Question

MainActivity.java

   package mycal1.example.bazinga.mycal1;

   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.Toolbar;
   import android.view.View;
   import android.view.Menu;
   import android.view.MenuItem;
   import android.widget.Button;
   import android.widget.EditText;

   public class MainActivity extends AppCompatActivity {
   Button          button1,button2,button3,button4,button5,button6,button7,button8,button9,buttonDot,buttonZero,buttonCancel,buttonAdd,buttonSub,buttonMul,buttonDiv,buttonEquals;
   EditText edit;
   float value1,value2;
   boolean addition,subtraction,multiplication,division;
   @Override
   protected void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
   setContentView(R.layout.activity_main);
   Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
   setSupportActionBar(toolbar);
   button1=(Button)findViewById(R.id.button1);
   button2=(Button)findViewById(R.id.button2);
   button3=(Button)findViewById(R.id.button3);
   button4=(Button)findViewById(R.id.button4);
   button5=(Button)findViewById(R.id.button5);
   button6=(Button)findViewById(R.id.button6);
   button7=(Button)findViewById(R.id.button7);
   button8=(Button)findViewById(R.id.button8);
   button9=(Button)findViewById(R.id.button9);
   buttonDot=(Button)findViewById(R.id.Dot);
   buttonZero=(Button)findViewById(R.id.Zero);
   buttonCancel=(Button)findViewById(R.id.Cancel);
   buttonAdd=(Button)findViewById(R.id.Addition);
   buttonSub=(Button)findViewById(R.id.Subtraction);
   buttonMul=(Button)findViewById(R.id.Multiplication);
   buttonDiv=(Button)findViewById(R.id.Division);
   buttonEquals=(Button)findViewById(R.id.Equals);
   edit=(EditText)findViewById(R.id.editText);

   button1.setOnClickListener(new View.OnClickListener(){
        @Override
        public void onClick(View v) {
         edit.setText(edit.getText()+ "1");
        }
    });
    button2.setOnClickListener(new View.OnClickListener(){
        @Override
        public void onClick(View v) {
            edit.setText(edit.getText()+ "2");
        }
    });
    button3.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            edit.setText(edit.getText() + "3");
        }
    });
    button4.setOnClickListener(new View.OnClickListener(){
        @Override
        public void onClick(View v) {
            edit.setText(edit.getText() + "4");
        }
    });
    button5.setOnClickListener(new View.OnClickListener(){
        @Override
        public void onClick(View v) {
            edit.setText(edit.getText() + "5");
        }
    });
    button6.setOnClickListener(new View.OnClickListener(){
        @Override
        public void onClick(View v) {
            edit.setText(edit.getText() + "6");
        }
    });
    button7.setOnClickListener(new View.OnClickListener(){
        @Override
        public void onClick(View v) {
            edit.setText(edit.getText() + "7");
        }
    });
    button8.setOnClickListener(new View.OnClickListener(){
        @Override
        public void onClick(View v) {
            edit.setText(edit.getText() + "8");
        }
    });
    button9.setOnClickListener(new View.OnClickListener(){
        @Override
        public void onClick(View v) {
            edit.setText(edit.getText() + "9");
        }
    });
    buttonZero.setOnClickListener(new View.OnClickListener(){
        @Override
        public void onClick(View v) {
            edit.setText(edit.getText() + "0");
        }
    });
    buttonAdd.setOnClickListener(new View.OnClickListener(){
        @Override
        public void onClick(View v) {
            if(edit==null){
                edit.setText("");
            }else{
                value1=Float.parseFloat(edit.getText()+ " ");
                addition=true;
                edit.setText("");
            }
        }
    });
    buttonSub.setOnClickListener(new View.OnClickListener(){
        @Override
        public void onClick(View v) {

                value1=Float.parseFloat(edit.getText()+ " ");
                subtraction=true;
                edit.setText("");
            }

    });
    buttonMul.setOnClickListener(new View.OnClickListener(){
        @Override
        public void onClick(View v) {

                value1=Float.parseFloat(edit.getText()+ " ");
                multiplication=true;
                edit.setText("");
            }

    });
    buttonDiv.setOnClickListener(new View.OnClickListener(){
        @Override
        public void onClick(View v) {

                value1=Float.parseFloat(edit.getText()+ " ");
                division=true;
                edit.setText("");
            }

    });
    buttonEquals.setOnClickListener(new View.OnClickListener(){
        @Override
        public void onClick(View v) {
            value2=Float.parseFloat(edit.getText()+ "");
            if(addition=true){
                edit.setText((value1 + value2) + "");
                addition=false;
            }
            if(subtraction=true){
                edit.setText((value1 - value2)+ "");
                subtraction=false;
            }
            if(multiplication=true){
                edit.setText((value1 * value2)+ " ");
                multiplication=false;
            }
            if(division=true){
                edit.setText((value1 / value2)+ " ");
                division=false;
            }
        }
    });
    buttonCancel.setOnClickListener(new View.OnClickListener(){
        @Override
        public void onClick(View v) {
            edit.setText("");
        }
    });
    buttonDot.setOnClickListener(new View.OnClickListener(){
        @Override
        public void onClick(View v) {
            edit.setText(edit.getText() + ".");
        }
    });

    FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Snackbar.make(view, "Replace with your own action",      Snackbar.LENGTH_LONG)
                    .setAction("Action", null).show();
        }
    });
}

 @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);
     }
    }

我正在创建一个简单的计算器应用程序，它将执行基本功能计算
1. 只有分部操作才能正常进行。如果我试试乘法然后我得到的结果是除法。
2. 相同的是减法，加法。这段代码有什么问题？

Answer 1

您正在使用=赋值运算符而不是== isequal运算符。如果条件如下，您应该使用==。因为当您放置一个=时，它不检查相等性，而是指定值true。

if(addition==true){
            edit.setText((value1 + value2) + "");
            addition=false;
        }
        if(subtraction==true){
            edit.setText((value1 - value2)+ "");
            subtraction=false;
        }
        if(multiplication==true){
            edit.setText((value1 * value2)+ " ");
            multiplication=false;
        }
        if(division==true){
            edit.setText((value1 / value2)+ " ");
            division=false;
        }

已经构建了一个简单的计算器，可以执行加法，乘法，除法和减法。只有分工才能正常进行。

1 个答案: