如何保存位圖

我通常不使用圖像。我嘗試過這個。應用程序將onBttnClick顯示圖庫和用戶可以選擇圖片，他必須裁剪它。這將節省很多，但我想保存它並使用裁剪圖像，直到用戶更改它。如何保存位圖

那麼請你能告訴我如何保存圖像供以後使用？

下面是活動代碼

public void onImage(View view){ 
    //Přechod do třídy GalleryUtil 
    Intent gallery_Intent = new Intent(getApplicationContext(), GalleryUtil.class); 
    startActivityForResult(gallery_Intent, GALLERY_ACTIVITY_CODE); 
} 

//Vyhodnocení zadaných údajů 
@Override 
public void onActivityResult(int requestCode, int resultCode, Intent data) { 
    super.onActivityResult(requestCode, resultCode, data); 
    if (requestCode == GALLERY_ACTIVITY_CODE) { 
     if(resultCode == Activity.RESULT_OK){ 
      String picturePath = data.getStringExtra("picturePath"); 
      performCrop(picturePath); 
     } 
    } 

    if (requestCode == RESULT_CROP) { 
     if(resultCode == Activity.RESULT_OK){ 

      Bundle extras = data.getExtras(); 
      Bitmap selectedBitmap = extras.getParcelable("data"); 
      ImageView imageView=(ImageView)findViewById(R.id.imageView); 
      imageView.setImageBitmap(getCroppedBitmap(selectedBitmap)); 
      imageView.setScaleType(ImageView.ScaleType.FIT_XY); 

      String path = Environment.getExternalStorageDirectory().getAbsolutePath() +"/images"; // save to SD Card in images folder. Make sure path is there ! 
      OutputStream fOut = null; 

      SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd_HHmmss"); 
      String currentDateandTime = sdf.format(new Date()); 
      File file = new File(path, "Cropped_Image_"+currentDateandTime+".jpg"); // the File to save to 
      try { 
       fOut = new FileOutputStream(file); 
      } catch (FileNotFoundException e) { 
       e.printStackTrace(); 
      } 

      Bitmap pictureBitmap = getCroppedBitmap(selectedBitmap); // Using the cropped bitmap. 
      pictureBitmap.compress(Bitmap.CompressFormat.JPEG, 85, fOut); // saving the Bitmap to a file compressed as a JPEG with 85% compression rate 
      try { 
       fOut.flush(); 
      } catch (IOException e) { 
       e.printStackTrace(); 
      } 
      try { 
       fOut.close(); // do not forget to close the stream 
      } catch (IOException e) { 
       e.printStackTrace(); 
      } 

      try { 
       MediaStore.Images.Media.insertImage(getContentResolver(),file.getAbsolutePath(),file.getName(),file.getName()); 
      } catch (FileNotFoundException e) { 
       e.printStackTrace(); 
      } 

     } 
    } 
} 

private void performCrop(String picUri) { 
    try { 


     Intent cropIntent = new Intent("com.android.camera.action.CROP"); 
     // indicate image type and Uri 
     File f = new File(picUri); 
     Uri contentUri = Uri.fromFile(f); 

     cropIntent.setDataAndType(contentUri, "image/*"); 
     // set crop properties 
     cropIntent.putExtra("crop", "true"); 
     // indicate aspect of desired crop 
     cropIntent.putExtra("aspectX", 1); 
     cropIntent.putExtra("aspectY", 1); 
     // indicate output X and Y 
     cropIntent.putExtra("outputX", 280); 
     cropIntent.putExtra("outputY", 280); 

