Double Lepping Plus或等于

Question

基本的计算器应用程序，但是当我双击按钮12或按钮11时它会崩溃。当我双击这些按钮时，我不需要发生任何事情，只是不会崩溃。

按钮11等于（=）。按钮12是添加（+）。

    package com.example.administrator.calculator;

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


    public class MainActivity extends AppCompatActivity {

    public String sign = "";
    public String total= "";
    public Double tempDouble, tempDouble2;


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

        // Buttons for Felony
        Button button1 =(Button)findViewById(R.id.button1);
        Button button2 =(Button)findViewById(R.id.button2);
        Button button3 =(Button)findViewById(R.id.button3);
        Button button4 =(Button)findViewById(R.id.button4);
        Button button5 =(Button)findViewById(R.id.button5);
        //Buttons for misdemeanors
        Button button6 =(Button)findViewById(R.id.button7);
        Button button7 =(Button)findViewById(R.id.button8);
        Button button8 =(Button)findViewById(R.id.button6);
        //Buttons for Infraction
        Button button9 =(Button)findViewById(R.id.button9);
        //clear, +, =
        Button button10=(Button)findViewById(R.id.button10);
        Button button11 =(Button)findViewById(R.id.button11);
        Button button12 =(Button)findViewById(R.id.button12);


        // button 1 event handler
        button1.setOnClickListener(
                //button 1 interface
                 new Button.OnClickListener()
                {
                    //Button 1 callback method
                    public void onClick(View v)
                     {
                         TextView output = (TextView)findViewById(R.id.editText);
                         output.append("100 years");
                     }
                }
        );
        // button 2 event handler
        button2.setOnClickListener(
                //button 2 interface
                new Button.OnClickListener()
                {
                    //Button 2 callback method
                    public void onClick(View v)
                    {
                        TextView output = (TextView)findViewById(R.id.editText);
                        output.append("25 years");
                    }
                }
        );
        // button 3 event handler
        button3.setOnClickListener(
                //button 3 interface
                new Button.OnClickListener()
                {
                    //Button 3 callback method
                    public void onClick(View v)
                    {
                        TextView output = (TextView)findViewById(R.id.editText);
                        output.append("10 years");
                    }
                }
        );
        // button 4 event handler
        button4.setOnClickListener(
                //button 4 interface
                new Button.OnClickListener()
                {
                    //Button 4 callback method
                    public void onClick(View v)
                    {
                        TextView output = (TextView)findViewById(R.id.editText);
                        output.append("5 years");
                    }
                }
        );
        // button 5 event handler
        button5.setOnClickListener(
                //button 5 interface
                new Button.OnClickListener()
                {
                    //Button 5 callback method
                    public void onClick(View v)
                    {
                        TextView output = (TextView)findViewById(R.id.editText);
                        output.append("1 years");
                    }
                }
        );
        // button 6 event handler
        button6.setOnClickListener(
                //button 1 interface
                new Button.OnClickListener()
                {
                    //Button 6 callback method
                    public void onClick(View v)
                    {
                        TextView output = (TextView)findViewById(R.id.editText);
                        output.append("1 years");
                    }
                }
        );
        // button 7 event handler
        button7.setOnClickListener(
                //button 7 interface
                new Button.OnClickListener()
                {
                    //Button 7 callback method
                    public void onClick(View v)
                    {
                        TextView output = (TextView)findViewById(R.id.editText);
                        output.append("0.5 years");
                    }
                }
        );
        // button 8 event handler
        button8.setOnClickListener(
                //button 8 interface
                new Button.OnClickListener()
                {
                    //Button 8 callback method
                    public void onClick(View v)
                    {
                        TextView output = (TextView)findViewById(R.id.editText);
                        output.append("0.25 years");
                    }
                }
        );
        // button 9 event handler
        button9.setOnClickListener(
                //button 9 interface
                new Button.OnClickListener()
                {
                    //Button 9 callback method
                    public void onClick(View v)
                    {
                        TextView output = (TextView)findViewById(R.id.editText);
                        output.append("0.013 years");
                    }
                }
        );
        // button 10 event handler
        button10.setOnClickListener(
                //button 10 interface
                new Button.OnClickListener()
                {
                    //Button 10 callback method
                    public void onClick(View v)
                    {
                        TextView output = (TextView)findViewById(R.id.editText);
                        output.setText("");
                    }
                }
        );
        // button 12 event handler
        button12.setOnClickListener(
                //button 12 interface
                new Button.OnClickListener()
                {
                    //Button 12 callback method
                    public void onClick(View v)
                    {
                        TextView output = (TextView)findViewById(R.id.editText);
                        tempDouble = Double.parseDouble(output.getText().toString());
                        output.setText("");
                        sign = "+";
                    }
                }
        );

        // button 11 event handler
        button11.setOnClickListener(
                //button 11 interface
                new Button.OnClickListener()
                {
                    //Button 11 callback method
                    public void onClick(View v)
                    {
                        TextView output = (TextView)findViewById(R.id.editText);
                        tempDouble2 = Double.parseDouble(output.getText().toString());
                        if (sign=="+")
                        {
                          output.setText(Double.toString(tempDouble+tempDouble2));
                        sign="";
                        }
                    }
                }
        );
    }
}