Java 在Android中，我如何实现使用按键增加双倍值的逻辑

我已经创建了按钮

     <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:paddingBottom="@dimen/activity_vertical_margin"
        android:paddingLeft="@dimen/activity_horizontal_margin"
        android:paddingRight="@dimen/activity_horizontal_margin"
        android:paddingTop="@dimen/activity_vertical_margin"
        tools:context="com.paulk.tipcalc.TipCalc" >

        <EditText
            android:id="@+id/BillEditText"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignBaseline="@+id/billTextView"
            android:layout_alignBottom="@+id/billTextView"
            android:layout_toEndOf="@+id/billTextView"
            android:layout_toRightOf="@+id/billTextView"
            android:ems="5"
            android:inputType="numberDecimal"
            android:text="@string/bill_edit_text" >

            <requestFocus />
        </EditText>

        <TextView
            android:id="@+id/billTextView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentStart="true"
            android:layout_alignParentLeft="true"
            android:layout_alignParentTop="true"
            android:layout_marginStart="19dp"
            android:layout_marginLeft="19dp"
            android:layout_marginTop="20dp"
            android:text="@string/bill_text_view" />

        <TextView
            android:id="@+id/tipTextView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignBottom="@+id/BillEditText"
            android:layout_marginStart="34dp"
            android:layout_marginLeft="34dp"
            android:layout_toEndOf="@+id/billTextView"
            android:layout_toRightOf="@+id/BillEditText"
            android:text="@string/tip_text_view" />

        <Button
            android:id="@+id/incrementButton"
            android:layout_width="30dp"
            android:layout_height="30dp"
            android:layout_alignEnd="@+id/tipEditText"
            android:layout_alignRight="@+id/tipEditText"
            android:layout_alignTop="@+id/tipTextView"
            android:onClick="increaaseTip"
            android:text="@string/increment"
            android:textSize="12sp" />

        <TextView
            android:id="@+id/totalTextView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@+id/tipEditText"
            android:layout_toEndOf="@+id/billTextView"
            android:layout_toRightOf="@+id/billTextView"
            android:text="@string/total_text_view" />

        <EditText
            android:id="@+id/totalEditText"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@+id/totalTextView"
            android:layout_marginTop="19dp"
            android:layout_toStartOf="@+id/tipTextView"
            android:layout_toLeftOf="@+id/tipTextView"
            android:ems="5"
            android:inputType="numberDecimal"
            android:text="@string/total_edit_text" />

        <EditText
            android:id="@+id/tipEditText"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@+id/incrementButton"
            android:layout_marginTop="20dp"
            android:layout_toEndOf="@+id/billTextView"
            android:layout_toRightOf="@+id/tipTextView"
            android:ems="4"
            android:inputType="numberDecimal"
            android:text="@string/tip_edit_text" />

        <Button
            android:id="@+id/decrementButton"
            android:layout_width="30dp"
            android:layout_height="30dp"
            android:layout_above="@+id/tipEditText"
            android:layout_marginEnd="12dp"
            android:layout_marginRight="12dp"
            android:layout_toLeftOf="@+id/incrementButton"
            android:layout_toStartOf="@+id/incrementButton"
            android:text="@string/decrement"
            android:textSize="12sp" 
            android:onClick="DecreaseTip"/>

        <SeekBar
            android:id="@+id/changeTipSeekBar"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_alignLeft="@+id/billTextView"
            android:layout_alignRight="@+id/BillEditText"
            android:layout_alignTop="@+id/tipEditText"
            android:progress="15" />

        <TextView
            android:id="@+id/changeTipTextView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_above="@+id/changeTipSeekBar"
            android:layout_alignLeft="@+id/changeTipSeekBar"
            android:text="@string/change_tip_text_view" />

