Cannot resolve symbol issues in making a stopwatch

Question

(Keep in mind i'm very new to coding) I'm having an issue when coding a stopwatch app, I've scavenged this site and found no solution to my issue, comparing my code to another user's who attempted the same tutorial, i found that they are the same, yet I am getting several unresolved symbols when to my knowledge, everything is correct...

Ok, i updated the file with some corrections, now im not having any more errors with start/stop, but i have new errors with the m(start/stop/etc)Listener code...

(Here's the Main Activity Java File)

package com.jackson.eason.stopwatch.;
import android.app.Activity;
import android.os.Bundle;
import android.os.SystemClock;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Chronometer;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import your.package.R;

public class MainActivity extends Activity {
    Chronometer mChronometer;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        Button button;

        mChronometer = (Chronometer) findViewById(R.id.Chronometer);

        // Watch for button clicks.
        button = (Button) findViewById(R.id.start);
        button.setOnClickListener(mStartListener);

        button = (Button) findViewById(R.id.stop);
        button.setOnClickListener(mStopListener);

        button = (Button) findViewById(R.id.reset);
        button.setOnClickListener(mResetListener);

        button = (Button) findViewById(R.id.set_format);
        button.setOnClickListener(mSetFormatListener);

        button = (Button) findViewById(R.id.clear_format);
        button.setOnClickListener(mClearFormatListener);

        View.OnClickListener mStartListener = new OnClickListener() {
            public void onClick(View v) {
                mChronometer.start();
            }
        };

        View.OnClickListener mStopListener = new OnClickListener() {
            public void onClick(View v) {
                mChronometer.stop();
            }
        };

        View.OnClickListener mResetListener = new OnClickListener() {
            public void onClick(View v) {
                mChronometer.setBase(SystemClock.elapsedRealtime());
            }
        };

        View.OnClickListener mClearFormatListener = new OnClickListener() {
            public void onClick(View v) {
                mChronometer.setFormat(null);
            }
        };
    }


    }

(Also, here's my xml file, which Android Developer says is fine)

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:padding="4dip"
    android:gravity="center_horizontal"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">

    <Chronometer android:id="@+id/chronometer"
        android:format="@string/chronometer_initial_format"
        android:layout_width="wrap_content"
        android:layout_height="0dp"
        android:layout_weight="0"
        android:paddingBottom="30dip"
        android:paddingTop="30dip"
        />

    <Button android:id="@+id/start"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="start">
        <requestFocus />
    </Button>

    <Button android:id="@+id/stop"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="chronometer_stop">
    </Button>

    <Button android:id="@+id/reset"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="reset">
        </Button>

    <Button android:id="@+id/set_format"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="format">
    </Button>

    <Button android:id="@+id/clear_format"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="clear_format">
    </Button>

    </LinearLayout>

I appreciate any help anyone can offer!

The import `import android.R;` is wrong. This imports a general `R` version that has no idea about your project resources. — Tom, Feb 06 '15 at 12:46

score 0 · Answer 1 · answered Feb 06 '15 at 12:43

0

I think that all the listeners should be inside a method. Am I wrong? Try placing them inside the onCreate method (at the very end of it).

answered Feb 06 '15 at 12:43

Thanos

3,627
3
24
35

score 0 · Accepted Answer · edited May 23 '17 at 11:56

Your problem is that you are importing the wrong R class. android.R is different from the R file generated for your app and referencing your resources, it is the R file from the framework itself, allowing you to use convenience resources, see this question for an example.

import android.R;

replace that with

import your.package.R;

Also, as Thanos suggested, put your listener declarations inside the onCreate method.

UPDATE :

When I said your.package.R, it was just an example. The package depends on what you chose it to be when creating your project, but judging by the code you provided, you probably need import com.jackson.eason.stopwatch.R

Secondly, you need to declare your listeners first before you use them. If you don't, if you call setOnClickListener(mClearFormatListener) but mClearFormatListener is declared after, the compiler doesn't know about mClearFormatListener yet so it shows a compilation error. The below code should work.

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);

    // Get references to views
    mChronometer = (Chronometer) findViewById(R.id.Chronometer);
    Button button1 = (Button) findViewById(R.id.start);
    Button button2 = (Button) findViewById(R.id.stop);
    Button button3 = (Button) findViewById(R.id.reset);
    Button button4 = (Button) findViewById(R.id.set_format);
    Button button5 = (Button) findViewById(R.id.clear_format);

    // Declare the listeners
    View.OnClickListener mStartListener = new OnClickListener() {
        public void onClick(View v) {
            mChronometer.start();
        }
    };

    View.OnClickListener mStopListener = new OnClickListener() {
        public void onClick(View v) {
            mChronometer.stop();
        }
    };

    View.OnClickListener mResetListener = new OnClickListener() {
        public void onClick(View v) {
            mChronometer.setBase(SystemClock.elapsedRealtime());
        }
    };

   // You forgot to declare a listener for set format in your updated code
   View.OnClickListener mSetFormatListener = new OnClickListener() {
        public void onClick(View v) {
            // TODO : set the format
        }
    };

    View.OnClickListener mClearFormatListener = new OnClickListener() {
        public void onClick(View v) {
            mChronometer.setFormat(null);
        }
    };

    // Assign the listeners to your buttons
    button1.setOnClickListener(mStartListener);
    button2.setOnClickListener(mStopListener);
    button3.setOnClickListener(mResetListener);
    button4.setOnClickListener(mSetFormatListener);
    button.setOnClickListener(mClearFormatListener);


}

One last thing : in the notation mVariable, m stands for "member", meaning a member variable of a class, as opposed to a variable inside a method. Since your listeners are only declared inside a method, we usually don't use mListener but rather listener. Of course, this is just a naming convention and it will not prevent the code to compile and run ;)

Much appreciated,now, what exactly do I put in place of "your"? — Jackson Eason, Feb 06 '15 at 12:59
Ok, so i added the listeners inside the oncreate, which fixed the error for the start/stop/etc, but caused new errors for all of the m(stop/start/reset/etc)Listener lines — Jackson Eason, Feb 06 '15 at 13:06
Can you update your question with the changes you made and the error you're getting ? We'll get there ;-) — 2Dee, Feb 06 '15 at 13:07
Sure, but i have class now, and will add them in about 90 minutes — Jackson Eason, Feb 06 '15 at 13:15
I updated my answer. Let me know if there are still things you have problem with. — 2Dee, Feb 06 '15 at 16:01
Thanks for the help! There's only 2 errors left, and it's an error with mChronometer = (Chronometer) findViewById(R.id.Chronometer); and an error on button4.setOnClickListener(mSetformatListener); — Jackson Eason, Feb 09 '15 at 12:29
Actually, only one error now, With the mChronometer class... Not sure what is wrong... — Jackson Eason, Feb 09 '15 at 12:41
And I'm not sure how to set the format for the mSetFormatListener — Jackson Eason, Feb 09 '15 at 12:48
OK, all errors gone now, but when i run the app and tap a button, there is no display of time..... how can i fix this?? — Jackson Eason, Feb 09 '15 at 13:15

Cannot resolve symbol issues in making a stopwatch

2 Answers2