//最开始是没想写Blog的,不过零星的知识也确实需要总结,以后也会不断补充这本书的内容和安卓学习中的收获
画重点:调用摄像头分为简单的2步
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1、新建文件,以保留拍摄的照片
2、相机就是一个活动,需要利用内容提供器获得相机拍摄的照片
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新建CameraAlbumTest项目
见代码:
AndroidManifest.xml,注册内容提供器,在Android4.4系统之前,访问SD卡的应用关联目录也是要声明权限的。为了兼容,在其中声明一下SD卡的权限。
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.hms.cameraalbumtest"> <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/> <application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:supportsRtl="true" android:theme="@style/AppTheme"> <activity android:name=".MainActivity"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> <provider android:name="android.support.v4.content.FileProvider" android:authorities="com.example.cameraalbumtest.fileprovider" android:exported="false" android:grantUriPermissions="true"> <meta -data android:name="android.support.FILE_PROVIDER_PATHS" android:resource="@xml/file_paths"/> </provider> </application> </manifest>
res中新建xml文件夹,新建files_path.xml。指定Uri共享,name的值随便填,path的值表示共享的具体路径,这里设置空值表示整个SD卡都进行共享,当然你也可以仅共享我们存放output_image.jpg这张图片的路径
<?xml version="1.0" encoding="utf-8"?> <paths xmlns:android="http://schemas.android.com/apk/res/android"> <external-path name = "my_images" path="" /> </paths>
布局文件activity_main.xml
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/activity_main" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent"> <Button android:id="@+id/take_photo" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="Take photo"/> <ImageView android:id="@+id/picture" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_horizontal" /> </LinearLayout>
MainActivity代码
package com.example.hms.cameraalbumtest;import android.content.Intent;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.net.Uri;import android.os.Build;import android.provider.MediaStore;import android.support.v4.content.FileProvider;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.View;import android.widget.Button;import android.widget.ImageView;import java.io.File;import java.io.FileNotFoundException;import java.io.IOError;import java.io.IOException; public class MainActivity extends AppCompatActivity { public static final int TAKE_PHOTO = 1; private ImageView picture; private Uri imageUri; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Button takePhoto = (Button) findViewById(R.id.take_photo); picture = (ImageView) findViewById(R.id.picture); takePhoto.setOnClickListener(new View.OnClickListener(){ @Override public void onClick(View v) { File outputImage = new File(getExternalCacheDir(), "output_image.jpg"); try { if(outputImage.exists() ) { outputImage.delete(); } outputImage.createNewFile(); } catch (IOException e) { e.printStackTrace(); } if(Build.VERSION.SDK_INT >= 24) { imageUri = FileProvider.getUriForFile(MainActivity.this, "com.example.cameraalbumtest.fileprovider", outputImage); } else { imageUri = Uri.fromFile(outputImage); } Intent intent = new Intent("android.media.action.IMAGE_CAPTURE"); intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri); startActivityForResult(intent, TAKE_PHOTO); } }); } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { switch (requestCode) { case TAKE_PHOTO: if( resultCode == RESULT_OK ) { try{ Bitmap bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(imageUri)); picture.setImageBitmap(bitmap); } catch (FileNotFoundException e) { e.printStackTrace(); } } break; default: break; } } }
结果如图: