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:
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:
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:
<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:
<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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