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
        }
    }

}