update ui from another thread in android
11,128
Solution 1
You can't call UI methods from threads other than the main thread. You should use Activity#runOnUiThread() method.
public class FileObserverActivity extends Activity
{
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
tv = (TextView) findViewById(R.id.textView1);
tv.setText("new world");
MyFileObserver myFileObserver = new MyFileObserver("/sdcard/", this);
myFileObserver.startWatching();
}
String mySTR = "";
TextView tv ;
public void event(String absolutePath,String path,int event)
{
runOnUiThread(action);
}
private Runnable action = new Runnable() {
@Override
public void run() {
mySTR = absolutePath+path+"\t"+event;
tv.setText(mySTR);
}
};
}
public class MyFileObserver extends FileObserver
{
public String absolutePath;
FileObserverActivity fileobserveractivity;
public MyFileObserver(String path,FileObserverActivity foa)
{
super(path, FileObserver.ALL_EVENTS);
absolutePath = path;
fileobserveractivity = foa;
}
@Override
public void onEvent(int event, String path)
{
if (path == null)
{
return;
}
else if(event!=0)
{
fileobserveractivity.event(absolutePath, path, event);
}
else
{
return;
}
}
}
Solution 2
Try as follows
public class FileObserverActivity extends Activity
{
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
tv = (TextView) findViewById(R.id.textView1);
tv.setText("new world");
MyFileObserver myFileObserver = new MyFileObserver("/sdcard/", this);
myFileObserver.startWatching();
registerReceiver(onBroadcast,new IntentFilter("abcd"));
}
String mySTR = "";
TextView tv ;
public void event(String absolutePath,String path,int event)
{
mySTR = absolutePath+path+"\t"+event;
tv.setText(mySTR); // program crash here!
}
@Override
protected void onDestroy() {
super.onDestroy();
unregisterReceiver(onBroadcast);
}
private final BroadcastReceiver onBroadcast = new BroadcastReceiver() {
@Override
public void onReceive(Context ctxt, Intent i) {
// do stuff to the UI
event(absolutePath, path, event);
}
};
}
public class MyFileObserver extends FileObserver
{
public String absolutePath;
FileObserverActivity fileobserveractivity;
public MyFileObserver(String path,FileObserverActivity foa)
{
super(path, FileObserver.ALL_EVENTS);
absolutePath = path;
fileobserveractivity = foa;
}
@Override
public void onEvent(int event, String path)
{
if (path == null)
{
return;
}
else if(event!=0)
{
context.sendBroadcast(new Intent("abcd"));
//fileobserveractivity.event(absolutePath, path, event);
}
else
{
return;
}
}
}
Author by
M.Movaffagh
Updated on August 12, 2022Comments
-
M.Movaffagh over 1 year
i want to change UI in android.
my main class make a second class then second class call a method of main class.method in main class should update UI but program crash in runtime.
what should i do?
my main class :
public class FileObserverActivity extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); tv = (TextView) findViewById(R.id.textView1); tv.setText("new world"); MyFileObserver myFileObserver = new MyFileObserver("/sdcard/", this); myFileObserver.startWatching(); } String mySTR = ""; TextView tv ; public void event(String absolutePath,String path,int event) { mySTR = absolutePath+path+"\t"+event; tv.setText(mySTR); // program crash here! } }
and my second class :
public class MyFileObserver extends FileObserver { public String absolutePath; FileObserverActivity fileobserveractivity; public MyFileObserver(String path,FileObserverActivity foa) { super(path, FileObserver.ALL_EVENTS); absolutePath = path; fileobserveractivity = foa; } @Override public void onEvent(int event, String path) { if (path == null) { return; } else if(event!=0) { fileobserveractivity.event(absolutePath, path, event); } else { return; } } }
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M.Movaffagh over 12 yearswhats context ? 9 line to end?
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M.Movaffagh over 12 yearsthansk...it s worked.with ContextWrapper context = new ContextWrapper(fileobserveractivity);