Question

我正在尝试制作一个基本的Android计算器。当我按下编辑文字显示的按钮数字，但没有什么是幸福的。谢谢你的帮助。

这是我的MainActivity.java` 公共类MainActivity扩展了AppCompatActivity {

private EditText Scr;
private float NumerBf;
private String Operation;
private ButtonClickListener btnClick;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);


    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    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();
        }
    });

    Scr=(EditText)findViewById(R.id.editText3);
    Scr.setEnabled(false);
    int idList[]={R.id.button0,R.id.button1,R.id.button1,R.id.button2,R.id.button3,R.id.button4,R.id.button5,
            R.id.button6,R.id.button7,R.id.button8,R.id.button9,R.id.buttonAdd,R.id.buttonC,R.id.buttonDivide,
            R.id.buttonEqu,R.id.buttonMinus,R.id.buttonMultiply};



    for(int id:idList){
        View v=(View)findViewById(id);
        v.setOnClickListener(btnClick);
    }
}

@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;
}
public void mMath(String str){
    NumerBf=Float.parseFloat(Scr.getText().toString());
    Operation =str;
    Scr.setText("0");
}


public void getKeyboard(String str){
    String SrcCurrent = Scr.getText().toString();
    if(SrcCurrent.equals("0"))
        SrcCurrent="";
    SrcCurrent +=str;
    Scr.setText(SrcCurrent);
}

public void mResult(){
    float NumAf=Float.parseFloat(Scr.getText().toString());
    float result=0;
    if(Operation.equals("+")){
        result=NumAf+NumerBf;
    }
    else if(Operation.equals("-")){
        result=NumerBf-NumAf;
    }

    else if(Operation.equals("*")){
        result=NumAf*NumerBf;
    }
    else if(Operation.equals("/")){
        result=NumerBf/NumAf;
    }
    Scr.setText(String.valueOf(result));
}


private  class ButtonClickListener implements View.OnClickListener {
    public void onClick(View v){
        switch(v.getId()){
            case R.id.buttonC: //ekranı temizle
                Scr.setText("0");
                NumerBf=0;
                Operation="";
                break;
            case R.id.buttonAdd:
                mMath("+");
                break;
            case R.id.buttonMinus:
                mMath("-");
                break;
            case R.id.buttonMultiply:
                mMath("*");
                break;
            case R.id.buttonDivide:
                mMath("/");
                break;
            case R.id.buttonEqu:
                mResult();
                break;
            default:
                String numb= ((Button) v).getText().toString();
                getKeyboard(numb);
                break;
        }
    }
}

`

这是我的content_main.xml`

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="3"
    android:id="@+id/button3"
    android:textStyle="bold"
    android:layout_above="@+id/button5"
    android:layout_toRightOf="@+id/button5"
    android:layout_toEndOf="@+id/button5" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="C"
    android:id="@+id/buttonC"
    android:textStyle="bold"
    android:longClickable="true"
    android:layout_alignTop="@+id/button3"
    android:layout_alignRight="@+id/buttonDivide"
    android:layout_alignEnd="@+id/buttonDivide"
    android:layout_alignLeft="@+id/buttonDivide"
    android:layout_alignStart="@+id/buttonDivide" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="1"
    android:id="@+id/button1"
    android:textStyle="bold"
    android:layout_above="@+id/button4"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="4"
    android:id="@+id/button4"
    android:textStyle="bold"
    android:layout_above="@+id/button7"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="6"
    android:id="@+id/button6"
    android:textStyle="bold"
    android:layout_below="@+id/button3"
    android:layout_toRightOf="@+id/button5"
    android:layout_toEndOf="@+id/button5" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="5"
    android:id="@+id/button5"
    android:textStyle="bold"
    android:layout_above="@+id/button8"
    android:layout_toRightOf="@+id/button4"
    android:layout_toEndOf="@+id/button4" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="8"
    android:id="@+id/button8"
    android:textStyle="bold"
    android:layout_above="@+id/button0"
    android:layout_toRightOf="@+id/button7"
    android:layout_toEndOf="@+id/button7" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="7"
    android:id="@+id/button7"
    android:textStyle="bold"
    android:layout_below="@+id/button5"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="9"
    android:id="@+id/button9"
    android:textStyle="bold"
    android:layout_alignTop="@+id/button8"
    android:layout_toRightOf="@+id/button8"
    android:layout_toEndOf="@+id/button8" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="0"
    android:id="@+id/button0"
    android:textStyle="bold"
    android:layout_above="@+id/buttonMinus"
    android:layout_alignLeft="@+id/button8"
    android:layout_alignStart="@+id/button8" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="+"
    android:id="@+id/buttonAdd"
    android:textStyle="bold"
    android:layout_centerVertical="true"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="-"
    android:id="@+id/buttonMinus"
    android:textStyle="bold"
    android:layout_alignTop="@+id/buttonAdd"
    android:layout_alignLeft="@+id/button0"
    android:layout_alignStart="@+id/button0" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="*"
    android:id="@+id/buttonMultiply"
    android:textStyle="bold"
    android:layout_alignBottom="@+id/buttonMinus"
    android:layout_toRightOf="@+id/buttonMinus"
    android:layout_toEndOf="@+id/buttonMinus" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="/"
    android:id="@+id/buttonDivide"
    android:textStyle="bold"
    android:layout_alignTop="@+id/buttonMultiply"
    android:layout_toRightOf="@+id/buttonMultiply"
    android:layout_toEndOf="@+id/buttonMultiply" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="="
    android:id="@+id/buttonEqu"
    android:textStyle="bold"
    android:layout_below="@+id/buttonMinus"
    android:layout_alignLeft="@+id/buttonMinus"
    android:layout_alignStart="@+id/buttonMinus" />

<EditText
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/editText3"
    android:layout_alignParentTop="true"
    android:layout_alignParentRight="true"
    android:layout_alignParentEnd="true"
    android:layout_toLeftOf="@+id/button3"
    android:gravity="right"
    android:text="0" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="2"
    android:id="@+id/button2"
    android:textStyle="bold"
    android:layout_alignBottom="@+id/button3"
    android:layout_toLeftOf="@+id/button3"
    android:layout_toStartOf="@+id/button3" />

`

Answer 1

ButtonClickListener btnClick未初始化。您正在设置null onClickListener。因此按下按钮无效

android计算器按钮不起作用

1 个答案: