خطای nunllpointException

package com.example.datis.callculator;


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

public class MathActivity extends AppCompatActivity {
    Button Btn_CLR, btn_rad, btn_pow, btn_log, btn_Mem, btn_on, btn_pos, btn_bin, btn_tan, btn_negat, btn_dec, btn_cos, btn_oct, btn_hex, btn_zarb,
            btn_divid, btn_qual, btn_fact,
            btn_one, btn_sin, btn_two, btn_three, btn_four, btn_five, btn_six, btn_seven, btn_eight, btn_nine, btn_off;
    EditText edt_Text;

    int num1, num2;
    int nume;
    String OP = "";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_math);
        Btn_CLR = (Button) findViewById(R.id.Btn_CLR);
        btn_rad = (Button) findViewById(R.id.btn_rad);
        btn_pow = (Button) findViewById(R.id.btn_pow);
        btn_log = (Button) findViewById(R.id.btn_log);
        btn_Mem = (Button) findViewById(R.id.btn_Mem);
        btn_on = (Button) findViewById(R.id.btn_on);
        btn_pos = (Button) findViewById(R.id.btn_pos);
        btn_bin = (Button) findViewById(R.id.btn_bin);
        btn_tan = (Button) findViewById(R.id.btn_tan);
        btn_negat = (Button) findViewById(R.id.btn_negat);
        btn_dec = (Button) findViewById(R.id.btn_dec);
        btn_cos = (Button) findViewById(R.id.btn_cos);
        btn_oct = (Button) findViewById(R.id.btn_oct);
        btn_off = (Button) findViewById(R.id.btn_off);
        btn_hex = (Button) findViewById(R.id.btn_hex);
        btn_zarb = (Button) findViewById(R.id.btn_zarb);
        btn_divid = (Button) findViewById(R.id.btn_divid);
        btn_qual = (Button) findViewById(R.id.btn_qual);
        btn_fact = (Button) findViewById(R.id.btn_fact);
        edt_Text = (EditText) findViewById(R.id.edt_Text);
        btn_sin = (Button) findViewById(R.id.btn_sin);
        btn_cos = (Button) findViewById(R.id.btn_cos);
        btn_one = (Button) findViewById(R.id.btn_one);
        btn_two = (Button) findViewById(R.id.btn_two);
        btn_three = (Button) findViewById(R.id.btn_three);


        btn_negat.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
              
                    setnegat(num1,num2);

            }
            public void setnegat(int num1,int num2){
                int temp = edt_Text.getText().toString().length();
                if (edt_Text.getText().toString().length() != 0)
                    
                    if(OP == "-")
                        nume = num1 - num2;
            }
        });
















        btn_pos.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                setplus( num1, num2);
            }
            public void setplus(int num1,int num2){
                String temp = edt_Text.getText().toString();
                if (edt_Text.getText().toString().length() != 0)

                if (OP == "+")
                nume = num1 + num2;

            }
        });















        btn_nine.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                setnice(9);
            }

            public void setnice(int nice) {
                String temp = edt_Text.getText().toString();
                if (edt_Text.getText().toString().length() != 0)

                    edt_Text.setText(nice + "");

                else {
                    edt_Text.setText(temp + nice + "");
                }


                btn_eight.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View view) {
                        setnike(8);
                    }

                    public void setnike(int nike) {
                        String temp = edt_Text.getText().toString();
                        if (edt_Text.getText().toString().length() != 0)

                            edt_Text.setText(nike + "");

                        else {
                            edt_Text.setText(temp + nike + "");
                        }


                        btn_seven.setOnClickListener(new View.OnClickListener() {
                            @Override
                            public void onClick(View view) {
                                setnesus(7);
                            }

                            public void setnesus(int nesus) {
                                String temp = edt_Text.getText().toString();
                                if (edt_Text.getText().toString().length() != 0)

                                    edt_Text.setText(nesus + "");

                                else {
                                    edt_Text.setText(temp + nesus + "");
                                }


                                btn_six.setOnClickListener(new View.OnClickListener() {
                                    @Override
                                    public void onClick(View view) {


                                        setnulex(6);
                                    }


                                    public void setnulex(int nulex) {
                                        String temp = edt_Text.getText().toString();
                                        if (edt_Text.getText().toString().length() != 0)

                                            edt_Text.setText(nulex + "");

                                        else {
                                            edt_Text.setText(temp + nulex + "");
                                        }


                                        btn_five.setOnClickListener(new View.OnClickListener() {
                                            @Override
                                            public void onClick(View view) {
                                                setnext(5);
                                            }


                                            public void setnext(int next) {
                                                String temp = edt_Text.getText().toString();
                                                if (edt_Text.getText().toString().length() != 0)

                                                    edt_Text.setText(next + "");

                                                else {
                                                    edt_Text.setText(temp + next + "");
                                                }


                                                btn_four.setOnClickListener(new View.OnClickListener() {
                                                    @Override
                                                    public void onClick(View view) {
                                                        setnump(4);
                                                    }


                                                    public void setnump(int nump) {
                                                        String temp = edt_Text.getText().toString();
                                                        if (edt_Text.getText().toString().length() != 0)

                                                            edt_Text.setText(nump + "");

                                                        else {
                                                            edt_Text.setText(temp + nump + "");
                                                        }


                                                        btn_three.setOnClickListener(new View.OnClickListener() {
                                                            @Override
                                                            public void onClick(View view) {
                                                                setnome(3);
                                                            }

                                                            public void setnome(int nome) {
                                                                String temp = edt_Text.getText().toString();
                                                                if (edt_Text.getText().toString().length() != 0)

                                                                    edt_Text.setText(nome + "");

                                                                else {
                                                                    edt_Text.setText(temp + nome + "");
                                                                }


                                                                btn_two.setOnClickListener(new View.OnClickListener() {
                                                                    @Override
                                                                    public void onClick(View view) {
                                                                        setnum(2);
                                                                    }

                                                                    public void setnum(int num) {

                                                                        String temp = edt_Text.getText().toString();
                                                                        if (edt_Text.getText().toString().length() != 0)

                                                                            edt_Text.setText(num + "");

                                                                        else {
                                                                            edt_Text.setText(temp + num + "");
                                                                        }


                                                                        btn_one.setOnClickListener(new View.OnClickListener() {
                                                                            @Override
                                                                            public void onClick(View view) {
                                                                                setname(1);
                                                                            }


                                                                            public void setname(int name) {

                                                                                String temp = edt_Text.getText().toString();
                                                                                if (edt_Text.getText().toString().length() != 0)

                                                                                    edt_Text.setText(name + "");

                                                                                else {
                                                                                    edt_Text.setText(temp + name + "");
                                                                                }
                                                                            }
                                                                        });
                                                                    }
                                                                });
                                                            }
                                                        });
                                                    }
                                                });
                                            }
                                        });
                                    }
                                });
                            }
                        });
                    }
                });
            }
        });
    }
}