android调用系统的相机服务

本功能实现的是调用相机拍照，并利用img标签显示：

思路一：拍照时刻进行保存

package com.bobo.mypic;



import java.io.File;

import java.text.SimpleDateFormat;

import java.util.Date;



import com.bobo.util.BitmapUtil;



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.view.Menu;

import android.view.View;

import android.widget.Button;

import android.widget.ImageView;



public class MainActivity extends Activity {

    private Button btn_takePic;

    private Button btn_fromPic;

    private File mediaFile;

    private int CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE = 0;

    private ImageView img_view;

    private Button btn_jump;



    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        btn_takePic = (Button) this.findViewById(R.id.btn_takePic);

         btn_fromPic = (Button) this.findViewById(R.id.btn_viewPic);

        btn_takePic.setOnClickListener(new TakePicListener());

        img_view = (ImageView) this.findViewById(R.id.img_viewPic);

        btn_jump = (Button) this.findViewById(R.id.btn_jump);

        btn_jump.setOnClickListener(new View.OnClickListener() {



            @Override

            public void onClick(View arg0) {

                Intent intent = new Intent();

                intent.setClass(MainActivity.this, SecondActivity.class);

                startActivity(intent);

            }

        });

    }



    class TakePicListener implements View.OnClickListener {



        @Override

        public void onClick(View arg0) {

            takePhoto();

        }



    }



    private void takePhoto() {

        if (!Environment.getExternalStorageState().equals(

                Environment.MEDIA_MOUNTED)) {

            return;

        }

        File file = new File(

                Environment

                        .getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES)

                        + File.separator + "shareImg");

        if (!file.exists()) {

            if (!file.mkdirs())

                return;

        }

        String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss")

                .format(new Date());

        mediaFile = new File(file.getPath() + File.separator + "IMG_"

                + timeStamp + ".jpg");

        Uri fileUri = Uri.fromFile(mediaFile);

        Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);

        intent.putExtra(MediaStore.EXTRA_OUTPUT, fileUri);

        startActivityForResult(intent, CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE);

    }



    @Override

    public boolean onCreateOptionsMenu(Menu menu) {

        // Inflate the menu; this adds items to the action bar if it is present.

        getMenuInflater().inflate(R.menu.activity_main, menu);

        return true;

    }



    @Override

    protected void onActivityResult(int requestCode, int resultCode, Intent data) {

        super.onActivityResult(requestCode, resultCode, data);

        if (requestCode == this.CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE) {

            long len = mediaFile.length();

            if (len == 0) {

                mediaFile = null;

                return;

            }

            // 从文件中加载位图

            System.out.println("文件存储路径：" + mediaFile.getPath());

            Bitmap bitmap = new BitmapUtil().loadBitmap(mediaFile.getPath());

            img_view.setImageBitmap(bitmap);

        }

    }



}

其中，从文件中加载位图的代码如下：

若是由于图片本身较大，直接用Widge中的图片控件打不开，但通过BitmapFactory.Options的inJustDecodeBounds和inSampleSize可以压缩打开，但是在通过手势放大的时候，图片本身就不是很清晰。

package com.bobo.util;



import java.io.FileOutputStream;



import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

import android.graphics.BitmapFactory.Options;



public class BitmapUtil {

    // 从文件中加载位图

    public Bitmap loadBitmap(String path) {

        //这样可以显示，但是图片的质量很差

        BitmapFactory.Options opts = new Options();

        opts.inJustDecodeBounds = true;

        // 告诉解析�?不要真的去解析图�?只是把图片的宽高信息给提供出�?

        BitmapFactory.decodeFile(path, opts);

        int width = opts.outWidth;

        int height = opts.outHeight;

        // 得到手机屏幕的宽高信�?

        int windowwidth = 50;

        int windowheigth = 50;



        int scalex = width / windowwidth;

        int scaley = height / windowheigth;



        if (scalex > scaley && scaley > 1) { // 水平方向的缩放比例比较大

            opts.inSampleSize = scalex;

        }

        if (scaley > scalex && scalex > 1) { // 竖直方向的缩放比例比较大

            opts.inSampleSize = scaley;

        }

        opts.inJustDecodeBounds = false;

        // 告诉解析�?按照 opts.inSampleSize 比例真实的返回位�?

        Bitmap bitmap = BitmapFactory.decodeFile(path, opts);



        return bitmap;

    }



}

 

思路二，在activity的onactivityResult方法中进行保存

package com.bobo.mypic;



import java.io.File;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import java.text.SimpleDateFormat;

import java.util.Calendar;

import java.util.Locale;



import com.bobo.mypic.MainActivity.TakePicListener;

import com.bobo.util.BitmapUtil;



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.widget.Button;

import android.widget.ImageView;



public class SecondActivity extends Activity {

    private Button btn_takePic;

    private Button btn_fromPic;

    private File mediaFile;

    private int CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE = 1;

    private ImageView img_view;



    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        btn_takePic = (Button) this.findViewById(R.id.btn_takePic);

        btn_fromPic = (Button) this.findViewById(R.id.btn_viewPic);

        btn_takePic.setOnClickListener(new TakePicListener());

        img_view = (ImageView) this.findViewById(R.id.img_viewPic);

    }



    class TakePicListener implements View.OnClickListener {



        @Override

        public void onClick(View arg0) {

            takePhoto();

        }



    }



    public void takePhoto() {

        Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);

        startActivityForResult(intent, CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE);

    }



    @Override

    protected void onActivityResult(int requestCode, int resultCode, Intent data) {

        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;

            }

            String name = new DateFormat().format("yyyyMMdd_hhmmss",

                    Calendar.getInstance(Locale.CHINA))

                    + ".jpg";

            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/myImage/");

            file.mkdirs();// 创建文件夹

            String fileName = "/sdcard/myImage/" + 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();

                }

            }

            ((ImageView) findViewById(R.id.img_viewPic)).setImageBitmap(bitmap);// 将图片显示在ImageView里

        }

    }



}