使用内置的Camera应用程序

该小节非常简单，讲的就三件事：
一，调用Camera相机拍照并获取照片；
二、调用Camera相机拍照并获得原图；
三、获得原图后根据屏幕的宽高比来显示图片。
调用Camera相机拍照并获取照片源码如下：
package com.hhqy.withme;

import android.content.Intent;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.widget.ImageView;

public class ContextActivity extends FragmentActivity {

private ImageView image;  @Override  protected void onCreate(Bundle savedInstanceState) {      super.onCreate(savedInstanceState);      setContentView(R.layout.activity_context);      image = (ImageView)findViewById(R.id.cursor);      Intent  intent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);    //android.provider.MediaStore.ACTION_IMAGE_CAPTURE    //打开相机的意图    startActivityForResult(intent, 100);}  @Overrideprotected void onActivityResult(int requestCode, int resultCode, Intent intent) {    super.onActivityResult(requestCode, resultCode, intent);    if(requestCode == 100 && resultCode == RESULT_OK)    {        Bundle bundle = intent.getExtras();        image.setImageBitmap((Bitmap)bundle.get("data"));    }}

}
布局文件只有一个imageView控件，所以就不写了，后面一样！
通过运行你会发现图片缩小了

那如何获得原图大小呢？书中给的代码是这样的：
package com.hhqy.withme;

import java.io.File;
import java.util.ArrayList;

import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.Display;
import android.view.Menu;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.TranslateAnimation;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

public class ContextActivity extends FragmentActivity {

private ImageView image;  @Override  protected void onCreate(Bundle savedInstanceState) {      super.onCreate(savedInstanceState);      setContentView(R.layout.activity_context);      image = (ImageView)findViewById(R.id.cursor);      String path = Environment.getExternalStorageDirectory().getAbsolutePath()+"/hello.jpg";    Intent  intent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);    intent.putExtra(android.provider.MediaStore.EXTRA_OUTPUT, Uri.fromFile(new File(path)));    //也可这样写uri:Uri.parse("file:///sdcard/hello.jpg")，但是上一种更规范一些    startActivityForResult(intent, 100);}  @Overrideprotected void onActivityResult(int arg0, int arg1, Intent arg2) {    super.onActivityResult(arg0, arg1, arg2);    if(arg1 == RESULT_OK)    {        Bundle bundle = arg2.getExtras();        image.setImageBitmap((Bitmap)bundle.get("data"));    }}

}
但是一运行的时候，你会发现拿不到图片了！！

后来上网查询了一下，我们可以通过文件名来获取，直接取是取不到了，修改一小段：
@Override
protected void onActivityResult(int arg0, int arg1, Intent arg2)
{
super.onActivityResult(arg0, arg1, arg2);
if(arg1 == RESULT_OK)
{
Bundle bundle = arg2.getExtras();
image.setImageBitmap((Bitmap)bundle.get(“data”));

        BitmapFactory.Options option = new BitmapFactory.Options();        option.inJustDecodeBounds = false;        Bitmap bitmapTure = BitmapFactory.decodeFile(                Environment.getExternalStorageDirectory().getAbsolutePath()+"/hello.jpg",                option);        image.setImageBitmap(bitmapTure);    }}![这里还是不行，具体原因我也不知道了，或许是时间的原因请知道的朋友指教！最后还是贴上能运行的代码：](http://img.blog.csdn.net/20160426235309571)效果大家可以自己试一下，我只是随手拍的！最后，图片太大了，如何根据屏幕的宽高比来显示图片呢？不说话，上源码：package com.hhqy.withme;

import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.support.v4.app.FragmentActivity;
import android.view.Display;
import android.widget.ImageView;

public class ContextActivity extends FragmentActivity {

private ImageView image;  @Override  protected void onCreate(Bundle savedInstanceState) {      super.onCreate(savedInstanceState);      setContentView(R.layout.activity_context);      image = (ImageView)findViewById(R.id.cursor);      String path = Environment.getExternalStorageDirectory().getAbsolutePath()+"/hello.jpg";    Intent  intent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);    intent.putExtra(android.provider.MediaStore.EXTRA_OUTPUT, Uri.parse("file:///sdcard/hello.jpg"));    startActivityForResult(intent, 100);}  @Overrideprotected void onActivityResult(int arg0, int arg1, Intent arg2) {    super.onActivityResult(arg0, arg1, arg2);    if(arg1 == RESULT_OK)    {

// Bundle bundle = arg2.getExtras();
// image.setImageBitmap((Bitmap)bundle.get(“data”));
Display display = getWindowManager().getDefaultDisplay();
int dw = display.getWidth();//窗口宽度
int dh = display.getHeight();//窗口高度

        BitmapFactory.Options option = new BitmapFactory.Options();        option.inJustDecodeBounds = true;//只加载图像尺寸，而不用加载图像本身，例如只问参加活动的人数，而不问具体哪些人参加一样！        Bitmap bitmapFalse = BitmapFactory.decodeFile(                Environment.getExternalStorageDirectory().getAbsolutePath()+"/hello.jpg",                option);        int hRatio = (int) Math.ceil(option.outHeight/dh);        int wRatio = (int) Math.ceil(option.outWidth/dw);        if(hRatio>1 && wRatio>1)        {            if(hRatio>wRatio)            {                option.inSampleSize = hRatio;            }else             {                option.inSampleSize = wRatio;            }        }        option.inJustDecodeBounds = false;        Bitmap bitmapTure = BitmapFactory.decodeFile(                Environment.getExternalStorageDirectory().getAbsolutePath()+"/hello.jpg",                option);        image.setImageBitmap(bitmapTure);

// ContentResolver c = this.getContentResolver();
// try {
// Bitmap bmp = BitmapFactory.decodeStream(c.openInputStream(Uri.parse(“file:///sdcard/hello.jpg”)));
// if(bmp!=null)image.setImageBitmap(bmp);
// } catch (FileNotFoundException e) {
// Toast.makeText(this, “图片取出来有问题”, Toast.LENGTH_SHORT).show();
// e.printStackTrace();
// }
}
}

}

重点不是我照片拍的丑，重点是技术的实现和熟练，欢迎大家交流：QQ3332168769
（我至今也不明白为什么给了一个uri之后为什么会取不出来图片这个问题，求指教！！！）