溫馨提示×
您好，登錄后才能下訂單哦！
點擊 登錄注冊 即表示同意《億速云用戶服務條款》
您好，登錄后才能下訂單哦！
本篇文章為大家展示了Android中怎么實現圖片識別功能，內容簡明扼要并且容易理解，絕對能使你眼前一亮，通過這篇文章的詳細介紹希望你能有所收獲。
1、界面
我采用了一個SurfaceView用來顯示攝像頭的預覽畫面，重寫了一個SurfaceView來進行紅色方框還有菜品名字的繪制。圖片是一個ImageVIew，相當于拍照按鈕的功能。
<?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" tools:context="com.hd.hd.MainActivity"> <SurfaceView android:layout_width="match_parent" android:layout_height="match_parent" android:id="@+id/surfaceView" android:layout_centerHorizontal="true" android:layout_centerVertical="true"/> <com.hd.hd.SVDraw android:layout_width="match_parent" android:layout_height="match_parent" android:id="@+id/mySurfaceView" android:layout_centerHorizontal="true" android:layout_centerVertical="true"/> <LinearLayout android:layout_width="wrap_content" android:layout_height="wrap_content" android:orientation="horizontal" android:layout_alignParentBottom="true" > <ImageView android:id="@+id/btngal" android:layout_width="wrap_content" android:layout_height="wrap_content" android:gravity="center_horizontal" android:layout_alignParentBottom="true" android:src="@drawable/s_8" android:layout_alignParentLeft="true" /> <TextView android:id="@+id/textview" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center" android:textColor="@color/white" android:textSize="20dp" android:layout_toRightOf="@id/btngal" android:layout_alignParentTop="true" /> </LinearLayout> </RelativeLayout>
SVDraw,，繼承SurfaceView，用于繪制紅色方框
package com.hd.hd;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.graphics.PorterDuff;
import android.util.AttributeSet;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import java.util.List;
/*定義一個畫矩形框的類*/
public class SVDraw extends SurfaceView implements SurfaceHolder.Callback{
protected SurfaceHolder sh;
private int mWidth;
private int mHeight;
public SVDraw(Context context, AttributeSet attrs) {
super(context, attrs);
// TODO Auto-generated constructor stub
sh = getHolder();
sh.addCallback(this);
sh.setFormat(PixelFormat.TRANSPARENT);
setZOrderOnTop(true);
}
public void surfaceChanged(SurfaceHolder arg0, int arg1, int w, int h) {
// TODO Auto-generated method stub
}
public void surfaceCreated(SurfaceHolder sh) {
// TODO Auto-generated method stub
mWidth = this.getWidth();
mHeight = this.getHeight();
}
public void surfaceDestroyed(SurfaceHolder arg0) {
// TODO Auto-generated method stub
}
void clearDraw()
{
Canvas canvas = sh.lockCanvas();
canvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR);
sh.unlockCanvasAndPost(canvas);
}
public void drawLine(List<String> keys, List<String> values)
{
Canvas canvas = sh.lockCanvas();
canvas.drawColor(Color.TRANSPARENT);
Paint p = new Paint();
p.setAntiAlias(true);
p.setColor(Color.RED);
p.setStrokeWidth(6);
p.setStyle(Paint.Style.STROKE);//設置空心
p.setTextSize(160);
Paint p1 = new Paint();
p1.setColor(Color.WHITE);
p1.setTextSize(80);
for(int i = 0;i < keys.size();i++){
String v = values.get(i);
v = v.replace("[","");
v = v.replace("]","");
String[] value = v.split(",");
canvas.drawRect(mWidth - Integer.parseInt(value[3]), Integer.parseInt(value[0]), mHeight - Integer.parseInt(value[1]), Integer.parseInt(value[2]), p);// 正方形
canvas.drawText(keys.get(i), mWidth - Integer.parseInt(value[3]), Integer.parseInt(value[0])-5, p1);
}
sh.unlockCanvasAndPost(canvas);
}
}2、上傳圖片到服務器，我沒有采用JSon的格式，而是直接將圖片文件轉化為字節數組，發送給服務器。使用一個異步任務，完成后，直接在onPostExcute()方法里繪制。
package com.hd.hd;
import android.os.AsyncTask;
import android.util.Log;
import android.widget.TextView;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.UUID;
/**
* Created by asus on 2017/8/13.
