Eclipse for android: Issues with R

Question

I am trying to do a location app and am in the trouble shooting phase right now. I am down to my last two problems and they both relate to R. blah blah. It says main is either not a field or cannot be resolved and the same message but with mapview instead of main. Below are my imports and the lines of code where the issue is.

Code:

    setContentView(R.layout.main);
    mapview = (MapView)findViewById(R.id.mapview);

Imports:

    import android.R;
    import android.R.layout;
    import android.R.id;
    import android.location.Location;
    import android.location.LocationListener;
    import android.location.LocationManager;
    import android.os.Bundle;
    import android.widget.Toast;

    import com.google.android.maps.GeoPoint;
    import com.google.android.maps.MapActivity;
    import com.google.android.maps.MapController;
    import com.google.android.maps.MapView;

I've tried everything. I know people keep saying to take out android.R but that is where R.layout and R.id are found in the jar files. I have right clicked the folder and validated the code. I have gone to Project/Clean and done that. No luck. Please help? And this is my first post so I'm sorry if its formatted wrong. I thank you in advance for any help you give me. Here is my main.xml

    <?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="vertical"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        >
    <TextView android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Waiting for location..."
        android:id="@+id/lblLocationInfo"
    />
    <com.google.android.maps.MapView
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/mapview"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:clickable="true"
        android:apiKey="0vFrUOhHMkbahT9zXqiz_DuNVWfPqlEyqcO8ftg"
    />
    </LinearLayout>

Answer 1

Try removing the line:

import android.R;

And then do Build Clean, this can fix the issue.

Answer 2

unless you are using resources from android you shouldn't need the lines

import android.R; 
import android.R.Id;
import android.R.layout;

Remove those lines

R is resolving to androids R and not com.yourpackage.yourproject.R .

Remove the import if it's not needed. If it is your need to be explicit in your code. ex.

ImageView.setDrawable(android.R.ic_menu_search); //uses an android resource

findViewById(R.id.mapView); //uses your resource file

setContentView(R.layout.activity_main); // must have an activity_main.xml file in YourProject/res/layout

Edit:

changes to your code below:

//import android.R;
//import android.R.layout;    //comment or delete these lines
//import android.R.id;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.widget.Toast;

import com.google.android.maps.GeoPoint;
import com.google.android.maps.MapActivity;
import com.google.android.maps.MapController;
import com.google.android.maps.MapView;

setContentView(R.layout.activity_main);  //changed main to activity_main
mapview = (MapView)findViewById(R.id.mapview);

Edit 2

At the very top of your MainActivity.java it should have a line that starts with package what does the rest of that line say?

In your AndroidManifest.xml there is also an entry for package what does it say?

Answer 3

R.java它是一个自生成的文件，您需要重新构建它才能生成它，忽略警告并“构建清理”您的文件

Answer 4

This might also have to do with your project setup. What I typically do when I create a new project is setup 'Order and Export' options. That way you do not have to import any R.* packages.

In Eclipse, right click on your project go to Properties -> Java Build Path -> Order and Export . Just make sure that yourprojectname/gen folder is above the yourprojectname/src folder.