Question

我无法设置contentView：

如何使用此代码做得更好，我尝试使用asyncTask类但返回相同的错误。

代码退出错误：此行上的JavaNullPointer addContentView（surface，new ActionBar.LayoutParams（ViewGroup.LayoutParams.MATCH_PARENT））;

private SurfaceView cameraView;
private String barcodeInfo;
private CameraSource cameraSource;
private Renderer renderer;
private RajawaliSurfaceView surface;

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

    //--------------------------------------------------------
    cameraView = (SurfaceView) findViewById(R.id.cameraView);
    //barcodeInfo = (TextView) findViewById(R.id.infoTextView);

    BarcodeDetector detector = new BarcodeDetector.Builder(this).setBarcodeFormats(Barcode.QR_CODE).build();
    cameraSource = new CameraSource.Builder(this, detector).setRequestedPreviewSize(640, 480).build();

    cameraView.getHolder().addCallback(new SurfaceHolder.Callback() {
        @Override
        public void surfaceCreated(SurfaceHolder holder) {
            try {
                cameraSource.start(cameraView.getHolder());
            } catch (IOException e) {
                Log.e("CAMERA SOURCE", e.getMessage());
            }
        }

        @Override
        public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {

        }

        @Override
        public void surfaceDestroyed(SurfaceHolder holder) {
            cameraSource.stop();
        }
    });

    detector.setProcessor(new Detector.Processor<Barcode>() {
        @Override
        public void release() {

        }

        @Override
        public void receiveDetections(Detector.Detections<Barcode> detections) {
            release();
            final SparseArray<Barcode> barcodes = detections.getDetectedItems();
            if (barcodes.size() == 1) {

                MainActivity.this.runOnUiThread(new Runnable() {
                    public void run() {
                        muestraMono();
                    }
                });
            }
        }
    });
}
public void muestraMono(){
    setContentView(R.layout.activity_main);
    RajawaliSurfaceView surface = new RajawaliSurfaceView(this);
    surface.setFrameRate(60.0);
    surface.setRenderMode(IRajawaliSurface.RENDERMODE_WHEN_DIRTY);
    surface.setTransparent(true);
    addContentView(surface, new ActionBar.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT));
    renderer = new Renderer(this);
    surface.setSurfaceRenderer(renderer);
}

E / AndroidRuntime：致命异常：主要处理：com.dsinteg.lectorqr，PID：2822 显示java.lang.NullPointerException 在android.opengl.GLSurfaceView.onResume（GLSurfaceView.java:567）在 org.rajawali3d.surface.RajawaliSurfaceView.onResume（RajawaliSurfaceView.java:106）在 org.rajawali3d.surface.RajawaliSurfaceView.onAttachedToWindow（RajawaliSurfaceView.java:125）在android.view.View.dispatchAttachedToWindow（View.java:12618）在android.view.ViewGroup.addViewInner（ViewGroup.java:3621）在android.view.ViewGroup.addView（ViewGroup.java:3435）在android.view.ViewGroup.addView（ViewGroup.java:3411）在 com.android.internal.policy.impl.PhoneWindow.addContentView（PhoneWindow.java:321）在android.app.Activity.addContentView（Activity.java:2016）在com.dsinteg.lectorqr.MainActivity.muestraMono（MainActivity.java:93）在com.dsinteg.lectorqr.MainActivity $ 2 $ 1.run（MainActivity.java:81）在android.os.Handler.handleCallback（Handler.java:733）在android.os.Handler.dispatchMessage（Handler.java:95）在android.os.Looper.loop（Looper.java:136）在android.app.ActivityThread.main（ActivityThread.java:5336） at java.lang.reflect.Method.invokeNative（Native Method）在java.lang.reflect.Method.invoke（Method.java:515）在 com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:871）在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:687）在dalvik.system.NativeStart.main（本地方法）

Answer 1

试试这个，

getWindow().addContentView(surface, new ActionBar.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT));

发生错误，因为活动不知道父母。

Answer 2

SetContentView将覆盖布局，并将其替换为新布局。通常，您只想在onCreate中执行此操作一次。你可以做得更多，但它涉及重新绘制整个布局，所以尝试删除这一行

setContentView(R.layout.activity_main);

使用muestraMono方法。

<强>更新

像这样创建方法

public void muestraMono(){
    surface = new RajawaliSurfaceView(this); // make RajawaliSurfaceView a class variable
    surface.setFrameRate(60.0);
    surface.setRenderMode(IRajawaliSurface.RENDERMODE_WHEN_DIRTY);
    surface.setTransparent(true);
    addContentView(surface, new ActionBar.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT));
    renderer = new Renderer(this);
    surface.setSurfaceRenderer(renderer);
}

然后在onCreate中调用此方法，在扫描QR码后再次调用此方法

add-ContentView上的Android-JavaNullPointer

我无法设置contentView：

2 个答案: