Android的 - 如何定位查看屏幕外？ [英] Android -- How to position View off-screen?

问题描述

我想在我的应用动画一个简单的ImageView，我希望它从屏幕底部滑出，并得出一个静止位置，其视图顶部的50像素是在屏幕的顶部（如： ImageView的最终位置应-50px在Ⅹ）。我试着用AbsoluteLayout要做到这一点，但是这实际上切断的ImageView使得顶部50像素从未呈现的顶部50像素。我需要有ImageView的可见光/，而它的动画渲染的顶部50像素，然后简单地把它来休息稍微偏离屏幕。我希望我已经解释说，不够好。

I'm trying to animate a simple ImageView in my application and I want it to slide in from the bottom of the screen and come to a resting position where the top 50px of the view is off the top of the screen (e.g. the final position of the ImageView should be -50px in X). I've tried to use the AbsoluteLayout to do this, but this actually cuts off the top 50px of the ImageView such that the top 50px is never rendered. I need to have the top 50px of the ImageView visible/rendered while it's animating and then simply have it come to a rest slightly off-screen. I hope I've explained that well enough.

下面是我目前使用作为布局和幻灯片的动画（这个目前不呈现ImageView的顶部50像素）：

Here is what I'm currently using as a layout and the slide-in animation (this currently doesn't render the top 50px of the ImageView):

布局：

<?xml version="1.0" encoding="utf-8"?>
   <AbsoluteLayout xmlns:android="http://schemas.android.com/apk/res/android"
      android:layout_height="fill_parent" 
      android:layout_width="fill_parent" 
      android:id="@+id/QuickPlayClipLayout">
      <ImageView android:id="@+id/Clip"
         android:background="@drawable/clip" 
         android:layout_width="fill_parent" 
         android:layout_height="wrap_content" 
         android:layout_y="-50dp">
      </ImageView>
   </AbsoluteLayout>

动画：

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
   <translate android:fromYDelta="100%p" 
       android:toYDelta="0"
       android:duration="1000"/>
   <alpha android:fromAlpha="0.0" 
       android:toAlpha="1.0"
       android:duration="1000" />
</set>

在此先感谢。

Thanks in advance.

推荐答案

我想出了一个解决方案，这一点，应该是很容易实现。它涉及到修改的布局和活动膨胀的布局......见下图：

I figured out a solution to this that should be easy to implement. It involves modifying the layout and the Activity inflating the layout... see below:

活动（QuickPlay.java）：

Activity (QuickPlay.java):

public class QuickPlay extends Activity implements AnimationListener
{
    private ImageView myImageView;
    private LinearLayout LL;

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        this.setContentView(R.layout.quick_play_screen);

        myImageView = (ImageView) this.findViewById(R.id.Clip);
        LL = (LinearLayout) this.findViewById(R.id.QuickPlayClipLayout);

        //finally
        Animation anim = AnimationUtils.loadAnimation(this, R.anim.slide_in_quickplay);
        anim.setAnimationListener(this);
        LL.startAnimation(anim);
    }
    @Override
    public void onAnimationEnd(Animation animation){}

    @Override
    public void onAnimationRepeat(Animation animation){}

    @Override
    public void onAnimationStart(Animation animation)
    {
        // This is the key...
        //set the coordinates for the bounds (left, top, right, bottom) based on the offset value (50px) in a resource XML
        LL.layout(0, -(int)this.getResources().getDimension(R.dimen.quickplay_offset), 
                LL.getWidth(), LL.getHeight() + (int)this.getResources().getDimension(R.dimen.quickplay_offset));
    }
}

新的LinearLayout（CustomLinearLayout.java）：

New LinearLayout (CustomLinearLayout.java):

public class CustomLinearLayout extends LinearLayout
{
    private Context myContext;

    public CustomLinearLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
        myContext = context;
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
    {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec+((int)myContext.getResources().getDimension(R.dimen.quickplay_offset)));
    }
}

布局（/res/layout/quick_play_screen.xml）：

Layout (/res/layout/quick_play_screen.xml):

<?xml version="1.0" encoding="utf-8"?>
   <com.games.mygame.CustomLinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
      android:layout_height="fill_parent" 
      android:layout_width="fill_parent" 
      android:id="@+id/QuickPlayClipLayout">
      <ImageView android:id="@+id/Clip"
         android:background="@drawable/clip" 
         android:layout_width="fill_parent" 
         android:layout_height="wrap_content">
      </ImageView>
   </com.games.mygame.CustomLinearLayout>

资源（/res/values​​/constants.xml）：

Resource (/res/values/constants.xml):

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <dimen name="quickplay_offset">50dp</dimen>
</resources>

动画（/res/anim/slide_in_quickplay.xml）：

Animation (/res/anim/slide_in_quickplay.xml):

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
   <translate android:fromYDelta="100%p" 
       android:toYDelta="0"
       android:duration="1000"/>
   <alpha android:fromAlpha="0.0" 
       android:toAlpha="1.0"
       android:duration="1000" />
</set>

该程序现在不正是我需要做的。整个布局开始了屏幕底部，滑动在1秒来休息在布局的顶部实际上是50像素在屏幕的顶部（即 LL.getTop（）= - 50 ）和布局的底部搁在屏幕（即 LL.getBottom（）=底部530 = 480 + 50 ）

The program now does exactly what I need it to do. The entire layout starts off screen at the bottom, slides in in 1 sec and comes to a rest where the top of the layout is actually 50px off the top of the screen (i.e. LL.getTop() = -50) and the bottom of the layout is resting at the bottom of the screen (i.e. LL.getBottom() = 530 = 480 + 50).

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