Convert android.graphics.path value into String?

I have an ArrayList of Path values. I need to convert it into String values and know what all coordinates were covered in the Path. Here's the code that I worked up:

private ArrayList<Path> pointsToDraw = new ArrayList<Path>();

private List<String> stringPoints ;







synchronized(pointsToDraw){

                    for(Path path : pointsToDraw)

                    {

                        stringPoints.add(String.valueOf(path));

                    }



                    TextView b1Text = (TextView) findViewById(R.id.GText);

                    for(String s : stringPoints)

                    {

                        b1Text.setText(s);

                    }

                    }

I get an exception during runtime. The following is the log content :

02-21 18:18:29.323: E/AndroidRuntime(512): FATAL EXCEPTION: main

02-21 18:18:29.323: E/AndroidRuntime(512): java.lang.NullPointerException

02-21 18:18:29.323: E/AndroidRuntime(512):  at learn.myandroidapp.hr.HRCanvas$1.onClick(HRCanvas.java:78)

02-21 18:18:29.323: E/AndroidRuntime(512):  at android.view.View.performClick(View.java:3511)

02-21 18:18:29.323: E/AndroidRuntime(512):  at android.view.View$PerformClick.run(View.java:14105)

02-21 18:18:29.323: E/AndroidRuntime(512):  at android.os.Handler.handleCallback(Handler.java:605)

02-21 18:18:29.323: E/AndroidRuntime(512):  at android.os.Handler.dispatchMessage(Handler.java:92)

02-21 18:18:29.323: E/AndroidRuntime(512):  at android.os.Looper.loop(Looper.java:137)

02-21 18:18:29.323: E/AndroidRuntime(512):  at android.app.ActivityThread.main(ActivityThread.java:4424)

02-21 18:18:29.323: E/AndroidRuntime(512):  at java.lang.reflect.Method.invokeNative(Native Method)

02-21 18:18:29.323: E/AndroidRuntime(512):  at java.lang.reflect.Method.invoke(Method.java:511)

02-21 18:18:29.323: E/AndroidRuntime(512):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)

02-21 18:18:29.323: E/AndroidRuntime(512):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)

02-21 18:18:29.323: E/AndroidRuntime(512):  at dalvik.system.NativeStart.main(Native Method)

Where am I going wrong? Please help!