如何捕獲圖像並將其保存在存儲器中並在ImageView中顯示？

Question

我幾個小時試圖拍照並將其保存到手機的內部存儲並將其設置爲ImageView。

我嘗試了幾個代碼從Stackoverflow和YouTube但只是得到FileUriExposedException ...我不知道爲什麼。也許你有一個想法。

我讀過你應該使用content：//而不是file：//，但這是我的問題的原因嗎？

即時得到：

Caused by: android.os.FileUriExposedException: file:///storage/emulated/0/Pictures/test.jpg exposed beyond app through ClipData.Item.getUri() 
                  at android.os.StrictMode.onFileUriExposed(StrictMode.java:1799) 
                  at android.net.Uri.checkFileUriExposed(Uri.java:2346) 
                  at android.content.ClipData.prepareToLeaveProcess(ClipData.java:845) 
                  at android.content.Intent.prepareToLeaveProcess(Intent.java:8941) 
                  at android.content.Intent.prepareToLeaveProcess(Intent.java:8926) 
                  at android.app.Instrumentation.execStartActivity(Instrumentation.java:1517) 
                  at android.app.Activity.startActivityForResult(Activity.java:4225) 
                  at android.support.v4.app.BaseFragmentActivityJB.startActivityForResult(BaseFragmentActivityJB.java:50) 
                  at android.support.v4.app.FragmentActivity.startActivityForResult(FragmentActivity.java:79) 
                  at android.app.Activity.startActivityForResult(Activity.java:4183) 
                  at android.support.v4.app.FragmentActivity.startActivityForResult(FragmentActivity.java:859) 
                  at ibas.orosol.BildActivity.takePicture(BildActivity.java:86) 
                  at java.lang.reflect.Method.invoke(Native Method)  
                  at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)  
                  at android.view.View.performClick(View.java:5637)  
                  at android.view.View$PerformClick.run(View.java:22429)  
                  at android.os.Handler.handleCallback(Handler.java:751)  
                  at android.os.Handler.dispatchMessage(Handler.java:95)  
                  at android.os.Looper.loop(Looper.java:154)  
                  at android.app.ActivityThread.main(ActivityThread.java:6119)  
                  at java.lang.reflect.Method.invoke(Native Method)  
                  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)  
                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)  

Here's我的活動

final private int REQUEST_CODE_ASK_PERMISSION = 123; //kann jegliche Zahl sein. Wir benutzens halt später 
final private int CAMERA_REQUEST = 555; //kann jegliche Zahl sein. Wir benutzens halt später 

private File imageFile; 

private ImageView mImageView; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_bild); 
    getSupportActionBar().setTitle(""); 
    getSupportActionBar().setBackgroundDrawable(ResourcesCompat.getDrawable(getResources(), R.drawable.kopf_app, null)); 
    getSupportActionBar().setDisplayHomeAsUpEnabled(true); 

    mImageView = (ImageView) findViewById(R.id.imageView); 

    // wenn die Permission NICHT gegeben wurde... und was wir dann machen kommt in diesem Block 
    if(ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED){ 

     if(ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.CAMERA)){ 

      //Hier können wir eintragen, wieso wir eigentlich die Permission brauchen/verlangen 
     }else{ 

      //Permission anfragen 
      ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA, Manifest.permission.READ_EXTERNAL_STORAGE, Manifest.permission.WRITE_EXTERNAL_STORAGE}, REQUEST_CODE_ASK_PERMISSION); 
     } 
    } 
    //--------------------------------------------------------------------------------------------- 
    ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE, Manifest.permission.READ_EXTERNAL_STORAGE}, REQUEST_CODE_ASK_PERMISSION); 

} 

public void takePicture(View view) throws IOException { 

    Intent cameraIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE); 

    File file = getFile(); 

    imageFile = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES), "test.jpg"); 

    Uri tempUri = Uri.fromFile(imageFile); 
    String path = "sdcard/orosol/captured_image.jpg"; 

    cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, tempUri); 
    startActivityForResult(cameraIntent, CAMERA_REQUEST); 

} 


@Override 
protected void onActivityResult(int requestCode, int resultCode, Intent data) { 

    String path = "sdcard/orosol/captured_image.jpg"; 
    if(imageFile.exists()){ 
     Log.i("imagefile", "exists in: " + imageFile.getAbsolutePath()); 
    }else{ 
     Log.i("imagefile", "existiert nicht!"); 
    } 

} 

Answer 1

如果您targetSdkVersion爲24或更高，我們必須使用FileProvider類給訪問特定文件或文件夾以使其他應用程序可以訪問它們。

步驟來替換文件：// URI的內容：// URI：

添加到您的清單

<?xml version="1.0" encoding="utf-8"?> 
<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
... 
<application 
... 
<provider 
    android:name="android.support.v4.content.FileProvider" 
    android:authorities="${applicationId}.provider" 
    android:exported="false" 
    android:grantUriPermissions="true"> 
    <meta-data 
     android:name="android.support.FILE_PROVIDER_PATHS" 
     android:resource="@xml/provider_paths"/> 
</provider> 
</application> 
</manifest> 

然後創建res文件夾下的XML文件夾中的文件provider_paths.xml。如果文件夾不存在，可能需要創建它。該文件的內容如下所示。它描述了我們希望在名稱爲external_files的根文件夾（path =「。」）中共享對外部存儲的訪問。

<?xml version="1.0" encoding="utf-8"?> 
<paths xmlns:android="http://schemas.android.com/apk/res/android"> 
<external-path name="external_files" path="."/> 
</paths> 

的最後一步是要改變的下面代碼行中

Uri photoURI = Uri.fromFile(createImageFile()); 

到

Uri photoURI = FileProvider.getUriForFile(context, context.getApplicationContext().getPackageName() + ".provider", createImageFile());