我想在我的应用程序中调用onPreviewCallback，但它不会启动。目前onPreviewCallback上没有任何useufull，我只是想让它工作。我试图将回调放在Camerapreview.java中，但仍然没有。有谁能告诉我我犯了哪些错误？这是我的代码： activity_main.xml中
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.example.nikola.camera.MainActivity">
<FrameLayout
android:id="@+id/camera_preview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
/>
</RelativeLayout>
MainActivity.java
package com.example.nikola.camera;
import android.content.Context;
import android.content.pm.PackageManager;
import android.graphics.ImageFormat;
import android.hardware.Camera;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.widget.FrameLayout;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
public Camera mCamera;
private CameraPreview mPreview;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if(checkCameraHardware(this)==false){
Toast.makeText(MainActivity.this, "This device does not have camera", Toast.LENGTH_LONG).show();
finish();
}
mCamera = getCameraInstance();
mCamera.setPreviewCallback(new Camera.PreviewCallback() {
@Override
public void onPreviewFrame(byte[] data, Camera camera) {
Log.d("Camera1","data lenght is:"+data.length);
}
});
if(mCamera==null){
Toast.makeText(MainActivity.this, "Can't access camera", Toast.LENGTH_LONG).show();
finish();
}
Camera.Parameters cameraParametars = mCamera.getParameters();
cameraParametars.setPreviewSize(640,480);
cameraParametars.setPreviewFormat(ImageFormat.RGB_565);
mCamera.setParameters(cameraParametars);
mPreview = new CameraPreview(this, mCamera);
FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview);
preview.addView(mPreview);
}
private boolean checkCameraHardware(Context context) {
if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)){
// this device has a camera
return true;
} else {
// no camera on this device
return false;
}
}
public static Camera getCameraInstance(){
Camera c = null;
try {
c = Camera.open(); // attempt to get a Camera instance
}
catch (Exception e){
// Camera is not available (in use or does not exist)
}
return c; // returns null if camera is unavailable
}
}
CameraPreview.java
package com.example.nikola.camera;
/**
* Created by Nikola on 8/4/2016.
*/
import android.content.Context;
import android.hardware.Camera;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import java.io.IOException;
/** A basic Camera preview class */
public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
private SurfaceHolder mHolder;
private Camera mCamera;
public CameraPreview(Context context, Camera camera) {
super(context);
mCamera = camera;
// Install a SurfaceHolder.Callback so we get notified when the
// underlying surface is created and destroyed.
mHolder = getHolder();
mHolder.addCallback(this);
// deprecated setting, but required on Android versions prior to 3.0
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
public void surfaceCreated(SurfaceHolder holder) {
// The Surface has been created, now tell the camera where to draw the preview.
try {
mCamera.setPreviewDisplay(holder);
mCamera.startPreview();
} catch (IOException e) {
Log.d("Camera_app", "Error setting camera preview: " + e.getMessage());
}
}
public void surfaceDestroyed(SurfaceHolder holder) {
// empty. Take care of releasing the Camera preview in your activity.
}
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
// If your preview can change or rotate, take care of those events here.
// Make sure to stop the preview before resizing or reformatting it.
if (mHolder.getSurface() == null){
// preview surface does not exist
return;
}
// stop preview before making changes
try {
mCamera.stopPreview();
} catch (Exception e){
// ignore: tried to stop a non-existent preview
}
// set preview size and make any resize, rotate or
// reformatting changes here
// start preview with new settings
try {
mCamera.setPreviewDisplay(mHolder);
mCamera.startPreview();
} catch (Exception e){
Log.d("Camera_app", "Error starting camera preview: " + e.getMessage());
}
}
}
答案 0 :(得分：0)
添加相机的第一个权限并在SD卡中拍摄图像
<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
点击预览图片点击并预览您将获得回调路径
preview.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
mCamera.takePicture(null, null, mPicture);
}
});
Take In class Imagepath您的图片路径会在您的课程中
private Camera.PictureCallback mPicture = new Camera.PictureCallback() {
public void onPictureTaken(byte[] data, Camera camera) {
// Replacing the button after a photho was taken.
// File name of the image that we just took.
String fileName = "IMG_" + new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date()).toString() + ".jpg";
// Creating the directory where to save the image. Sadly in older
// version of Android we can not get the Media catalog name
File sdRoot = Environment.getExternalStorageDirectory();
// have the object build the directory structure, if needed.
String dir = "/Capture/path/";
File mkDir = new File(sdRoot, dir);
mkDir.mkdirs();
// Main file where to save the data that we recive from the camera
File pictureFile = new File(sdRoot, dir + fileName);
String imagePath=pictureFile.getPath();
System.out.print("imagePath"+imagePath);
try {
FileOutputStream purge = new FileOutputStream(pictureFile);
purge.write(data);
purge.close();
} catch (FileNotFoundException e) {
Log.d("DG_DEBUG", "File not found: " + e.getMessage());
} catch (IOException e) {
Log.d("DG_DEBUG", "Error accessing file: " + e.getMessage());
}
// Adding Exif data for the orientation. For some strange reason the
// ExifInterface class takes a string instead of a file.
try {
exif = new ExifInterface("/sdcard/" + dir + fileName);
exif.setAttribute(ExifInterface.TAG_ORIENTATION, "" + orientation);
exif.saveAttributes();
} catch (IOException e) {
e.printStackTrace();
}
}
};
但我向你推荐了Camera2Basic ......其中有很多例子，因为这是不推荐使用的
我建议你做这个在marashmallow中运行的例子，或者所有设备都能正常工作......
https://github.com/googlesamples/android-Camera2Basic
用于面部剔除
您必须注册FaceDetectionListener，然后致电camera.startFaceDetection()。
请参阅面部扭曲的链接..
https://docs.google.com/open?id=0B2Nu5U2Cz81qZExGQ25sWVdRd21IOExUUTZsZzFoZw