Why doesn't setVisibility work after a view is

问题:

Why doesn't the textView become invisible?

Here is my layout xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <TextView
    android:id="@+id/tvRotate"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Rotate Me"
/>
</LinearLayout>

..and here is my activity:

public class RotateMeActivity extends Activity
{
    @Override
    public void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        TextView tvRotate = (TextView) findViewById(R.id.tvRotate);

        RotateAnimation r = new RotateAnimation(0, 180, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);
        r.setDuration(0);
        r.setFillAfter(true);
        tvRotate.startAnimation(r);
        tvRotate.setVisibility(View.INVISIBLE);
    }
}

My goal is to rotate a view and then be able to hide and show it in code by setting setVisibility. The following works, but setRotation is available only in API Level 11. I need a way to do it in API Level 10.

tvRotate.setRotation(180);//instead of the RotateAnimation, only works in API Level 11
tvRotate.setVisibility(View.INVISIBLE);

回答1:

For me calling clearAnimation of the View fixed the problem. In my case I wanted to set the View back to its original position after doing a translation with fillAfter set to true.

回答2:

All the animations (before android 3.0) are actually applied to a bitmap which is a snapshot of your view instead of on your original view. When you are setting the fill after to true this actually means that the bitmap will continue to be displayed on the screen instead of your view. This is the reason why the visibility won't change upon using setVisibility and also the reason why your view will not be receiving touch events in its new (rotated) bounds. (but since you're rotating on 180 degrees that's not an issue).

回答3:

Another way to work around this is to wrap your animated view in another view and set the visibility of that wrapper view.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:orientation="vertical" >
    <FrameLayout 
        android:id="@+id/animationHoldingFrame"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">
        <TextView
             android:id="@+id/tvRotate"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:text="Rotate Me"
        />
    </FrameLayout>
</LinearLayout>

And the code then becomes this:

TextView tvRotate = (TextView) findViewById(R.id.tvRotate);
FrameLayout animationContainer = (FrameLayout)findViewById(R.id.animationHoldingFrame)

RotateAnimation r = new RotateAnimation(0, 180, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);
r.setDuration(0);
r.setFillAfter(true);
tvRotate.startAnimation(r);
animationContainer.setVisibility(View.INVISIBLE);

回答4:

Use this before setVisibility after animation is completed:

anim.reverse();
anim.removeAllListeners();
anim.end();
anim.cancel();

where anim is your ObjectAnimator

but if you are using the Animation class, then just do:

view.clearAnimation();

on the view upon which the animation was performed

回答5:

I ended up requiring API Level 11 and using setRotation to accomplish this. This seems like a pretty simple requirement that can't be done pre-Honeycomb though. All i wanted to do was rotate a button and then hide/show it.

回答6:

I came up with a workaround for this: basically right before you call setVisibility(View.GONE), do an animation with duration=0 setFillAfter(false) and have the angle from/to set to the current angle of rotation.

This will clear the setFillAfter bitmap and allow the view to be gone.