    </RelativeLayout>

我已经把它注释掉了，因为我不确定这是创建按钮逻辑的最佳方式

/*public void onClick(View view){
        if(increment.){

            tipAmount = 
            tipAmount = tipAmount * 0.01;
            tipAmount + 0.01;
            //double tipAmount = Double.parseDouble(tipAmountET.getText().toString());
            tipAmountET.setText(String.format("%.02f", tipAmount));

        }else if(view == decrement){

        }
    }*/

private void updateTipandTotalAmount(){
    //converts the double value into a string value
    double tipAmount = Double.parseDouble(tipAmountET.getText().toString());
    //how the total amount is calculated
    double totalAmount = billBeforeTip + (billBeforeTip * tipAmount);
    //formating the total amount
    totalAmountET.setText(String.format("%.02f", totalAmount));
}
protected void onSaveInstanceState(Bundle outState){
    super.onSaveInstanceState(outState);
    outState.putDouble(BILL_WITHOUT_TIP, billBeforeTip);
    outState.putDouble(CURRENT_TIP, tipAmount);
    outState.putDouble(TOTAL_BILL, totalAmount);

}

private OnSeekBarChangeListener tipSeekBarChangeListener =  new OnSeekBarChangeListener() {

    @Override
    public void onStopTrackingTouch(SeekBar seekBar) {
        // TODO Auto-generated method stub

    }

    @Override
    public void onStartTrackingTouch(SeekBar seekBar) {
        // TODO Auto-generated method stub

    }

    @Override
    public void onProgressChanged(SeekBar seekBar, int progress,boolean fromUser) {
        tipAmount = (tipSeekBar.getProgress()*.01);

        tipAmountET.setText(String.format("%.02f", tipAmount));
    }
};

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.tip_calc, 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();
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}

---

}

通过设置按钮的侦听器，可以使用按钮增加或减少计数器

/*public void onClick(View view){
        if(increment.){

            tipAmount = 
            tipAmount = tipAmount * 0.01;
            tipAmount + 0.01;
            //double tipAmount = Double.parseDouble(tipAmountET.getText().toString());
            tipAmountET.setText(String.format("%.02f", tipAmount));

        }else if(view == decrement){

        }
    }*/

private void updateTipandTotalAmount(){
    //converts the double value into a string value
    double tipAmount = Double.parseDouble(tipAmountET.getText().toString());
    //how the total amount is calculated
    double totalAmount = billBeforeTip + (billBeforeTip * tipAmount);
    //formating the total amount
    totalAmountET.setText(String.format("%.02f", totalAmount));
}
protected void onSaveInstanceState(Bundle outState){
    super.onSaveInstanceState(outState);
    outState.putDouble(BILL_WITHOUT_TIP, billBeforeTip);
    outState.putDouble(CURRENT_TIP, tipAmount);
    outState.putDouble(TOTAL_BILL, totalAmount);

}

private OnSeekBarChangeListener tipSeekBarChangeListener =  new OnSeekBarChangeListener() {

    @Override
    public void onStopTrackingTouch(SeekBar seekBar) {
        // TODO Auto-generated method stub

    }

    @Override
    public void onStartTrackingTouch(SeekBar seekBar) {
        // TODO Auto-generated method stub

    }

    @Override
    public void onProgressChanged(SeekBar seekBar, int progress,boolean fromUser) {
        tipAmount = (tipSeekBar.getProgress()*.01);

        tipAmountET.setText(String.format("%.02f", tipAmount));
    }
};

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.tip_calc, 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();
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}

increment.setOnclickListener（）

现在重写onClick（）方法，检查单击了哪个按钮，并编写所需的代码

 @override
    public void onClick(View view){
        if(view.getId==R.id.incrementButton){

            tipAmount = 
            tipAmount = tipAmount * 0.01;
            tipAmount + 0.01;
            //double tipAmount = Double.parseDouble(tipAmountET.getText().toString());
            tipAmountET.setText(String.format("%.02f", tipAmount));

        }
     if(view.getId==R.id.decrementButton){
      //decrement code.
        }
    }