android 打开系统相机，

1.第一步在androidmanifest。xml中注册

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
        <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

2.第二步创建activity_creama.xml

<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:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    tools:context="com.cqytjr.www.networkreceiver.CramaActivity">

    <Button
        android:id="@+id/btn_creama"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"

        android:text="@string/hello_world"
        tools:context=".CramaActivity" />

    <ImageView
        android:id="@+id/img_creama"
        android:layout_width="150dip"
        android:layout_height="150dip"
        android:layout_margin="15dip"
        android:layout_centerHorizontal="true"
        android:layout_below="@+id/btn_creama"
        android:scaleType="fitXY"

        />
    <TextView
        android:id="@+id/text"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/img_creama"
        android:textSize="16sp"
        android:background="#22000000"

        />

</RelativeLayout>

3. 第三步创建cramaactivity

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.text.SimpleDateFormat;
import java.util.Date;

import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.app.Activity;
import android.content.Intent;
import android.graphics.Bitmap;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;

public class CramaActivity extends Activity {

    private Button creama=null;

    private ImageView img=null;

    private TextView text=null;

    private File tempFile = new File(Environment.getExternalStorageDirectory(),
            getPhotoFileName());

    private static final int PHOTO_REQUEST_TAKEPHOTO = 1;// 拍照
    private static final int PHOTO_REQUEST_GALLERY = 2;// 从相册中选择
    private static final int PHOTO_REQUEST_CUT = 3;// 结果

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_crama);
        init();
        Log.i("TAG-->", ""+Environment.getExternalStorageDirectory());
    }

    private void init() {
        // TODO Auto-generated method stub

        creama=(Button) findViewById(R.id.btn_creama);

        img=(ImageView) findViewById(R.id.img_creama);

        creama.setOnClickListener(listener);
        text=(TextView) findViewById(R.id.text);

    }
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        switch (requestCode) {
            case PHOTO_REQUEST_TAKEPHOTO:// 当选择拍照时调用
                startPhotoZoom(Uri.fromFile(tempFile));
                break;
            case PHOTO_REQUEST_GALLERY:// 当选择从本地获取图片时
                // 做非空判断，当我们觉得不满意想重新剪裁的时候便不会报异常，下同
                if (data != null)
                    startPhotoZoom(data.getData());
                break;
            case PHOTO_REQUEST_CUT:// 返回的结果
                if (data != null)
                    // setPicToView(data);
                    sentPicToNext(data);
                break;
        }
        super.onActivityResult(requestCode, resultCode, data);
    }
    private OnClickListener listener = new OnClickListener(){

        @Override
        public void onClick(View arg0) {
            // TODO Auto-generated method stub

            Intent cameraintent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
            // 指定调用相机拍照后照片的储存路径
            cameraintent.putExtra(MediaStore.EXTRA_OUTPUT,
                    Uri.fromFile(tempFile));
            startActivityForResult(cameraintent, PHOTO_REQUEST_TAKEPHOTO);

        }};

    private void startPhotoZoom(Uri uri) {
        Intent intent = new Intent("com.android.camera.action.CROP");
        intent.setDataAndType(uri, "image/*");
        // crop为true是设置在开启的intent中设置显示的view可以剪裁
        intent.putExtra("crop", "true");

        // aspectX aspectY 是宽高的比例
        intent.putExtra("aspectX", 1);
        intent.putExtra("aspectY", 1);

        // outputX,outputY 是剪裁图片的宽高
        intent.putExtra("outputX", 300);
        intent.putExtra("outputY", 300);
        intent.putExtra("return-data", true);
        intent.putExtra("noFaceDetection", true);
        startActivityForResult(intent, PHOTO_REQUEST_CUT);
    }

    // 将进行剪裁后的图片传递到下一个界面上
    private void sentPicToNext(Intent picdata) {
        Bundle bundle = picdata.getExtras();
        if (bundle != null) {
            Bitmap photo = bundle.getParcelable("data");
            if (photo==null) {
                img.setImageResource(R.drawable.ic_launcher);
            }else {
                img.setImageBitmap(photo);
//                设置文本内容为    图片绝对路径和名字
                text.setText(tempFile.getAbsolutePath());
            }

            ByteArrayOutputStream baos = null;
            try {
                baos = new ByteArrayOutputStream();
                photo.compress(Bitmap.CompressFormat.JPEG, 100, baos);
                byte[] photodata = baos.toByteArray();
                System.out.println(photodata.toString());
                // Intent intent = new Intent();
                // intent.setClass(RegisterActivity.this, ShowActivity.class);
                // intent.putExtra("photo", photodata);
                // startActivity(intent);
                // finish();
            } catch (Exception e) {
                e.getStackTrace();
            } finally {
                if (baos != null) {
                    try {
                        baos.close();
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
            }
        }
    }

    // 使用系统当前日期加以调整作为照片的名称
    private String getPhotoFileName() {
        Date date = new Date(System.currentTimeMillis());
        SimpleDateFormat dateFormat = new SimpleDateFormat(
                "'IMG'_yyyyMMdd_HHmmss");
        return dateFormat.format(date) + ".jpg";
    }
}

第二种方式，我们不需要剪裁，直接用：

androidmanifest注册

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
        <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

第二部：

xml文件添加一个imageview

 <ImageView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:src="@drawable/ic_launcher"
        android:id="@+id/imageView"/>

activity代码

public class MainActivity extends Activity {

    GridView gridView;
    ImageView imageView;
    private Bitmap bitmap;

    final  static  int REQUEST_CODE_PICK_IMAGE = 1;
    final  static  int REQUEST_CODE_CAPTURE_CAMEIA = 2;

    protected void getImageFromAlbum() {
        Intent intent = new Intent(Intent.ACTION_PICK);
        intent.setType("image/*");//相片类型
        startActivityForResult(intent, REQUEST_CODE_PICK_IMAGE);
    }
    protected void getImageFromCamera() {
        String state = Environment.getExternalStorageState();
        if (state.equals(Environment.MEDIA_MOUNTED)) {
            Intent getImageByCamera = new Intent("android.media.action.IMAGE_CAPTURE");
            startActivityForResult(getImageByCamera, REQUEST_CODE_CAPTURE_CAMEIA);
        }
        else {
            Toast.makeText(getApplicationContext(), "请确认已经插入SD卡", Toast.LENGTH_LONG).show();
        }
    }
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.activity_main);

//        gridView = (GridView)findViewById(R.id.grid_view);

        imageView = (ImageView) findViewById(R.id.imageView);
        imageView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                getImageFromAlbum();
            }
        });

    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (requestCode == REQUEST_CODE_PICK_IMAGE) {

            Uri uri = data.getData();
//            Bitmap bitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), uri);

            try {
                Bitmap bitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(),uri);
                imageView.setImageBitmap(bitmap);
            } catch (IOException e) {
                e.printStackTrace();
            }

        } else if (requestCode == REQUEST_CODE_CAPTURE_CAMEIA ) {

            Bundle extras = data.getExtras();
            Bitmap map = (Bitmap)extras.get("data");
            imageView.setImageBitmap(map);

        } }

}