我想在我的代码中添加一个切换相机按钮。 这是守则。 我不知道我该怎么做。 请建议一些方法。
先谢谢你。
CameraDemo.java
public class CameraDemo extends Activity {
private static final String TAG = "CameraDemo";
Camera camera;
Preview preview;
Button buttonClick,switchCam;
int which=0;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
switchCam=(Button)findViewById(R.id.switchcam);
preview = new Preview(this);
((RelativeLayout) findViewById(R.id.preview)).addView(preview);
buttonClick = (Button) findViewById(R.id.buttonClick);
buttonClick.setOnClickListener( new OnClickListener() {
public void onClick(View v) {
preview.camera.takePicture(shutterCallback, rawCallback, jpegCallback);
AlertDialog.Builder alertDialog = new AlertDialog.Builder(CameraDemo.this);
// Setting Dialog Title
alertDialog.setTitle("Confirm");
// Setting Dialog Message
alertDialog.setMessage("Are You Done ?");
// Setting Icon to Dialog
alertDialog.setIcon(R.drawable.doneimg);
// Setting Positive "Yes" Button
alertDialog.setPositiveButton("YES", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int which) {
AlertDialog.Builder alertDialog = new AlertDialog.Builder(CameraDemo.this);
// Setting Dialog Title
alertDialog.setTitle("Confirm Student");
// Setting Dialog Message
alertDialog.setMessage("Are you a Student?");
// Setting Icon to Dialog
alertDialog.setIcon(R.drawable.student);
// Setting Positive "Yes" Button
alertDialog.setPositiveButton("YES", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int which) {
// Write your code here to invoke YES event
Intent i = new Intent(getApplicationContext(),
ScanId.class);
startActivity(i);
finish();
}
});
// Setting Negative "NO" Button
alertDialog.setNegativeButton("NO", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
// Write your code here to invoke NO event
Toast.makeText(getApplicationContext(), "Sorry, Only Students Allowed", Toast.LENGTH_SHORT).show();
dialog.cancel();
}
});
// Showing Alert Message
alertDialog.show();
}
});
// Setting Negative "NO" Button
alertDialog.setNegativeButton("NO", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
// Write your code here to invoke NO event
Toast.makeText(getApplicationContext(), "Sorry, Only Students Allowed", Toast.LENGTH_SHORT).show();
dialog.cancel();
}
});
// Showing Alert Message
alertDialog.show();
}
});
Log.d(TAG, "onCreate'd");
}
ShutterCallback shutterCallback = new ShutterCallback() {
public void onShutter() {
Log.d(TAG, "onShutter'd");
}
};
/** Handles data for raw picture */
PictureCallback rawCallback = new PictureCallback() {
public void onPictureTaken(byte[] data, Camera camera) {
Log.d(TAG, "onPictureTaken - raw");
}
};
/** Handles data for jpeg picture */
PictureCallback jpegCallback = new PictureCallback() {
public void onPictureTaken(byte[] data, Camera camera) {
FileOutputStream outStream = null;
long time = 0;
try {
// write to local sandbox file system
// outStream = CameraDemo.this.openFileOutput(String.format("%d.jpg", System.currentTimeMillis()), 0);
// Or write to sdcard
time = System.currentTimeMillis();
outStream = new FileOutputStream(String.format("/sdcard/%d.jpg",time));
outStream.write(data);
outStream.close();
Log.d(TAG, "onPictureTaken - wrote bytes: " + data.length);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
}
Log.d(TAG, "onPictureTaken - jpeg");
}
};
}
NExxt Java文件＆gt;＆gt; Preview.java
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.hardware.Camera;
import android.hardware.Camera.PreviewCallback;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.widget.Button;
class Preview extends SurfaceView implements SurfaceHolder.Callback {
private static final String TAG = "Preview";
SurfaceHolder mHolder;
public Camera camera;
int which=0;
Preview(Context context) {
super(context);
// Install a SurfaceHolder.Callback so we get notified when the
// underlying surface is created and destroyed.
mHolder = getHolder();
mHolder.addCallback(this);
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
public void surfaceCreated(SurfaceHolder holder) {
// The Surface has been created, acquire the camera and tell it where
// to draw.
camera = Camera.open();
try {
camera.setPreviewDisplay(holder);
camera.setDisplayOrientation(90);
camera.setPreviewCallback(new PreviewCallback() {
public void onPreviewFrame(byte[] data, Camera arg1) {
FileOutputStream outStream = null;
try {
outStream = new FileOutputStream(String.format("/sdcard/%d.jpg", System.currentTimeMillis()));
outStream.write(data);
outStream.close();
Log.d(TAG, "onPreviewFrame - wrote bytes: " + data.length);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
}
Preview.this.invalidate();
}
});
} catch (IOException e) {
e.printStackTrace();
}
}
public void surfaceDestroyed(SurfaceHolder holder) {
// Surface will be destroyed when we return, so stop the preview.
// Because the CameraDevice object is not a shared resource, it's very
// important to release it when the activity is paused.
camera.stopPreview();
camera = null;
}
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
// Now that the size is known, set up the camera parameters and begin
// the preview.
Camera.Parameters parameters = camera.getParameters();
// parameters.setPreviewSize(w, h);
camera.setParameters(parameters);
camera.startPreview();
}
@Override
public void draw(Canvas canvas) {
super.draw(canvas);
Paint p= new Paint(Color.RED);
Log.d(TAG,"draw");
canvas.drawText("PREVIEW", canvas.getWidth()/2, canvas.getHeight()/2, p );
}
}
XML文件
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent" android:id="@+id/layout">
<RelativeLayout android:id="@+id/preview"
android:layout_weight="1" android:layout_width="fill_parent"
android:layout_height="match_parent">
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="New Button"
android:id="@+id/switchcam"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="170dp" />
</RelativeLayout>
<Button android:layout_width="80dp"
android:layout_height="80dp"
android:id="@+id/buttonClick"
android:text=""
android:layout_gravity="center_horizontal|bottom"
android:layout_marginBottom="50dp"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:background="@drawable/circlebutton"
/>
<Button
android:layout_width="40dp"
android:layout_height="40dp"
android:id="@+id/gallery"
android:background="@drawable/grid"
android:layout_marginBottom="50dp"
android:layout_marginLeft="60dp"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
</RelativeLayout>
答案 0 :(得分：2)
只需使用open(int cameraId)方法重新打开相机。
//swap the id of the camera to be used
if(currentCameraId == Camera.CameraInfo.CAMERA_FACING_BACK){
currentCameraId = Camera.CameraInfo.CAMERA_FACING_FRONT;
}
else {
currentCameraId = Camera.CameraInfo.CAMERA_FACING_BACK;
}
camera = Camera.open(currentCameraId);