我想制作一款有2项活动的应用。第一个是api演示的CameraPreview，默认情况下有一个选项菜单。我添加了第二个按钮，启动第二个活动，什么是ImageSwitcher。我想以指定的宽度和高度将选定的照片放回预览的前面。
此块适用于获取并在普通活动的onCreate方法中显示照片，但我不知道如何使用CameraPreview执行此操作：
setContentView(R.layout.picturelay);
int theID = getIntent().getExtras().getInt("the_image_id");
ImageView i = (ImageView) findViewById(R.id.cameralay);
i.setImageResource(theID);
我的开始活动：
public class CameraPreview extends Activity {
private
Preview mPreview;
Camera mCamera;
int numberOfCameras;
int cameraCurrentlyLocked;
String uzenet;
// The first rear facing camera
int defaultCameraId;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Hide the window title.
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
// Create a RelativeLayout container that will hold a SurfaceView,
// and set it as the content of our activity.
mPreview = new Preview(this);
setContentView(mPreview);
try {
int theID = getIntent().getExtras().getInt("the_image_id");
ImageView i = (ImageView) findViewById(R.id.cameralay);
i.setImageResource(theID);
} catch (Exception e){
Toast.makeText(this, e.getMessage(), Toast.LENGTH_LONG);
}
// Find the total number of cameras available
numberOfCameras = Camera.getNumberOfCameras();
// Find the ID of the default camera
CameraInfo cameraInfo = new CameraInfo();
for (int i = 0; i < numberOfCameras; i++) {
Camera.getCameraInfo(i, cameraInfo);
if (cameraInfo.facing == CameraInfo.CAMERA_FACING_BACK) {
defaultCameraId = i;
}
}
}
@Override
protected void onResume() {
super.onResume();
// Open the default i.e. the first rear facing camera.
mCamera = Camera.open();
cameraCurrentlyLocked = defaultCameraId;
mPreview.setCamera(mCamera);
}
@Override
protected void onPause() {
super.onPause();
// Because the Camera object is a shared resource, it's very
// important to release it when the activity is paused.
if (mCamera != null) {
mPreview.setCamera(null);
mCamera.release();
mCamera = null;
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate our menu which can gather user input for switching camera
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.camera_menu, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle item selection
switch (item.getItemId()) {
case R.id.switch_cam:
// check for availability of multiple cameras
if (numberOfCameras == 1) {
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage(this.getString(R.string.camera_alert))
.setNeutralButton("Close", null);
AlertDialog alert = builder.create();
alert.show();
return true;
}
// OK, we have multiple cameras.
// Release this camera -> cameraCurrentlyLocked
if (mCamera != null) {
mCamera.stopPreview();
mPreview.setCamera(null);
mCamera.release();
mCamera = null;
}
// Acquire the next camera and request Preview to reconfigure
// parameters.
mCamera = Camera
.open((cameraCurrentlyLocked + 1) % numberOfCameras);
cameraCurrentlyLocked = (cameraCurrentlyLocked + 1)
% numberOfCameras;
mPreview.switchCamera(mCamera);
// Start the preview
mCamera.startPreview();
return true;
case R.id.get_picture:
Intent intent2 = new Intent(CameraPreview.this, ImageSwitcher1.class);
//startActivityForResult(intent, 0);
startActivity(intent2);
return true;
}
return super.onOptionsItemSelected(item);
}
}
class Preview extends ViewGroup implements SurfaceHolder.Callback {
private final String TAG = "Preview";
SurfaceView mSurfaceView;
SurfaceHolder mHolder;
Size mPreviewSize;
List<Size> mSupportedPreviewSizes;
Camera mCamera;
Preview(Context context) {
super(context);
mSurfaceView = new SurfaceView(context);
addView(mSurfaceView);
// Install a SurfaceHolder.Callback so we get notified when the
// underlying surface is created and destroyed.
mHolder = mSurfaceView.getHolder();
mHolder.addCallback(this);
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
public void setCamera(Camera camera) {
mCamera = camera;
if (mCamera != null) {
mSupportedPreviewSizes = mCamera.getParameters().getSupportedPreviewSizes();
requestLayout();
}
}
public void switchCamera(Camera camera) {
setCamera(camera);
try {
camera.setPreviewDisplay(mHolder);
} catch (IOException exception) {
Log.e(TAG, "IOException caused by setPreviewDisplay()", exception);
}
Camera.Parameters parameters = camera.getParameters();
parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
requestLayout();
camera.setParameters(parameters);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
// We purposely disregard child measurements because act as a
// wrapper to a SurfaceView that centers the camera preview instead
// of stretching it.
