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POCannot Access LinkedHashMap in inner class
 

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  1. POCannot Access LinkedHashMap in inner class
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    <p>I have the following code:</p> <pre><code>final LinkedHashMap&lt;String, Line&gt; trainLinesMap = MetraRail.myDbHelper.getTrainLinesHashMap(); // Create an array of proper line names for the listview adapter. String[] train_lines_long_names = new String[trainLinesMap.size()]; Iterator&lt;Entry&lt;String, Line&gt;&gt; it = trainLinesMap.entrySet().iterator(); for (int i = 0; it.hasNext(); i++) { Map.Entry&lt;String, Line&gt; pairs = (Map.Entry&lt;String, Line&gt;) it.next(); train_lines_long_names[i] = (String) pairs.getKey(); } // Override the default list adapter so we can do 2 things: 1) set custom background colors // on each item, and 2) so we can more easily add onclick handlers to each item. listview.setAdapter( new ArrayAdapter&lt;String&gt;(this, R.layout.select_line_row_layout, R.id.select_line_line_label, train_lines_long_names) { @Override public View getView(int position, View convertView, ViewGroup parent) { TextView textView = (TextView) super.getView(position, convertView, parent); // Change the background color of each item in the list. final String line_label_long = textView.getText().toString(); final int line_color = trainLinesMap.get(line_label_long).getColorInt(); textView.setBackgroundColor(line_color); // Add onclick handlers to each item. textView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Intent i = new Intent(); i.setClassName("garrettp.metrarail", "garrettp.metrarail.screens.SelectStations"); i.putExtra("garrettp.metrarail.line.short", trainLinesMap.get(line_label_long).getShortName()); i.putExtra("garrettp.metrarail.line.long", line_label_long); i.putExtra("garrettp.metrarail.line.color", line_color); startActivity(i); } }); return textView; } }); </code></pre> <p>At the line:</p> <pre><code>final int line_color = trainLinesMap.get(line_label_long).getColorInt(); </code></pre> <p>I get a NullPointerException:</p> <pre><code>10-26 16:10:35.922: E/AndroidRuntime(1785): java.lang.NullPointerException 10-26 16:10:35.922: E/AndroidRuntime(1785): at garrettp.metrarail.screens.SelectLine$1.getView(SelectLine.java:74) </code></pre> <p>Why is this? In a debugger, I've verified that trainLinesMap is correctly initialized and filled with values. It is successfully iterated over in the first for loop, so I know there are values there. But, when accessing the LinkedHashMap from my anonymous inner class, it is always null.</p> <p>I was able to access a String array from this inner class, why can't I access a LinkedHashMap?</p>
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      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. This table or related slice is empty.
    1. USpwnsauce
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    1. This table or related slice is empty.
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    1. This table or related slice is empty.
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    1. COyou can, the NPE is most likely from your map, right before that line add "System.err.println(line_label_long + " : " + trainLinesMap.get(line_label_long));" it will probably be null
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      1. POCannot Access LinkedHashMap in inner class
      1. USChris Lohfink
    2. COSee my answer below, I solved this by assigning the result of trainLinesMap.get(line_label_long) to a temporary variable, and called .getColorInt() from the temporary variable.
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      1. POCannot Access LinkedHashMap in inner class
      1. USpwnsauce
 

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