Android TextView setText 覆盖之前的Text

Question

我想将文本设置到我的应用程序(许可)的 TextView 中。这是我使用的代码:

TextView lonTextView = (TextView) findViewById(R.id.textViewLonWert);
lonTextView.setText(longitude.toString());

居然能用，但是还是显示之前的Text!例如，4 覆盖了 8(您无法再阅读文本)。

我有一个启动服务的 Activity 。然后向 Activity 注册一个 LocalBroadcastReceiver。该服务定期将位置对象发送到 Activity 。从我得到的位置经度并想用新经度更新 TextView (仅包含经度)。

如果有人有解决这个问题的想法，我将非常高兴。

更新:完整的代码很长，所以这里是相关的 fragment :

TrackingActivity.java

public class TrackingActivity extends Activity {

// GPSTracker class
GPSTracker gps; 

public String filename;

/* Um eigene Position anzuzeigen */
ArrayList<OverlayItem> overlayItemArray;
protected MapView mapView;
protected MapController mapController;
public Boolean isPause;
public Boolean isTracking;
public MyLocationOverlay myLocationOverlay;
PathOverlay myPath;
List<GeoPoint> path;

public BroadcastReceiver screenReceiver;

/* Textviews setzen */
TextView lonTextView;
TextView latTextView;
TextView altTextView;
TextView accTextView;

// Initiating Menu XML file (menu.xml)
/*@Override
public boolean onCreateOptionsMenu(Menu menu)
{

    MenuInflater menuInflater = getMenuInflater();
    menuInflater.inflate(R.menu.menu_tracking, menu);
    MenuItem mi_startTracking = menu.findItem(R.id.start_tracking);
    mi_startTracking.setVisible(true);
    return true;
}*/

/**
 * Event Handling for Individual menu item selected
 * Identify single menu item by it's id
 * */
@Override
public boolean onOptionsItemSelected(MenuItem item)
{
    ...
}    

@Override

public boolean onPrepareOptionsMenu(Menu menu) {
   ...
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_tracking);

    isTracking  = false;
    isPause     = false;

    // create GPS-class object
    gps = new GPSTracker(TrackingActivity.this
                        ,null);

    myPath  = new PathOverlay(Color.RED, this);
    path    = new ArrayList<GeoPoint>();

   /* Map anzeigen */
    mapView = new MapView(this, 500);
    mapView.setTileSource(TileSourceFactory.MAPNIK);
    org.osmdroid.views.MapView.LayoutParams mapParams = new                   org.osmdroid.views.MapView.LayoutParams(
            org.osmdroid.views.MapView.LayoutParams.MATCH_PARENT,
            org.osmdroid.views.MapView.LayoutParams.MATCH_PARENT,
            null, 0, 0, 0);
    /*löst Fehler aus: mapView.setClickable(true);*/
    mapView.setBuiltInZoomControls(true);
    mapController = new MapController(mapView);
    mapView.getController().setZoom(15);


    //--- Create Overlay
    overlayItemArray = new ArrayList<OverlayItem>();

    DefaultResourceProxyImpl defaultResourceProxyImpl   = new DefaultResourceProxyImpl(this);
    MyItemizedIconOverlay myItemizedIconOverlay         = new MyItemizedIconOverlay(
                                                        overlayItemArray, null, defaultResourceProxyImpl);
    mapView.getOverlays().add(myItemizedIconOverlay);
    //---

    //Add current position
    myLocationOverlay = new MyLocationOverlay(this, mapView);
    mapView.getOverlays().add(myLocationOverlay);

    /* Lege Pfad auf Karte */
    mapView.getOverlays().add(myPath);
    mapView.invalidate();
    LinearLayout myLayout = (LinearLayout) findViewById(R.id.trackingLinearLayoutMap);

    myLayout.addView(mapView,mapParams);

}

private BroadcastReceiver gpsDataReceiver = new BroadcastReceiver() {

    @Override
    public void onReceive(Context context, Intent intent) {

        //Log.d("TrackingActivity", "in Receiver");
        /* alles was der Service liefert */
        String action       = intent.getAction();
        Double altitude     = intent.getDoubleExtra("altitude", 0);
        Double longitude    = intent.getDoubleExtra("longitude", 0);
        Double latitude     = intent.getDoubleExtra("latitude", 0);
        Bundle b            = intent.getExtras();
        Location location   = (Location)b.get("location");

        Log.d("received","Receiver: "+longitude+" ; "+latitude);


        //Log.d("TrackingActivity", "vor GeoPoint");
        GeoPoint locGeoPoint = new GeoPoint(latitude, longitude);

