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如何使用java将摄像头拍摄的图像添加到Android的imageviewer中?我已经尝试了以下代码

以下是使用Java将摄像头拍摄的图像添加到Android的ImageViewer中的示例代码:

代码语言:txt
复制
import android.Manifest;
import android.content.pm.PackageManager;
import android.hardware.Camera;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;

import java.io.IOException;

public class MainActivity extends AppCompatActivity implements SurfaceHolder.Callback, Camera.PreviewCallback {

    private static final int CAMERA_PERMISSION_REQUEST_CODE = 100;

    private Camera camera;
    private SurfaceView surfaceView;
    private ImageView imageView;
    private Button captureButton;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        surfaceView = findViewById(R.id.surfaceView);
        imageView = findViewById(R.id.imageView);
        captureButton = findViewById(R.id.captureButton);

        SurfaceHolder surfaceHolder = surfaceView.getHolder();
        surfaceHolder.addCallback(this);

        captureButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                captureImage();
            }
        });
    }

    @Override
    protected void onResume() {
        super.onResume();
        requestCameraPermission();
    }

    private void requestCameraPermission() {
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA}, CAMERA_PERMISSION_REQUEST_CODE);
        } else {
            startCameraPreview();
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        if (requestCode == CAMERA_PERMISSION_REQUEST_CODE) {
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                startCameraPreview();
            }
        }
    }

    private void startCameraPreview() {
        try {
            camera = Camera.open();
            camera.setPreviewDisplay(surfaceView.getHolder());
            camera.setPreviewCallback(this);
            camera.startPreview();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private void captureImage() {
        camera.takePicture(null, null, new Camera.PictureCallback() {
            @Override
            public void onPictureTaken(byte[] data, Camera camera) {
                camera.stopPreview();
                camera.release();

                Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
                imageView.setImageBitmap(bitmap);
            }
        });
    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        if (camera != null) {
            camera.stopPreview();
            camera.release();
        }
    }

    @Override
    public void onPreviewFrame(byte[] data, Camera camera) {
    }
}

这段代码实现了以下功能:

  1. 在Android应用中显示一个SurfaceView用于预览摄像头的图像。
  2. 当点击按钮时,拍摄一张照片并将其显示在ImageView中。

请注意,为了使代码正常工作,您需要在AndroidManifest.xml文件中添加相机权限:

代码语言:txt
复制
<uses-permission android:name="android.permission.CAMERA" />

此外,您还需要在布局文件中添加SurfaceView、ImageView和Button:

代码语言:txt
复制
<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=".MainActivity">

    <SurfaceView
        android:id="@+id/surfaceView"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:visibility="gone" />

    <Button
        android:id="@+id/captureButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_alignParentBottom="true"
        android:text="Capture" />

</RelativeLayout>

这段代码中使用了Android的Camera类来访问摄像头,并使用SurfaceView来显示摄像头的预览图像。当点击按钮时,调用takePicture()方法拍摄照片,并在PictureCallback中将照片显示在ImageView中。

这是一个简单的示例,您可以根据自己的需求进行修改和扩展。

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