请帮忙。有没有办法使用Camera API（Android SDK 19和17之间的版本）使相机在长按关闭按钮拍照之前对焦？
换句话说，我长按相机按钮（我的意思是它可能是相机按钮或屏幕上的按钮）焦点必须开始，在第一秒我释放该按钮它应该拍照
请帮忙。
答案 0 :(得分：0)
好的，对于这个功能，两个方法是重要的onTouchEvent（我可以检测释放按钮）和setOnLongClickListener（以检测拍摄照片的长按按钮）。在下面的代码中，我创建了一个自定义视图（名为DrawCameraOptions类），它在SurfaceView上方的屏幕上绘制一个红色圆圈，另一个自定义视图（名为DrawingRectForFocalisationAreaView类）在焦点区域的SurfaceView上绘制一个rect。
fragment_take_picture.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<SurfaceView
android:id="@+id/surfaceView"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<customs.cameras.DrawingRectForFocalisationAreaView
android:id="@+id/drawingFocusRectangle_FragmentTakePicture"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<customs.cameras.DrawCameraOptions
android:id="@+id/takePicture_FragmentTakePicture2"
android:layout_width="match_parent"
android:layout_height="100dp"
android:background="@android:color/transparent"
android:layout_alignParentBottom="true"/>
</RelativeLayout>
UpdateDrawingFocusAreaRect接口
package network.callbacks;
import android.graphics.Rect;
import android.hardware.Camera;
/**
* Created by EmiG on 02.02.2017.
*/
public interface UpdateDrawingFocusAreaRect {
public void repaintRectFocusArea(final Rect touchRect);
public void takePictureOnLongPress();
}
DrawCameraOptions类
package customs.cameras;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import network.callbacks.UpdateDrawingFocusAreaRect;
/**
* Created by EmiG on 18.01.2017.
*/
public class DrawCameraOptions extends View {
private Paint paint;
private UpdateDrawingFocusAreaRect callback;
private static final String TAG="TakePictureFragment2";
public DrawCameraOptions(Context context) {
super(context);
this.initComponets();
}
public void setCallback(UpdateDrawingFocusAreaRect callback) {
this.callback = callback;
}
public DrawCameraOptions(Context context, AttributeSet attrs) {
super(context, attrs);
this.initComponets();
}
public DrawCameraOptions(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
this.initComponets();
}
private void initComponets()
{
this.paint=new Paint(paint.ANTI_ALIAS_FLAG);
this.paint.setStyle(Paint.Style.FILL_AND_STROKE);
this.paint.setColor(Color.RED);
}
@Override
protected void onDraw(Canvas canvas) {
//super.onDraw(canvas);
final int width=getWidth() - getPaddingLeft() - getPaddingRight();//of the view
final int height=getHeight() - getPaddingTop() - getPaddingBottom();
final int cx=width/2 + getPaddingLeft();
final int cy=height/2 + getPaddingTop();
final float diameter= Math.min(width, height) - paint.getStrokeWidth();
final float radious=diameter/2;
canvas.drawCircle(cx,cy,radious,this.paint);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_UP:
Log.i(TAG,"ACTION_UP");
if(null!=this.callback)
{
this.callback.takePictureOnLongPress();
}
break;
}
return super.onTouchEvent(event);
}
}
DrawingRectForFocalisationAreaView类
package customs.cameras;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.View;
/**
* Created by EmiG on 25.01.2017.
*/
public class DrawingRectForFocalisationAreaView extends View {
private Paint drawingPaint;
boolean haveTouch;
private Rect touchArea;
private static final int RECT_DIMENSIONS=50;
public DrawingRectForFocalisationAreaView(Context context) {
super(context);
this.init();
}
public DrawingRectForFocalisationAreaView(Context context, AttributeSet attrs) {
super(context, attrs);
this.init();
}
public DrawingRectForFocalisationAreaView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
this.init();
}
private void init()
{
this.drawingPaint = new Paint();
this.drawingPaint.setColor(Color.RED);
this.drawingPaint.setStyle(Paint.Style.STROKE);
this.drawingPaint.setStrokeWidth(2);
this.haveTouch = false;
}
public void setHaveTouch(boolean t, Rect tArea){
this.drawingPaint.setColor(Color.RED);
this.haveTouch = t;
this.touchArea = tArea;
}
public void validateFocus()
{
if(Color.RED == this.drawingPaint.getColor())
{
this.drawingPaint.setColor(Color.GREEN);
this.haveTouch=true;
invalidate();
}
}
@Override
protected void onDraw(Canvas canvas) {
if(this.haveTouch && null!=canvas&& null!=this.drawingPaint){
canvas.drawRect(this.touchArea.left-RECT_DIMENSIONS, this.touchArea.top-RECT_DIMENSIONS, this.touchArea.right+RECT_DIMENSIONS, this.touchArea.bottom+RECT_DIMENSIONS, this.drawingPaint);
this.haveTouch=false;
}
}
}
TakePictureFragment2类
public class TakePictureFragment2 extends Fragment implements SurfaceHolder.Callback, View.OnTouchListener, UpdateDrawingFocusAreaRect {
private static final String TAG = TakePictureFragment2.class.getSimpleName();
//region Focus variabiles
private boolean bIsPictureTaking, bIsAutoFocusStarted, bIsAutoFocused, USE_AUTOFOCUS, isFocusated, isLongPressed, canTakePicture;
private static final int FOCUS_AREA_SIZE = 300;
//endregion
private boolean camCondition = false; // conditional variable for camera preview checking and set to false
//region Camera object
private Camera camera;
private SurfaceView surfaceView;
private SurfaceHolder surfaceHolder;
private Camera.PictureCallback jpegCallback;
//endregion
//region Execute multiple calculation functionality for drawing
private ThreadPoolExecutor threadPoolExecutor;
public static final int NUMBER_OF_CORES = Runtime.getRuntime().availableProcessors();
//endregion
//region Custom Objects that draw on the screen
private DrawCameraOptions takePictureButton;// Draw shuttbutton for capture image
//Desenare pe ecran punct de focalizare
private DrawingRectForFocalisationAreaView drawingRectangleOnScreen;//Draw blue rectangle on focus area
//endregion
//region Fragent methods
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
Log.i(TAG, "onCreateView()");
View view = inflater.inflate(R.layout.fragment_take_picture, container, false);
if (null != view) {
return view;
}
return super.onCreateView(inflater, container, savedInstanceState);
}
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
Log.i(TAG, "onActivityCreated()");
this.initOnTouchListener();
}
@Override
public void onResume() {
super.onResume();
Log.i(TAG, "onResume()");
this.initComponents();
if (null != camera) {
try {
camera.setPreviewDisplay(surfaceHolder); // setting preview of camera
camera.startPreview();
} catch (IOException e) {
e.printStackTrace();
}
}
}
//endregion
//region Initial Components
private void initOnTouchListener() {
if (null != this.getView()) {
this.getView().setOnTouchListener(TakePictureFragment2.this);
}
}
private void initComponents() {
if (null != getView()) {
this.drawingRectangleOnScreen = (DrawingRectForFocalisationAreaView) getView().findViewById(R.id.drawingFocusRectangle_FragmentTakePicture);
takePictureButton = (DrawCameraOptions) getView().findViewById(R.id.takePicture_FragmentTakePicture2);
takePictureButton.setCallback(TakePictureFragment2.this);
takePictureButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Log.i(TAG,"Simple click");
camera.takePicture(null, null, jpegCallback);
}
});
takePictureButton.setOnLongClickListener(new View.OnLongClickListener() {
@Override
public boolean onLongClick(View v) {
Log.i(TAG,"Long click");
final Context context=getView().getContext();
isLongPressed=true;
synchronized (this) {
if (camera != null) {
camera.cancelAutoFocus();