*/
public class MyTask extends AsyncTask<String, Integer, String> {
private static String TAG = "MainActivity";
private File file; //需要發送的圖片
private String result_content; //服務器返回的結果
private SVDraw surfaceView; //需要繪制的surfaceview
private TextView tv; //顯示文字
private static final int TIME_OUT = 10 * 1000; // 超時時間
private static final String CHARSET = "utf-8"; // 設置編碼
public MyTask(File f,SVDraw s,TextView tv){
this.file = f;
this.surfaceView = s;
this.tv = tv;
}
@Override
protected void onPreExecute() {
}
//doInBackground方法內部執行后臺任務,不可在此方法內修改UI
@Override
protected String doInBackground(String... params) {
//調用文件上傳方法
result_content = uploadFile(file,"http://13.76.211.62/");
return null;
}
//onProgressUpdate方法用于更新進度信息
@Override
protected void onProgressUpdate(Integer... progresses) {
}
//onPostExecute方法用于在執行完后臺任務后更新UI,顯示結果
@Override
protected void onPostExecute(String result) {
//由于返回的是一個python的字典形式的字符串，用json來解析
JSONObject obj = null;
List<String> keys = new ArrayList<String>();
List<String> values = new ArrayList<String>();
try {
obj = new JSONObject(result_content);
//json對象的Key的迭代器，用來遍歷json
Iterator it = obj.keys();
while (it.hasNext()) {
String key = (String) it.next();
String value = obj.getString(key);
keys.add(key);
values.add(value);
}
} catch (JSONException e) {
e.printStackTrace();
}
//繪制圖形
surfaceView.clearDraw();
surfaceView.drawLine(keys,values);
tv.setText("搭配很贊哦");
}
//onCancelled方法用于在取消執行中的任務時更改UI
@Override
protected void onCancelled() {
}
/**
* 上傳圖片文件到服務器
* @param file
* @param RequestURL
* @return
*/
public static String uploadFile(File file, String RequestURL) {
String result = null;
String BOUNDARY = UUID.randomUUID().toString(); // 邊界標識 隨機生成
String PREFIX = "--", LINE_END = "\r\n";
String CONTENT_TYPE = "multipart/form-data"; // 內容類型
try {
//創建URL連接，指明連接地址
URL url = new URL(RequestURL);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
//設置http請求的屬性為POST
conn.setReadTimeout(TIME_OUT);
conn.setConnectTimeout(TIME_OUT);
conn.setDoInput(true); // 允許輸入流
conn.setDoOutput(true); // 允許輸出流
conn.setUseCaches(false); // 不允許使用緩存
conn.setRequestMethod("POST"); // 請求方式
conn.setRequestProperty("Charset", CHARSET); // 設置編碼
conn.setRequestProperty("connection", "keep-alive");
conn.setRequestProperty("Content-Type", CONTENT_TYPE + ";boundary=" + BOUNDARY);
if (file != null) {
/**
* 當文件不為空，把文件包裝并且上傳
*/
Log.i(TAG,"upload");
DataOutputStream dos = new DataOutputStream(conn.getOutputStream());
Log.e(TAG,"not null");
/**
* 這里重點注意： name里面的值為服務端需要key 只有這個key 才可以得到對應的文件
* filename是文件的名字，包含后綴名的 比如:abc.png
*/
InputStream is = new FileInputStream(file);
byte[] bytes = new byte[1024];
int len;
while ((len = is.read(bytes)) != -1) {
dos.write(bytes, 0, len);
}
is.close();
dos.flush();
Log.e(TAG,"sent");
/**
* 獲取響應碼 200=成功 當響應成功，獲取響應的流
*/
int res = conn.getResponseCode();
Log.e(TAG, "response code:" + res);
Log.e(TAG, "request success");
InputStream input = conn.getInputStream();
StringBuffer sb1 = new StringBuffer();
int ss;
while ((ss = input.read()) != -1) {
sb1.append((char) ss);
}
result = sb1.toString();
Log.e(TAG, "result : " + result);
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return result;
}
}3、初始化界面、照相機，使得照相機能夠實時預覽，并實現拍照功能
package com.hd.hd;
import android.Manifest;
import android.content.Context;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.ImageFormat;
import android.hardware.camera2.CameraAccessException;
import android.hardware.camera2.CameraCaptureSession;
