如何拋出一個不存在的圖像的異常選擇

在我的方案中，我從圖庫中選擇一張圖片並將其顯示在同一個佈局的圖像查看中，並且我可以使用圖像處理另一個活動。但是當我點擊意圖按鈕時沒有選擇任何圖像時，我有一個強制停止。如何拋出一個不存在的圖像的異常選擇

誰有解決這個問題的想法？

public void onCreate(Bundle savedInstanceState){ 

    super.onCreate(savedInstanceState); 
    setContentView (R.layout.browse_page); 

    //action for browse Image 

     Intent intent = new Intent();  
     intent.setType("image/*"); 
     intent.setAction(Intent.ACTION_GET_CONTENT); 
     startActivityForResult(Intent.createChooser(intent,"Select Picture"), SELECT_PICTURE); 


    //declare image and button 
    image = (ImageView) findViewById (R.id.image); 
    chooseNewImage = (Button) findViewById (R.id.chooseNewImage); 
    grayScale = (Button) findViewById (R.id.greyscale); 

    //back to previous page 
    chooseNewImage.setOnClickListener(new View.OnClickListener() { 

     public void onClick(View v) { 
      // TODO Auto-generated method stub 
      finish(); 
     } 
    }); 

    //go to set the image to grayScale 
    grayScale.setOnClickListener(new View.OnClickListener() { 

     public void onClick(View v) { 

       Intent greyScale = new Intent(browsePage.this, grayScale.class); 
       greyScale.putExtra("imagePath", path_selectedImage); 
       startActivity(greyScale); 

     } 
    }); 
} 

    public void onActivityResult(int requestCode, int resultCode, Intent data) { 
     if (resultCode == RESULT_OK && requestCode == SELECT_PICTURE) { 


        Uri_selectedImage = data.getData(); 
        path_selectedImage = getPath(Uri_selectedImage);     
        image.setImageURI(Uri_selectedImage); 
        System.out.println(path_selectedImage); 
        Toast.makeText(getBaseContext(), "Your selected picture", Toast.LENGTH_SHORT).show(); 
      } 


    } 

    private String getPath(Uri uri) { 
     // TODO Auto-generated method stub 
     String[] project = {MediaStore.Images.Media.DATA}; 
     Cursor c = managedQuery(uri, project, null, null, null); 
     startManagingCursor(c); 
     int column_index = c.getColumnIndexOrThrow(MediaStore.Images.Media.DATA); 
     c.moveToFirst(); 
     return c.getString(column_index); 


}

每當我沒有選擇圖像，我按下灰度按鈕，它強制停止。是否需要嘗試抓住？

來源

2012-05-21 user1381427

當點擊灰度並且沒有圖像被選中時，你想要發生什麼？或者您應該只在選擇圖像時啓用灰度按鈕？請同時發佈崩潰的logcat。 – Simon

我想彈出一個敬酒〜 – user1381427

//go to set the image to grayScale  
grayScale.setOnClickListener(new View.OnClickListener() { 
     public void onClick(View v) { 

      if (path_selectedImage==null){ 
      // show toast here 
      } else {  
      Intent greyScale = new Intent(browsePage.this,grayScale.class); 
      greyScale.putExtra("imagePath",path_selectedImage); 
      startActivity(greyScale);   
     } 
});

來源

2012-05-22 09:04:02 Simon

如何拋出一個不存在的圖像的異常選擇

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