[英]Using the camera in android
我正在尝试构建一个仅使用相机拍照而不启动默认相机应用程序的Android应用程序。 换句话说,我想制作一个自定义的相机应用。 我可以使用Camera硬件对象类来执行此操作,但是不建议使用,我想使用camerax的一些新功能,而不必担心一段时间后代码无法正常工作。 我还阅读了相机API文档,但是仍不清楚如何使用相机。 有没有非常简单的分步教程或指南可以对我有所帮助? 谢谢,
您可以查看有关如何使用AndroidX库和TextureView进行相机自定义的示例。
https://github.com/icerrate/Custom-Camera-App
首先,定义您的布局。 这是我的activity_main.xml文件:
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<TextureView
android:id="@+id/view_finder"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent" />
<com.google.android.material.floatingactionbutton.FloatingActionButton
android:id="@+id/take_photo"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
android:layout_margin="@dimen/horizontal_margin"
app:layout_constraintStart_toStartOf="parent"
android:src="@drawable/ic_camera"/>
</androidx.constraintlayout.widget.ConstraintLayout>
请记住, TextureView将接收相机预览,并且“ 浮动动作”按钮用作“拍摄照片”按钮。
然后添加您的MainActivity.java文件:
public class MainActivity extends AppCompatActivity implements LifecycleOwner {
private static final int RC_PERMISSIONS = 100;
private TextureView viewFinder;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.activity_main);
viewFinder = findViewById(R.id.view_finder);
FloatingActionButton takePhotoFab = findViewById(R.id.take_photo);
//Check permissions
if (allPermissionGranted()) {
viewFinder.post(new Runnable() {
@Override
public void run() {
startCamera();
}
});
} else {
ActivityCompat.requestPermissions(this,
new String[] {Manifest.permission.CAMERA}, RC_PERMISSIONS);
}
takePhotoFab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
takePhoto();
}
});
}
private void startCamera() {
Point screenSize = getScreenSize();
int width = screenSize.x;
int height = screenSize.y;
//Get real aspect ratio
DisplayMetrics displayMetrics = new DisplayMetrics();
Display display = getWindowManager().getDefaultDisplay();
display.getRealMetrics(displayMetrics);
Rational rational = new Rational(displayMetrics.widthPixels, displayMetrics.heightPixels);
//Build the camera preview
PreviewConfig build = new PreviewConfig.Builder()
.setTargetAspectRatio(rational)
.setTargetResolution(new Size(width,height))
.build();
Preview preview = new Preview(build);
preview.setOnPreviewOutputUpdateListener(new Preview.OnPreviewOutputUpdateListener() {
@Override
public void onUpdated(Preview.PreviewOutput output) {
ViewGroup group = (ViewGroup) viewFinder.getParent();
group.removeView(viewFinder);
group.addView(viewFinder, 0);
viewFinder.setSurfaceTexture(output.getSurfaceTexture());
}
});
CameraX.bindToLifecycle(this, preview);
}
private void takePhoto() {
Toast.makeText(this, "Shot!",
Toast.LENGTH_SHORT).show();
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if (requestCode == RC_PERMISSIONS) {
if (allPermissionGranted()) {
viewFinder.post(new Runnable() {
@Override
public void run() {
startCamera();
}
});
} else {
Toast.makeText(this, "Permission not granted",
Toast.LENGTH_SHORT).show();
finish();
}
}
}
private boolean allPermissionGranted() {
return ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED;
}
private Point getScreenSize() {
Display display = getWindowManager(). getDefaultDisplay();
Point size = new Point();
display.getSize(size);
return size;
}
}
在此类中,您将能够在PreviewConfig.Builder()的帮助下将摄像机预览发送到TextureView ,并使用CameraX.bindToLifeCycle()将其绑定到Activity生命周期
同样,不要忘记将Camera权限添加到清单中并考虑运行时权限。
屏幕截图: 自定义相机预览
希望这对您有所帮助!
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