android previewview怎样设置

在Android中，PreviewView是一个用于预览相机捕获的图像或视频的视图。要设置PreviewView，请按照以下步骤操作：

1. 首先，在您的项目的build.gradle文件中添加CameraX库的依赖项（如果尚未添加）：

dependencies { implementation 'androidx.camera:camera-core:1.0.0' implementation 'androidx.camera:camera-preview:1.0.0' implementation 'androidx.camera:camera-camera2:1.0.0' } 

2. 在布局文件（例如activity_main.xml）中添加PreviewView元素：

<androidx.camera.core.PreviewView android:id="@+id/previewView" android:layout_width="match_parent" android:layout_height="match_parent" /> 

3. 在Activity（例如MainActivity.java）中，初始化PreviewView并设置相机预览：

import androidx.camera.core.CameraSelector; import androidx.camera.core.ImageAnalysis; import androidx.camera.core.ImageProxy; import androidx.camera.core.Preview; import androidx.camera.core.SurfaceTextureProvider; import androidx.camera.core.VideoCapture; import androidx.camera.core.VideoCaptureConfig; import androidx.camera.lifecycle.ProcessCameraProvider; import androidx.camera.view.PreviewView; import androidx.compose.ui.platform.LocalContext; import androidx.compose.material3.Text; import androidx.compose.runtime.Composable; import androidx.compose.ui.unit.dp; import androidx.compose.ui.window.DialogWindowState; import com.google.common.util.concurrent.ListenableFuture; public class MainActivity extends AppCompatActivity { private PreviewView previewView; private ProcessCameraProvider cameraProviderFuture; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); previewView = findViewById(R.id.previewView); // Configure the camera and preview configureCamera(previewView); } private void configureCamera(PreviewView previewView) { // Obtain an instance of the camera provider cameraProviderFuture = ProcessCameraProvider.getInstance(this); // Select an appropriate camera and its configuration cameraProviderFuture.addListener(() -> { try { ProcessCameraProvider cameraProvider = cameraProviderFuture.get(); // Create a preview configuration PreviewConfig previewConfig = new PreviewConfig.Builder().build(); // Create a preview Preview preview = new Preview(previewConfig); // Attach the preview to the preview view previewView.setSurfaceProvider(preview.getSurfaceProvider()); // Set up video capture VideoCaptureConfig videoCaptureConfig = new VideoCaptureConfig.Builder() .set三脚架Mode(VideoCaptureConfig.三脚架Mode.OFF) .build(); VideoCapture videoCapture = cameraProvider.createVideoCapture(videoCaptureConfig); // Bind the video capture to the preview preview.setSurfaceProvider(videoCapture.getSurfaceProvider()); } catch (Exception e) { e.printStackTrace(); } }, ContextCompat.getMainExecutor(this)); } } 

这个示例展示了如何设置PreviewView以预览相机捕获的图像和视频。请注意，这个示例使用了CameraX库，它是Android Jetpack的一部分，用于简化相机功能的实现。