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.GINGERBREAD) {
if (!bIsPictureTaking && !bIsAutoFocusStarted) {
bIsAutoFocusStarted = true;
new AsyncTask<Void, Void, Void>() {
@Override
protected Void doInBackground(Void... params) {
try {
Camera.Parameters parameters = camera.getParameters();
if (parameters.getMaxNumMeteringAreas() > 0) {
Log.i(TAG, "fancy !");
Display display = ((WindowManager) context.getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
Point screenDsiplay=new Point();
display.getSize(screenDsiplay);
Rect rect = calculateFocusArea(screenDsiplay.x/2, screenDsiplay.y/2);
display=null;
screenDsiplay=null;
parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_AUTO);
List<Camera.Area> meteringAreas = new ArrayList<Camera.Area>();
meteringAreas.add(new Camera.Area(rect, 1000));
parameters.setFocusAreas(meteringAreas);
camera.setParameters(parameters);
camera.autoFocus(mAutoFocusTakePictureCallback);
} else {
camera.autoFocus(mAutoFocusTakePictureCallback);
}
bIsAutoFocusStarted = false;
} catch (Exception e) {
Log.e(TAG, "Error " + e.getMessage());
e.printStackTrace();
}
System.gc();
return null;
}
}.execute((Void[]) null);
}
} else {
if (!bIsPictureTaking && !bIsAutoFocusStarted) {
bIsAutoFocusStarted = true;
new AsyncTask<Void, Void, Void>() {
@Override
protected Void doInBackground(Void... params) {
try {
Camera.Parameters parameters = camera.getParameters();
if (parameters.getMaxNumMeteringAreas() > 0) {
Log.i(TAG, "fancy !");
Display display2 = ((WindowManager) context.getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
Point screenDsiplay2=new Point();
display2.getSize(screenDsiplay2);
Rect rect = calculateFocusArea(screenDsiplay2.x/2, screenDsiplay2.y/2);
display2=null;
screenDsiplay2=null;
parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_AUTO);
List<Camera.Area> meteringAreas = new ArrayList<Camera.Area>();
meteringAreas.add(new Camera.Area(rect, 1000));
parameters.setFocusAreas(meteringAreas);
camera.setParameters(parameters);
camera.autoFocus(mAutoFocusTakePictureCallback);
} else {
camera.autoFocus(mAutoFocusTakePictureCallback);
}
bIsAutoFocusStarted = false;
} catch (Exception e) {
Log.e(TAG, "Error " + e.getMessage());
e.printStackTrace();
}
System.gc();
return null;
}
}.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, (Void[]) null);
}
}
}
}
return true;
}
});
surfaceView = (SurfaceView) getView().findViewById(R.id.surfaceView);
surfaceHolder = surfaceView.getHolder();
// deprecated setting, but required on Android versions prior to 3.0
surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
// Install a SurfaceHolder.Callback so we get notified when the
// underlying surface is created and destroyed.
surfaceHolder.addCallback(this);
jpegCallback = new Camera.PictureCallback() {
public void onPictureTaken(final byte[] data, Camera camera) {
USE_AUTOFOCUS=false;
canTakePicture=false;
final Context context = getView().getContext();
if(Build.VERSION.SDK_INT < Build.VERSION_CODES.GINGERBREAD) {
new AsyncTask<Void, Void, Void>() {
@Override
protected Void doInBackground(Void... params) {
bIsPictureTaking = true; //set it to true to avoid onKeyDown dispatching during taking picture. it may be time-consuming
bIsAutoFocused = false; //reset to false
bIsAutoFocusStarted = false; //reset to false
FileOutputStream outStream = null;
try {
final GregorianCalendar gregorianCalendar = new GregorianCalendar();
gregorianCalendar.setTime(new Date());
final StringBuffer stringBufferFileName = new StringBuffer();
stringBufferFileName.append(gregorianCalendar.get(Calendar.YEAR));
stringBufferFileName.append("_");
stringBufferFileName.append(gregorianCalendar.get(Calendar.MONTH) + 1);
stringBufferFileName.append("_");
stringBufferFileName.append(gregorianCalendar.get(Calendar.DAY_OF_MONTH) + 1);
final File root = new File(Environment.getExternalStorageDirectory() + File.separator + "Rompetrol", stringBufferFileName.toString());
if (!root.exists()) {
root.mkdirs();
}
final File gpxfile = new File(root, System.currentTimeMillis() + ".jpg");
outStream = new FileOutputStream(gpxfile);
outStream.write(data);
outStream.close();
Log.d("Log", "onPictureTaken - wrote bytes: " + data.length);
final AudioManager meng = (AudioManager) context.getSystemService(Context.AUDIO_SERVICE);
