I'm trying out making an app using Android Studio and I want to constantly update a text view.
I at first thought I should use a loop but that ended up not even running for some reason.
TextView amount = findViewById(R.id.amountTextView);
final SeekBar seekBar = findViewById(R.id.seekBar);
int p = seekBar.getProgress() + 1;
amount.setText(String.valueOf(p));
});
}
}
With this method it doesn't update the results text view. I would like it to constantly update the text view so it shows what number the seek bar is on.
You will need an event for update the state of SeekBar and TextView, in this case I user a Handler(android.os) for update the views each 100 milliseconds of time, but you can use another event like the load of a web service or another.
In your case, it doesn't update because you just update the state of variable, but never update the state of seekbar, that is the reason it will never increment the current state.
private void startLoopUntilEnd() {
final Handler handler = new Handler();
final Runnable runnable = new Runnable() {
#Override
public void run() {
int progress = seekBar.getProgress();
textView.setText(String.valueOf(progress));
progress++;
seekBar.setProgress(progress);
startLoopUntilEnd();
}
};
if (currentState <seekBar.getMax()){
handler.postDelayed(runnable,100);
}
}
You can call this method from onCreate in case of Activity or onResume in case of Fragment and after it will go until the SeekBar is complete recursively.
If you want to change the max of seekBar, you can set it in xml or in code.
Use onSeekBarChangeListener:
seekBar.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {
#Override
public void onStopTrackingTouch(SeekBar seekBar) {
}
#Override
public void onStartTrackingTouch(SeekBar seekBar) {
}
#Override
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
amount.setTextprogress);
}
});
Related
I came across a piece of code,now I am stuck with it.
SeekBar volumeControl=(SeekBar)findViewById(R.id.volumeSeekBar);
volumeControl.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
#Override
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
audioManager.setStreamVolume(AudioManager.STREAM_MUSIC,progress,0 );
}
#Override
public void onStartTrackingTouch(SeekBar seekBar) {
}
#Override
public void onStopTrackingTouch(SeekBar seekBar) {
}
});
Here I know that volumeControl is a variable of type SeekBar. In the second line of code volume control is set with a function setOnSeekBarChangeListener. I am unable to understand what's written inside the brackets of setOnSeekBarChangeListener. Can anyone please explain it in detail. I am just introduced to java and don't have much knowledge
This is a small piece of code to control volume using a seek bar.
Inside the brackets of onSeekBarChangeListener, we declare a new SeekBar.onSeekBarChangeListener which implements three methods :
onProgressChanged : This basically tracks the change in the seek bar and then sets the volume according to the amount of change.
onStartTrackingTouch : This methods contains the code which should be executed when the touch gesture starts.
onStopTrackingTouch:
This method contains the code which should be executed which the touch gesture stops.
I have the following code, which I was hoping would count up to 3 million on the screen.
It compiles and runs, displaying 3,000,000 at the end on the emulator. My question is how do I force a redraw / display of the textbox during the loop please?
/** Called when the activity has become visible. */
#Override
protected void onResume() {
super.onResume();
Log.d(msg, "The onResume() event");
TextView textbox1=(TextView)findViewById(R.id.TextView1);
for(double l=0; l<=3000000; l++){
textbox1.setText("" + l);
}
}
The view is only disabled after onResume has finished running.
You may want to set the text in the textview, update some state in the activity (like an int field), and register some code to run after a while and increment. Look at using Handler, AsyncTask, or other options to defer code.
Here's a quick-and-dirty example with Handler.
final long DELAY_MILLIS = 50;
final Handler handler = new Handler();
int num = 0;
final Runnable runnable = new Runnable() {
public void run() {
if (num >= 3000000) return;
textbox1.setText("" + num);
num++;
// re-register ourself to run in DELAY_MILLIS;
handler.postDelayed(runnable, DELAY_MILLIS);
}
};
TextView textbox1;
protected void onResume() {
// more efficient to look this up once
this.textbox1 = (TextView)findViewById(R.id.TextView1);
runnable.run(); // will register itself to re-run
}
According to this answer the best way to show an incremental value in a TextView is to use ValueAnimator
public void animateTextView(int initialValue, int finalValue, final TextView textview) {
ValueAnimator valueAnimator = ValueAnimator.ofInt(initialValue, finalValue);
valueAnimator.setDuration(1500);
valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
#Override
public void onAnimationUpdate(ValueAnimator valueAnimator) {
textview.setText(valueAnimator.getAnimatedValue().toString());
}
});
valueAnimator.start();
}
I have a ViewPager in my app, and I'd like it to shake when it is loaded for the first time. This is to show the user that there are more pages available. How can I achieve that programmatically?
However, I don't want the pager to automatically scroll to the next page.
ViewPager has a method for swiping programmatically: fakeDragBy
https://developer.android.com/reference/android/support/v4/view/ViewPager.html#fakeDragBy(float)
Here's how you can achieve this:
Call viewPager.beginFakeDrag()
Start an animator. In the AnimatorUpdateListener override onAnimationUpdate so it calls viewPager.fakeDragBy()
In the AnimatorListener override onAnimationEnd so it calls viewPager.endFakeDrag() After this call, the ViewPager should settle back to the initial page.
vpaliyX's answer using translation won't show the next page. You need to use fakeDragBy so that the user can briefly see the edge of the next page.
As requested, here is a code snippet:
private float drag;
...
#Override
protected void onResume() {
super.onResume();
mViewPager.postDelayed(new Runnable() {
#Override
public void run() {
mViewPager.beginFakeDrag();
drag = 0;
float density = getResources().getDisplayMetrics().density;
// 120 is the number of dps you want the page to move in total
ValueAnimator animator = ValueAnimator.ofFloat(0, 120 * density);
animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
#Override
public void onAnimationUpdate(ValueAnimator valueAnimator) {
float progress = (float) valueAnimator.getAnimatedValue();
mViewPager.fakeDragBy(drag - progress);
drag = progress;
}
});
animator.addListener(new Animator.AnimatorListener() {
#Override
public void onAnimationStart(Animator animator) { }
#Override
public void onAnimationEnd(Animator animator) {
mViewPager.endFakeDrag();
}
#Override
public void onAnimationCancel(Animator animator) { }
#Override
public void onAnimationRepeat(Animator animator) { }
});
animator.setDuration(400);
animator.start();
}
}, 300);
}
I put in a 300 ms start delay. I don't really know if that's necessary or not.
Note the expression drag - progress which gives a negative number. To get a leftward swipe, you have to use a negative value.
Also note that I didn't include any code to determine if this was the first time the app was opened.
You can play with the start delay, the animation duration, and the number of dps to swipe until you get the effect you are looking for.
If you want to shake it, you can use animation for it.
I had done the same stuff for FloatingActionButton, and it worked perfectly.
For ViewPager check out this code:
ObjectAnimator shakeAnimation=ObjectAnimator.ofFloat(yourViewPager,View.TRANSLATION_X,-25f,25f);
shakeAnimation.setDuration(100);
shakeAnimation.setRepeatCount(2);
shakeAnimation.addListener(new AnimatorListenerAdapter() {
#Override
public void onAnimationEnd(Animator animation) {
super.onAnimationEnd(animation);
yourViewPager.setTranslationY(0f);
}
});
shakeAnimation.start();
You can adjust the translation as convenient for, in my case it's just [-25,25].Also you can set a duration of animation, and the repeat count.
You can use this code for your ViewPager when the data has been loaded for the first time, however, you need to determine when the data has been loaded for the first time. But I don't think you will have problems with that.
Good luck!
