I am trying to make a remote control for a Google TV.
I want to change the text I have in a layout (TextView statusText) with connected when the device has successfully connected. But I get an exception when I try to do this:
“07-07 22:42:20.870: E/AndroidRuntime(5750):android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
“
Appreciate any help/pointers
Here is my MainActivity.java and main.xml:
MainActivity.java:
package uk.co.mypack.gtvremote;
//imports removed for paste
public class MainActivity extends Activity implements ClientListener{
private AnymoteSender anymoteSender;
private TextView statusText;
protected AnymoteClientService mAnymoteClientService;
private static String statusPrefix = "Status: ";
private Context mContext;
private ProgressBar progressBar;
private Handler handler;
private TouchHandler touchPadHandler;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
progressBar = (ProgressBar) findViewById(R.id.a_progressbar);
progressBar.setVisibility(View.VISIBLE);
mContext = this;
ImageButton upArrowButton = (ImageButton) findViewById(R.id.upArrow);
ImageButton leftArrowButton = (ImageButton) findViewById(R.id.leftArrow);
ImageButton centreButton = (ImageButton) findViewById(R.id.centreButton);
ImageButton rightArrowButton = (ImageButton) findViewById(R.id.rightArrow);
ImageButton downArrowButton = (ImageButton) findViewById(R.id.downArrow);
upArrowButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
sendKeyEvent(KeyEvent.KEYCODE_DPAD_UP);
}
});
leftArrowButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
sendKeyEvent(KeyEvent.KEYCODE_DPAD_LEFT);
}
});
centreButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
sendKeyEvent(KeyEvent.KEYCODE_DPAD_CENTER);
}
});
rightArrowButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
sendKeyEvent(KeyEvent.KEYCODE_DPAD_RIGHT);
}
});
downArrowButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
sendKeyEvent(KeyEvent.KEYCODE_DPAD_DOWN);
}
});
handler = new Handler();
// Bind to the AnymoteClientService
Intent intent = new Intent(mContext, AnymoteClientService.class);
bindService(intent, mConnection, Context.BIND_AUTO_CREATE);
statusText = (TextView) findViewById(R.id.statusText);
}
/** Defines callbacks for service binding, passed to bindService() */
private ServiceConnection mConnection = new ServiceConnection() {
/*
* ServiceConnection listener methods.
*/
@Override
public void onServiceConnected(ComponentName name, IBinder service) {
mAnymoteClientService = ((AnymoteClientService.AnymoteClientServiceBinder) service)
.getService();
mAnymoteClientService.attachClientListener(MainActivity.this);
}
@Override
public void onServiceDisconnected(ComponentName name) {
mAnymoteClientService.detachClientListener(MainActivity.this);
mAnymoteClientService = null;
}
};
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public void onConnected(AnymoteSender anymoteSender) {
if (anymoteSender != null) {
// Send events to Google TV using anymoteSender.
// save handle to the anymoteSender instance.
this.anymoteSender = anymoteSender;
//THIS IS WHERE I AM TRYING TO SET THE TEXTVIEW
TextView localStatusText = (TextView) findViewById(R.id.statusText);
localStatusText.setText(statusPrefix + "Connected to GoogleTV");
//ABOVE IS WHERE I AM TRYING TO SET THE TEXTVIEW
// Attach touch handler to the touchpad view
touchPadHandler = new TouchHandler(
findViewById(R.id.touchPad), Mode.POINTER_MULTITOUCH, anymoteSender);
} else {
statusText.setText(statusPrefix + "Connection attempt failed, cant find send handler");
//attempt to connect again?
//attemptToConnect();
}
// Hide the progressBar once connection to Google TV is established.
handler.post(new Runnable() {
public void run() {
progressBar.setVisibility(View.INVISIBLE);
}
});
}
@Override
public void onDisconnected() {
// show message to tell the user about disconnection.
statusText.setText(statusPrefix + "Disconnected");
// Try to connect again if needed. This may be need to be done via button
attemptToConnect();
this.anymoteSender = null;
}
@Override
public void onConnectionError() {
// show message to tell the user about disconnection.
statusText.setText(statusPrefix + "Connection error encountered");
// Try to connect again if needed.
attemptToConnect();
this.anymoteSender = null;
}
@Override
protected void onDestroy() {
if (mAnymoteClientService != null) {
mAnymoteClientService.detachClientListener(this);
}
unbindService(mConnection);
super.onDestroy();
}
public void attemptToConnect()
{
//stub to invoke connection attempt
}
private void sendKeyEvent(final int keyEvent) {
// create new Thread to avoid network operations on UI Thread
if (anymoteSender == null) {
Toast.makeText(MainActivity.this, "Waiting for connection",
Toast.LENGTH_LONG).show();
return;
}
anymoteSender.sendKeyPress(keyEvent);
}
}
Main.xml:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/LinearLayout1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/control_message"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:padding="@dimen/padding_medium"
android:text="@string/control_msg"
android:textSize="90dp"
tools:context=".MainActivity" />
<LinearLayout
android:id="@+id/middlePanel"
android:layout_width="wrap_content"
android:layout_height="wrap_content" >
<TextView
android:id="@+id/statusText"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Status: Disconnected - startup"
android:textSize="20dp" />
<ImageView
android:id="@+id/touchPad"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:src="@drawable/greysquare"
/>
<LinearLayout
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="wrap_content"
android:gravity="center_horizontal"
android:orientation="vertical" >
<ImageButton
android:id="@+id/upArrow"
android:layout_width="150dp"
android:layout_height="150dp"
android:background="@drawable/blackuparrow" />
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center"
android:orientation="horizontal" >
<ImageButton
android:id="@+id/leftArrow"
android:layout_width="150dp"
android:layout_height="150dp"
android:background="@drawable/blackleftarrow" />
<ImageButton
android:id="@+id/centreButton"
android:layout_width="150dp"
android:layout_height="150dp"
android:background="@drawable/emptycircle"
android:paddingBottom="10dp"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:paddingTop="10dp" />
<ImageButton
android:id="@+id/rightArrow"
android:layout_width="150dp"
android:layout_height="150dp"
android:background="@drawable/blackrightarrow" />
</LinearLayout>
<ImageButton
android:id="@+id/downArrow"
android:layout_width="150dp"
android:layout_height="150dp"
android:background="@drawable/blackdownarrow" />
</LinearLayout>
</LinearLayout>
<ProgressBar
android:id="@+id/a_progressbar"
style="@android:style/Widget.ProgressBar.Large"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center" />
</LinearLayout>
The onConnected() callback is not called on the Main UI thread, but on a separate thread that is used by the Service. So it is not able to access the TextView created in Main UI thread. What you should do is create a Handler in the main UI thread and then use that handler to post a runnable that makes changes to the TextView. You can read more about Handlers on the Android developer site.