Question

我试图打开我的相机而不点击我的按钮但它不起作用...

我按照此处的说明操作：http://developer.android.com/guide/topics/media/camera.html#custom-camera

这是我的结果：

enter image description here

当我按下“Capture”按钮时，它会激活相机，但我想在此之前激活相机，只需在我点击像Snapchat这样的按钮时进行记录。当我打开相机但我没有发现错误时，我想我会错过某个地方......

这是我的班级：

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

    preview = (FrameLayout) findViewById(R.id.camera_preview);


    if (checkCameraHardware(this)) {
        mCamera = getCameraInstance();
        mPreview = new CameraPreview(this, mCamera);
        mCamera.setDisplayOrientation(90);

        initButton();

        preview.addView(mPreview);
        preview.removeAllViews();
        preview.addView(mPreview);
        preview.addView(captureButton);
    }
}

之后，我有启动按钮的方法：

public void initButton () {
    captureButton = (Button) findViewById(R.id.button_capture);

    captureButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (isRecording) {
                // stop recording and release camera
                mMediaRecorder.stop();
                releaseMediaRecorder();
                mCamera.lock();

                // inform the user that recording has stopped
                captureButton.setText("Capture");
                isRecording = false;
            } else {
                // initialize video camera
                if (prepareVideoRecorder()) {
                    // Camera is available and unlocked, MediaRecorder is prepared,
                    // now you can start recording
                    mMediaRecorder.start();

                    captureButton.setText("Stop");
                    isRecording = true;
                } else {
                    releaseMediaRecorder();
                    Toast.makeText(MainActivity.this, "Camera doesn't work", Toast.LENGTH_LONG).show();
                }
            }
        }
    });

}

这是我获取相机实例的方法：

public static Camera getCameraInstance() {
    Camera c = null;
    try {
        c = Camera.open();
    } catch (Exception e) {
        Log.i("CAMERA INFO : >", "Camera doesn't exist");
    }
    return c;
}

以下是准备记录的方法：

private boolean prepareVideoRecorder() {
    mMediaRecorder = new MediaRecorder();

    // Step 1: Unlock and set camera to MediaRecorder
    mCamera.unlock();
    mMediaRecorder.setCamera(mCamera);

    // Step 2: Set sources
    mMediaRecorder.setAudioSource(MediaRecorder.AudioSource.CAMCORDER);
    mMediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);

    // Step 3: Set a CamcorderProfile (requires API Level 8 or higher)
    CamcorderProfile camcorderProfile = CamcorderProfile.get(CamcorderProfile.QUALITY_HIGH);

    mMediaRecorder.setProfile(camcorderProfile);

    // Step 4: Set output file
    mMediaRecorder.setOutputFile(getOutputMediaFile(CAPTURE_VIDEO_FILE).toString());

    // Step 5: Set the preview output
    mMediaRecorder.setPreviewDisplay(mPreview.getHolder().getSurface());

    // Step 6: Prepare configured MediaRecorder
    try {
        mMediaRecorder.prepare();
    } catch (IllegalStateException e) {
        Log.d("PREPARE MEDIARECORDER : >", ": > > IllegalStateException preparing MediaRecorder: " + e.getMessage());
        releaseMediaRecorder();
        return false;
    } catch (IOException e) {
        Log.d("PREPARE MEDIARECORDER : >", " : > > IOException preparing MediaRecorder: " + e.getMessage());
        releaseMediaRecorder();
        return false;
    }
    return true;
}

然后我尝试在实例化之前打开相机，但我不知道如何...如果有人有想法，对我有用。

Answer 1

我发现了我的错误。我在CameraPreview类的mCamera.setPreview()方法中调用了onSurfaceCreated()。

我需要在mCamera.setPreview()中致电onSurfaceChanged()！现在它可以工作

问题解决了！

Answer 2

您需要在按下捕获按钮之前设置摄像机的预览流。您的代码中的mPreview参考中似乎已经有一个预览类。您需要确保它包含Camera#startPreview() call when the preview surface is created才能显示来自摄像头的实时图像。要记住的另一件事是预览类，它是一个Android视图，需要是可见的，以便正确设置其表面，这意味着你必须确保它正确创建及其visibility设置为VISIBLE。

直接在活动中打开相机而不点击按钮而没有意图？

2 个答案: