Android 自定义相机拍照代码实现
在Android开发中,有时我们需要使用自定义相机来实现特定的拍照功能。本文将介绍如何在Android应用中实现自定义相机拍照功能,包括调用相机、拍照、保存图片等操作。
准备工作
在开始之前,我们需要在AndroidManifest.xml文件中添加相机权限:
<uses-permission android:name="android.permission.CAMERA"/>
<uses-feature android:name="android.hardware.camera" />
创建自定义相机界面
首先,我们需要创建一个布局文件来显示自定义相机界面。在res/layout目录下创建一个camera_layout.xml文件:
<FrameLayout xmlns:android="
android:id="@+id/camera_preview"
android:layout_width="match_parent"
android:layout_height="match_parent">
<SurfaceView
android:id="@+id/surface_view"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<Button
android:id="@+id/btn_capture"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Capture"
android:layout_gravity="bottom|center" />
</FrameLayout>
调用相机并拍照
接下来,我们需要在Activity中调用相机并实现拍照功能。在MainActivity.java文件中添加以下代码:
public class MainActivity extends AppCompatActivity {
private Camera mCamera;
private CameraPreview mPreview;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mCamera = getCameraInstance();
mPreview = new CameraPreview(this, mCamera);
FrameLayout preview = findViewById(R.id.camera_preview);
preview.addView(mPreview);
Button captureButton = findViewById(R.id.btn_capture);
captureButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
mCamera.takePicture(null, null, mPicture);
}
});
}
private Camera.PictureCallback mPicture = new Camera.PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
// 保存图片到文件
File pictureFile = getOutputMediaFile();
if (pictureFile == null){
Log.d(TAG, "Error creating media file, check storage permissions");
return;
}
try {
FileOutputStream fos = new FileOutputStream(pictureFile);
fos.write(data);
fos.close();
} catch (FileNotFoundException e) {
Log.d(TAG, "File not found: " + e.getMessage());
} catch (IOException e) {
Log.d(TAG, "Error accessing file: " + e.getMessage());
}
}
};
private static Camera getCameraInstance(){
Camera c = null;
try {
c = Camera.open();
}
catch (Exception e){
Log.d(TAG, "Camera is not available: " + e.getMessage());
}
return c;
}
private static File getOutputMediaFile(){
File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_PICTURES), "MyCameraApp");
if (!mediaStorageDir.exists()){
if (!mediaStorageDir.mkdirs()){
Log.d(TAG, "Failed to create directory");
return null;
}
}
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
File mediaFile;
mediaFile = new File(mediaStorageDir.getPath() + File.separator +
"IMG_"+ timeStamp + ".jpg");
return mediaFile;
}
}
权限处理
在Android 6.0及以上版本中,需要动态申请相机权限。在MainActivity中添加以下代码:
private static final int REQUEST_CAMERA_PERMISSION = 200;
@Override
protected void onResume() {
super.onResume();
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.CAMERA)
!= PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(this,
new String[]{Manifest.permission.CAMERA},
REQUEST_CAMERA_PERMISSION);
}
}
@Override
public void onRequestPermissionsResult(int requestCode,
String[] permissions, int[] grantResults) {
if (requestCode == REQUEST_CAMERA_PERMISSION) {
if (grantResults.length > 0
&& grantResults[0] == PackageManager.PERMISSION_GRANTED) {
// 权限已获取
} else {
// 权限被拒绝
}
}
}
实现自定义相机预览
为了实现自定义相机预览,我们需要创建一个CameraPreview类来显示相机预览界面。在CameraPreview.java文件中添加以下代码:
public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
private SurfaceHolder mHolder;
private Camera mCamera;
public CameraPreview(Context context,