     // retrieve data on return 
     cropIntent.putExtra("return-data", true); 
     // start the activity - we handle returning in onActivityResult 
     startActivityForResult(cropIntent, RESULT_CROP); 
    } 
    // respond to users whose devices do not support the crop action 
    catch (ActivityNotFoundException anfe) { 
     // display an error message 
     String errorMessage = "your device doesn't support the crop action!"; 
     Toast toast = Toast.makeText(this, errorMessage, Toast.LENGTH_SHORT); 
     toast.show(); 
    } 
} 

public Bitmap getCroppedBitmap(Bitmap bitmap) { 
    Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), 
      bitmap.getHeight(), Bitmap.Config.ARGB_8888); 
    Canvas canvas = new Canvas(output); 

    final int color = 0xff424242; 
    final Paint paint = new Paint(); 
    final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight()); 

    paint.setAntiAlias(true); 
    canvas.drawARGB(0, 0, 0, 0); 
    paint.setColor(color); 
    canvas.drawCircle(bitmap.getWidth()/2, bitmap.getHeight()/2, 
      bitmap.getWidth()/2, paint); 
    paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN)); 
    canvas.drawBitmap(bitmap, rect, rect, paint); 


    return output; 
}

}

這裏是我的GalleryUtil代碼

public class GalleryUtil extends Activity{ 

private final static int RESULT_SELECT_IMAGE = 100; 
public static final int MEDIA_TYPE_IMAGE = 1; 
private static final String TAG = "GalleryUtil"; 

String mCurrentPhotoPath; 
File photoFile = null; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    try{ 
     //Pick Image From Gallery 
     Intent i = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI); 
     startActivityForResult(i, RESULT_SELECT_IMAGE); 
    }catch(Exception e){ 
     e.printStackTrace(); 
    } 
} 

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

    switch(requestCode){ 
     case RESULT_SELECT_IMAGE: 

      if (resultCode == Activity.RESULT_OK && data != null && data.getData() != null) { 
       try{ 
        Uri selectedImage = data.getData(); 
        String[] filePathColumn = {MediaStore.Images.Media.DATA }; 
        Cursor cursor = getContentResolver().query(selectedImage, 
          filePathColumn, null, null, null); 
        cursor.moveToFirst(); 
        int columnIndex = cursor.getColumnIndex(filePathColumn[0]); 
        String picturePath = cursor.getString(columnIndex); 


        //return Image Path to the Main Activity 
        Intent returnFromGalleryIntent = new Intent(); 
        returnFromGalleryIntent.putExtra("picturePath",picturePath); 
        setResult(RESULT_OK,returnFromGalleryIntent); 
        finish(); 
       }catch(Exception e){ 
        e.printStackTrace(); 
        Intent returnFromGalleryIntent = new Intent(); 
        setResult(RESULT_CANCELED, returnFromGalleryIntent); 
        finish(); 
       } 
      }else{ 
       Log.i(TAG,"RESULT_CANCELED"); 
       Intent returnFromGalleryIntent = new Intent(); 
       setResult(RESULT_CANCELED, returnFromGalleryIntent); 
       finish(); 
      } 
      break; 
    } 
}

}

錯誤：

12-04 23:00:25.521 1728-1728/com.tomiktuts.tom.mygirlfriendapp E/AndroidRuntime: FATAL EXCEPTION: main Process: com.tomiktuts.tom.mygirlfriendapp, PID: 1728 java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=400, result=-1, data=Intent { (has extras) }} to activity {com.tomiktuts.tom.mygirlfriendapp/com.tomiktuts.tom.mygirlfriendapp.DashBoardActivity}: java.lang.NullPointerException at android.app.ActivityThread.deliverResults(ActivityThread.java:4067) at android.app.ActivityThread.handleSendResult(ActivityThread.java:4110) at android.app.ActivityThread.access$1400(ActivityThread.java:177) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1498) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:145) at android.app.ActivityThread.main(ActivityThread.java:5951) at java.lang.reflect.Method.invoke(Native Method) at java.lang.reflect.Method.invoke(Method.java:372) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1400) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1195) Caused by: java.lang.NullPointerException at android.graphics.Bitmap.compress(Bitmap.java:1143) at com.tomiktuts.tom.mygirlfriendapp.DashBoardActivity.onActivityResult(DashBoardActivity.java:161) at android.app.Activity.dispatchActivityResult(Activity.java:6549) at android.app.ActivityThread.deliverResults(ActivityThread.java:4063) at android.app.ActivityThread.handleSendResult(ActivityThread.java:4110) at android.app.ActivityThread.access$1400(ActivityThread.java:177) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1498) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:145) at android.app.ActivityThread.main(ActivityThread.java:5951) at java.lang.reflect.Method.invoke(Native Method) at java.lang.reflect.Method.invoke(Method.java:372) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1400) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1195)

