Android 调用摄像头拍照 以及 从相册中选择照片

参考：《第一行代码》第8章
https://github.com/zxing/zxing
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新建一个工程CameraAndAlbumDemo：



一路默认，点击OK即可

修改activity_main.xml代码：

<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:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
android:orientation="vertical"
tools:context=".MainActivity">

<Button
android:id="@+id/btnCamera"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="take a photo" />

<Button
android:id="@+id/btnSelect"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="select an image" />

<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content" >

<ImageView
android:id="@+id/ivCaptured"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentRight="true" />

</RelativeLayout>

</LinearLayout>

布局xml生成两个按钮，一个开启摄像头拍照，一个从相册中选择照片返回；同时设置一个ImageView用于显示返回的图片

修改MainActivity.java的代码：

package com.zj.cameraandalbumdemo;

import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.util.Log;
import android.view.View;
import android.view.Window;
import android.widget.Button;
import android.widget.ImageView;

import java.io.File;
import java.text.SimpleDateFormat;
import java.util.Date;

public class MainActivity extends Activity {
private static final String LOG_TAG = "MainActivity";
private static final int REQUEST_IMAGE_CAPTURE = 100;  //request Code for camera
private static final int REQUEST_IMAGE_SELECT = 200;   //request Code for album
public static final int MEDIA_TYPE_IMAGE = 1;  //choose camera image type

private Button btnCamera; //相机拍摄
private Button btnSelect; //相册选择照片
private ImageView ivCaptured; //显示拍摄或相册选择的结果
private Uri fileUri;  //用于存储相机拍摄的照片
private Bitmap bmp;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE); //不显示标题栏
setContentView(R.layout.activity_main);

ivCaptured = (ImageView) findViewById(R.id.ivCaptured);

btnCamera = (Button) findViewById(R.id.btnCamera);
btnCamera.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
initPrediction();
fileUri = getOutputMediaFileUri(MEDIA_TYPE_IMAGE); //得到存储地址的Uri
Intent i = new Intent(MediaStore.ACTION_IMAGE_CAPTURE); //此action表示进行拍照
i.putExtra(MediaStore.EXTRA_OUTPUT, fileUri);  //指定图片的输出地址
startActivityForResult(i, REQUEST_IMAGE_CAPTURE);
}
});

btnSelect = (Button) findViewById(R.id.btnSelect);
btnSelect.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
initPrediction();
Intent i = new Intent(Intent.ACTION_PICK, MediaStore.Images.Media.EXTERNAL_CONTENT_URI); //从相册选取一张图片
startActivityForResult(i, REQUEST_IMAGE_SELECT);
}
});
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if ((requestCode == REQUEST_IMAGE_CAPTURE || requestCode == REQUEST_IMAGE_SELECT) && resultCode == RESULT_OK) {
String imgPath;

if (requestCode == REQUEST_IMAGE_CAPTURE) {
imgPath = fileUri.getPath(); //取得拍照存储的地址
} else { //解析得到所选相册图片的地址
Uri selectedImage = data.getData();
String[] filePathColumn = { MediaStore.Images.Media.DATA };
Cursor cursor = MainActivity.this.getContentResolver().query(selectedImage, filePathColumn, null, null, null);
cursor.moveToFirst();
int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
imgPath = cursor.getString(columnIndex);
cursor.close();
}

bmp = BitmapFactory.decodeFile(imgPath); //将所选图片提取为bitmap格式
Log.d(LOG_TAG, imgPath);
Log.d(LOG_TAG, String.valueOf(bmp.getHeight()));
Log.d(LOG_TAG, String.valueOf(bmp.getWidth()));

ivCaptured.setImageBitmap(bmp); //show image
}
btnCamera.setEnabled(true);
btnSelect.setEnabled(true);
}

private void initPrediction() {
btnCamera.setEnabled(false);
btnSelect.setEnabled(false);
}

/** Create a file Uri for saving an image or video */
/** 为保存图片或视频创建一个文件地址 */
private static Uri getOutputMediaFileUri(int type){
return Uri.fromFile(getOutputMediaFile(type));
}

/** Create a File for saving an image or video */
private static File getOutputMediaFile(int type){
// To be safe, you should check that the SDCard is mounted
// using Environment.getExternalStorageState() before doing this.
// 首先检测外部SDCard是否存在并且可读可写
if (!Environment.getExternalStorageState().equals("mounted")) {
return null;
}

File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_PICTURES), "Caffe-Android-Demo");
// This location works best if you want the created images to be shared
// between applications and persist after your app has been uninstalled.

// 如果存储路径不存在，则创建
// Create the storage directory if it does not exist
if (! mediaStorageDir.exists()) {
if (! mediaStorageDir.mkdirs()) {
Log.d("MyCameraApp", "failed to create directory");
return null;
}
}

// Create a media file name
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
File mediaFile;
if (type == MEDIA_TYPE_IMAGE) {
mediaFile = new File(mediaStorageDir.getPath() + File.separator +
"IMG_"+ timeStamp + ".jpg");
} else {
return null;
}

return mediaFile;
}
}

AndroidManifest.xml代码：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.zj.cameraandalbumdemo" >

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<!-- CAMERA -->
<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />
<uses-feature android:name="android.hardware.camera.autofocus" />

<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".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>