嗨，我正在开发一个显示计算器活动的 Android 启动器。它显示布局很好，但是当您单击任何需要帮助的按钮时什么都不做 任何帮助都会很棒！
计算器.java：
package com.dva.schooltoolshome;
import java.text.DecimalFormat;
import android.annotation.SuppressLint;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.view.Menu;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
public class Calculator extends FragmentActivity implements OnClickListener {
private TextView calculatorDisplay;
private static final String DIGITS = "0123456789.";
private Boolean userIsInTheMiddleOfTypingANumber = false;
DecimalFormat df = new DecimalFormat("@###########");
CalculatorBrain brain;
@SuppressLint("NewApi")
@Override
protected void onCreate(Bundle savedInstanceState) {
// hide the window title.
requestWindowFeature(Window.FEATURE_NO_TITLE);
// hide the status bar and other OS-level chrome
getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_calculator);
brain = new CalculatorBrain();
calculatorDisplay = (TextView) findViewById(R.id.textView1);
df.setMinimumFractionDigits(0);
df.setMinimumIntegerDigits(1);
df.setMaximumIntegerDigits(8);
findViewById(R.id.button0).setOnClickListener(this);
findViewById(R.id.button1).setOnClickListener(this);
findViewById(R.id.button2).setOnClickListener(this);
findViewById(R.id.button3).setOnClickListener(this);
findViewById(R.id.button4).setOnClickListener(this);
findViewById(R.id.button5).setOnClickListener(this);
findViewById(R.id.button6).setOnClickListener(this);
findViewById(R.id.button7).setOnClickListener(this);
findViewById(R.id.button8).setOnClickListener(this);
findViewById(R.id.button9).setOnClickListener(this);
findViewById(R.id.buttonAdd).setOnClickListener(this);
findViewById(R.id.buttonSubtract).setOnClickListener(this);
findViewById(R.id.buttonMultiply).setOnClickListener(this);
findViewById(R.id.buttonDivide).setOnClickListener(this);
findViewById(R.id.buttonToggleSign).setOnClickListener(this);
findViewById(R.id.buttonDecimalPoint).setOnClickListener(this);
findViewById(R.id.buttonEquals).setOnClickListener(this);
findViewById(R.id.buttonClear).setOnClickListener(this);
findViewById(R.id.buttonClearMemory).setOnClickListener(this);
findViewById(R.id.buttonAddToMemory).setOnClickListener(this);
findViewById(R.id.buttonSubtractFromMemory).setOnClickListener(this);
findViewById(R.id.buttonRecallMemory).setOnClickListener(this);
// The following buttons only exist in layout-land (Landscape mode) and require extra attention.
// The messier option is to place the buttons in the regular layout too and set android:visibility="invisible".
if (findViewById(R.id.buttonSquareRoot) != null) {
findViewById(R.id.buttonSquareRoot).setOnClickListener(this);
}
if (findViewById(R.id.buttonInvert) != null) {
findViewById(R.id.buttonInvert).setOnClickListener(this);
}
if (findViewById(R.id.buttonCos) != null) {
findViewById(R.id.buttonCos).setOnClickListener(this);
}
if (findViewById(R.id.buttonSin) != null) {
findViewById(R.id.buttonSin).setOnClickListener(this);
}
// Another way to hide the window title and actionbar, but only in newer sdk's
// if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
// ActionBar actionBar = getActionBar();
// actionBar.setDisplayShowHomeEnabled(false);
// actionBar.setDisplayShowTitleEnabled(false);
// actionBar.hide();
// }
}
// @Override
public void onClick(View view) {
String buttonPressed = ((Button) view).getText().toString();
// String digits = "0123456789.";
if (DIGITS.contains(buttonPressed)) {
// digit was pressed
if (userIsInTheMiddleOfTypingANumber) {
calculatorDisplay.append(buttonPressed);
} else {
calculatorDisplay.setText(buttonPressed);
userIsInTheMiddleOfTypingANumber = true;
}
} else {
// operation was pressed
if (userIsInTheMiddleOfTypingANumber) {
brain.setOperand(Double.parseDouble(calculatorDisplay.getText().toString()));
userIsInTheMiddleOfTypingANumber = false;
}
brain.performOperation(buttonPressed);
calculatorDisplay.setText(df.format(brain.getResult()));
}
}
@Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
// Save variables on screen orientation change
outState.putDouble("OPERAND", brain.getResult());
outState.putDouble("MEMORY", brain.getMemory());
}
@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
super.onRestoreInstanceState(savedInstanceState);
// Restore variables on screen orientation change
brain.setOperand(savedInstanceState.getDouble("OPERAND"));
brain.setMemory(savedInstanceState.getDouble("MEMORY"));
calculatorDisplay.setText(df.format(brain.getResult()));
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.home, menu);
return true;
}
}
CalculatorBrain.java：
package com.dva.schooltoolshome;
public class CalculatorBrain {
// 3 + 6 = 9
// 3 & 6 are called the operand.
// The + is called the operator.
