 06:38:40.223: E/AndroidRuntime(16702):    at java.lang.reflect.Method.invokeNative(Native Method)
06-19 06:38:40.223: E/AndroidRuntime(16702):    at java.lang.reflect.Method.invoke(Method.java:511)
06-19 06:38:40.223: E/AndroidRuntime(16702):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
06-19 06:38:40.223: E/AndroidRuntime(16702):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
06-19 06:38:40.223: E/AndroidRuntime(16702):    at dalvik.system.NativeStart.main(Native Method)

如果有帮助,mCamera会从getCameraInstance()方法返回null.