Question

Can’t start new activity. Got problem in onClickListener.

I post a code an errors. Have not any idea why I got error in this line.

I think it can be not initialized variable Button b, but it’s initialized!

Help, plz.

Code:

public class newItem extends Activity {
    private EditText Quantity;
    private EditText Weight;
    private EditText Price;
    private EditText Title;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.new_list);
        this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);

        Button b = (Button) findViewById(R.id.ok_but);
        Quantity = (EditText) findViewById(R.id.Quantity);
        Weight = (EditText) findViewById(R.id.Weight);
        Price = (EditText) findViewById(R.id.Price);
        Title = (EditText) findViewById(R.id.Title);

        b.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent i = new Intent();
                i.putExtra("Quantity", Quantity.getText().toString());
                i.putExtra("Weight", Weight.getText().toString());
                i.putExtra("Price", Price.getText().toString());
                i.putExtra("Title", Title.getText().toString());
                setResult(RESULT_OK, i);
                Log.i("palval", "setResult(RESULT_OK, i); newItem");
                finish();
            }
        });
    }
}

Error:

07-08 17:26:42.402: E/AndroidRuntime(31626): FATAL EXCEPTION: main
07-08 17:26:42.402: E/AndroidRuntime(31626): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.ashopping_list/com.example.ashopping_list.newItem}: java.lang.NullPointerException
07-08 17:26:42.402: E/AndroidRuntime(31626):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2194)
07-08 17:26:42.402: E/AndroidRuntime(31626):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2229)
07-08 17:26:42.402: E/AndroidRuntime(31626):    at android.app.ActivityThread.access$600(ActivityThread.java:139)
07-08 17:26:42.402: E/AndroidRuntime(31626):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1261)
07-08 17:26:42.402: E/AndroidRuntime(31626):    at android.os.Handler.dispatchMessage(Handler.java:99)
07-08 17:26:42.402: E/AndroidRuntime(31626):    at android.os.Looper.loop(Looper.java:154)
07-08 17:26:42.402: E/AndroidRuntime(31626):    at android.app.ActivityThread.main(ActivityThread.java:4945)
07-08 17:26:42.402: E/AndroidRuntime(31626):    at java.lang.reflect.Method.invokeNative(Native Method)
07-08 17:26:42.402: E/AndroidRuntime(31626):    at java.lang.reflect.Method.invoke(Method.java:511)
07-08 17:26:42.402: E/AndroidRuntime(31626):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
07-08 17:26:42.402: E/AndroidRuntime(31626):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
07-08 17:26:42.402: E/AndroidRuntime(31626):    at dalvik.system.NativeStart.main(Native Method)
07-08 17:26:42.402: E/AndroidRuntime(31626): Caused by: java.lang.NullPointerException
07-08 17:26:42.402: E/AndroidRuntime(31626):    at com.example.ashopping_list.newItem.onCreate(newItem.java:32)
07-08 17:26:42.402: E/AndroidRuntime(31626):    at android.app.Activity.performCreate(Activity.java:4531)
07-08 17:26:42.402: E/AndroidRuntime(31626):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1071)
07-08 17:26:42.402: E/AndroidRuntime(31626):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2150)

Manifest:

    <activity
        android:name=".newItem"
        android:label="@string/title_activity_main"
        android:windowSoftInputMode="stateAlwaysVisible" >
    </activity>

Err here:

b.setOnClickListener(new OnClickListener() {

Answer 1

Try to use

implements View.OnClickListener

or try to use Listener as anonymous class and then tell me if it works.

Note: class names should start with uppercase and you should respect it.

Update:

So problem is elsewhere, make sure that your ID is correct! and belongs to Button.