I found a solution to the problem. Full lesson and source code can be downloaded here: click here
Or use the code below:
activity_main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<LinearLayout
android:id="@+id/header"
android:layout_width="match_parent"
android:layout_height="64dp"
android:layout_marginLeft="16dp"
android:layout_marginRight="16dp"
android:layout_marginTop="16dp"
android:background="#FCF"
android:orientation="horizontal" >
<TextView
android:id="@+id/color"
android:layout_width="48dp"
android:layout_height="48dp"
android:layout_marginBottom="8dp"
android:layout_marginLeft="8dp"
android:layout_marginTop="8dp"
android:background="@drawable/rectangle"
android:fontFamily="sans-serif-light"
android:gravity="center_vertical"
android:text=""
android:textAlignment="center"
android:textStyle="bold" />
<TextView
android:id="@+id/clickme"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="4dp"
android:fontFamily="sans-serif-light"
android:gravity="center_vertical"
android:text="click_here"
android:textStyle="bold" />
</LinearLayout>
<LinearLayout
android:id="@+id/expandable"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="16dp"
android:layout_marginRight="16dp"
android:background="#FFF"
android:orientation="vertical"
android:paddingLeft="4dp" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="text1" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="text2" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Слуга: text3" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="text4" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="text5" />
</LinearLayout>
MainActivity.java
public class MainActivity extends Activity {
LinearLayout mLinearLayout;
LinearLayout mLinearLayoutHeader;
ValueAnimator mAnimator;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
setTitle("title");
mLinearLayout = (LinearLayout) findViewById(R.id.expandable);
// mLinearLayout.setVisibility(View.GONE);
mLinearLayoutHeader = (LinearLayout) findViewById(R.id.header);
// Add onPreDrawListener
mLinearLayout.getViewTreeObserver().addOnPreDrawListener(
new ViewTreeObserver.OnPreDrawListener() {
@Override
public boolean onPreDraw() {
mLinearLayout.getViewTreeObserver()
.removeOnPreDrawListener(this);
mLinearLayout.setVisibility(View.GONE);
final int widthSpec = View.MeasureSpec.makeMeasureSpec(
0, View.MeasureSpec.UNSPECIFIED);
final int heightSpec = View.MeasureSpec
.makeMeasureSpec(0,
View.MeasureSpec.UNSPECIFIED);
mLinearLayout.measure(widthSpec, heightSpec);
mAnimator = slideAnimator(0,
mLinearLayout.getMeasuredHeight());
return true;
}
});
mLinearLayoutHeader.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (mLinearLayout.getVisibility() == View.GONE) {
expand();
} else {
collapse();
}
}
});
}
private void expand() {
// set Visible
mLinearLayout.setVisibility(View.VISIBLE);
mAnimator.start();
}
private void collapse() {
int finalHeight = mLinearLayout.getHeight();
ValueAnimator mAnimator = slideAnimator(finalHeight, 0);
mAnimator.addListener(new Animator.AnimatorListener() {
@Override
public void onAnimationEnd(Animator animator) {
// Height=0, but it set visibility to GONE
mLinearLayout.setVisibility(View.GONE);
}
@Override
public void onAnimationStart(Animator animator) {
}
@Override
public void onAnimationCancel(Animator animator) {
}
@Override
public void onAnimationRepeat(Animator animator) {
}
});
mAnimator.start();
}
private ValueAnimator slideAnimator(int start, int end) {
ValueAnimator animator = ValueAnimator.ofInt(start, end);
animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator valueAnimator) {
// Update Height
int value = (Integer) valueAnimator.getAnimatedValue();
ViewGroup.LayoutParams layoutParams = mLinearLayout
.getLayoutParams();
layoutParams.height = value;
mLinearLayout.setLayoutParams(layoutParams);
}
});
return animator;
}
}