import android.hardware.camera2.CameraCharacteristics;
import android.hardware.camera2.CameraDevice;
import android.hardware.camera2.CameraManager;
import android.hardware.camera2.CaptureRequest;
import android.hardware.camera2.CaptureResult;
import android.hardware.camera2.TotalCaptureResult;
import android.media.Image;
import android.media.ImageReader;
import android.os.Build;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.os.HandlerThread;
import android.support.annotation.NonNull;
import android.support.annotation.RequiresApi;
import android.support.v4.app.ActivityCompat;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.util.SparseIntArray;
import android.view.Surface;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.Arrays;
public class MainActivity extends AppCompatActivity{
private static final SparseIntArray ORIENTATIONS = new SparseIntArray();
private String TAG = "MainActivity";
///為了使照片豎直顯示
static {
ORIENTATIONS.append(Surface.ROTATION_0, 90);
ORIENTATIONS.append(Surface.ROTATION_90, 0);
ORIENTATIONS.append(Surface.ROTATION_180, 270);
ORIENTATIONS.append(Surface.ROTATION_270, 180);
}
private SurfaceView mSurfaceView;
private SurfaceHolder mSurfaceHolder;
private CameraManager mCameraManager;//攝像頭管理器
private Handler childHandler, mainHandler;
private String mCameraID;//攝像頭Id 0 為后 1 為前
private ImageReader mImageReader;
private CameraCaptureSession mCameraCaptureSession;
private CameraDevice mCameraDevice;
private SVDraw hSurfaceView;
private MyTask myTask;
private CaptureRequest.Builder captureRequestBuilder;
private TextView tv;
private final int DRAW_ORDER = 10;
private Handler myHandler;
private ImageView imageView;
private String dir = Environment.getExternalStorageDirectory().getAbsolutePath() + "/Healthy_d/";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//此步驟非常重要，安卓不用自動幫你創建文件夾來保存拍照的照片
File dirFirstFolder = new File(dir);//方法二：通過變量文件來獲取需要創建的文件夾名字
if(!dirFirstFolder.exists())
{ //如果該文件夾不存在，則進行創建
dirFirstFolder.mkdirs();//創建文件夾
}
//Android 6后有些敏感的權限不能隨意分配，必須向用戶發送請求賦予
//這里請求用戶賦予拍照，讀寫內存卡，連接網絡的權限，其實只有拍照權限需要向用戶請求，但是有備無患吧
if (ActivityCompat.checkSelfPermission(MainActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
Log.e(TAG,ActivityCompat.checkSelfPermission(MainActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE)+"");
ActivityCompat.requestPermissions(MainActivity.this,
new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},
43);
}
if (ActivityCompat.checkSelfPermission(MainActivity.this, Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(MainActivity.this,
new String[]{Manifest.permission.READ_EXTERNAL_STORAGE},
44);
}
if (ActivityCompat.checkSelfPermission(MainActivity.this, Manifest.permission.INTERNET) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(MainActivity.this,
new String[]{Manifest.permission.INTERNET},
45);
}
initVIew();
}
/**
* 初始化視圖
*/
private void initVIew() {
HandlerThread handlerThread = new HandlerThread("Camera2");
handlerThread.start();
childHandler = new Handler(handlerThread.getLooper());
//mSurfaceView
mSurfaceView = (SurfaceView) findViewById(R.id.surfaceView);
hSurfaceView = (SVDraw) findViewById(R.id.mySurfaceView);
imageView = (ImageView) findViewById(R.id.btngal);
tv = (TextView)findViewById(R.id.textview);
//設置ImageView監聽器，點擊圖片，拍照
imageView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(MainActivity.this, "正在識別，請稍等", Toast.LENGTH_LONG).show();
if (mCameraDevice == null) return;
// 創建拍照需要的CaptureRequest.Builder
try {
captureRequestBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE);
// 將imageReader的surface作為CaptureRequest.Builder的目標
captureRequestBuilder.addTarget(mImageReader.getSurface());
// 自動對焦
captureRequestBuilder.set(CaptureRequest.CONTROL_AF_MODE, CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE);
// 自動曝光
captureRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON_AUTO_FLASH);
// 獲取手機方向
int rotation = getWindowManager().getDefaultDisplay().getRotation();
// 根據設備方向計算設置照片的方向
captureRequestBuilder.set(CaptureRequest.JPEG_ORIENTATION, ORIENTATIONS.get(rotation));
//拍照
CaptureRequest mCaptureRequest = captureRequestBuilder.build();
mCameraCaptureSession.capture(mCaptureRequest, mSessionCaptureCallback, childHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
});
mSurfaceHolder = mSurfaceView.getHolder();
mSurfaceHolder.setKeepScreenOn(true);
// mSurfaceView添加回調
mSurfaceHolder.addCallback(new SurfaceHolder.Callback() {
@Override
public void surfaceCreated(SurfaceHolder holder) { //SurfaceView創建
// 初始化Camera
initCamera2();
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) { //SurfaceView銷毀
// 釋放Camera資源
if (null != mCameraDevice) {
mCameraDevice.close();
mCameraDevice = null;
}
}
});
}
//拍照時，可以對照片進行操作，這里可以不寫，因為我沒對其進行操作
private CameraCaptureSession.CaptureCallback mSessionCaptureCallback =
new CameraCaptureSession.CaptureCallback() {
@Override
public void onCaptureCompleted(CameraCaptureSession session, CaptureRequest request,
TotalCaptureResult result) {}
@Override
public void onCaptureProgressed(CameraCaptureSession session, CaptureRequest request,
CaptureResult partialResult){}};
/**
* 初始化Camera2
*/
@RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
private void initCamera2() {
HandlerThread handlerThread = new HandlerThread("Camera2");
handlerThread.start();
childHandler = new Handler(handlerThread.getLooper());
mainHandler = new Handler(getMainLooper());
mCameraID = "" + CameraCharacteristics.LENS_FACING_FRONT;//后攝像頭
mImageReader = ImageReader.newInstance(mSurfaceView.getWidth(), mSurfaceView.getHeight(), ImageFormat.JPEG,1);
mImageReader.setOnImageAvailableListener(new ImageReader.OnImageAvailableListener() { //可以在這里處理拍照得到的臨時照片 例如，寫入本地
@Override
public void onImageAvailable(ImageReader reader) {
Image image = reader.acquireNextImage();
ByteBuffer buffer = image.getPlanes()[0].getBuffer();
byte[] bytes = new byte[buffer.remaining()];
buffer.get(bytes);//由緩沖區存入字節數組
Bitmap bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
String fileName = "test";
File file = new File(dir + fileName + ".jpg");
String state = Environment.getExternalStorageState();
//如果狀態不是mounted，無法讀寫
if (!state.equals(Environment.MEDIA_MOUNTED)) {
return;
}
FileOutputStream out = null;
try {
out = new FileOutputStream(file);
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, out);//轉化為jpeg圖片
out.flush();
out.close();
image.close();//一定要記得關，否則會出現程序崩潰
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
new MyTask(file,hSurfaceView,tv).execute();
}
}, mainHandler);
//獲取攝像頭管理
mCameraManager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
try {
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(this,
new String[]{Manifest.permission.CAMERA},
42);
}
//打開攝像頭
mCameraManager.openCamera(mCameraID, stateCallback, mainHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
/**
* 當發送權限請求用戶響應時，回調該函數
* @param requestCode