謝謝你的幫助。祝你今天愉快。

來源

2015-12-04 Tomik Vítek

您應該使用Bitmap.compress()方法將位圖保存爲文件。它會壓縮你的圖片並將其推送到OutputStream中。

我認爲最好的辦法是在imageview設置爲getCroppedBitmap(Bitmap bitmap)（在執行performCrop(String picUri)後調用）時添加以下邏輯。

String baseDir = Environment.getExternalStorageDirectory().getAbsolutePath(); 

OutputStream fOut = null; 

// Lets save using date 
SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd_HHmmss"); 
String currentDateandTime = sdf.format(new Date()); 
String fileName = "Cropped_Image_" + currentDateandTime + ".png"; 

// Not sure if the/is on the path or not 
File file = new File(baseDir + File.separator + fileName); // the File to save to 
fOut = new FileOutputStream(file); 

Bitmap pictureBitmap = getCroppedBitmap(selectedBitmap); // Using the cropped bitmap. 
pictureBitmap.compress(Bitmap.CompressFormat.JPEG, 85, fOut); // saving the Bitmap to a file compressed as a JPEG with 85% compression rate 
fOut.flush(); 
fOut.close(); // do not forget to close the stream 

MediaStore.Images.Media.insertImage(getContentResolver(),file.getAbsolutePath(),file.getName(),file.getName());

希望這有助於！

記住下面添加體現，如果你還沒有：

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

完整的工作代碼：

GalleryUtil.java

package com.example.user.myapplication; 

    import android.app.Activity; 
    import android.content.Intent; 
    import android.database.Cursor; 
    import android.net.Uri; 
    import android.provider.MediaStore; 
    import android.os.Bundle; 
    import android.util.Log; 

    import java.io.File; 

    public class GalleryUtil extends Activity { 

     private final static int RESULT_SELECT_IMAGE = 100; 
     public static final int MEDIA_TYPE_IMAGE = 1; 
     private static final String TAG = "GalleryUtil"; 

     String mCurrentPhotoPath; 
     File photoFile = null; 

     @Override 
     protected void onCreate(Bundle savedInstanceState) { 
      super.onCreate(savedInstanceState); 
      try{ 
       //Pick Image From Gallery 
       Intent i = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI); 
       startActivityForResult(i, RESULT_SELECT_IMAGE); 
      }catch(Exception e){ 
       e.printStackTrace(); 
      } 
     } 

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

      switch(requestCode){ 
       case RESULT_SELECT_IMAGE: 

        if (resultCode == Activity.RESULT_OK && data != null && data.getData() != null) { 
         try{ 
          Uri selectedImage = data.getData(); 
          String[] filePathColumn = {MediaStore.Images.Media.DATA }; 
          Cursor cursor = getContentResolver().query(selectedImage, 
            filePathColumn, null, null, null); 
          cursor.moveToFirst(); 
          int columnIndex = cursor.getColumnIndex(filePathColumn[0]); 
          String picturePath = cursor.getString(columnIndex); 


          //return Image Path to the Main Activity 
          Intent returnFromGalleryIntent = new Intent(); 
          returnFromGalleryIntent.putExtra("picturePath",picturePath); 
          setResult(RESULT_OK,returnFromGalleryIntent); 
          finish(); 
         }catch(Exception e){ 
          e.printStackTrace(); 
          Intent returnFromGalleryIntent = new Intent(); 
          setResult(RESULT_CANCELED, returnFromGalleryIntent); 
          finish(); 
         } 
        }else{ 
         Log.i(TAG, "RESULT_CANCELED"); 
         Intent returnFromGalleryIntent = new Intent(); 
         setResult(RESULT_CANCELED, returnFromGalleryIntent); 
         finish(); 
        } 
        break; 
      } 
     } 
    }