int volume = meng.getStreamVolume(AudioManager.STREAM_NOTIFICATION);
if (volume != 0) {
final MediaPlayer _shootMP = MediaPlayer.create(context, Uri.parse("file:///system/media/audio/ui/camera_click.ogg"));
_shootMP.start();
}
bIsPictureTaking = false;
JSONObject jsonObjecte = new JSONObject();
try {
jsonObjecte.put(EventBusMessages.OPERATION_TO_PERFORM.getkey(), EventBusMessages.CHANGE_FRAGMENT.getkey());
jsonObjecte.put(EventBusMessages.CHANGE_FRAGMENT.getkey(), FragmentList.DISPLAY_PICTURE_FRAGMENT.getKey());
jsonObjecte.put(EventBusMessages.PICTURE_PATH.getkey(), gpxfile.getAbsolutePath());
EventBus.getDefault().post(jsonObjecte);
} catch (JSONException e) {
e.printStackTrace();
}
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
}.execute((Void[]) null);
}
else
{
new AsyncTask<Void, Void, Void>() {
@Override
protected Void doInBackground(Void... params) {
bIsPictureTaking = true; //set it to true to avoid onKeyDown dispatching during taking picture. it may be time-consuming
bIsAutoFocused = false; //reset to false
bIsAutoFocusStarted = false; //reset to false
FileOutputStream outStream = null;
try {
final GregorianCalendar gregorianCalendar = new GregorianCalendar();
gregorianCalendar.setTime(new Date());
final StringBuffer stringBufferFileName = new StringBuffer();
stringBufferFileName.append(gregorianCalendar.get(Calendar.YEAR));
stringBufferFileName.append("_");
stringBufferFileName.append(gregorianCalendar.get(Calendar.MONTH) + 1);
stringBufferFileName.append("_");
stringBufferFileName.append(gregorianCalendar.get(Calendar.DAY_OF_MONTH) + 1);
final File root = new File(Environment.getExternalStorageDirectory() + File.separator + "Rompetrol", stringBufferFileName.toString());
if (!root.exists()) {
root.mkdirs();
}
final File gpxfile = new File(root, System.currentTimeMillis() + ".jpg");
outStream = new FileOutputStream(gpxfile);
outStream.write(data);
outStream.close();
Log.d("Log", "onPictureTaken - wrote bytes: " + data.length);
final AudioManager meng = (AudioManager) context.getSystemService(Context.AUDIO_SERVICE);
int volume = meng.getStreamVolume(AudioManager.STREAM_NOTIFICATION);
if (volume != 0) {
final MediaPlayer _shootMP = MediaPlayer.create(context, Uri.parse("file:///system/media/audio/ui/camera_click.ogg"));
_shootMP.start();
}
bIsPictureTaking = false;
JSONObject jsonObjecte = new JSONObject();
try {
jsonObjecte.put(EventBusMessages.OPERATION_TO_PERFORM.getkey(), EventBusMessages.CHANGE_FRAGMENT.getkey());
jsonObjecte.put(EventBusMessages.CHANGE_FRAGMENT.getkey(), FragmentList.DISPLAY_PICTURE_FRAGMENT.getKey());
jsonObjecte.put(EventBusMessages.PICTURE_PATH.getkey(), gpxfile.getAbsolutePath());
EventBus.getDefault().post(jsonObjecte);
} catch (JSONException e) {
e.printStackTrace();
}
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
}.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR,(Void[]) null);
}
// stop preview before making changes
try {
camera.stopPreview();
surfaceView.invalidate();
surfaceHolder = null;
} catch (Exception e) {
// ignore: tried to stop a non-existent preview
}
}
};
this.threadPoolExecutor = new ThreadPoolExecutor(
NUMBER_OF_CORES * 2,
NUMBER_OF_CORES * 2,
20L,
TimeUnit.SECONDS,
new LinkedBlockingQueue<Runnable>());
this.USE_AUTOFOCUS = false;
this.bIsPictureTaking = false; //set it to true to avoid onKeyDown dispatching during taking picture. it may be time-consuming
this.bIsAutoFocused = false; //reset to false
this.bIsAutoFocusStarted = false; //reset to false
this.isLongPressed=false;//reset to false
this.canTakePicture=false;//reset to false
}
}
//endregion
public void repaintRectFocusArea(final Rect touchRect) {
if (Thread.currentThread() == Looper.getMainLooper().getThread()) {
drawingRectangleOnScreen.setHaveTouch(true, touchRect);
drawingRectangleOnScreen.invalidate();
} else {
getActivity().runOnUiThread(new Runnable() {
@Override
public void run() {
drawingRectangleOnScreen.setHaveTouch(true, touchRect);
drawingRectangleOnScreen.invalidate();
}
});
}
}
public void takePictureOnLongPress() {
if(this.isLongPressed)
{
Log.i(TAG,"ACTION_BUTTON_RELEASE");
this.isLongPressed=false;
this.canTakePicture=true;
camera.takePicture(null, null, jpegCallback);
}
}
请原谅我的错误代码写作。