下面是一个示例代码,展示了如何在Android设备上使用相机拍摄照片并保存到本地存储。
首先,确保你的Android项目中已经添加了相机权限:
然后,创建一个包含相机功能的Activity,例如CameraActivity:
public class CameraActivity extends AppCompatActivity {
private static final int REQUEST_IMAGE_CAPTURE = 1;
private ImageView imageView;
private String currentPhotoPath;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_camera);
imageView = findViewById(R.id.imageView);
Button captureButton = findViewById(R.id.captureButton);
captureButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
dispatchTakePictureIntent();
}
});
}
private void dispatchTakePictureIntent() {
Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
if (takePictureIntent.resolveActivity(getPackageManager()) != null) {
File photoFile = null;
try {
photoFile = createImageFile();
} catch (IOException ex) {
ex.printStackTrace();
}
if (photoFile != null) {
Uri photoURI = FileProvider.getUriForFile(this,
"com.example.android.fileprovider",
photoFile);
takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, photoURI);
startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE);
}
}
}
private File createImageFile() throws IOException {
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
String imageFileName = "JPEG_" + timeStamp + "_";
File storageDir = getExternalFilesDir(Environment.DIRECTORY_PICTURES);
File image = File.createTempFile(
imageFileName,
".jpg",
storageDir
);
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) {
galleryAddPic();
setPic();
}
}
private void galleryAddPic() {
Intent mediaScanIntent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
File f = new File(currentPhotoPath);
Uri contentUri = Uri.fromFile(f);
mediaScanIntent.setData(contentUri);
this.sendBroadcast(mediaScanIntent);
}
private void setPic() {
int targetW = imageView.getWidth();
int targetH = imageView.getHeight();
BitmapFactory.Options bmOptions = new BitmapFactory.Options();
bmOptions.inJustDecodeBounds = true;
BitmapFactory.decodeFile(currentPhotoPath, bmOptions);
int photoW = bmOptions.outWidth;
int photoH = bmOptions.outHeight;
int scaleFactor = Math.min(photoW / targetW, photoH / targetH);
bmOptions.inJustDecodeBounds = false;
bmOptions.inSampleSize = scaleFactor;
bmOptions.inPurgeable = true;
Bitmap bitmap = BitmapFactory.decodeFile(currentPhotoPath, bmOptions);
imageView.setImageBitmap(bitmap);
}
}
在上面的代码中,我们创建了一个CameraActivity,并在布局文件中添加了一个ImageView和一个用于触发拍照的按钮。当用户点击拍照按钮时,我们调用dispatchTakePictureIntent()方法来启动相机应用,并将拍摄的照片保存到一个临时文件中。
在createImageFile()方法中,我们创建了一个以时间戳命名的临时文件,并将其保存到应用的外部存储目录下的Pictures文件夹中。
在onActivityResult()方法中,我们调用galleryAddPic()方法将照片添加到Android的媒体库中,并调用setPic()方法将照片显示在ImageView中。
请注意,上面的代码中使用了FileProvider来获取拍摄照片的URI,并且需要在Manifest文件中添加FileProvider的配置:
在res/xml文件夹中创建一个名