使用相机 API,我能够成功拍摄照片并将其保存到文件夹中。这是我正在使用的代码:
主要.xml:
<FrameLayout
android:id="@+id/camera_preview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_weight="1" />
<Button
android:id="@+id/button_capture"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="Capture" />
辅助类:
import java.io.IOException;
import android.content.Context;
import android.hardware.Camera;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
public class CameraPreview extends SurfaceView implements
SurfaceHolder.Callback {
private SurfaceHolder mSurfaceHolder;
private Camera mCamera;
// Constructor that obtains context and camera
@SuppressWarnings("deprecation")
public CameraPreview(Context context, Camera camera) {
super(context);
this.mCamera = camera;
this.mSurfaceHolder = this.getHolder();
this.mSurfaceHolder.addCallback(this);
this.mSurfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
@Override
public void surfaceCreated(SurfaceHolder surfaceHolder) {
try {
mCamera.setPreviewDisplay(surfaceHolder);
mCamera.setDisplayOrientation(90);
mCamera.startPreview();
} catch (IOException e) {
// left blank for now
}
}
@Override
public void surfaceDestroyed(SurfaceHolder surfaceHolder) {
mCamera.stopPreview();
mCamera.release();
}
@Override
public void surfaceChanged(SurfaceHolder surfaceHolder, int format,
int width, int height) {
// start preview with new settings
try {
mCamera.setPreviewDisplay(surfaceHolder);
mCamera.startPreview();
} catch (Exception e) {
// intentionally left blank for a test
}
}
}
活动类别:
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import android.os.Bundle;
import android.os.Environment;
import android.app.Activity;
import android.hardware.Camera;
import android.hardware.Camera.PictureCallback;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.FrameLayout;
public class MyCamera extends Activity {
private Camera mCamera;
private CameraPreview mCameraPreview;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mCamera = getCameraInstance();
mCameraPreview = new CameraPreview(this, mCamera);
FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview);
preview.addView(mCameraPreview);
Button captureButton = (Button) findViewById(R.id.button_capture);
captureButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
mCamera.takePicture(null, null, mPicture);
}
});
}
/**
* Helper method to access the camera returns null if it cannot get the
* camera or does not exist
*
* @return
*/
private Camera getCameraInstance() {
Camera camera = null;
try {
camera = Camera.open();
} catch (Exception e) {
// cannot get camera or does not exist
}
return camera;
}
PictureCallback mPicture = new PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
File pictureFile = getOutputMediaFile();
if (pictureFile == null) {
return;
}
try {
FileOutputStream fos = new FileOutputStream(pictureFile);
fos.write(data);
fos.close();
} catch (FileNotFoundException e) {
} catch (IOException e) {
}
}
};
private static File getOutputMediaFile() {
File mediaStorageDir = new File(
Environment
.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES),
"MyCameraApp");
if (!mediaStorageDir.exists()) {
if (!mediaStorageDir.mkdirs()) {
Log.d("MyCameraApp", "failed to create directory");
return null;
}
}
// Create a media file name
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss")
.format(new Date());
File mediaFile;
mediaFile = new File(mediaStorageDir.getPath() + File.separator
+ "IMG_" + timeStamp + ".jpg");
return mediaFile;
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.my_camera, menu);
return true;
}
}
我还在清单文件中添加了以下内容:
<uses-feature android:name="android.hardware.camera" />
<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
我有以下问题:
我想做以下事情:
-
按下拍摄按钮后,我希望相机通过使用倒计时器自动继续每 5 秒拍摄一次照片。所以我添加了以下内容:
while(true){
new CountDownTimer(5000,1000){
@Override
public void onFinish() {
mCamera.takePicture(null, null, mPicture);
}
@Override
public void onTick(long millisUntilFinished) {
}
}.start();
}
然而,我再也看不到照片了。我添加了 while(true) 以使代码不重复。我已经在没有 while(true) 的情况下尝试过,并且正如预期的那样,图像捕获延迟了 5 秒
第二件事是:如何改变拍摄图片的质量?
任何帮助将不胜感激。