import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Calendar;
import java.util.Locale;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Intent;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.text.format.DateFormat;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.Toast;

@SuppressLint("SdCardPath")
public class MainActivity extends Activity {
	/** Called when the activity is first created. */
	private Button button;
	private ImageView view;

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		button = (Button) findViewById(R.id.button1);
		view= (ImageView)findViewById(R.id.imageView1);
		button.setOnClickListener(new OnClickListener() {

			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
				Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
				startActivityForResult(intent, 1);
			}
		});
	}

	@SuppressLint("SdCardPath")
	@Override
	protected void onActivityResult(int requestCode, int resultCode, Intent data) {
		// TODO Auto-generated method stub
		super.onActivityResult(requestCode, resultCode, data);
		if (resultCode == Activity.RESULT_OK) {
			String sdStatus = Environment.getExternalStorageState();
			if (!sdStatus.equals(Environment.MEDIA_MOUNTED)) { // 检测sd是否可用
				Log.i("TestFile",
						"SD card is not avaiable/writeable right now.");
				return;
			}
			new DateFormat();
			String name = DateFormat.format("yyyyMMdd_hhmmss",Calendar.getInstance(Locale.CHINA)) + ".jpg";	
			Toast.makeText(this, name, Toast.LENGTH_LONG).show();
			Bundle bundle = data.getExtras();
			Bitmap bitmap = (Bitmap) bundle.get("data");// 获取相机返回的数据，并转换为Bitmap图片格式
		
			FileOutputStream b = null;		   
			File file = new File("/sdcard/Image/");
			file.mkdirs();// 创建文件夹
			String fileName = "/sdcard/Image/"+name;

			try {
				b = new FileOutputStream(fileName);
				bitmap.compress(Bitmap.CompressFormat.JPEG, 100, b);// 把数据写入文件
			} catch (FileNotFoundException e) {
				e.printStackTrace();
			} finally {
				try {
					b.flush();
					b.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			try
			{
				view.setImageBitmap(bitmap);// 将图片显示在ImageView里
			}catch(Exception e)
			{
				Log.e("error", e.getMessage());
			}
			
		}
	}
}

xml文件

<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=".MainActivity" >

    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:src=http://www.mamicode.com/"@drawable/ic_launcher" />>
最后要记得加权限
<!-- 在SDCard中创建与删除文件权限 -->
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>
<!-- 往SDCard写入数据权限 -->
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
  <uses-feature android:name = "android.hardware.camera" />
<uses-feature android:name = "android.hardware.camera.autofocus" />