// Set up the user interaction to manually show or hide the system UI.
contentView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if (TOGGLE_ON_CLICK) {
mSystemUiHider.toggle();
((ZooView)contentView).editmode = mSystemUiHider.isVisible();
} else {
mSystemUiHider.show();
}
}
});
This is my code, I am trying to update a variable in a custom view (ZooView) to know whether or not the view is in which mode (editmode a custom variable changing OnDraw method primarily)... I tried to invalidate the view when it toggles on click but that's not it, because the logcat showed it wasn't even getting to this function regularly. (only sporadically)
Any ideas?
mSystemUiHider
.setOnVisibilityChangeListener(new SystemUiHider.OnVisibilityChangeListener() {
// Cached values.
int mControlsHeight, mControlsWidth;
int mShortAnimTime;
#Override
#TargetApi(Build.VERSION_CODES.HONEYCOMB_MR2)
public void onVisibilityChange(boolean visible) {
((ZooView)contentView).editmode = visible;
putting the change here fixed it totally! :)
I have an android app I am just experimenting things on and I cannot seem to figure out why my app force closes when I update a TextView via a while loop. When I comment out the updateText method it runs fine.
public class GameThread extends Thread {
Thread t;
private int i;
private boolean running;
private long sleepTime;
GameView gv;
public GameThread() {
t = new Thread(this);
t.start();
i = 0;
sleepTime = 1000;
}
public void initView(GameView v) {
this.gv = v;
}
public void setRunning(boolean b) {
this.running = b;
}
public boolean getRunning() {
return running;
}
public void run() {
while(running) {
i++;
update();
try {
t.sleep(sleepTime);
} catch(InterruptedException e) {
}
}
}
public void update() {
gv.setText(i); // when this is uncommented, it causes force close
Log.v("Semajhan", "i = " + i);
}
public class GameView extends LinearLayout {
public TextView tv;
public GameView(Context c) {
super(c);
this.setBackgroundColor(Color.WHITE);
tv = new TextView(c);
tv.setTextColor(Color.BLACK);
tv.setTextSize(20);
this.addView(tv);
}
public void setText(int i) {
tv.setText("i count: " + i);
}
public class Exp extends Activity {
GameThread t;
GameView v;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
v = new GameView(this);
setContentView(v);
t = new GameThread();
t.setRunning(true);
t.initView(v);
}
public boolean onTouchEvent(MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_DOWN) {
if (t.getRunning() == true) {
t.setRunning(false);
Log.v("Semajhan", "STOPPED");
} else {
t.setRunning(true);
Log.v("Semajhan", "RESTART");
}
}
return true;
}
protected void onDestroy() {
Log.v("Semajhan", "DESTROYING");
super.onDestroy();
}
protected void onStop() {
Log.v("Semajhan", "Stopping");
super.onStop();
}
I though i'd post the whole app since it is relatively small and so that I could get some help without confusion.
First, when you get a Force Close dialog, use adb logcat, DDMS, or the DDMS perspective in Eclipse to examine LogCat and look at the stack trace associated with your crash.
In this case, your exception will be something to the effect of "Cannot modify the user interface from a non-UI thread". You are attempting to call setText() from a background thread, which is not supported.
Using a GameThread makes sense if you are using 2D/3D graphics. It is not an appropriate pattern for widget-based applications. There are many, many, many, many examples that demonstrate how to create widget-based applications without the use of a GameThread.
You have to call it from the UI thread.
For more info check: Painless Threading .
If you decide to use a Handler, the easiest solution for you will be to:
Extend a View, override it's onDraw , in it draw the game objects, after you have calculated the game data for them first of course
The Handler: (in your Activity)
private Handler playHandler = new Handler() {
public void handleMessage(Message msg) {
gameView.postInvalidate(); // gameView is the View that you extended
}
};
The game thread has a simple
Message.obtain(playHandler).sendToTarget();
In 2 words, the View is responsible for the drawing (you can move the calculations in a separate class, and call it before the onDraw), the thread is responsible only for scheduled calls to the Handler, and the Handler is responsible only to tell the View to redraw itself.
You cannot update the UI of your app outside of the UI Thread, which is the 'main' thread you start in. In onCreate(Context) of you app, you are creating the game thread object, which is what is doing the updating of your UI.
You should use a Handler:
http://developer.android.com/reference/android/os/Handler.html