我试图在不预览相机的情况下拍摄照片。我已经提到了许多文章，其中一些是：
http://cell0907.blogspot.in/2014/01/android-camera-capture-without.html
http://android-er.blogspot.com.es/2010/12/implement-takepicture-function-of.html
我已添加了相机的权限并写入外部存储空间。
在我的活动的xml中，我正在使用宽度和高度为1dp的surfaceView组件。还有一个按钮，只需点击此按钮就可以捕获图片。下面是我的XML文件的代码：
<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=".CameraActivity"
android:background="#000000" >
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:text="capture" />
<SurfaceView
android:id="@+id/surfaceView1"
android:layout_width="1dp"
android:layout_height="1dp"
android:layout_below="@+id/button1"
android:layout_centerHorizontal="true"
android:layout_marginTop="78dp" />
</RelativeLayout>
现在参考上面提到的链接，我在相应的活动文件中执行了以下操作：
package com.samplecamera;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Date;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.hardware.Camera;
import android.hardware.Camera.CameraInfo;
import android.os.Bundle;
import android.os.Environment;
import android.app.Activity;
import android.text.format.DateFormat;
import android.view.Menu;
import android.view.SurfaceView;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class CameraActivity extends Activity {
SurfaceView sv=null;
Camera cam=null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_camera);
cam=Camera.open();
sv=(SurfaceView) findViewById(R.id.surfaceView1);
try {
cam.setPreviewDisplay(sv.getHolder());
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
cam.startPreview();
Camera.Parameters params = cam.getParameters();
params.setJpegQuality(100);
cam.setParameters(params);
Button btn=(Button) findViewById(R.id.button1);
btn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
cam.startPreview();
cam.takePicture(null, null, mCall);
}
});
}
Camera.PictureCallback mCall = new Camera.PictureCallback() {
public void onPictureTaken(byte[] data, Camera camera) {
//decode the data obtained by the camera into a Bitmap
//display.setImageBitmap(photo);
// Bitmap bitmapPicture
// = BitmapFactory.decodeByteArray(data, 0, data.length);
FileOutputStream fos = null;
try {
fos = new FileOutputStream(Environment.getExternalStorageDirectory()+"/"+
DateFormat.format("yyyy-MM-dd_kk-mm-ss", new Date().getTime())+".jpeg");
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
fos.write(data);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
fos.flush();
fos.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
};
@Override
protected void onDestroy() {
// TODO Auto-generated method stub
cam.release();
super.onDestroy();
}
@Override
public void onBackPressed() {
// TODO Auto-generated method stub
super.onBackPressed();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.camera, menu);
return true;
}
}
点击按钮，我得到以下异常：
03-21 11:55:44.404: E/AndroidRuntime(27544): FATAL EXCEPTION: main
03-21 11:55:44.404: E/AndroidRuntime(27544): java.lang.RuntimeException: takePicture failed
03-21 11:55:44.404: E/AndroidRuntime(27544): at android.hardware.Camera.native_takePicture(Native Method)
03-21 11:55:44.404: E/AndroidRuntime(27544): at android.hardware.Camera.takePicture(Camera.java:1163)
03-21 11:55:44.404: E/AndroidRuntime(27544): at android.hardware.Camera.takePicture(Camera.java:1108)
03-21 11:55:44.404: E/AndroidRuntime(27544): at com.samplecamera.CameraActivity$2.onClick(CameraActivity.java:55)
03-21 11:55:44.404: E/AndroidRuntime(27544): at android.view.View.performClick(View.java:4084)
03-21 11:55:44.404: E/AndroidRuntime(27544): at android.view.View$PerformClick.run(View.java:16987)
03-21 11:55:44.404: E/AndroidRuntime(27544): at android.os.Handler.handleCallback(Handler.java:615)
03-21 11:55:44.404: E/AndroidRuntime(27544): at android.os.Handler.dispatchMessage(Handler.java:92)
03-21 11:55:44.404: E/AndroidRuntime(27544): at android.os.Looper.loop(Looper.java:137)
03-21 11:55:44.404: E/AndroidRuntime(27544): at android.app.ActivityThread.main(ActivityThread.java:4802)
03-21 11:55:44.404: E/AndroidRuntime(27544): at java.lang.reflect.Method.invokeNative(Native Method)
03-21 11:55:44.404: E/AndroidRuntime(27544): at java.lang.reflect.Method.invoke(Method.java:511)
03-21 11:55:44.404: E/AndroidRuntime(27544): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:809)
03-21 11:55:44.404: E/AndroidRuntime(27544): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:576)
03-21 11:55:44.404: E/AndroidRuntime(27544): at dalvik.system.NativeStart.main(Native Method)
请提供帮助。
答案 0 :(得分：0)
从onclick事件中删除cam.startpreview（）函数，并在为媒体相关项目编码时尝试检查camera == null然后进一步移动，使用此代码不会崩溃