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        }    }}

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