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
}
}

}