final int width = resolveSize(getSuggestedMinimumWidth(), widthMeasureSpec);
final int height = resolveSize(getSuggestedMinimumHeight(), heightMeasureSpec);
setMeasuredDimension(width, height);
if (mSupportedPreviewSizes != null) {
mPreviewSize = getOptimalPreviewSize(mSupportedPreviewSizes, width, height);
}
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
if (changed && getChildCount() > 0) {
final View child = getChildAt(0);
final int width = r - l;
final int height = b - t;
int previewWidth = width;
int previewHeight = height;
if (mPreviewSize != null) {
previewWidth = mPreviewSize.width;
previewHeight = mPreviewSize.height;
}
// Center the child SurfaceView within the parent.
if (width * previewHeight > height * previewWidth) {
final int scaledChildWidth = previewWidth * height / previewHeight;
child.layout((width - scaledChildWidth) / 2, 0,
(width + scaledChildWidth) / 2, height);
} else {
final int scaledChildHeight = previewHeight * width / previewWidth;
child.layout(0, (height - scaledChildHeight) / 2,
width, (height + scaledChildHeight) / 2);
}
}
}
public void surfaceCreated(SurfaceHolder holder) {
// The Surface has been created, acquire the camera and tell it where
// to draw.
try {
if (mCamera != null) {
mCamera.setPreviewDisplay(holder);
}
} catch (IOException exception) {
Log.e(TAG, "IOException caused by setPreviewDisplay()", exception);
}
}
public void surfaceDestroyed(SurfaceHolder holder) {
// Surface will be destroyed when we return, so stop the preview.
if (mCamera != null) {
mCamera.stopPreview();
}
}
private Size getOptimalPreviewSize(List<Size> sizes, int w, int h) {
final double ASPECT_TOLERANCE = 0.1;
double targetRatio = (double) w / h;
if (sizes == null) return null;
Size optimalSize = null;
double minDiff = Double.MAX_VALUE;
int targetHeight = h;
// Try to find an size match aspect ratio and size
for (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);
}
}
// Cannot find the one match the aspect ratio, ignore the requirement
if (optimalSize == null) {
minDiff = Double.MAX_VALUE;
for (Size size : sizes) {
if (Math.abs(size.height - targetHeight) < minDiff) {
optimalSize = size;
minDiff = Math.abs(size.height - targetHeight);
}
}
}
return optimalSize;
}
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 = mCamera.getParameters();
parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
requestLayout();
mCamera.setParameters(parameters);
mCamera.startPreview();
}
}
第二项活动：
public class ImageSwitcher1 extends Activity implements
AdapterView.OnItemSelectedListener, ViewSwitcher.ViewFactory {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.image_switcher_1);
mSwitcher = (ImageSwitcher) findViewById(R.id.switcher);
mSwitcher.setFactory(this);
mSwitcher.setInAnimation(AnimationUtils.loadAnimation(this,
android.R.anim.fade_in));
mSwitcher.setOutAnimation(AnimationUtils.loadAnimation(this,
android.R.anim.fade_out));
Gallery g = (Gallery) findViewById(R.id.gallery);
g.setAdapter(new ImageAdapter(this));
g.setOnItemSelectedListener(this);
g.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView parent, View v, int position, long id) {
Intent intent = new Intent(ImageSwitcher1.this, CameraPreview.class);
intent.putExtra("the_image_id", mImageIds[position]);
startActivity(intent);
finish();
}
});
}
public void onItemSelected(AdapterView parent, View v, int position, long id) {
mSwitcher.setImageResource(mImageIds[position]);
}
public void onNothingSelected(AdapterView parent) {
}
public View makeView() {
ImageView i = new ImageView(this);
i.setBackgroundColor(0xFF000000);
i.setScaleType(ImageView.ScaleType.FIT_CENTER);
i.setLayoutParams(new ImageSwitcher.LayoutParams(LayoutParams.MATCH_PARENT,
LayoutParams.MATCH_PARENT));
return i;
}
private ImageSwitcher mSwitcher;
public class ImageAdapter extends BaseAdapter {
public ImageAdapter(Context c) {
mContext = c;
}
public int getCount() {
return mThumbIds.length;
}
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
ImageView i = new ImageView(mContext);