MainActivity：

  package com.example.user.myapplication; 

      import android.app.Activity; 
      import android.content.ActivityNotFoundException; 
      import android.content.Intent; 
      import android.graphics.Bitmap; 
      import android.graphics.Canvas; 
      import android.graphics.Paint; 
      import android.graphics.PorterDuff; 
      import android.graphics.PorterDuffXfermode; 
      import android.graphics.Rect; 
      import android.net.Uri; 
      import android.os.Bundle; 
      import android.os.Environment; 
      import android.provider.MediaStore; 
      import android.view.Menu; 
      import android.view.MenuItem; 
      import android.view.View; 
      import android.widget.ImageView; 
      import android.widget.Toast; 

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

      public class MainActivity extends Activity { 

       private final static int GALLERY_ACTIVITY_CODE = 100; 
       public static final int RESULT_CROP = 1; 

       @Override 
       protected void onCreate(Bundle savedInstanceState) { 
        super.onCreate(savedInstanceState); 
        setContentView(R.layout.activity_main); 

        // onImage can be called with anything doesn't matter : 
        onImage(null); 
       } 

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

       @Override 
       public boolean onOptionsItemSelected(MenuItem item) { 
        // Handle action bar item clicks here. The action bar will 
        // automatically handle clicks on the Home/Up button, so long 
        // as you specify a parent activity in AndroidManifest.xml. 
        int id = item.getItemId(); 

        //noinspection SimplifiableIfStatement 
        if (id == R.id.action_settings) { 
         return true; 
        } 

        return super.onOptionsItemSelected(item); 
       } 

       public void onImage(View view){ 
        //Přechod do třídy GalleryUtil 
        Intent gallery_Intent = new Intent(getApplicationContext(), GalleryUtil.class); 
        startActivityForResult(gallery_Intent, GALLERY_ACTIVITY_CODE); 
       } 

       //Vyhodnocení zadaných údajů 
       @Override 
       public void onActivityResult(int requestCode, int resultCode, Intent data) { 
        super.onActivityResult(requestCode, resultCode, data); 
        if (requestCode == GALLERY_ACTIVITY_CODE) { 
         if(resultCode == Activity.RESULT_OK){ 
          String picturePath = data.getStringExtra("picturePath"); 
          performCrop(picturePath); 
         } 
        } 

        if (requestCode == RESULT_CROP) { 
         if(resultCode == Activity.RESULT_OK){ 

          Bundle extras = data.getExtras(); 
          Bitmap selectedBitmap = extras.getParcelable("data"); 
          Bitmap croppedBitmap = getCroppedBitmap(selectedBitmap); 

          ImageView imageView=(ImageView)findViewById(R.id.imageView); 
          imageView.setImageBitmap(croppedBitmap); 
          imageView.setScaleType(ImageView.ScaleType.FIT_XY); 

          String baseDir = Environment.getExternalStorageDirectory().getAbsolutePath(); 
          FileOutputStream fOut = null; 
          String fileName = "Cropped_Image.jpg"; 

          try { 
           // Not sure if the/is on the path or not 
           File file = new File(baseDir + File.separator + fileName); // the File to save to 
           fOut = new FileOutputStream(file); 

           Bitmap pictureBitmap = getCroppedBitmap(selectedBitmap); // Using the cropped bitmap. 
           pictureBitmap.compress(Bitmap.CompressFormat.JPEG, 85, fOut); // saving the Bitmap to a file compressed as a JPEG with 85% compression rate 

           fOut.flush(); 
           fOut.close(); // do not forget to close the stream 
           MediaStore.Images.Media.insertImage(getContentResolver(), file.getAbsolutePath(), file.getName(), file.getName()); 
          } catch (Exception e) { 
           e.printStackTrace(); 
          } 

         } 
        } 
       } 

       private void performCrop(String picUri) { 
        try { 


         Intent cropIntent = new Intent("com.android.camera.action.CROP"); 
         // indicate image type and Uri 
         File f = new File(picUri); 
         Uri contentUri = Uri.fromFile(f); 

         cropIntent.setDataAndType(contentUri, "image/*"); 
         // set crop properties 
         cropIntent.putExtra("crop", "true"); 
         // indicate aspect of desired crop 
         cropIntent.putExtra("aspectX", 1); 
         cropIntent.putExtra("aspectY", 1); 
         // indicate output X and Y 
         cropIntent.putExtra("outputX", 280); 
         cropIntent.putExtra("outputY", 280); 

