title: java.lang.NumberFormatException: For input string: “null”
body: <p>I keep getting this error :(
  The Errors appear at Donasi.class</p>
  
  <p>This is in class Donasi:</p>
  
  <pre><code> int total = 0;
      for (Transaksi transaksi:donasi)
          total += (Integer.parseInt(transaksi.getMinimal()))*(Integer.parseInt(transaksi.getQuantity()));
          Locale locale = new Locale("in", "ID");
          NumberFormat fmt = NumberFormat.getCurrencyInstance(locale);
          txtTotalDonasi.setText(fmt.format(total));
  </code></pre>
  
  <p>This is in class DonationAdapter:</p>
  
  <pre><code>    int minimal = (Integer.parseInt(listData.get(position).getMinimal()))*(Integer.parseInt(listData.get(position).getQuantity()));
  
      holder.txt_minimal.setText(fmt.format(minimal));
  
      holder.txt_nama_donasi.setText(listData.get(position).getNamaDonasi());
  </code></pre>
  
  <p>This is my Logcat :</p>
  
  <pre><code>12-28 14:20:36.283 2579-2579/da.glowroz.donationapp E/AndroidRuntime: FATAL EXCEPTION: main
       Process: da.glowroz.donationapp, PID: 2579
       java.lang.RuntimeException: Unable to start activity ComponentInfo{da.glowroz.donationapp/da.glowroz.donationapp.Donasi}: java.lang.NumberFormatException: For input string: "null"
  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2646)
  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707)
  at android.app.ActivityThread.-wrap12(ActivityThread.java)
  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460)
  at android.os.Handler.dispatchMessage(Handler.java:102)
  at android.os.Looper.loop(Looper.java:154)
  at android.app.ActivityThread.main(ActivityThread.java:6077)
  at java.lang.reflect.Method.invoke(Native Method)
  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
  Caused by: java.lang.NumberFormatException: For input string: "null"
  at java.lang.Integer.parseInt(Integer.java:521)
  at java.lang.Integer.parseInt(Integer.java:556)
  at da.glowroz.donationapp.Donasi.loadListDonasi(Donasi.java:134)
  at da.glowroz.donationapp.Donasi.onCreate(Donasi.java:72)
  at android.app.Activity.performCreate(Activity.java:6662)
  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118)
  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2599)
  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707) 
  at android.app.ActivityThread.-wrap12(ActivityThread.java) 
  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460) 
  at android.os.Handler.dispatchMessage(Handler.java:102) 
  at android.os.Looper.loop(Looper.java:154) 
  at android.app.ActivityThread.main(ActivityThread.java:6077) 
  at java.lang.reflect.Method.invoke(Native Method) 
  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865) 
  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755) 
  </code></pre>
  
  <p>How to solve this problem?</p>