很抱歉在这里张贴一面墙，但我不确定还能做什么。
我认为这与清单中缺少CameraPreview有关，但我不确定，也不知道如何将它添加到清单中，因为它扩展了View。无论如何，应用程序的目标是我的设备的相应sdk，运行，然后只是显示一个白色的屏幕和＆＃34;捕获＆＃34;按钮。我尝试过使用SurfaceView，但后来我无法在视图中添加mpreview。非常困惑，并会感谢任何帮助或指针。谢谢。
CameraActivity.java：
package installation04.myapplication;
import android.app.Activity;
import android.content.Context;
import android.content.pm.PackageManager;
import android.hardware.Camera;
import android.hardware.camera2.CameraManager;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
public class CameraActivity extends Activity{
private Camera mCamera;
private CameraPreview mPreview;
private CameraManager mManager;
private String[] mCameraIds;
private SurfaceHolder mHolder;
private SurfaceHolder holder;
public static final int MEDIA_TYPE_IMAGE = 1;
public static final int MEDIA_TYPE_VIDEO = 2;
private static final String TAG = "CameraPreview";
LinearLayout camera_preview;
Button button_capture;
public CameraActivity() {
super();
}
@Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_camera);
button_capture = (Button) findViewById(R.id.button_capture);
if(checkCameraHardware(getApplicationContext())){
getCameraInstance();
}
// Create our Preview view and set it as the content of our activity.
mPreview = new CameraPreview(this, mCamera);
LinearLayout preview = (LinearLayout) findViewById(R.id.camera_preview);
preview.addView(mPreview);
}
private boolean checkCameraHardware(Context context) {
if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)){
// this device has a camera
return true;
} else {
// no camera on this device
return false;
}
}
public static Camera getCameraInstance(){
Camera c = null;
try {
c = Camera.open(); // attempt to get a Camera instance
}
catch (Exception e){
// Camera is not available (in use or does not exist)
}
return c; // returns null if camera is unavailable
}
public void onPictureTaken(byte[] data, Camera camera) {
File pictureFile = getOutputMediaFile(MEDIA_TYPE_IMAGE);
if (pictureFile == null){
Log.d(TAG, "Error creating media file, check storage permissions: ");
return;
}
try {
FileOutputStream fos = new FileOutputStream(pictureFile);
fos.write(data);
fos.close();
} catch (FileNotFoundException e) {
Log.d(TAG, "File not found: " + e.getMessage());
} catch (IOException e) {
Log.d(TAG, "Error accessing file: " + e.getMessage());
}
}
/** Create a file Uri for saving an image or video */
private static Uri getOutputMediaFileUri(int type){
return Uri.fromFile(getOutputMediaFile(type));
}
/** Create a File for saving an image or video */
private static File getOutputMediaFile(int type){
// To be safe, you should check that the SDCard is mounted
// using Environment.getExternalStorageState() before doing this.
File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_PICTURES), "MyCameraApp");
// This location works best if you want the created images to be shared
// between applications and persist after your app has been uninstalled.
// Create the storage directory if it does not exist
if (! mediaStorageDir.exists()){
if (! mediaStorageDir.mkdirs()){
Log.d("MyCameraApp", "failed to create directory");
return null;
}
}
// Create a media file name
String timeStamp = new SimpleDateFormat("yyyyMMdd_HH:mm:ss").format(new Date());
File mediaFile;
if (type == MEDIA_TYPE_IMAGE){
mediaFile = new File(mediaStorageDir.getPath() + File.separator +
"IMG_"+ timeStamp + ".jpg");
} else if(type == MEDIA_TYPE_VIDEO) {
mediaFile = new File(mediaStorageDir.getPath() + File.separator +
"VID_"+ timeStamp + ".mp4");
} else {
return null;
}
return mediaFile;
}
public void onClick() {
// Add a listener to the Capture button
Button captureButton = (Button) findViewById(R.id.button_capture);
captureButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
}
});
}
}
CameraPreview.java：
package installation04.myapplication;
import android.content.Context;
import android.hardware.Camera;
import android.util.AttributeSet;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.View;
import java.io.IOException;
public class CameraPreview extends View implements SurfaceHolder.Callback{
private static final String TAG = "CameraPreview: ";
private Camera mCamera;
private SurfaceHolder mHolder;
private SurfaceHolder holder;
public CameraPreview(Context context) {
super(context);
}
public CameraPreview(Context context, AttributeSet attrs) {
super(context, attrs);
}
public CameraPreview(Context cameraActivity, Camera camera){
super(cameraActivity);
mCamera = camera;
// Install a SurfaceHolder.Callback so we get notified when the
// underlying surface is created and destroyed.
mHolder = getHolder();
// deprecated setting, but required on Android versions prior to 3.0
if (mHolder != null) {
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
}
private SurfaceHolder getHolder() {
return null;
}
public void surfaceCreated(SurfaceHolder holder) {
// The Surface has been created, now tell the camera where to draw the preview.
try {
mCamera.setDisplayOrientation(90);
mCamera.setPreviewDisplay(holder);
mCamera.startPreview();
} catch (IOException e) {
Log.d(TAG, "Error setting camera preview: " + e.getMessage());
}
}
public void surfaceDestroyed(SurfaceHolder holder) {
// empty. Take care of releasing the Camera preview in your activity.
}
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
// If your preview can change or rotate, take care of those events here.
// Make sure to stop the preview before resizing or reformatting it.
if (mHolder.getSurface() == null){
// preview surface does not exist
return;
}
// stop preview before making changes
try {
mCamera.stopPreview();
} catch (Exception e){
// ignore: tried to stop a non-existent preview
}
// set preview size and make any resize, rotate or
// reformatting changes here
// start preview with new settings
try {
mCamera.setPreviewDisplay(mHolder);
mCamera.startPreview();
} catch (Exception e){
Log.d(TAG, "Error starting camera preview: " + e.getMessage());
}
}
}
的AndroidManifest.xml：
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:viewandroid="http://schemas.android.com/apk/res-auto"
package="installation04.myapplication">
<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera2" />
<uses-permission android:name="android.permission.RECORD_AUDIO" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".CameraActivity"
android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
</application>
</manifest>