dontknow

package com.example.er.latihan1;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.text.TextUtils;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

import com.example.er.latihan1.R;

public class MainActivity extends AppCompatActivity
    implements View.OnClickListener {
    private EditText edtWidth, edtHeight, edtLength;
    private Button btnCalculate;
    private TextView tvResult;

    private static String STATE_HASIL = "state_hasil";
    private String str;

    @Override
    protected void onCreate(Bundle saveInstanceState){
        super.onCreate(saveInstanceState);
        setContentView(R.layout.activity_main);

        edtWidth =(EditText)findViewById(R.id.edt_width);
        edtHeight = (EditText)findViewById(R.id.edt_height);
        edtLength = (EditText)findViewById(R.id.edt_length);
        btnCalculate = (Button)findViewById(R.id.btn_calculate);
        tvResult = (TextView)findViewById(R.id.tv_result);

        btnCalculate.setOnClickListener(this);
    }


    @Override
    public void onClick(View v) {
        if (v.getId()== R.id.btn_calculate) {
            String length = edtLength.getText().toString().trim();
            String width = edtWidth.getText().toString().trim();
            String height = edtHeight.getText().toString().trim();

            boolean isEmptyFields = false;
            boolean isInvalidDouble = false;

            if (TextUtils.isEmpty(length)) {
                isEmptyFields = true;
                edtLength.setError("Field ini tidak boleh kosong");
            }else if (!isDouble(length)) {
                isInvalidDouble = true;
                edtLength.setError("Field ini harus berupa nomor yang valid");
            }


            if (TextUtils.isEmpty(width)) {
                isEmptyFields = true;
                edtLength.setError("Field ini tidak boleh kosong");
            }else if (!isDouble(width)) {
                isInvalidDouble = true;
                edtLength.setError("Field ini harus berupa nomor yang valid");
            }


            if (TextUtils.isEmpty(height)) {
                isEmptyFields = true;
                edtLength.setError("Field ini tidak boleh kosong");
            }else if (!isDouble(height)) {
                isInvalidDouble = true;
                edtLength.setError("Field ini harus berupa nomor yang valid");
            }

            if (!isEmptyFields&&!isInvalidDouble) {
                double l = Double.parseDouble(length);
                double w = Double.parseDouble(width);
                double h = Double.parseDouble(height);

                double volume = l*w*h;
                tvResult.setText(String.valueOf(volume));
            }

            boolean isDouble(String str) {
                try {
                    Double.parseDouble(str);
                    return true;
                } catch (NumberFormatException e){
                    return false;
                }
            }





    }
}