* @param permissions
* @param grantResults
*/
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
if (requestCode == 42) {
Toast.makeText(this, "CAMERA PERMISSION GRANTED", Toast.LENGTH_SHORT).show();
if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
//申請成功，可以拍照
Log.i(TAG,"apply camera success");
CameraManager manager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
try {
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
Toast.makeText(this, "CAMERA PERMISSION DENIED", Toast.LENGTH_SHORT).show();
}
mCameraManager.openCamera(mCameraID, stateCallback, mainHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
} else {
Toast.makeText(this, "CAMERA PERMISSION DENIED", Toast.LENGTH_SHORT).show();
}
return;
}
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
}
/**
* 攝像頭創建監聽
*/
private CameraDevice.StateCallback stateCallback = new CameraDevice.StateCallback() {
@Override
public void onOpened(CameraDevice camera) {//打開攝像頭
mCameraDevice = camera;
//開啟預覽
takePreview();
}
@Override
public void onDisconnected(CameraDevice camera) {//關閉攝像頭
if (null != mCameraDevice) {
mCameraDevice.close();
mCameraDevice = null;
}
}
@Override
public void onError(CameraDevice camera, int error) {//發生錯誤
Toast.makeText(MainActivity.this, "攝像頭開啟失敗", Toast.LENGTH_SHORT).show();
}
};
/**
* 開始預覽
*/
private void takePreview() {
try {
// 創建預覽需要的CaptureRequest.Builder
final CaptureRequest.Builder previewRequestBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
// 將SurfaceView的surface作為CaptureRequest.Builder的目標
previewRequestBuilder.addTarget(mSurfaceHolder.getSurface());
// previewRequestBuilder.addTarget(mImageReader.getSurface());
// 創建CameraCaptureSession，該對象負責管理處理預覽請求和拍照請求
mCameraDevice.createCaptureSession(Arrays.asList(mSurfaceHolder.getSurface(), mImageReader.getSurface()), new CameraCaptureSession.StateCallback() // ③
{
@Override
public void onConfigured(CameraCaptureSession cameraCaptureSession) {
if (null == mCameraDevice) return;
// 當攝像頭已經準備好時，開始顯示預覽
mCameraCaptureSession = cameraCaptureSession;
try {
// 自動對焦
previewRequestBuilder.set(CaptureRequest.CONTROL_AF_MODE, CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE);
// 打開閃光燈
previewRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON_AUTO_FLASH);
// 顯示預覽
CaptureRequest previewRequest = previewRequestBuilder.build();
mCameraCaptureSession.setRepeatingRequest(previewRequest, null, childHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
@Override
public void onConfigureFailed(CameraCaptureSession cameraCaptureSession) {
Toast.makeText(MainActivity.this, "配置失敗", Toast.LENGTH_SHORT).show();
}
}, childHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
}4、AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.hd.hd"> <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/> <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/> <uses-permission android:name="android.permission.CAMERA"/> <uses-feature android:name="android.hardware.camera2.full" /> <uses-permission android:name="android.permission.INTERNET" /> <application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:supportsRtl="true" android:theme="@style/AppTheme"> <activity android:name=".MainActivity"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> </manifest>
上述內容就是Android中怎么實現圖片識別功能，你們學到知識或技能了嗎？如果還想學到更多技能或者豐富自己的知識儲備，歡迎關注億速云行業資訊頻道。
免責聲明：本站發布的內容（圖片、視頻和文字）以原創、轉載和分享為主，文章觀點不代表本網站立場，如果涉及侵權請聯系站長郵箱：is@yisu.com進行舉報，并提供相關證據，一經查實，將立刻刪除涉嫌侵權內容。
