Notes

package appcode.in;

import android.content.res.Resources;
import android.graphics.Paint;
import android.graphics.Rect;
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 android.widget.TextView;

import com.google.android.flexbox.FlexboxLayoutManager;

import java.util.ArrayList;
import java.util.Arrays;

public class MainActivity extends AppCompatActivity {
ArrayList personNames = new ArrayList<>(Arrays.asList("Android","IPhone","WindowsMobile","Blackberryregrg", "WebOS","Ubuntu","Windows7","Max OS X"));
int rowcount=0;
private static final int sColumnWidth = 120;
RecyclerView recyclerView;
int current_position=0;
GridLayoutManager layoutManager;
int count=0;
TextView textView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
recyclerView = findViewById(R.id.recyclerView);

layoutManager = new GridLayoutManager(this, 3);
recyclerView.setLayoutManager(layoutManager);
textView=findViewById(R.id.textview);

CustomAdapter adapter = new CustomAdapter( this,personNames);

recyclerView.setAdapter(adapter);
ViewTreeObserver viewTreeObserver = recyclerView.getViewTreeObserver();
viewTreeObserver.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {
calculateSize();
Log.e("count is nw","");
// layoutManager.setSpanCount(2);
// layoutManager.requestLayout();
}
});



}

@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);
}
private void calculateSize() {


Log.e("Call time ",""+count++);
Log.e("RecylceView widht ",""+recyclerView.getMeasuredWidth());
float width=0;
int spanCount=0;

for (int i=current_position;i<personNames.size();i++)
{


if (width<recyclerView.getMeasuredWidth())
{

// textView.setText("");
// textView.setText(personNames.get(i).toString());
Paint paint = new Paint();
paint.setTextSize(12);
Rect result = new Rect();
paint.getTextBounds(personNames.get(i).toString(), 0, personNames.get(i).toString().length(), result);
Log.e("less width is ",""+convertDPToPixels(result.width()));
width=width+convertDPToPixels(result.width()*2);
// width=width+textView.getMeasuredWidth();
Resources r = getResources();
float px = TypedValue.applyDimension(
TypedValue.COMPLEX_UNIT_DIP,
result.width(),
r.getDisplayMetrics()
);
Log.e("width is ",""+width+"float"+px);
spanCount++;
}

else
{

current_position=i-1;

Log.e("width is else ",""+width+"pos"+i);

// int spanCount = (int) Math.floor(recyclerView.getWidth() / convertDPToPixels((int) width));
if (spanCount==0)
{
spanCount=1;
}
Log.e("span count ",""+width+" span count"+spanCount);
layoutManager.setSpanCount(spanCount-1);
layoutManager.requestLayout();

break;

}


}






}

private float convertDPToPixels(int dp) {
DisplayMetrics metrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(metrics);
float logicalDensity = metrics.density;
return dp * logicalDensity;
}
}