Android - 尝试使用ImageView代码制作Dialog

Question

What I'm trying to do is when an Imageview item being preesed, then a Dialog will open up and show the inage in a large scale.

Now first of all this is the XML layout of the dialog -

    <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <ImageView
        android:id="@+id/imageView_large_pic"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/bkgnd_pressed" />

</LinearLayout>

Now the code to the Dialog is as follows -

Dialog settingsDialog = new Dialog(MainChat.this);

settingsDialog.getWindow().requestFeature(Window.FEATURE_NO_TITLE);

 settingsDialog.setContentView(getLayoutInflater().inflate(R.layout.image_large
          , null));

ImageView ivLarge = (ImageView) findViewById(R.id.imageView_large_pic);

String pathpic = v.getTag().toString();

ivLarge.setImageURI(Uri.parse(pathpic));

settingsDialog.show();

Now I tried to dubuging this code, and it get stuck at this line - ivLarge.setImageURI(Uri.parse(pathpic));

The logcat gives me that this is java.lang.NullPointerException error.

Thanks for any kind of help

Answer 1

You are looking in the wrong place for the ImageView

ImageView ivLarge = (ImageView) findViewById(R.id.imageView_large_pic);

is looking in the layout you inflate in setContentView() . Instead, you need to look in the Dialog 's layout. Try instead

ImageView ivLarge = (ImageView) settingsDialog .findViewById(R.id.imageView_large_pic);