android app parse values through intent

Question

I am trying to parse a value through intent while switching between activities. I know I should read values from last intent with getExtra but I don't know why it doesn't work.

Also when I switch between activities on button click, application crashes.

In activity main I read text from editText and put it in Intent :

public void schimba(View view){
    int value = Integer.parseInt(instances.getText().toString());;
    Intent intent = new Intent(this, Tabel.class);
    intent.putExtra("max", value);
    startActivity(intent);
}

When it switch to activity 2 I have this:

Intent intentObject = getIntent();
int value;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    value = intentObject.getIntExtra("max", 0);
    /*
    for(i=0;i<=value;i++)
    {
        LayoutInflater layoutinflate = null; 
        layoutinflate = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
        final View rowview = layoutinflate.inflate( R.layout.activity_tabel, null);
    }
    */
    setContentView(R.layout.activity_tabel);

    TextView showvalue;
    showvalue = (TextView) findViewById(R.id.ShowValue);
    showvalue.setText(""+value);

The idea is that I want to use this value in a for loop, I already know how to display the value in a textView but I don't need it, I wanna use it in for.

Logcat:

04-23 10:40:52.550: E/AndroidRuntime(1010): FATAL EXCEPTION: main
04-23 10:40:52.550: E/AndroidRuntime(1010): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.instances_temperature/com.example.instances_temperature.Tabel}: java.lang.NullPointerException
04-23 10:40:52.550: E/AndroidRuntime(1010):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
04-23 10:40:52.550: E/AndroidRuntime(1010):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
04-23 10:40:52.550: E/AndroidRuntime(1010):     at android.app.ActivityThread.access$2300(ActivityThread.java:125)
04-23 10:40:52.550: E/AndroidRuntime(1010):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
04-23 10:40:52.550: E/AndroidRuntime(1010):     at android.os.Handler.dispatchMessage(Handler.java:99)
04-23 10:40:52.550: E/AndroidRuntime(1010):     at android.os.Looper.loop(Looper.java:123)
04-23 10:40:52.550: E/AndroidRuntime(1010):     at android.app.ActivityThread.main(ActivityThread.java:4627)
04-23 10:40:52.550: E/AndroidRuntime(1010):     at java.lang.reflect.Method.invokeNative(Native Method)
04-23 10:40:52.550: E/AndroidRuntime(1010):     at java.lang.reflect.Method.invoke(Method.java:521)
04-23 10:40:52.550: E/AndroidRuntime(1010):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
04-23 10:40:52.550: E/AndroidRuntime(1010):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
04-23 10:40:52.550: E/AndroidRuntime(1010):     at dalvik.system.NativeStart.main(Native Method)
04-23 10:40:52.550: E/AndroidRuntime(1010): Caused by: java.lang.NullPointerException
04-23 10:40:52.550: E/AndroidRuntime(1010):     at com.example.instances_temperature.Tabel.onCreate(Tabel.java:26)
04-23 10:40:52.550: E/AndroidRuntime(1010):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
04-23 10:40:52.550: E/AndroidRuntime(1010):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
04-23 10:40:52.550: E/AndroidRuntime(1010):     ... 11 more

line 26 would be this:

value = intentObject.getIntExtra("max", 0);

Answer 1

You have to use the code below

int maxValue = getIntent().getExtras().getInt("max");

inside onCreate().

Hope it will solve your problem..

Answer 2

You have not declared intentObject...

Use this:

value = getIntent().getIntExtra("max", 0);

Answer 3

use this

value = getIntent().getStringExtra("max");

instead of this

value = intentObject.getIntExtra("max", 0);