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Rename Android project package issue in Eclipse - R cannot be resolved to a variable


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Issue: After after renaming package this problem occurred "R cannot be resolved to a variable".

Solution: Try Clean your project Project » Clean » Clean projects selected below » select your project and click OK.

Try to delete the invalid code and type it again:

LinearLayout layout = (LinearLayout) findViewById(R.id.layout); // delete R.id.layout
LinearLayout layout = (LinearLayout) findViewById(); 
LinearLayout layout = (LinearLayout) findViewById(R.id.layout); // re-write this code R.id.layout

397LW NO topic_id




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Další témata ....(Topics)


25

Copy sqlite database from apk package to device folder Android example | copy-sqlite-database-from-apk-to-device-folder-android-example


Put your sglite database to Android Eclipse project folder named Assets.
On device will copy database file to application folder as this example:



 public void createDatabase(Context myContext) throws IOException {
    String sPackName = myContext.getPackageName();
    InputStream assetsDB = myContext.getAssets().open("myDatabase");
    OutputStream dbOut = new FileOutputStream("/data/data/"+sPackName+"/database");
 
    byte[] buffer = new byte[1024];
    int length;
    while ((length = assetsDB.read(buffer))>0){
      dbOut.write(buffer, 0, length);
    }
 
    dbOut.flush();
    dbOut.close();
    assetsDB.close();
}


336

Android emulator freezes at startup create new virtual device | android-emulator-freezes-at-startup-create-new-virtual-device


If Android emulator freezes at startup, try create new virtual device with smaller memory and cpu usage, or select older version of Android, or buy new pc with higher performance.

  1. open AVD MANAGER

  2. press Create Virtual Device

  3. select Device with small memory usage (e.g. 480x800 of resolution) - Next

  4. check - Show downloadable ....

  5. Download - lower version of system Android, select, press - Next

  6. check data, Show Advanced Settings, check Use host... and press Finish


android-studio-create-virtual-device-emulator
116

AlertDialog - MessageBox - Alert - Toast - Android sample | alertdialog-like-messagebox-android-sample


AlertDialog like MessageBox by WinApi:
If error: Unable to add window -- token null is not for an application
try change get Context.

// you can put this text into some function body or case in switch statement
                new AlertDialog.Builder(this)
                    .setMessage("Hello boys!!!")
                    .setPositiveButton("OK", null)
                    .show();



Context context = getApplicationContext();
	AlertDialog.Builder builder = new AlertDialog.Builder(context);
	builder.setTitle("Select font size");
	final CharSequence[] chsSize= { "Small", "Medium", "Large"};
	builder.setSingleChoiceItems(chsSize, 0 /*sel.item*/, 
	new DialogInterface.OnClickListener() {
 	    public void onClick(DialogInterface dialog, int item) {
	    		 Toast.makeText(context, "Hello from dialog!!!", Toast.LENGTH_SHORT).show();
	        dialog.dismiss();
	    }
	});
	AlertDialog alert = builder.create();
	alert.show();
    
4

Read file from URL | read-file-from-url


Read file from URL to array of byte and convert to UTF-8 String Android examle source code.

URL urlLoc = new URL("//myweb.com/myfile.html");
URLConnection conexion = urlLoc.openConnection();
conexion.setConnectTimeout(4000);
conexion.setReadTimeout(1000);
conexion.connect();

// downlod the file
InputStream input = new BufferedInputStream(urlLoc
		.openStream());

StringBuffer responseBuffer = new StringBuffer();
byte[] byteArray = new byte[1024];
while (input.read(byteArray) != -1)
 {   
        String res = new String(byteArray, "UTF-8");
        responseBuffer.append(res);
        byteArray = null;
        byteArray = new byte[1024];
 }

String response = responseBuffer.toString().trim();



353

Android Fragment onAttach deprecated | android-fragment-onattach-deprecated



// Context instead Activity as a parameter
@Override
public void onAttach(Context context) {
    super.onAttach(context);

    Activity a;

    if (context instanceof Activity){
        a=(Activity) context;
    }

}

OnNoteClickedListener listener;
/* old emxample of usage
	@Override
	public void onAttach(Activity activity) {
		super.onAttach(activity);
		try {
			listener = (OnNoteClickedListener) activity;
		} catch (ClassCastException e) {
			throw new ClassCastException(activity.toString()
					+ " must implement OnNoteClickedListener");
		}
	}
*/
// new version of code
	@Override
	public void onAttach(Context context) {
		super.onAttach(context);

		Activity a;

		if (context instanceof Activity){
			a=(Activity) context;
			try {
				listener = (OnNoteClickedListener) a;
			} catch (ClassCastException e) {
				throw new ClassCastException(a.toString()
						+ " must implement OnNoteClickedListener");
			}
		}

	}




Editace: 2014-02-15 20:45:39
Počet článků v kategorii: 397
Url:rename-android-project-package-issue-in-eclipse

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