setText("test") is freezing UI

Question

I dont understand

I have a background thread which gets cpu load and then set it to text view

Problem is when setText() method is executed UI freezes for a second, i can feel it when scrolling through other elements of ui

Runnable runnable = new Runnable() {
        @Override
        public void run() {
            while(thread) {
                try {
                    RandomAccessFile reader = new RandomAccessFile("/proc/stat", "r");
                    String load = reader.readLine();

                    String[] toks = load.split(" ");

                    long idle1 = Long.parseLong(toks[5]);
                    long cpu1 = Long.parseLong(toks[2]) + Long.parseLong(toks[3]) + Long.parseLong(toks[4])
                        + Long.parseLong(toks[6]) + Long.parseLong(toks[7]) + Long.parseLong(toks[8]);

                    try {
                        Thread.sleep(360);
                    } catch (Exception e) {
                        }

                    reader.seek(0);
                    load = reader.readLine();
                    reader.close();

                    toks = load.split(" ");

                    long idle2 = Long.parseLong(toks[5]);
                    long cpu2 = Long.parseLong(toks[2]) + Long.parseLong(toks[3]) + Long.parseLong(toks[4])
                        + Long.parseLong(toks[6]) + Long.parseLong(toks[7]) + Long.parseLong(toks[8]);

                    fLoad =  (float)(cpu2 - cpu1) / ((cpu2 + idle2) - (cpu1 + idle1));

                } catch (IOException ex) {
                        }
                final int load =(int) (fLoad*100);
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                }
                mHandler.post(new Runnable() {
                        @Override
                        public void run() {

                            setCpuLoad(load);
                        }
                    });
            }
        }
    };
    new Thread(runnable).start();
}

.

 private final void setCpuLoad(int load){
    cpuLoad.setProgress(load);
    cpuLoadTxt.setText(load+"%");
}

I tried a lot of stuff and eventually figure out that problem is in setText() because when i comment it UI is smooth

Any chance that mHandler isn't a handler on the UI thread looper? — G. Blake Meike, Feb 05 '13 at 15:09
it looks like setText of android requires a char sequence instead of a string, so try casting your string to a charsequence and then use that inside the setText method — Jeff Hawthorne, Feb 05 '13 at 15:10
http://developer.android.com/reference/android/widget/TextView.html http://stackoverflow.com/questions/1391970/how-to-convert-a-string-to-charsequence — Jeff Hawthorne, Feb 05 '13 at 15:10
How complex is the UI? Changing a `TextView`, especially when sized as `wrap_content` can cause the entire view hierarchy to be relaid out, which can be slow if you have lots of layouts and views. — iagreen, Feb 05 '13 at 15:42
@iagreen It's camplicated, it has a lot of views, so I guess that us the problem. — pedja, Feb 05 '13 at 15:53

score 1 · Answer 1 · answered Feb 05 '13 at 15:11

1

Checkout in which thread do you create a Handler. You should do it on main (UI) thread .

answered Feb 05 '13 at 15:11

Korniltsev Anatoly

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Its directly in class. Should it be in onCreate maybe? – pedja Feb 05 '13 at 15:13
However you are free to do it wherever you whant if you are shure that it will use main thread Lopper – Korniltsev Anatoly Feb 05 '13 at 15:17
Use a breakpoint before you set the text and use the debugging view in eclipse... or another IDE if it has an android debugger – Mgamerz Feb 05 '13 at 15:20

setText("test") is freezing UI

1 Answers1