Notes

package appcode.in;

import android.content.res.Resources;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.Typeface;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.util.DisplayMetrics;
import android.util.Log;
import android.util.TypedValue;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.view.ViewTreeObserver;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

// String[] mobileArray = {"Android","IPhone","WindowsMobile","Blackberry",
// "WebOS","Ubuntu","Windows7","Max OS X"};

String[] mobileArray = {"A","IPhone","WindowsMobile","Blackberry",
"WebOS","Ubuntu","Windows7","Max OS X"};

int rowcount=0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);

//create and initialize recycler view object
final RecyclerView recyclerView = findViewById(R.id.recyclerView);

final GridLayoutManager layoutManager = new GridLayoutManager(this, 3);
recyclerView.setLayoutManager(layoutManager);

MyAdapter adapter = new MyAdapter(mobileArray, this);

recyclerView.setAdapter(adapter);

recyclerView.getViewTreeObserver().addOnGlobalLayoutListener(
new ViewTreeObserver.OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {

int count=recyclerView.getChildCount();
if(rowcount < count)
{
String data=mobileArray[rowcount];
Paint paint = new Paint();
paint.setTextSize(15);
Rect result = new Rect();
paint.getTextBounds(data, 0, data.length(), result);
float width = (result.width());

int viewWidth = recyclerView.getMeasuredWidth();

Resources r = getResources();
float px = TypedValue.applyDimension(
TypedValue.COMPLEX_UNIT_DIP, width,
r.getDisplayMetrics()
);



// Paint paint = new Paint();
//
// paint.setTypeface(Typeface.create("sans-serif", Typeface.BOLD));
// int spSize = 18;
// float scaledSizeInPixels = TypedValue.applyDimension(
// TypedValue.COMPLEX_UNIT_DIP,
// spSize,
// getResources().getDisplayMetrics());
// paint.setTextSize(scaledSizeInPixels);
//
//// Now compute!
// Rect bounds = new Rect();
//
// paint.getTextBounds(data, 0, data.length(), bounds);
// // Log.d(TAG, "width: " + bounds.width() + " height: " + bounds.height());
// int viewWidth = recyclerView.getMeasuredWidth();

// context.getResources().getDisplayMetrics().density;
int newSpanCount = (int) Math.floor(viewWidth / (px));
layoutManager.setSpanCount(newSpanCount);
layoutManager.requestLayout();
rowcount++;
}
}
});


}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();

//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}

return super.onOptionsItemSelected(item);
}
}