我想出了一个应该很容易实现的解决方案。它涉及修改布局和使布局膨胀的活动......见下文:
活动(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));
}
}
新的线性布局(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):
<?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):
<?xml version="1.0" encoding="utf-8"?>
<resources>
<dimen name="quickplay_offset">50dp</dimen>
</resources>
动画(/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>
该程序现在完全符合我的需要。整个布局从屏幕底部开始,在 1 秒内滑入并停止,布局顶部实际上距离屏幕顶部 50px(即LL.getTop() = -50
),而布局底部位于屏幕(即LL.getBottom() = 530 = 480 + 50
)。