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我正在製作Android應用程序,當類的屬性maxDbRecorded
發生更改時,我想更新標籤。所以我在我的Activity中實現了一個PropertyChangeListener。如何從線程觸發PropertyChange事件?
public class AndroidCalibrationTestActivity extends Activity implements PropertyChangeListener {
private Recorder recorder;
private Thread recorderThread;
private Measure measures;
private TextView numberOfMaxDecibels;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
numberOfMaxDecibels = (TextView)findViewById(R.id.txtNumberOfMaxDecibels);
measures = new Measure();
measures.addPropertyChangeListener(this);
recorderThread = new Thread((Runnable) Recorder.getInstance().runRecorder);
recorderThread.start();
}
public void propertyChange(PropertyChangeEvent event) {
numberOfMaxDecibels.setText(event.getNewValue() + "");
}
}
現在我想從我的線程中設置值maxDbRecorded
。以便textview numberOfMaxDecibels更新。
public class Measure {
private double maxDbRecorded;
private PropertyChangeSupport pcs = new PropertyChangeSupport(this);
public Measure() {
}
//Getters and setters
public double getMaxDbRecorded() {
return maxDbRecorded;
}
public void setMaxDbRecorded(double maxDbRecorded) {
double oldValue = this.maxDbRecorded;
this.maxDbRecorded = maxDbRecorded;
//Fires a property change event
pcs.firePropertyChange("maxDbRecorded", oldValue, maxDbRecorded);
}
//To let classes subscribe for property changed listener
public void addPropertyChangeListener(PropertyChangeListener listener){
pcs.addPropertyChangeListener("maxDbRecorded", listener);
}
}
在課堂上錄音,我有我的線,我設置maxDbRecorded
,但PropertyChanged事件不會被解僱。 如果我直接從活動中設置maxDbRecorded
,它確實有效。
public class Recorder {
protected Measure m;
private Recorder() {
m = new Measure();
}
public static Recorder getInstance() {
if(instance == null){
instance = new Recorder();
}
return instance;
}
Runnable runRecorder = new Runnable() {
public void run() {
startRecording();
}
};
public void startRecording() {
//Here happens some recording stuff
double maxDB;
m.setMaxDbRecorded(maxDB);
}
}
我也嘗試在我的Activity中創建一個Measure對象,並將此實例提供給Recorder線程。這給出了一個錯誤:$ CalledFromWrongThreadException:只有創建視圖層次結構的原始線程可以觸及其視圖。
非常感謝,這解決了我的問題 – dieters 2012-04-27 08:02:19