                /* Erstelle Pfad */
        if(isTracking){
            path.add(locGeoPoint);
            myPath.addPoint(locGeoPoint);
        }
        //Log.d("TrackingActivity", "nach GeoPoint: "+locGeoPoint.toString());
        mapController.setCenter(locGeoPoint);

        setOverlayLoc(location);

        /* Textviews Werte setzen */
        lonTextView = (TextView) findViewById(R.id.textViewLonWert);
        lonTextView.setText(longitude.toString());
        //lonTextView.invalidate();

        latTextView = (TextView) findViewById(R.id.textViewLatWert);
        latTextView.setText(latitude.toString());
        //latTextView.invalidate();

        altTextView = (TextView) findViewById(R.id.textViewAltWert);
        altTextView.setText(altitude.toString());
        //altTextView.invalidate();

        accTextView = (TextView) findViewById(R.id.textViewAccWert);
        accTextView.setText(Float.toString(location.getAccuracy())+" m");
        //accTextView.invalidate();

        /* Karte aktualisieren */
        mapView.invalidate();

    }
};
...
@Override
protected void onResume() {
    super.onResume();
    /* Registriere BroadcastReceiver für GPSDaten */
    LocalBroadcastManager.getInstance(this).registerReceiver(gpsDataReceiver, new IntentFilter("gpsdata"));

        ...

}
...

这是我的布局 .xml:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/trackingLinearLayout"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >

<LinearLayout
    android:id="@+id/trackingStatusOuterWrapper"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="kein GPS Signal"
        android:textAppearance="?android:attr/textAppearanceSmall"
        android:textSize="10sp" />

    <LinearLayout
    android:id="@+id/trackingStautsInnerWrapper2"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal" >
        <TextView
        android:id="@+id/textViewLonLabel"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Länge: "
        android:textAppearance="?android:attr/textAppearanceSmall"
        android:textSize="10sp" />
        <TextView
        android:id="@+id/textViewLonWert"
        android:layout_width="80dp"
        android:layout_height="wrap_content"
        android:text=""
        android:textAppearance="?android:attr/textAppearanceSmall"
        android:textSize="10sp" />
        <TextView
        android:id="@+id/textViewLatLabel"
        android:layout_marginLeft="40dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Breite: "
        android:textAppearance="?android:attr/textAppearanceSmall"
        android:textSize="10sp" />
        <TextView
        android:id="@+id/textViewLatWert"
        android:layout_width="80dp"
        android:layout_height="wrap_content"
        android:text=""
        android:textAppearance="?android:attr/textAppearanceSmall"
        android:textSize="10sp" />

    </LinearLayout>
    <LinearLayout
    android:id="@+id/trackingStautsInnerWrapper3"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal" >

        <TextView
        android:id="@+id/textViewAltLabel"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Höhe: "
        android:textAppearance="?android:attr/textAppearanceSmall"
        android:textSize="10sp" />
        <TextView
        android:id="@+id/textViewAltWert"
        android:layout_width="80dp"
        android:layout_height="wrap_content"
        android:text=""
        android:textAppearance="?android:attr/textAppearanceSmall"
        android:textSize="10sp" />
        <TextView
        android:id="@+id/textViewAccLabel"
        android:layout_marginLeft="40dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Genauigkeit: "
        android:textAppearance="?android:attr/textAppearanceSmall"
        android:textSize="10sp" />
        <TextView
        android:id="@+id/textViewAccWert"
        android:layout_width="80dp"
        android:layout_height="wrap_content"
        android:text=""
        android:textAppearance="?android:attr/textAppearanceSmall"
        android:textSize="10sp" />
    </LinearLayout>
</LinearLayout>
<!--  
<org.osmdroid.views.MapView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/mapview"
    android:layout_width="fill_parent"
    android:layout_height="match_parent"
    android:clickable="true"/>
-->

<LinearLayout
    android:id="@+id/trackingLinearLayoutMap"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

</LinearLayout>

希望对您有所帮助!

Answer 1

你永远不会相信这一点，但如果你前往 How often can you update a textview without mess您会找到我认为可以解决问题的问题和答案。

如果这些不能解决问题，您可能需要将按钮替换为自定义 View ，并使用 canvas.drawText() 覆盖 onDraw 以放置文本。然后您可以确保删除任何以前的历史记录......

如果您只想要一个非透明的黑色背景，请在您的 res 目录中创建(或添加到)colors.xml 文件:

<resources>
    <color name="black">#ff000000</color>
</resources>

并添加:

    android:background="@color/black"

到 TextView 的 xml。