调用摄像头拍照并显示

package com.example.choosepictest;import android.content.Intent;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.net.Uri;import android.os.Environment;import android.provider.MediaStore;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.View;import android.widget.Button;import android.widget.ImageButton;import android.widget.ImageView;import java.io.File;import java.io.FileNotFoundException;import java.io.IOException;public class MainActivity extends AppCompatActivity {    public static  final  int TAKE_PHOTO = 1;    public  static final int CROP_PHOTO = 2 ;    private Button takephoto;    private ImageView picture ;    private Uri imageUri ;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        takephoto = (Button) findViewById(R.id.take_phone);        picture = (ImageView) findViewById( R.id.picture) ;        takephoto.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                //创建File对象，用于存储拍照后的照片                File outputImage = new File(Environment.getExternalStorageDirectory(),"output_image.jpg");                System.out.println(Environment.getExternalStorageDirectory());                try {                    if(outputImage.exists()){                        outputImage.delete();                    }                    outputImage.createNewFile();                }catch (IOException e){                    e.printStackTrace();                }                imageUri = Uri.fromFile(outputImage);                Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");                intent.putExtra(MediaStore.EXTRA_OUTPUT,imageUri);                startActivityForResult(intent , TAKE_PHOTO);//需要返回结果判断拍照成功的故用这个方法            }        });    }    @Override    protected void onActivityResult(int requestCode, int resultCode, Intent data) {        switch (requestCode){            case TAKE_PHOTO:                if(resultCode == RESULT_OK){                    Intent intent = new Intent("com.android.camera.action.CROP");//为系统剪裁的Action                    intent.setDataAndType(imageUri ,"image/*"); //设置剪裁的属性类型                    intent.putExtra("scale",true);//scale为缩放的意思                    intent.putExtra(MediaStore.EXTRA_OUTPUT , imageUri);                    startActivityForResult(intent , CROP_PHOTO); //需要返回结果来判断是否截图成功的故用这个方法                }                break;            case CROP_PHOTO:                if(resultCode==RESULT_OK){                    try{                        Bitmap bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(imageUri));//而contentresolver则是用于管理所有程序的contentprovider实例                        picture.setImageBitmap(bitmap);                    }catch (FileNotFoundException e){                        e.printStackTrace();                    }                }                break;            default:break;        }    }}

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical"   ><Button    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:text="Take photo"    android:id="@+id/take_phone"/>    <ImageView        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:id="@+id/picture"        android:layout_gravity="center_vertical"/></LinearLayout>

总结：1 Environment.getExternalStorageDirectory() 得到SD卡的根目录
2 剪裁照片的属性设置
3 解析成位图