layout_belowパラメータを適用したときにAndroidビューが描画されない

Question

私はこのビューを実装しようとしています。これは基本的に水平トラックの周りを移動可能な親指です。

layout_belowのような特別なレイアウトパラメータがなくても、RelativeLayoutにあるときにはうまく描画されますが、layout_belowパラメータを配置すると描画されません。

この原因は何ですか？

は

パブリッククラスTrackSliderビュー{

/** 
* The thumb of the slider will be limited to move so that it's center does 
* not go beyond the width of the track. 
*/ 
public static final int THUMB_ANCHOR_CENTER = 0; 

/** 
* The thumb of the slider will be limited to move so that it's edges do not 
* go beyond the width of the track. 
*/ 
public static final int THUMB_ANCHOR_EDGES = 1; 

private float mSliderPosition; 
private float mSnapPosition = 0f; 
private boolean mSnapEnabled = false; 
private int mThumbAnchor; 

private Drawable mThumbDrawable; 
private Drawable mTrackDrawable; 
private int mTrackWidth; 
private int mSlideRange; 
private int mThumbWidth; 
private int mThumbXOffset; 

public TrackSlider(Context context, AttributeSet attrs) { 
    super(context, attrs); 
    TypedArray a = getContext().obtainStyledAttributes(attrs, 
      styleable.TrackSlider); 
    final int N = a.getIndexCount(); 
    for (int i = 0; i < N; i++) { 
     int attr = a.getIndex(i); 
     switch (attr) { 
     case styleable.TrackSlider_snapEnabled: 
      setSnapEnabled(a.getBoolean(i, false)); 
      break; 
     case styleable.TrackSlider_snapPosition: 
      setSnapPosition(a.getFloat(i, 0.0f)); 
      break; 
     case styleable.TrackSlider_startPosition: 
      setThumbPosition(a.getFloat(i, 0.0f)); 
      break; 
     case styleable.TrackSlider_thumb: 
      setThumbDrawable(a.getDrawable(i)); 
      break; 
     case styleable.TrackSlider_track: 
      setTrackDrawable(a.getDrawable(i)); 
      break; 
     case styleable.TrackSlider_thumbAnchor: 
      mThumbAnchor = 0;//a.getInt(i, THUMB_ANCHOR_CENTER); 
      break; 
     } 
    } 
} 

@Override 
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 
    int measuredWidth = 0, measuredHeight = 0; 
    switch (MeasureSpec.getMode(widthMeasureSpec)) { 
    case MeasureSpec.EXACTLY: 
     measuredWidth = MeasureSpec.getSize(widthMeasureSpec); 
     break; 
    case MeasureSpec.AT_MOST: 
     measuredWidth = Math.min(
       MeasureSpec.getSize(widthMeasureSpec), 
       Math.max(mTrackDrawable.getIntrinsicWidth(), 
         mThumbDrawable.getIntrinsicWidth())); 
     break; 
    case MeasureSpec.UNSPECIFIED: 
     measuredWidth = Math.max(mTrackDrawable.getIntrinsicWidth(), 
       mThumbDrawable.getIntrinsicWidth()); 
     break; 
    } 
    switch (MeasureSpec.getMode(heightMeasureSpec)) { 
    case MeasureSpec.AT_MOST: 
     measuredHeight = Math.min(MeasureSpec.getSize(heightMeasureSpec), 
       Math.max(mTrackDrawable.getIntrinsicHeight(), 
         mThumbDrawable.getIntrinsicHeight())); 
     break; 
    case MeasureSpec.EXACTLY: 
     measuredHeight = MeasureSpec.getSize(heightMeasureSpec); 
     break; 
    case MeasureSpec.UNSPECIFIED: 
     measuredHeight = Math.max(mTrackDrawable.getIntrinsicHeight(), 
       mThumbDrawable.getIntrinsicHeight()); 
     break; 
    } 
    setMeasuredDimension(measuredWidth, measuredHeight); 
} 

@Override 
protected void onLayout(boolean changed, int left, int top, int right, 
     int bottom) { 
    super.onLayout(changed, left, top, right, bottom); 
    int w = right - left; 
    if (mThumbAnchor == THUMB_ANCHOR_CENTER) { 
     mTrackWidth = w - getPaddingRight() - getPaddingLeft() 
       - mThumbWidth; 
    } else { 
     mTrackWidth = w - getPaddingRight() - getPaddingLeft(); 
    } 
    mThumbXOffset = getPaddingLeft(); 
    mSlideRange = w - getPaddingRight() - getPaddingLeft() 
      - mThumbWidth; 
    mTrackDrawable.setBounds((w - mTrackWidth)/2, top + getPaddingTop(), (w + mTrackWidth)/2, getBottom() - getPaddingBottom()); 
    mThumbDrawable.setBounds(mThumbXOffset, 
      getPaddingTop() + getTop(), mThumbXOffset + mThumbWidth, 
      getBottom() - getPaddingBottom()); 
} 

@Override 
protected void onDraw(Canvas canvas) { 
    super.onDraw(canvas); 
    int pos = (int) (mSliderPosition * mSlideRange); 
    Rect r = new Rect(); 
    mThumbDrawable.copyBounds(r); 
    r.offset(pos, 0); 
    mThumbDrawable.setBounds(r); 
    mTrackDrawable.draw(canvas); 
    mThumbDrawable.draw(canvas); 
    r.offset(-pos, 0); 
    mThumbDrawable.setBounds(r); 
} 

    /* getters and setters... */ 

}

レイアウトファイル延び：

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:twoday="http://schemas.android.com/apk/res/com...." 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:orientation="vertical" 
    android:paddingLeft="10dp" 
    android:paddingRight="10dp" > 

    <TextView 
     android:id="@+id/message" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:textStyle="normal" /> 

    <Button 
     android:id="@+id/btnContinue" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignParentRight="true" 
     android:layout_below="@id/message" 
     android:layout_marginRight="10dp" 
     android:background="@drawable/btn_dialog_continue" /> 

    <Button 
     android:id="@+id/btnCancel" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignTop="@+id/btnContinue" 
     android:layout_toLeftOf="@id/btnContinue" 
     android:background="@drawable/btn_dialog_cancel" /> 

    <com.twoday.gallerys.views.TrackSlider 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:layout_below="@id/btnCancel" 
     twoday:snapEnabled="true" 
     twoday:startPosition="0.5" 
     twoday:thumb="@drawable/confirm_slider_thumb" 
     twoday:thumbAnchor="center" 
     twoday:track="@drawable/confirm_slider_track" /> 

</RelativeLayout> 

Answer 1

OKを、私はこの問題の回避策を発見した - 適用その後のLinearLayoutのビューをラップlayout_below属性をビュー自体ではなくレイアウトに追加します。