i.setImageResource(mThumbIds[position]);
i.setAdjustViewBounds(true);
i.setLayoutParams(new Gallery.LayoutParams(
LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
i.setBackgroundResource(R.drawable.picture_frame);
return i;
}
private Context mContext;
}
private Integer[] mThumbIds = {
R.drawable.1, R.drawable.2,
R.drawable.3, R.drawable.4,
R.drawable.5, R.drawable.6,
R.drawable.7, R.drawable.8,
R.drawable.9
};
private Integer[] mImageIds = {
R.drawable.1, R.drawable.2,
R.drawable.3, R.drawable.4,
R.drawable.5, R.drawable.6,
R.drawable.7, R.drawable.8,
R.drawable.9
};
}
感谢您的回复！
答案 0 :(得分：1)
我有一个具有不同预览活动的解决方案。所以我可以在相机预览的前面看到所选图像。这是使用过的预览活动：
public class PreviewDemo extends Activity {
private SurfaceView preview=null;
private SurfaceHolder previewHolder=null;
private Camera camera=null;
private boolean inPreview=false;
private boolean cameraConfigured=false;
private Context context;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
preview=(SurfaceView)findViewById(R.id.preview);
previewHolder=preview.getHolder();
previewHolder.addCallback(surfaceCallback);
previewHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
try {
int theID = getIntent().getExtras().getInt("the_image_id");
ImageView i = (ImageView) findViewById(R.id.cameralay);
i.setImageResource(theID);
} catch (Exception e){
Toast.makeText(this, e.getMessage(), Toast.LENGTH_LONG);
}
}
@Override
public void onResume() {
super.onResume();
camera=Camera.open();
startPreview();
}
@Override
public void onPause() {
if (inPreview) {
camera.stopPreview();
}
camera.release();
camera=null;
inPreview=false;
super.onPause();
}
private Camera.Size getBestPreviewSize(int width, int height,
Camera.Parameters parameters) {
Camera.Size result=null;
for (Camera.Size size : parameters.getSupportedPreviewSizes()) {
if (size.width<=width && size.height<=height) {
if (result==null) {
result=size;
}
else {
int resultArea=result.width*result.height;
int newArea=size.width*size.height;
if (newArea>resultArea) {
result=size;
}
}
}
}
return(result);
}
private void initPreview(int width, int height) {
if (camera!=null && previewHolder.getSurface()!=null) {
try {
camera.setPreviewDisplay(previewHolder);
}
catch (Throwable t) {
Log.e("PreviewDemo-surfaceCallback",
"Exception in setPreviewDisplay()", t);
Toast
.makeText(PreviewDemo.this, t.getMessage(), Toast.LENGTH_LONG)
.show();
}
if (!cameraConfigured) {
Camera.Parameters parameters=camera.getParameters();
Camera.Size size=getBestPreviewSize(width, height,
parameters);
if (size!=null) {
parameters.setPreviewSize(size.width, size.height);
camera.setParameters(parameters);
cameraConfigured=true;
}
}
}
}
private void startPreview() {
if (cameraConfigured && camera!=null) {
camera.startPreview();
inPreview=true;
}
}
SurfaceHolder.Callback surfaceCallback=new SurfaceHolder.Callback() {
public void surfaceCreated(SurfaceHolder holder) {
// no-op -- wait until surfaceChanged()
}
public void surfaceChanged(SurfaceHolder holder,
int format, int width,
int height) {
initPreview(width, height);
startPreview();
}
public void surfaceDestroyed(SurfaceHolder holder) {
// no-op
}
};
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate our menu which can gather user input for switching camera
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.camera_menu2, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle item selection
switch (item.getItemId()) {
case R.id.take_photo:
//code of taking a photo will be here...
return true;
}
return super.onOptionsItemSelected(item);
}
}
我的布局文件包含表面视图和图像视图：
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.view.SurfaceView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/preview"
android:layout_width="match_parent"
android:layout_height="match_parent">
</android.view.SurfaceView>
<ImageView
android:id="@+id/cameralay"
android:layout_width="150dp"
android:layout_height="150dp"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:contentDescription="@+id/app_name">
</ImageView>
</RelativeLayout>