         // retrieve data on return 
         cropIntent.putExtra("return-data", true); 
         // start the activity - we handle returning in onActivityResult 
         startActivityForResult(cropIntent, RESULT_CROP); 
        } 
        // respond to users whose devices do not support the crop action 
        catch (ActivityNotFoundException anfe) { 
         // display an error message 
         String errorMessage = "your device doesn't support the crop action!"; 
         Toast toast = Toast.makeText(this, errorMessage, Toast.LENGTH_SHORT); 
         toast.show(); 
        } 
       } 

       public Bitmap getCroppedBitmap(Bitmap bitmap) { 
        Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), 
          bitmap.getHeight(), Bitmap.Config.ARGB_8888); 
        Canvas canvas = new Canvas(output); 

        final int color = 0xff424242; 
        final Paint paint = new Paint(); 
        final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight()); 

        paint.setAntiAlias(true); 
        canvas.drawARGB(0, 0, 0, 0); 
        paint.setColor(color); 
        canvas.drawCircle(bitmap.getWidth()/2, bitmap.getHeight()/2, 
          bitmap.getWidth()/2, paint); 
        paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN)); 
        canvas.drawBitmap(bitmap, rect, rect, paint); 


        return output; 
       } 
      }

AndroidManifest.xml中

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

       <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" 
         android:label="@string/app_name" 
         android:theme="@style/AppTheme.NoActionBar"> 
         <intent-filter> 
          <action android:name="android.intent.action.MAIN" /> 

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

      </manifest>

activity_main.xml中

  <?xml version="1.0" encoding="utf-8"?> 
      <RelativeLayout 
       xmlns:android="http://schemas.android.com/apk/res/android" 
       xmlns:app="http://schemas.android.com/apk/res-auto" 
       xmlns:tools="http://schemas.android.com/tools" 
       android:layout_width="match_parent" 
       android:layout_height="match_parent" 
       android:fitsSystemWindows="true" 
       tools:context="com.example.user.myapplication.MainActivity"> 

       <ImageView 
        android:id="@+id/imageView" 
        android:layout_width="wrap_content" 
        android:layout_height="wrap_content" /> 
      </RelativeLayout>

上面的代碼工作絕對沒問題。我能夠將圖片裁剪並保存在我的SD卡中。比較並檢查你做錯的地方。

讀取每一個應用程序打開的時候，我們需要添加下列主要活動：

. 
. 
. 
@Override 
protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 

     // Adding code for reading if file is already saved : 
    loadImageFromStorage(Environment.getExternalStorageDirectory().getAbsolutePath() + File.separator + "Cropped_Image.jpg") 

     // onImage can be called with anything doesn't matter : 
     onImage(null); 
} 

private void loadImageFromStorage(String path) 
{ 

    try { 
     File f=new File(path); 
     Bitmap b = BitmapFactory.decodeStream(new FileInputStream(f)); 
     ImageView img=(ImageView)findViewById(R.id.imageView); 
     img.setImageBitmap(b); 
    } 
    catch (FileNotFoundException e) 
    { 
     e.printStackTrace(); 
    } 

} 

...

來源

2015-12-04 20:45:17

喜在最後3行，我不得不添加的try/catch並不能化解getImageBitmap我把它低於 'imageView.setImageBitmap（getCroppedBitmap（selectedBitmap））; imageView.setScaleType（ImageView.ScaleType.FIT_XY）;' 我不知道如何使用它對不起。你能幫助我嗎？ –

根據我對你的代碼邏輯的理解，你已經正確放置了行並添加了try/catch，並且關於getImageBitmap，它是我給定代碼中的一個錯誤......沒有默認的getImageBitmap函數，它在我的代碼中被我使用...我已更正並更新了我的上述評論。現在希望它有幫助！ –

在我嘗試它之前，我想問你是否將它放在我的代碼中的正確位置（在imageView.setImageBitmap（getCroppedBitmap（selectedBitmap））; imageView.setScaleType（ImageView.ScaleType.FIT_XY）;'） onActivityResult方法。感謝答覆 –

如何保存位圖

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