java - 如何从 Android 中的应用程序访问我的相机

Question

我正在创建一个应用程序。在此应用程序中，我想打开我的相机并保存它。

所以我编写了代码来做到这一点

takepic.setOnClickListener(new View.OnClickListener() {

        @Override

        public void onClick(View v) {

            count++;
            String file = dir+count+".jpg";
            File newfile = new File(file);

            try {
                newfile.createNewFile();
            }
            catch (IOException e)
            {

            }

            Uri outputFileUri = Uri.fromFile(newfile);

            Intent cameraIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
            cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, outputFileUri);

            startActivityForResult(cameraIntent, TAKE_PHOTO_CODE);

        }
    });

我还添加了 list 文件的权限

<?xml version="1.0" encoding="utf-8"?>

<uses-feature android:name="android.hardware.camera"
    android:required="true" />


<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.CAMERA"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <meta-data
        android:name="com.facebook.sdk.ApplicationId"
        android:value="@string/app_id" />

    <activity android:name=".LoginActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity
        android:name="com.facebook.FacebookActivity"
        android:configChanges="keyboard|keyboardHidden|screenLayout|screenSize|orientation"
        android:label="@string/app_name"
        android:theme="@android:style/Theme.Translucent.NoTitleBar" />
    <activity
        android:name=".MainActivity"
        android:label="@string/title_activity_main"
        android:theme="@style/AppTheme.NoActionBar"></activity>
</application>

但是当我尝试打开相机时出现此错误:

java.lang.SecurityException: Permission Denial: 

既然我已经添加了权限，为什么我会收到此消息

这是我在日志中的错误

04-05 14:03:56.839 9562-9562/com.example.pavithraprabodha.selfimania E/AndroidRuntime: FATAL EXCEPTION: main
                                                                                   Process: com.example.pavithraprabodha.selfimania, PID: 9562
                                                                                   java.lang.SecurityException: Permission Denial: starting Intent { act=android.media.action.IMAGE_CAPTURE flg=0x3 cmp=com.android.camera/.Camera clip={text/uri-list U:file:///storage/emulated/0/Pictures/Selfimania/1.jpg} (has extras) } from ProcessRecord{420a1c9 9562:com.example.pavithraprabodha.selfimania/u0a58} (pid=9562, uid=10058) with revoked permission android.permission.CAMERA
                                                                                       at android.os.Parcel.readException(Parcel.java:1599)
                                                                                       at android.os.Parcel.readException(Parcel.java:1552)
                                                                                       at android.app.ActivityManagerProxy.startActivity(ActivityManagerNative.java:2658)
                                                                                       at android.app.Instrumentation.execStartActivity(Instrumentation.java:1507)
                                                                                       at android.app.Activity.startActivityForResult(Activity.java:3917)
                                                                                       at android.support.v4.app.ActivityCompatJB.startActivityForResult(ActivityCompatJB.java:30)
                                                                                       at android.support.v4.app.ActivityCompat.startActivityForResult(ActivityCompat.java:162)
                                                                                       at android.support.v4.app.FragmentActivity.startActivityFromFragment(FragmentActivity.java:925)
                                                                                       at android.support.v4.app.FragmentActivity$HostCallbacks.onStartActivityFromFragment(FragmentActivity.java:1008)
                                                                                       at android.support.v4.app.Fragment.startActivityForResult(Fragment.java:940)
                                                                                       at android.support.v4.app.Fragment.startActivityForResult(Fragment.java:929)
                                                                                       at com.example.pavithraprabodha.selfimania.Add_new_fragement$2.onClick(Add_new_fragement.java:89)
                                                                                       at android.view.View.performClick(View.java:5198)
                                                                                       at android.view.View$PerformClick.run(View.java:21147)
                                                                                       at android.os.Handler.handleCallback(Handler.java:739)
                                                                                       at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                                       at android.os.Looper.loop(Looper.java:148)
                                                                                       at android.app.ActivityThread.main(ActivityThread.java:5417)
                                                                                       at java.lang.reflect.Method.invoke(Native Method)
                                                                                       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
                                                                                       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

Answer 1

如果你的compileSdkVersion小于23，低于marshmallow，你只需要在Manifest中定义以下权限:

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

如果您要保存图像或视频，请同时定义 WRITE_EXTERNAL_STORAGE 权限。

现在对于棉花糖，您必须动态定义权限，如下所示:

    private static final int REQUEST_CAMERARESULT=201;

ibtn_cam.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                if(getActivity().checkSelfPermission(Manifest.permission.CAMERA)== PackageManager.PERMISSION_GRANTED){
                    ///method to get Images
                    takeVideo();
                }else{
                    if(shouldShowRequestPermissionRationale(Manifest.permission.CAMERA)){
                        Toast.makeText(getActivity(),"Your Permission is needed to get access the camera",Toast.LENGTH_LONG).show();
                    }
                    requestPermissions(new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE,Manifest.permission.READ_EXTERNAL_STORAGE,Manifest.permission.CAMERA}, REQUEST_CAMERARESULT);
                }
            }else{
                takeVideo();
            }
        }
    });

代替takeVideo，你可以使用任何方法来打开相机，我已经使用过

public void takeVideo(){
    Intent intent = new Intent(MediaStore.ACTION_VIDEO_CAPTURE);

    fileUri = getOutputMediaFileUri(MEDIA_TYPE_VIDEO);

    // set video quality
    // 1- for high quality video
    intent.putExtra(MediaStore.EXTRA_VIDEO_QUALITY, 1);
    intent.putExtra(MediaStore.EXTRA_OUTPUT, fileUri);
    // start the video capture Intent
    getParentFragment().startActivityForResult(intent, CAMERA_CAPTURE_VIDEO_REQUEST_CODE);

    Intent mediaScanIntent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
    File f = new File(fileUri.getPath());
    Uri contentUri = Uri.fromFile(f);
    mediaScanIntent.setData(contentUri);
    sendBroadcast(mediaScanIntent);

}

要将视频保存到图库，您必须使用带有 sendBroadcast(mediaScanIntent) 的新 Intent ，如上所示

如果您在 feagment 中编写所有这些代码，请不要忘记使用上下文来调用 sendBroadcast(mediaScanIntent) 作为 getActivity().sendBroadcast(mediaScanIntent)

检查这个:question