Android下相机的调用

Android下相机的调用

      Android下相机的调用分别为调用系统相机和Building a Camera App两种用法；

一、调用系统相机

1.MainActivity.java文件

package com.example.takephoto;

import java.io.File;

import android.net.Uri;
import android.os.Bundle;
import android.provider.MediaStore;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.media.*;

public class MainActivity extends Activity {
    private Button button;
    

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        button=(Button)findViewById(R.id.button1);
        button.setOnClickListener(new View.OnClickListener() {
            
            @Override
            public void onClick(View v) {
                // TODO 自动生成的方法存根
                Intent intent=new Intent();
                intent.setAction("android.media.action.IMAGE_CAPTURE");
                intent.addCategory("android.intent.category.DEFAULT");
                File file=new File("/sdcard/0000image.jpg");
                Uri uri=Uri.fromFile(file);
                intent.putExtra(MediaStore.EXTRA_OUTPUT,uri);
                startActivity(intent);
            }
        });
        
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
}

2.activity_main.xml布局文件

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <Button
        android:id="@+id/button1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginLeft="73dp"
        android:text="拍照" />
   
</RelativeLayout>

3.AndroidManifest.xml文件

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.takephoto"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="18" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.takephoto.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

4.注：因为是调用的系统摄像头进行拍照，系统相机可以自由获取本地文件的存储权限，所以无需在声明权限。

二、Building a Camera App

1.MainActivity.java文件

package com.example.takemyphoto;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.content.pm.PackageManager;
import android.hardware.Camera;
import android.hardware.Camera.AutoFocusCallback;
import android.hardware.Camera.PictureCallback;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.FrameLayout;

public class MainActivity extends Activity {
    private Camera mCamera;
    private CreamPrivew mPreview;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
     // Create an instance of Camera
        mCamera = getCameraInstance();

        // Create our Preview view and set it as the content of our activity.
        mPreview = new CreamPrivew(this, mCamera);
        FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview);
        preview.addView(mPreview);
        
     // Add a listener to the Capture button
        Button captureButton = (Button) findViewById(R.id.button_capture);
        captureButton.setOnClickListener(
            new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    // get an image from the camera
                    mCamera.autoFocus(new AutoFocusCallback(){

                        @Override
                        public void onAutoFocus(boolean succeed, Camera camera) {
                            // TODO 自动生成的方法存根
                            mCamera.takePicture(null, null, mPicture);
                        }
                        
                    });
                    
                }
            }
        );
        
    }
   
        
        /** Check if this device has a camera */
        private boolean checkCameraHardware(Context context) {
            if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)){
                // this device has a camera
                return true;
            } else {
                // no camera on this device
                return false;
            }
        }
        /** A safe way to get an instance of the Camera object. */
        public static Camera getCameraInstance(){
            Camera c = null;
            try {
                c = Camera.open(); // attempt to get a Camera instance，api9之后支持（1），打开前置摄像机
            }
            catch (Exception e){
                // Camera is not available (in use or does not exist)
            }
            return c; // returns null if camera is unavailable
        }
   


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
    private PictureCallback mPicture = new PictureCallback() {

        @Override
        public void onPictureTaken(byte[] data, Camera camera) {

            File pictureFile = new File("/scard/"+System.currentTimeMillis()+".jpg");

            try {
                FileOutputStream fos = new FileOutputStream(pictureFile);
                fos.write(data);
                fos.close();
            } catch (FileNotFoundException e) {
                Log.d("TAG", "File not found: " + e.getMessage());
            } catch (IOException e) {
                Log.d("TAG", "Error accessing file: " + e.getMessage());
            }
        }
    };
    public void onDestory(){
        if(mCamera!=null){
            mCamera.release();
            mCamera=null;
            
        }
    }
}

2.CreamPrivew.java文件

package com.example.takemyphoto;

import java.io.IOException;

import android.content.Context;
import android.hardware.Camera;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

public class CreamPrivew extends SurfaceView implements SurfaceHolder.Callback {
    /** A basic Camera preview class */
        private SurfaceHolder mHolder;
        private Camera mCamera;

        public CreamPrivew(Context context, Camera camera) {
            super(context);
            mCamera = camera;

            // Install a SurfaceHolder.Callback so we get notified when the
            // underlying surface is created and destroyed.
            mHolder = getHolder();
            mHolder.addCallback(this);
            // deprecated setting, but required on Android versions prior to 3.0
            mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
        }

        public void surfaceCreated(SurfaceHolder holder) {
            // The Surface has been created, now tell the camera where to draw the preview.
            try {
                mCamera.setPreviewDisplay(holder);
                mCamera.startPreview();
            } catch (IOException e) {
                Log.d(VIEW_LOG_TAG, "Error setting camera preview: " + e.getMessage());
            }
        }

        public void surfaceDestroyed(SurfaceHolder holder) {
            // empty. Take care of releasing the Camera preview in your activity.
        }

        public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
            // If your preview can change or rotate, take care of those events here.
            // Make sure to stop the preview before resizing or reformatting it.

            if (mHolder.getSurface() == null){
              // preview surface does not exist
              return;
            }

            // stop preview before making changes
            try {
                mCamera.stopPreview();
            } catch (Exception e){
              // ignore: tried to stop a non-existent preview
            }

            // set preview size and make any resize, rotate or
            // reformatting changes here

            // start preview with new settings
            try {
                mCamera.setPreviewDisplay(mHolder);
                mCamera.startPreview();

            } catch (Exception e){
                Log.d(VIEW_LOG_TAG, "Error starting camera preview: " + e.getMessage());
            }
        }
        }

3.activity_main.xml布局文件

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="fill_parent"
    android:layout_height="fill_parent"  
    android:orientation="horizontal"
    tools:context=".MainActivity" >
    <FrameLayout
    android:id="@+id/camera_preview"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:layout_weight="1"
    />

  <Button
    android:id="@+id/button_capture"
    android:text="Capture"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center"
    />
  

</LinearLayout>

4.AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.takemyphoto"
    android:versionCode="1"
    android:versionName="1.0" >
    <uses-permission android:name="android.permission.CAMERA" />
    <uses-feature android:name="android.hardware.camera" />
    <uses-feature android:name="android.hardware.camera" android:required="false" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="18" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.takemyphoto.MainActivity"
            android:label="@string/app_name" 
             android:screenOrientation="landscape">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

     相关API网址：http://developer.android.com/guide/topics/media/camera.html