Question

In my program I am trying to display an image from a file using an ImageView. I have declared the ImageView to be related to an ImageView XML file and have set the value to be an image from a file using BitmapFactory. After all this, I still am receiving a NullPointerException because the ImageView variable is apparently still null. If you have any ideas or advice, please let me know, thanks!

Here’s the code I am talking about:

public void imageViewMethod(String file){
    Logger log = Logger.getLogger("com.example.myclass");

    try {

    File fileName = new File(root, file);
    if(fileName.exists()){
    String dirFileName = fileName.toString();
    Toast.makeText(getApplicationContext(), dirFileName, Toast.LENGTH_LONG).show();
    ImageView iv = (ImageView)findViewById(R.id.image);

    iv.setImageBitmap(BitmapFactory.decodeFile(dirFileName));
    super.setContentView(iv);
    }
    }catch(Exception e){
        Toast.makeText(getApplicationContext(), "Hit Exception", Toast.LENGTH_LONG).show();
        log.log(Level.SEVERE, "uncaught exception", e);
    }
}

And the corresponding XML file:

<?xml version="1.0" encoding="utf-8"?>
<ImageView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/image"
    android:layout_width="match_parent"
    android:layout_height="match_parent" 

android:layout_margin="5dp">
</ImageView>

Answer 1

looks you have not set the ContentView in oncreate you have to set ContentView before getting ImageView

public void onCreate(Bundle savedInstanceState) {

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