效果图:
原理是在onMeasure中得到隐藏内容的高度，点击这个view的时候对隐藏的view startAnimation,让它的高度从0增长到onMeasure得到的这个View的measureHeight
代码是:
public class ExpandableLayout extends LinearLayout {
private Context mContext;
private LinearLayout mHandleView;
private RelativeLayout mContentView;
private ImageView mIconExpand;
int mContentHeight = 0;
int mTitleHeight = 0;
private boolean isExpand;
private Animation animationDown;
private Animation animationUp;
public ExpandableLayout(Context context, AttributeSet attrs) {
super(context, attrs);
this.mContext = context;
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
if (this.mContentHeight == 0) {
this.mContentView.measure(widthMeasureSpec, 0);
this.mContentHeight = this.mContentView.getMeasuredHeight();
}
if (this.mTitleHeight == 0) {
this.mHandleView.measure(widthMeasureSpec, 0);
this.mTitleHeight = this.mHandleView.getMeasuredHeight();
}
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
@Override
protected void onFinishInflate() {
super.onFinishInflate();
this.mHandleView = (LinearLayout) this
.findViewById(R.id.collapse_value);
this.mContentView = (RelativeLayout) this.findViewById(R.id.expand_value);
this.mIconExpand = (ImageView) this.findViewById(R.id.icon_value);
this.mHandleView.setOnClickListener(new ExpandListener());
this.mContentView.setOnClickListener(new ExpandListener());
mContentView.setVisibility(View.GONE);
}
private class ExpandListener implements View.OnClickListener {
@Override
public final void onClick(View paramView) {
clearAnimation();
if (!isExpand) {
if (animationDown == null) {
animationDown = new DropDownAnim(mContentView,
mContentHeight, true);
animationDown.setDuration(200); // SUPPRESS CHECKSTYLE
}
startAnimation(animationDown);
mContentView.startAnimation(AnimationUtils.loadAnimation(
mContext, R.anim.animalpha));
mIconExpand.setImageResource(R.drawable.update_detail_up);
isExpand = true;
} else {
isExpand = false;
if (animationUp == null) {
animationUp = new DropDownAnim(mContentView,
mContentHeight, false);
animationUp.setDuration(200); // SUPPRESS CHECKSTYLE
}
startAnimation(animationUp);
mIconExpand.setImageResource(R.drawable.update_detail_down);
}
}
}
class DropDownAnim extends Animation {
private int targetHeight;
private View view;
private boolean down;
public DropDownAnim(View targetview, int vieweight, boolean isdown) {
this.view = targetview;
this.targetHeight = vieweight;
this.down = isdown;
}
@Override
protected void applyTransformation(float interpolatedTime,
Transformation t) {
int newHeight;
if (down) {
newHeight = (int) (targetHeight * interpolatedTime);
} else {
newHeight = (int) (targetHeight * (1 - interpolatedTime));
}
view.getLayoutParams().height = newHeight;
view.requestLayout();
if (view.getVisibility() == View.GONE) {
view.setVisibility(View.VISIBLE);
}
}
@Override
public void initialize(int width, int height, int parentWidth,
int parentHeight) {
super.initialize(width, height, parentWidth, parentHeight);
}
@Override
public boolean willChangeBounds() {
return true;
}
}
}xml文件为:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:background="#FFFFFF" > <com.example.view.ExpandableLayout android:id="@+id/app_detail_safety_info" android:layout_width="fill_parent" android:layout_height="wrap_content" android:orientation="vertical" > <LinearLayout android:id="@+id/collapse_value" android:layout_width="fill_parent" android:layout_height="34dip" android:layout_marginLeft="14dip" android:gravity="center_vertical" android:orientation="horizontal" > <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginLeft="30dp" android:text="点击我会显示隐藏的内容" android:textColor="#000000" android:textSize="18sp" > </TextView> <LinearLayout android:layout_width="fill_parent" android:layout_height="fill_parent" android:gravity="right|center_vertical" android:orientation="horizontal" > <ImageView android:id="@+id/icon_value" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginRight="22dip" android:src="@drawable/update_detail_down" /> </LinearLayout> </LinearLayout> <RelativeLayout android:id="@+id/expand_value" android:layout_width="fill_parent" android:layout_height="wrap_content" android:background="@drawable/app_detail_safety_info_bg" android:orientation="horizontal" android:paddingBottom="8dip" android:paddingTop="8dip" > <ImageButton android:id="@+id/btn" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerVertical="true" android:layout_marginLeft="30dp" android:background="@null" android:src="@drawable/btn_icon" android:textColor="#0A84BD" android:textSize="16sp" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginLeft="30dp" android:layout_toRightOf="@id/btn" android:text="隐藏的内容" android:textColor="#000000" android:textSize="18sp" > </TextView> </RelativeLayout> </com.example.view.ExpandableLayout> </RelativeLayout>
Activity中引用:
public class TestDropdownHideActivity extends Activity {
public static void startActivity(Context context) {
Intent intent = new Intent();
intent.setClass(context,TestDropdownHideActivity.class);
context.startActivity(intent);
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.test_layout);
}
}