Question

Brand new to android and facing a weird problem.Check out the code below

FirstActivity.java:

package experiment.on.it;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class FirstActivity extends Activity implements Button.OnClickListener {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        Button timeDatePicker = (Button) findViewById(R.id.timeDatePickerBtn);
        Button customSpinner = (Button) findViewById(R.id.spinnerBtn);

        timeDatePicker.setOnClickListener(this);
        customSpinner.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {

        switch (v.getId()) {

        case R.id.timeDatePickerBtn:
            startActivity(new Intent(this, TimeDatePicker.class));
        case R.id.spinnerBtn:
            startActivity(new Intent(this, CustomSpinner.class));
        }

    }
}

As I/you expected that by clicking on the two buttons i.e.

timeDatePicker

customSpinner

a new Activity will starts (TimeDatePicker and CustomSpinner respectively).

Our expectation is correct. But the problem i’m facing that when i click on the timeDatePicker the second activity (CustomSpinner) starts. But if i press the emulator’s back button (i.e. the device back button) the first activity(TimeDatePicker) appears. I cant find any keyword to describe this kind of problem. So writing this boring question. Any help will be greatly appreciated from a beginner.(…And i think the answer will be pretty easy and small, which i couldnt get. :-P) The Activities code are given below.

TimeDatePicker.java:

package experiment.on.it;

import java.util.Calendar;

import android.app.Activity;
import android.app.DatePickerDialog;
import android.app.Dialog;
import android.app.TimePickerDialog;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.TextView;
import android.widget.TimePicker;

public class TimeDatePicker extends Activity {

    private TextView mDateDisplay;
    private Button mPickDate;
    private int mYear;
    private int mMonth;
    private int mDay;
    private TextView mTimeDisplay;
    private Button mPickTime;

    private int mhour;
    private int mminute;

    static final int TIME_DIALOG_ID = 3;

    static final int DATE_DIALOG_ID = 2;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.timedatepicker);

        mDateDisplay = (TextView) findViewById(R.id.date);
        mPickDate = (Button) findViewById(R.id.datepicker);
        mTimeDisplay = (TextView) findViewById(R.id.time);
        mPickTime = (Button) findViewById(R.id.timepicker);

        // Pick time's click event listener
        mPickTime.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                showDialog(TIME_DIALOG_ID);
            }

        });

        // PickDate's click event listener
        mPickDate.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                showDialog(DATE_DIALOG_ID);

            }
        });

        final Calendar c = Calendar.getInstance();
        mYear = c.get(Calendar.YEAR);
        mMonth = c.get(Calendar.MONTH);
        mDay = c.get(Calendar.DAY_OF_MONTH);
        mhour = c.get(Calendar.HOUR_OF_DAY);
        mminute = c.get(Calendar.MINUTE);

    }

    // -------------------------------------------update
    // date----------------------------------------//
    private void updateDate() {

        mDateDisplay.setText(new StringBuilder()
                // Month is 0 based so add 1
                .append(mDay).append("/").append(mMonth + 1).append("/")
                .append(mYear).append(" "));
        showDialog(TIME_DIALOG_ID);

    }

    // -------------------------------------------update
    // time----------------------------------------//
    public void updatetime() {
        mTimeDisplay.setText(new StringBuilder().append(pad(mhour)).append(":")
                .append(pad(mminute)));
    }

    private static String pad(int c) {
        if (c >= 10)
            return String.valueOf(c);
        else
            return "0" + String.valueOf(c);
    }

    // Datepicker dialog generation

    private DatePickerDialog.OnDateSetListener mDateSetListener = new DatePickerDialog.OnDateSetListener() {

        public void onDateSet(DatePicker view, int year, int monthOfYear,
                int dayOfMonth) {
            mYear = year;
            mMonth = monthOfYear;
            mDay = dayOfMonth;
            updateDate();
        }
    };

    // Timepicker dialog generation
    private TimePickerDialog.OnTimeSetListener mTimeSetListener = new TimePickerDialog.OnTimeSetListener() {
        public void onTimeSet(TimePicker view, int hourOfDay, int minute) {
            mhour = hourOfDay;
            mminute = minute;
            updatetime();
        }

    };

    @Override
    protected Dialog onCreateDialog(int id) {
        switch (id) {
        case DATE_DIALOG_ID:
            return new DatePickerDialog(this, mDateSetListener, mYear, mMonth,
                    mDay);

        case TIME_DIALOG_ID:
            return new TimePickerDialog(this, mTimeSetListener, mhour, mminute,
                    true);

        }
        return null;
    }
}

CustomSpinner.java:

package experiment.on.it;

import android.app.Activity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.Spinner;

public class CustomSpinner extends Activity {

    String[] items = { "this", "is", "a", "really", "really2", "really3",
            "really4", "really5", "silly", "list" };

    @Override
    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        setContentView(R.layout.spinnerlayout);
        
        Spinner spin =(Spinner)findViewById(R.id.sPinner);
        ArrayAdapter adapter = new ArrayAdapter(this,R.layout.radio,R.id.txt,items);
        spin.setAdapter(adapter);
        
        
    }

    
}

Answer 1

You are missing break; statement in your switch case block.

So, thought the first activity starts and is in your backstack, it is immediately pushed down by the second one due to the missing break and the back button behaves as it should and return you to the the first one.