// 9 is the result of the operation.
private double operand = 0;
private double waitingOperand = 0;
private String waitingOperator = "";
private double calculatorMemory = 0;
public void setOperand(double operand) {
this.operand = operand;
}
public double getResult() {
return operand;
}
// used on screen orientation change
public void setMemory(double calculatorMemory) {
this.calculatorMemory = calculatorMemory;
}
// used on screen orientation change
public double getMemory() {
return calculatorMemory;
}
public String toString() {
return Double.toString(operand);
}
protected double performOperation(String operator) {
/*
* If you are using Java 7, then you can use switch in place of if statements
*
* switch (operator) {
* case "MC":
* calculatorMemory = 0;
* break;
* case "M+":
* calculatorMemory = calculatorMemory + operand;
* break;
* }
*/
if (operator.equals("MC")) {
calculatorMemory = 0;
} else if (operator.equals("M+")) {
calculatorMemory = calculatorMemory + operand;
} else if (operator.equals("M-")) {
calculatorMemory = calculatorMemory - operand;
} else if (operator.equals("MR")) {
operand = calculatorMemory;
} else if (operator.equals("C")) {
operand = 0;
waitingOperator = "";
waitingOperand = 0;
calculatorMemory = 0;
} else if (operator.equals("Sqrt")) {
operand = Math.sqrt(operand);
} else if (operator.equals("1/x")) {
if (operand != 0) {
operand = 1 / operand;
}
} else if (operator.equals("+/-")) {
operand = -operand;
} else if (operator.equals("sin")) {
operand = Math.sin(operand);
} else if (operator.equals("cos")) {
operand = Math.cos(operand);
} else {
performWaitingOperation();
waitingOperator = operator;
waitingOperand = operand;
}
return operand;
}
protected void performWaitingOperation() {
if (waitingOperator.equals("+")) {
operand = waitingOperand + operand;
} else if (waitingOperator.equals("*")) {
operand = waitingOperand * operand;
} else if (waitingOperator.equals("-")) {
operand = waitingOperand - operand;
} else if (waitingOperator.equals("/")) {
if (operand != 0) {
operand = waitingOperand / operand;
}
}
}
}
活动计算器.xml：
<RelativeLayout xmlns:tools="http://schemas.android.com/tools"
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/bg" >
<LinearLayout
android:id="@+id/linearLayout1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true" >
<TextView
android:id="@+id/textView1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="right"
android:maxLines="1"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:text="0"
android:textAppearance="?android:attr/textAppearanceLarge"
android:textSize="40sp" />
</LinearLayout>
<LinearLayout
android:id="@+id/linearLayout2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="@+id/linearLayout1" >
<Button
android:id="@+id/buttonAddToMemory"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight=".25"
android:text="M+" />
<Button
android:id="@+id/buttonSubtractFromMemory"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight=".25"
android:text="M-" />
<Button
android:id="@+id/buttonRecallMemory"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight=".25"
android:text="MR" />
</LinearLayout>
<LinearLayout
android:id="@+id/linearLayout3"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="@+id/linearLayout2" >
<Button
android:id="@+id/buttonClear"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight=".25"
android:text="C" />
<Button
android:id="@+id/buttonToggleSign"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight=".25"
android:text="+/-" />
<Button
android:id="@+id/buttonDivide"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight=".25"
android:text="/" />
<Button
android:id="@+id/buttonMultiply"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight=".25"
android:text="*" />
</LinearLayout>
<LinearLayout
android:id="@+id/linearLayout4"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="@+id/linearLayout3" >
<Button
android:id="@+id/button7"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight=".25"
android:text="@string/button7" />
<Button
android:id="@+id/button8"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight=".25"
android:text="@string/button8" />
<Button
android:id="@+id/button9"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight=".25"
android:text="@string/button9" />
<Button
android:id="@+id/buttonSubtract"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight=".25"
android:text="-" />
</LinearLayout>
<LinearLayout
android:id="@+id/linearLayout5"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="@+id/linearLayout4" >
<Button
android:id="@+id/button4"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight=".25"
android:text="@string/button4" />
<Button
android:id="@+id/button5"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight=".25"
android:text="@string/button5" />
<Button
android:id="@+id/button6"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight=".25"
android:text="@string/button6" />
<Button
android:id="@+id/buttonAdd"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight=".25"
android:text="+" />
</LinearLayout>
<LinearLayout
android:id="@+id/linearLayout6"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="@+id/linearLayout5"
android:baselineAligned="false" >
<LinearLayout
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".75"
android:orientation="vertical" >
<LinearLayout
android:id="@+id/linearLayout7"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<Button
android:id="@+id/button1"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight=".33"
android:text="@string/button1" />
<Button
android:id="@+id/button2"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight=".33"
android:text="@string/button2" />
<Button
android:id="@+id/button3"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight=".34"
android:text="@string/button3" />
</LinearLayout>
<LinearLayout
android:id="@+id/linearLayout8"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<Button
android:id="@+id/button0"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight=".66"
android:text="@string/button0" />
<Button
android:id="@+id/buttonDecimalPoint"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight=".34"
android:text="." />
</LinearLayout>
</LinearLayout>
<Button
android:id="@+id/buttonEquals"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".25"
android:text="=" />
</LinearLayout>
<ImageButton
android:id="@+id/apps"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="@+id/wbrowser"
android:background="@drawable/appdrawer"
android:src="@drawable/appdrawer" />
<ImageButton
android:id="@+id/wbrowser"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:src="@drawable/browser" />
<ImageButton
android:id="@+id/ImageButton01"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_alignTop="@+id/wbrowser"
android:background="@drawable/appdrawer"
android:src="@drawable/appdrawer" />
<Button
android:id="@+id/tools"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/ImageButton01"
android:layout_centerHorizontal="true"
android:text="Tools" />
<Button
android:id="@+id/buttonClearMemory"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_above="@+id/ImageButton01"
android:layout_alignLeft="@+id/tools"
android:layout_marginBottom="163dp"
android:layout_weight=".25"
android:text="MC" />
</RelativeLayout>
我还是 android 开发的新手，所以请不要评判
问候
说唱11