java private static final int REQUEST_IMAGE_CAPTURE = 1; private void dispatchTakePictureIntent() { Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE); if (takePictureIntent.resolveActivity(getPackageManager()) != null) { startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE); } } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK) { Bundle extras = data.getExtras(); Bitmap imageBitmap = (Bitmap) extras.get("data"); // 处理照片数据 } }这段代码中data是图片的路径吗
时间: 2023-12-06 11:41:50 浏览: 36
不是,data并不是图片的路径。在这段代码中,我们使用了 `startActivityForResult` 方法来启动一个拍照的 Intent,并传入了一个请求码 `REQUEST_IMAGE_CAPTURE`。当拍照完成后,系统会调用 `onActivityResult` 方法,并传入请求码、结果码以及包含了拍摄照片数据的 Intent 对象。我们可以从这个 Intent 对象中获取照片数据,而不是照片的路径。在这个例子中,我们使用了 `getExtras()` 方法获取 Intent 中的 Bundle 对象,然后从这个 Bundle 对象中获取了照片数据。
相关问题
static final int REQUEST_IMAGE_CAPTURE = 1; private void dispatchTakePictureIntent() { Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE); try { startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE); } catch (ActivityNotFoundException e) { // display error state to the user } }怎么用SurfaceView预览
要使用SurfaceView预览相机画面,可以通过Camera API获取相机实例,并在SurfaceView上绘制预览画面。以下是示例代码:
1. 在布局文件中添加SurfaceView
```
<SurfaceView
android:id="@+id/surfaceView"
android:layout_width="match_parent"
android:layout_height="match_parent" />
```
2. 在Activity中获取SurfaceView实例,并在SurfaceView的生命周期方法中处理相机预览
```
public class CameraPreviewActivity extends AppCompatActivity implements SurfaceHolder.Callback {
private Camera mCamera;
private SurfaceView mSurfaceView;
private SurfaceHolder mHolder;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_camera_preview);
mSurfaceView = findViewById(R.id.surfaceView);
mHolder = mSurfaceView.getHolder();
mHolder.addCallback(this);
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
// 获取相机实例
mCamera = Camera.open();
try {
// 设置预览显示
mCamera.setPreviewDisplay(holder);
// 启动预览
mCamera.startPreview();
} catch (IOException e) {
e.printStackTrace();
}
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
// 相机预览尺寸发生变化时,重新启动预览
mCamera.stopPreview();
try {
mCamera.setPreviewDisplay(holder);
mCamera.startPreview();
} catch (IOException e) {
e.printStackTrace();
}
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
// 释放相机资源
mCamera.stopPreview();
mCamera.release();
mCamera = null;
}
}
```
在以上代码中,我们通过SurfaceHolder.Callback接口监听SurfaceView的生命周期方法,并在surfaceCreated方法中获取Camera实例、设置预览显示、启动预览,在surfaceChanged方法中处理预览尺寸变化,在surfaceDestroyed方法中释放相机资源。
需要注意的是,为了保证顺利运行,需要在AndroidManifest.xml文件中添加相应的权限:
```
<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />
```
@AfterPermissionGranted(REQUEST_CAMERA_PERMISSION) private void takePicture() { String[] perms = {Manifest.permission.CAMERA}; if (EasyPermissions.hasPermissions(this, perms)) { Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE); if (intent.resolveActivity(getPackageManager()) != null) { startActivityForResult(intent, REQUEST_IMAGE_CAPTURE); } } else { EasyPermissions.requestPermissions(this, "需要相机权限来拍照", REQUEST_CAMERA_PERMISSION, perms); } }怎么写,写在哪里,如果加上创建文档用来存储照片,怎么写,完整示例
这段代码是一个使用 EasyPermissions 库来请求相机权限,并启动相机拍照的方法。如果您需要在拍照后将照片保存到文件中,可以在 `onActivityResult()` 方法中处理照片数据并保存到指定位置。
完整示例如下:
```java
private static final int REQUEST_CAMERA_PERMISSION = 1;
private static final int REQUEST_IMAGE_CAPTURE = 2;
private String currentPhotoPath;
@AfterPermissionGranted(REQUEST_CAMERA_PERMISSION)
private void takePicture() {
String[] perms = {Manifest.permission.CAMERA, Manifest.permission.WRITE_EXTERNAL_STORAGE};
if (EasyPermissions.hasPermissions(this, perms)) {
Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
if (intent.resolveActivity(getPackageManager()) != null) {
// Create the File where the photo should go
File photoFile = null;
try {
photoFile = createImageFile();
} catch (IOException ex) {
// Error occurred while creating the File
ex.printStackTrace();
}
// Continue only if the File was successfully created
if (photoFile != null) {
Uri photoURI = FileProvider.getUriForFile(this,
"com.example.android.fileprovider",
photoFile);
intent.putExtra(MediaStore.EXTRA_OUTPUT, photoURI);
startActivityForResult(intent, REQUEST_IMAGE_CAPTURE);
}
}
} else {
EasyPermissions.requestPermissions(this, "需要相机权限来拍照和存储照片", REQUEST_CAMERA_PERMISSION, perms);
}
}
private File createImageFile() throws IOException {
// Create an image file name
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
String imageFileName = "JPEG_" + timeStamp + "_";
File storageDir = getExternalFilesDir(Environment.DIRECTORY_PICTURES);
File image = File.createTempFile(
imageFileName, /* prefix */
".jpg", /* suffix */
storageDir /* directory */
);
// Save a file: path for use with ACTION_VIEW intents
currentPhotoPath = image.getAbsolutePath();
return image;
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK) {
// Get the dimensions of the View
int targetW = imageView.getWidth();
int targetH = imageView.getHeight();
// Get the dimensions of the bitmap
BitmapFactory.Options bmOptions = new BitmapFactory.Options();
bmOptions.inJustDecodeBounds = true;
BitmapFactory.decodeFile(currentPhotoPath, bmOptions);
int photoW = bmOptions.outWidth;
int photoH = bmOptions.outHeight;
// Determine how much to scale down the image
int scaleFactor = Math.min(photoW/targetW, photoH/targetH);
// Decode the image file into a Bitmap sized to fill the View
bmOptions.inJustDecodeBounds = false;
bmOptions.inSampleSize = scaleFactor;
bmOptions.inPurgeable = true;
Bitmap bitmap = BitmapFactory.decodeFile(currentPhotoPath, bmOptions);
imageView.setImageBitmap(bitmap);
// Save the bitmap to a file
try {
FileOutputStream out = new FileOutputStream(currentPhotoPath);
bitmap.compress(Bitmap.CompressFormat.JPEG, 90, out);
out.flush();
out.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
```
这个示例中,我们在 `takePicture()` 方法中请求了相机和存储权限,然后创建了一个用于保存照片的文件,并启动相机拍照。在 `onActivityResult()` 方法中,我们获取了拍摄的照片数据,并将其显示在一个 ImageView 中。然后,我们将照片保存到之前创建的文件中。请注意,在 `createImageFile()` 方法中,我们使用了 FileProvider 来获取照片文件的 Uri,以便在 Android N 及以上版本中能够正常使用。