CODEWITHSUNDEEP
androidandroid-layout
jsjrobotics
jsjrobotics

Reputation: 1933

Adding a view from background thread

I am attempting to add multiple textviews to an already inflated layout. The information displayed is being pulled from a database, with one textview created for each row in the database. Since the database can be extremely large, I create each textview one at a time in a background thread, and add it to the foreground.

Here is the function called in the background thread to update the foreground:

private TextView temp;
private void addClickableEvent(ReviewHistoryEvent e){
    if(e == null){
        Log.e(tag,"Attempted to add a null event to review history");
        return;
    }
    TextView t = new TextView(getBaseContext());
    t.setTag(e);
    t.setText(e.getTime()+"  "+e.getEvent());
    t.setClickable(true);
    t.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
    t.setTextAppearance(getBaseContext(), R.style.Information_RegularText);
    t.setGravity(Gravity.CENTER);
    t.setOnClickListener(this);

    temp = t;
    runOnUiThread(new Runnable() {
         public void run() {
             LinearLayout display = (LinearLayout) findViewById(R.id.reviewHistory_display);
            display.addView(temp);
        }
    });
}

This function runs once successfully and the first textview appears. However, when it is called a second time, it fails on the display.addView(temp); line with the following error:

java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the childs's parent first.

I am unsure why my textview already has a parent if it is supposedly newly instantiated. Also I use the temp textview to get around my runnable not being able to reference the local textview t. Is this correct? Any help would be appreciated.

Upvotes: 5

Views: 3092

Answers (1)

Cat
Cat

Reputation: 67502

Instead of using a member variable (which can be modified and which is not local, of course), use a final TextView instead:

final TextView t = new TextView(getBaseContext());
// ...

temp = t; // Remove this
runOnUiThread(new Runnable() {
     public void run() {
        // ...
        display.addView(t);
    }
});

Upvotes: 4

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