我目前正在设计一款只需点击一下按钮即可调用相机的应用。我现在想要将出现在相机中心的形状（例如，现在是一个圆/矩形，具体取决于设备）更改为自定义形状。我正在使用主要活动类和相机预览类制作自定义相机。到目前为止，这是我的代码：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent" android:id="@+id/layout">
<TextView android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:contentDescription="@string/camstring"
android:textSize="24sp" />
<FrameLayout android:id="@+id/preview"
android:layout_weight="1"
android:layout_width="fill_parent"
android:layout_height="0dp">
</FrameLayout>
<Button android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/buttonClick"
android:contentDescription="@string/action"
android:layout_gravity="center"></Button>
</LinearLayout>
package com.test.Nurse_Cam;
import android.os.Bundle;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import android.app.Activity;
import android.hardware.Camera;
import android.hardware.Camera.PictureCallback;
import android.hardware.Camera.ShutterCallback;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.FrameLayout;
public class MainActivity extends Activity {
private static final String TAG = "CameraDemo";
Camera camera;
Preview preview;
Button buttonClick;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
preview = new Preview(this);
((FrameLayout) findViewById(R.id.preview)).addView(preview);
buttonClick = (Button) findViewById(R.id.buttonClick);
buttonClick.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
preview.camera.takePicture(shutterCallback, rawCallback,
jpegCallback);
}
});
Log.d(TAG, "onCreate'd");
}
ShutterCallback shutterCallback = new ShutterCallback() {
public void onShutter() {
Log.d(TAG, "onShutter'd");
}
};
/** Handles data for raw picture */
PictureCallback rawCallback = new PictureCallback() {
public void onPictureTaken(byte[] data, Camera camera) {
Log.d(TAG, "onPictureTaken - raw");
}
};
/** Handles data for jpeg picture */
PictureCallback jpegCallback = new PictureCallback() {
public void onPictureTaken(byte[] data, Camera camera) {
FileOutputStream outStream = null;
try {
// write to local sandbox file system
// outStream =
// CameraDemo.this.openFileOutput(String.format("%d.jpg",
// System.currentTimeMillis()), 0);
// Or write to sdcard
outStream = new FileOutputStream(String.format(
getString(R.string._sdcard_d_jpg), System.currentTimeMillis()));
outStream.write(data);
outStream.close();
Log.d(TAG, "onPictureTaken - wrote bytes: " + data.length);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
}
Log.d(TAG, "onPictureTaken - jpeg");
}
};
}
package com.test.Nurse_Cam;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
//import java.util.Iterator;
import java.util.List;
import android.annotation.SuppressLint;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.hardware.Camera;
import android.hardware.Camera.PreviewCallback;
import android.hardware.Camera.Size;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
@SuppressLint("SdCardPath")
class Preview extends SurfaceView implements SurfaceHolder.Callback {
private static final String TAG = "Preview";
//private final static double epsilon = 0.17;
private Size mPreviewSize;
SurfaceHolder mHolder;
public Camera camera;
public List<Size> mSupportedPreviewSizes = camera.getParameters().getSupportedPreviewSizes();
@SuppressWarnings("deprecation")
Preview(Context context) {
super(context);
// Install a SurfaceHolder.Callback so we get notified when the
// underlying surface is created and destroyed.
mHolder = getHolder();
mHolder.addCallback(this);
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
public void surfaceCreated(SurfaceHolder holder) {
// The Surface has been created, acquire the camera and tell it where
// to draw.
camera = Camera.open();
try {
camera.setPreviewDisplay(holder);
camera.setPreviewCallback(new PreviewCallback() {
public void onPreviewFrame(byte[] data, Camera arg1) {
FileOutputStream outStream = null;
try {
outStream = new FileOutputStream(String.format(
"/sdcard/%d.jpg", System.currentTimeMillis()));
outStream.write(data);
outStream.close();
Log.d(TAG, "onPreviewFrame - wrote bytes: "
+ data.length);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
}
Preview.this.invalidate();
}
});
} catch (IOException e) {
e.printStackTrace();
}
}
public void surfaceDestroyed(SurfaceHolder holder) {
// Stopping preview because surface will be destroyed upon return
camera.stopPreview();
camera = null;
}
private Camera.Size getOptimalPreviewSize(List<Camera.Size> sizes, int w, int h) {
final double ASPECT_TOLERANCE = 0.1;
double targetRatio=(double)h / w;
if (sizes == null) return null;
Camera.Size optimalSize = null;
double minDiff = Double.MAX_VALUE;
int targetHeight = h;
for (Camera.Size size : sizes) {
double ratio = (double) size.width / size.height;
if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE) continue;
if (Math.abs(size.height - targetHeight) < minDiff) {
optimalSize = size;
minDiff = Math.abs(size.height - targetHeight);
}
}
if (optimalSize == null) {
minDiff = Double.MAX_VALUE;
for (Camera.Size size : sizes) {
if (Math.abs(size.height - targetHeight) < minDiff) {
optimalSize = size;
minDiff = Math.abs(size.height - targetHeight);
}
}
}
return optimalSize;
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
final int width = resolveSize(getSuggestedMinimumWidth(), widthMeasureSpec);
final int height = resolveSize(getSuggestedMinimumHeight(), heightMeasureSpec);
setMeasuredDimension(width, height);
if (mSupportedPreviewSizes != null) {
mPreviewSize = getOptimalPreviewSize(mSupportedPreviewSizes, width, height);
}
}
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
// Now that the size is known, set up the camera parameters and begin
// the preview.
Camera.Parameters parameters = camera.getParameters();
parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
camera.setParameters(parameters);
camera.startPreview();
}
// This adds a canvas to the app
@Override
public void draw(Canvas canvas) {
super.draw(canvas);
Paint p = new Paint(Color.RED);
Log.d(TAG, "draw");
canvas.drawText("PREVIEW", canvas.getWidth() / 2,
canvas.getHeight() / 2, p);
}
}
当我在Galaxy S5上使用应用程序时，相机预览显示失真，我无法看到通常出现在中心的形状。关于在中心放置自定义形状的最佳方式的任何输入，取代通常的形状，将不胜感激。谢谢！
答案 0 :(得分：0)
使用相对布局作为XML的父布局，并使用centerInParent=true属性将按钮置于中心，希望它不会在任何设备上扭曲