试图将浮点数转换为int时出现问题

Question

我有一个编程任务，我应该将地震大小的大小与另一个大小进行比较。我应该使用Comparable接口并实施compareTo方法。地震大小为float值，compareTo方法应返回int类型。所以，我的代码如下所示：

public int compareTo(EarthquakeMarker marker){ 
    return ((int)this.getMagnitude().compareTo((int)marker.getMagnitude()));  
} 

但我得到一个错误，说我“不能援引int compareTo()到float基本类型”。

这是为那些有兴趣的完整代码：

package module6; 

import de.fhpotsdam.unfolding.data.PointFeature; 
import processing.core.PConstants; 
import processing.core.PGraphics; 

/** Implements a visual marker for earthquakes on an earthquake map 
* 
* @author UC San Diego Intermediate Software Development MOOC team 
* 
*/ 
// TODO: Implement the comparable interface 
public abstract class EarthquakeMarker extends CommonMarker implements Comparable<EarthquakeMarker> 
{ 

// Did the earthquake occur on land? This will be set by the subclasses. 
protected boolean isOnLand; 

// The radius of the Earthquake marker 
// You will want to set this in the constructor, either 
// using the thresholds below, or a continuous function 
// based on magnitude. 
protected float radius; 


// constants for distance 
protected static final float kmPerMile = 1.6f; 

/** Greater than or equal to this threshold is a moderate earthquake */ 
public static final float THRESHOLD_MODERATE = 5; 
/** Greater than or equal to this threshold is a light earthquake */ 
public static final float THRESHOLD_LIGHT = 4; 

/** Greater than or equal to this threshold is an intermediate depth */ 
public static final float THRESHOLD_INTERMEDIATE = 70; 
/** Greater than or equal to this threshold is a deep depth */ 
public static final float THRESHOLD_DEEP = 300; 

// ADD constants for colors 


// abstract method implemented in derived classes 
public abstract void drawEarthquake(PGraphics pg, float x, float y); 


// constructor 
public EarthquakeMarker (PointFeature feature) 
{ 
    super(feature.getLocation()); 
    // Add a radius property and then set the properties 
    java.util.HashMap<String, Object> properties = feature.getProperties(); 
    float magnitude = Float.parseFloat(properties.get("magnitude").toString()); 
    properties.put("radius", 2*magnitude); 
    setProperties(properties); 
    this.radius = 1.75f*getMagnitude(); 
} 

// TODO: Add the method: 
public int compareTo(EarthquakeMarker marker){ 
    return ((int)this.getMagnitude().compareTo((int)marker.getMagnitude()); 

} 


// calls abstract method drawEarthquake and then checks age and draws X if needed 
@Override 
public void drawMarker(PGraphics pg, float x, float y) { 
    // save previous styling 
    pg.pushStyle(); 

    // determine color of marker from depth 
    colorDetermine(pg); 

    // call abstract method implemented in child class to draw marker shape 
    drawEarthquake(pg, x, y); 

    // IMPLEMENT: add X over marker if within past day  
    String age = getStringProperty("age"); 
    if ("Past Hour".equals(age) || "Past Day".equals(age)) { 

     pg.strokeWeight(2); 
     int buffer = 2; 
     pg.line(x-(radius+buffer), 
       y-(radius+buffer), 
       x+radius+buffer, 
       y+radius+buffer); 
     pg.line(x-(radius+buffer), 
       y+(radius+buffer), 
       x+radius+buffer, 
       y-(radius+buffer)); 

    } 

    // reset to previous styling 
    pg.popStyle(); 

} 

/** Show the title of the earthquake if this marker is selected */ 
public void showTitle(PGraphics pg, float x, float y) 
{ 
    String title = getTitle(); 
    pg.pushStyle(); 

    pg.rectMode(PConstants.CORNER); 

    pg.stroke(110); 
    pg.fill(255,255,255); 
    pg.rect(x, y + 15, pg.textWidth(title) +6, 18, 5); 

    pg.textAlign(PConstants.LEFT, PConstants.TOP); 
    pg.fill(0); 
    pg.text(title, x + 3 , y +18); 


    pg.popStyle(); 

} 


/** 
* Return the "threat circle" radius, or distance up to 
* which this earthquake can affect things, for this earthquake. 
* DISCLAIMER: this formula is for illustration purposes 
* only and is not intended to be used for safety-critical 
* or predictive applications. 
*/ 
public double threatCircle() { 
    double miles = 20.0f * Math.pow(1.8, 2*getMagnitude()-5); 
    double km = (miles * kmPerMile); 
    return km; 
} 

// determine color of marker from depth 
// We use: Deep = red, intermediate = blue, shallow = yellow 
private void colorDetermine(PGraphics pg) { 
    float depth = getDepth(); 

    if (depth < THRESHOLD_INTERMEDIATE) { 
     pg.fill(255, 255, 0); 
    } 
    else if (depth < THRESHOLD_DEEP) { 
     pg.fill(0, 0, 255); 
    } 
    else { 
     pg.fill(255, 0, 0); 
    } 
} 


/** toString 
* Returns an earthquake marker's string representation 
* @return the string representation of an earthquake marker. 
*/ 
public String toString() 
{ 
    return getTitle(); 
} 
/* 
* getters for earthquake properties 
*/ 

public float getMagnitude() { 
    return Float.parseFloat(getProperty("magnitude").toString()); 
} 

public float getDepth() { 
    return Float.parseFloat(getProperty("depth").toString()); 
} 

public String getTitle() { 
    return (String) getProperty("title"); 

} 

public float getRadius() { 
    return Float.parseFloat(getProperty("radius").toString()); 
} 

public boolean isOnLand() 
{ 
    return isOnLand; 
} 

}

Answer 1

正如消息说，您不能调用方法原始类型。

你应该自己实现compareTo()，因为它很简单，我认为每创建一个对象IntegercompareTo()可能会花费太多。

public int compareTo(EarthquakeMarker marker){ 
    int t = (int)this.getMagnitude() 
    int m = (int)marker.getMagnitude(); 
    if (t > m) return 1; 
    if (t < m) return -1; 
    return 0; 
} 

Answer 2

有比较原始的花车内置静态便捷功能Float.compare(float, float)：

public int compareTo(EarthquakeMarker marker){ 
    return Float.compare(this.getMagnitude(), marker.getMagnitude()); 
}