Question

我只是尝试了我的第一个Android应用程序并遇到了一个我没有真正领先的问题。在我的应用程序中，我创建了一个ArrayList，它将填充对象。每个对象都有四个属性。现在我想在每个Object的特定TextView中编写每个属性。但是有我的问题。如果相同的代码在普通的Java应用程序中运行，并且我使用System.out.Print("getter method")我得到了我想要的值，但如果我使用.setText("getter method")，我会得到你在屏幕截图上看到的内容。

ActivityClass：

public class ShowBeaconActivity extends Activity {

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_showbeacons);
    setUpShowBeacons();
}

public void setUpShowBeacons(){
    //
    //Beacon 1
    //
    TextView beaconOneUUID = (TextView)findViewById(R.id.txtBeaconOneUUIDValue);
    beaconOneUUID.setText(BeaconListe.getBeacon(0,"UUID"));

    TextView beaconOneMajor = (TextView)findViewById(R.id.txtBeaconOneMajorValue);
    beaconOneMajor.setText(BeaconListe.getBeacon(0,"Major"));

    TextView beaconOneMinor = (TextView)findViewById(R.id.txtBeaconOneMinorValue);
    beaconOneMinor.setText(BeaconListe.getBeacon(0,"Minor"));

    TextView beaconOneRSSI = (TextView)findViewById(R.id.txtBeaconOneRSSIValue);
    beaconOneRSSI.setText(BeaconListe.getBeacon(0,"RSSI"));
    //
    //Beacon 2
    //
    TextView beaconTwoUUID = (TextView)findViewById(R.id.txtBeaconTwoUUIDValue);
    beaconTwoUUID.setText(BeaconListe.getBeacon(1,"UUID"));
   ...
}

}

BeaconClass：

public class Beacon {
private String UUID;
private String Major;
private String Minor;
private int RSSI;

public Beacon(String UUID, String Major,String Minor, int RSSI){
    this.UUID = UUID;
    this.Major = Major;
    this.Minor = Minor;
    this.RSSI = RSSI;
}
//
//Getter
//
public String getUUID(){
    return UUID;
}

public String getMajor(){
    return Major;
}

public String getMinor() {
    return Minor;
}

public int getRSSI() {
    return  RSSI;
}
//
//Setter
//
public void setRSSI(int RSSI){
    this.RSSI = RSSI;
}

}

BeaconListeClass

public class BeaconListe {
private static ArrayList<Beacon>Liste = new ArrayList<Beacon>();
//
//Getter
//
public static String getBeacon(int index, String value){
    String result = "";
    switch(value){
        case "UUID":    result = Liste.get(index).getUUID();
            break;
        case "Major":   result = Liste.get(index).getMajor();
            break;
        case "Minor":   result = Liste.get(index).getMinor();
            break;
        case "RSSI":    int resultTemp = Liste.get(index).getRSSI();
            result = String.valueOf(resultTemp);
            break;
    }
    return result;
}
//
//Setter
//
public static void addBeacon(String UUID, String Major, String Minor, int RSSI){
    Liste.add(new Beacon(UUID, Major, Minor, RSSI));
}

} App Screenshot

Answer 1

试试这个

 TextView beaconOneUUID = (TextView)findViewById(R.id.txtBeaconOneUUIDValue);
if(BeaconListe.getBeacon(0,"UUID") != null){
beaconOneUUID.setText(BeaconListe.getBeacon(0,"UUID"));
}

    TextView beaconOneMajor = (TextView)findViewById(R.id.txtBeaconOneMajorValue);
if(BeaconListe.getBeacon(0,"Major") != null){
 beaconOneMajor.setText(BeaconListe.getBeacon(0,"Major"));
}

    TextView beaconOneMinor = (TextView)findViewById(R.id.txtBeaconOneMinorValue);
if(BeaconListe.getBeacon(0,"Minor") != null){
 beaconOneMinor.setText(BeaconListe.getBeacon(0,"Minor"));
}
    TextView beaconOneRSSI = (TextView)findViewById(R.id.txtBeaconOneRSSIValue);
if(BeaconListe.getBeacon(0,"RSSI") != null){
beaconOneRSSI.setText(BeaconListe.getBeacon(0,"RSSI"));
}
    //
    //Beacon 2
    //
    TextView beaconTwoUUID = (TextView)findViewById(R.id.txtBeaconTwoUUIDValue);
if(BeaconListe.getBeacon(1,"UUID")){
beaconTwoUUID.setText(BeaconListe.getBeacon(1,"UUID"));
}

Answer 2

因为空值而崩溃;

public static String getBeacon(int index, String value)
    {
        String result = "";
        switch(value){
            Beacon becon = Liste.get(index);
            case "UUID":    
                result = becon!=null?becon.getUUID():"";
                break;
            case "Major":   
                result = becon!=null?becon.getMajor():"";
                break;
            case "Minor":   
                result = becon!=null?becon.getMinor():"";
                break;
            case "RSSI": 
                resultTemp = becon!=null?becon.getRSSI():0;
                result = String.valueOf(resultTemp);
                break;
        }
        return result==null?"":result;
    }

Answer 3

从我看到的情况来看，.setText("getter methods")工作正常。问题是它设置的文本。检查您填充BeaconListe的功能，您在此处未显示。我尝试了您的代码，但使用以下

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_showbeacons);
    populateBeaconListe();
    setUpShowBeacons();
}
public void populateBeaconListe(){
    BeaconListe.addBeacon("B1UUID","B1MAJOR","B1MINOR",1111);
    BeaconListe.addBeacon("B2UUID","B2MAJOR","B2MINOR",2222);
    BeaconListe.addBeacon("B3UUID","B3MAJOR","B3MINOR",3333);
    BeaconListe.addBeacon("B4UUID","B4MAJOR","B4MINOR",4444);
}

它工作得很好。请参见屏幕截图

带有Getter返回的Android TextView setText

3 个答案: